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OK its been an hour now and the fuel pressure has dropped to 20 PSI

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That sounds like it's normal leakdown, probably through the FPR or the fuel pump valves. 17 psig vacuum sounds normal for a 275 hp with 288 degrees of total duration and 22 degrees of overlap, but it might be just a tad low; I would check the FSM pages on the PCM data normal ranges.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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That sounds like it's normal leakdown, probably through the FPR or the fuel pump valves. 17 psig vacuum sounds normal for a 275 hp with 288 degrees of total duration and 22 degrees of overlap, but it might be just a tad low; I would check the FSM pages on the PCM data normal ranges.

Thanks Jim, its two hours later and I am at 10 PSI, started the car and it felt normal with no roughness. I am sure that it eventually reaches 0 PSI.

This is still a mystery, why when I floor it twice on start up when its a rough idle does the rough idle go away?

If this is coolant leaking into a cylinder, shouldnt compression/combustion which is MUCH higher go in the other direction and superheat the coolant, my temps appear normal now, I need to get into traffic and see what happens

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Mike,

This is just a W A G ... but could a sticking Throttle Position Sensor cause your roughness during cold start?

Maybe when you punch it a couple of times...it frees it up?

Don't know...just another thing for you to consider.

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I really don't see this as a symptom of leakage into the cylinder. That would also be marked by a coolant smell at the exhaust on start-up and I'm sure that you would have noticed that. A test for combustion products is so simple and cheap that you can eliminate head leakage that way if you like. When I had it, the first symptom was coolant loss over a period of months. Then, after a WOT episode in 3rd gear, the temperature spiked about a minute later and quickly returned to normal. Things got slowly worse from there until I had boil-offs every time I pulled a grade on the freeway, and I was doing daily commutes. The whole process took about 18 months.

If you haven't driven it much since the WOT session, I would still think about loose carbon in the cylinders. The gentlest treatment for that is some time cruising on the highway. And, it's summertime. Fifteen minutes at a steady 65 mph should do it.

You've probably noticed by now that my favorite low-cost remedy for minor driveability problems is a road trip. That's because of long experience that a car tends to collect carbon in the cylinders when it is never driven on the highway, particularly if it is mostly driven on short trips, i.e. much of its mileage is driven with the car not fully warmed up.

An extreme case of this was with my 427 cid (seven liters displacement) Chevrolet station wagon. If I put regular gas in it, you could hear detonation above quarter throttle, and when you parked it when fully warmed up it would run on, sometimes for fifteen minutes or longer. I enjoyed watching the guys form a circle of astonished spectators in the parking lot in the mornings; I watched out the window. I could kill it by putting it in gear but it was more fun to watch. But, once I had it for a few months I always put premium gas in it and it was fine. Once in the late 1970's I took a long trip in it, and once I got out of the big city you could buy only regular grade gas. So, I just drove with a very light foot and kept asking the truckers about high-test gas on the CB, but always cleared the channel when I asked. After about 1,000 miles on regular gas at 65 mph, I began to notice that the car ran just about as well on regular as it ever had on premium. Even a WOT from a standing start was clean and strong, with no pinging or detonation.

I think that aluminum heads are more susceptible to carbon build-up than iron heads because the combustion chamber surfaces are cooler, an attribute that lets these engines run with higher compression ratios than those with iron heads with the same octane fuel. The Northstar now runs a 10.3 compression ratio with regular gas and gets 320 hp, something not possible with iron heads and 4.6 liters. DFI reduces carbon build-up almost to the point of it not being much of a problem by providing the leanest possible healthy fuel-air mixture for light engine loads. But, driving around a lot with an engine that isn't fully warmed up dramatically increases carbon build-up. Second gear WOT sessions are a good substitute for 15 minutes a week at a steady 65 mph, but the steady cruise is cleaner and also gives the EVAP system a chance to purge. Unfortunately that is not always convenient or even possible for some people.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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  • 2 weeks later...

I am pretty sure I have a head bolt pull.

Today I was doing 60 to 70 and all was fine in 70 degree ambient temps, my overheating begins when I hit traffic

Well the traffic hits, and for awhile my temp hovers around 215 degrees for about 15 minutes, then

it hits 217, 219, 222, 226 and then quickly it goes to 230, 233, 238, 242 then 245 and I moved to the shoulder and chanced getting a ticket to get moving

Once I started moving, it dropped to 226, then 222

I am going to need to do something soon, this car is not good for trips where there is a potential for traffic

Pre-1995 - DTC codes OBD1  >>

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I am pretty sure I have a head bolt pull.

Today I was doing 60 to 70 and all was fine in 70 degree ambient temps, my overheating begins when I hit traffic

Well the traffic hits, and for awhile my temp hovers around 215 degrees for about 15 minutes, then

it hits 217, 219, 222, 226 and then quickly it goes to 230, 233, 238, 242 then 245 and I moved to the shoulder and chanced getting a ticket to get moving

Once I started moving, it dropped to 226, then 222

I am going to need to do something soon, this car is not good for trips where there is a potential for traffic

OK, I have not been around for a bit but the problems you are describing are a mirror to what was happening with my 1999 Seville. I did find the problem and both were cheap to fix.

Hard starting and odd backfire. I would have to put the peddle to the floor to start the car because it was flooded. Fuel pressure regulator was leaking down fuel after i shut off the car and filling cylinders with fuel. To check this, take off the top cover from the engine and remove the vacuum line from the fuel pressure regulator. If it is wet there, that is gas on the vacuum side so the fuel pressure regulator is bad. 50.00 to replace.

As for the overheating, that one was a easy fix after I fugured out what it was. With the engine cold, remove the small hose from the coolant overflow tank. Start the engine and check for coolant flow crom the small hose. If there is no flow, rev the engine and watch for flow. The fix is easy if there is no flow. On the thermastat housing is the other end of that hose. Take it off and check for flow coming out of the nipple. If there is not flow, simply take a 6 inch piece of clothes hanger and bend a small L into the end of it so you have something to hold on to. Now insert the hanger into the nipple and work it back and forth until you get coolant flow. Once you do, hook back up your hose and your overheating problem will be gone.

Now to tell you why this works.

That nipple is where the air is blead out of the coolant system. If the air can not be purged from the system, it will have a air pocket and it will prevent coolant flow and cause the engine to overheat.

This fix will not cost anything to fix if it is indeed your problem like it was on mine.

My northstar has not overheated since I unclogged that nipple.

Good Luck!

Paul

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Thanks Paul for the info on your fix, I have checked my bleed line and it is fine.

I need to have my coolant tested for combustion by products and have begun looking for a shop that can do it, my radiator shop can't and they didnt have good things to say about the retail coolant testers we can buy at NAPA

I am hoping my problem is a two fold problem, leaking injectors and something else

I observed my coolant fans yesterday and as my temp increased to 228 there was NO change in their speed at all, they seem to just spin at a so so speed. I need to diagnose my coolant fans, maybe I have a bad relay contact, the relay is responding but the contacts within it are charred.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I really don't see this as a symptom of leakage into the cylinder. That would also be marked by a coolant smell at the exhaust on start-up and I'm sure that you would have noticed that. A test for combustion products is so simple and cheap that you can eliminate head leakage that way if you like. When I had it, the first symptom was coolant loss over a period of months. Then, after a WOT episode in 3rd gear, the temperature spiked about a minute later and quickly returned to normal. Things got slowly worse from there until I had boil-offs every time I pulled a grade on the freeway, and I was doing daily commutes. The whole process took about 18 months.

If you haven't driven it much since the WOT session, I would still think about loose carbon in the cylinders. The gentlest treatment for that is some time cruising on the highway. And, it's summertime. Fifteen minutes at a steady 65 mph should do it.

You've probably noticed by now that my favorite low-cost remedy for minor driveability problems is a road trip. That's because of long experience that a car tends to collect carbon in the cylinders when it is never driven on the highway, particularly if it is mostly driven on short trips, i.e. much of its mileage is driven with the car not fully warmed up.

An extreme case of this was with my 427 cid (seven liters displacement) Chevrolet station wagon. If I put regular gas in it, you could hear detonation above quarter throttle, and when you parked it when fully warmed up it would run on, sometimes for fifteen minutes or longer. I enjoyed watching the guys form a circle of astonished spectators in the parking lot in the mornings; I watched out the window. I could kill it by putting it in gear but it was more fun to watch. But, once I had it for a few months I always put premium gas in it and it was fine. Once in the late 1970's I took a long trip in it, and once I got out of the big city you could buy only regular grade gas. So, I just drove with a very light foot and kept asking the truckers about high-test gas on the CB, but always cleared the channel when I asked. After about 1,000 miles on regular gas at 65 mph, I began to notice that the car ran just about as well on regular as it ever had on premium. Even a WOT from a standing start was clean and strong, with no pinging or detonation.

I think that aluminum heads are more susceptible to carbon build-up than iron heads because the combustion chamber surfaces are cooler, an attribute that lets these engines run with higher compression ratios than those with iron heads with the same octane fuel. The Northstar now runs a 10.3 compression ratio with regular gas and gets 320 hp, something not possible with iron heads and 4.6 liters. DFI reduces carbon build-up almost to the point of it not being much of a problem by providing the leanest possible healthy fuel-air mixture for light engine loads. But, driving around a lot with an engine that isn't fully warmed up dramatically increases carbon build-up. Second gear WOT sessions are a good substitute for 15 minutes a week at a steady 65 mph, but the steady cruise is cleaner and also gives the EVAP system a chance to purge. Unfortunately that is not always convenient or even possible for some people.

I hope you are right Jim, its funny, my engine does NOT overheat at highway speeds, although it seems its only overheating after I slow down to stop and go, I observed my fans, and they dont seem to be turning with any type of speed, all the way up to 228, they just seem to turn lazily... that would explain my uncontrolled stop and go spike, what do you think?

Combine that with a couple of leaking injectors and that could be my problem

I need to get my coolant tested

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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  • 1 month later...

Today I spoke to my scrap yard. They have two Northstar Engines, 1) a 98 with 90,000 miles on it, that my friend heard run for $800, and 2) a 96 that he described as a CORE, that he did not hear run for $100, he said it might need a head gasket.

I plan to leave my engine in place, and rebuild an engine I purchase, doing the case half seal and head gaskets along with all seals.

I am not sure if a 98 will fit my 96, does anyone know?

Since I am going to rebuild the engine, I am leaning toward buying the core for $100, what do you all think?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Jasper listed my engine as a 1995-1997. I suspect that the accessory mounts are different for 1998-1999. This engine did NOT include the cam covers, so that could mean that accessory mount holes on the heads or block are different. I would go with the 1996, since it's the same year as your car. You can switch between a VIN "9" and VIN "Y" with the intake cams if necessary, and you will likely want new cams anyway. If you can't use it for any reason, you still have a lot of parts for $100.

The running engine is a good thing, but the price is for a drop-in, and I would want to Timesert any used engine, running or not, because I wouldn't want to ever, ever pull it out again. That's just me, but if you are gong to tear it down and remanufacture it to like-new specs, why pay for more than a core?

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I agree with Jims_97_ETC.

Why pay any more than the 100 bucks for the core engine, since you are going to rebuild it anyway.

It is also the correct year for your car, so you don't run into mounting issues when installing it.

I would then use the $700.00 that I saved to help offset the cost of rebuilding the core engine.

$700.00 bucks will buy quite a few parts.

This is all on the assumption that the $100.00 core is basically sound. :D

I see no reason to pay an extra $700.00 for a running engine that I was going to tear down and rebuild anyway.

This is just my opinion but remember ....

Free advice is worth what you paid for it. :D:D:D

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Did the $100 engine come out of a wrecked car? If so, it must have been running to cause a wreck.

You know I dont know that answer, I will go to see it however, its currently sitting in a 96 Deville. What I worry about is how it has been canibilized by the scrap yard rats that come to remove parts. But, many of my parts would just transfer across, something I was trying to avoid.

The core sounds good, but I need to see it, I was hoping to have a complete engine, and as Jiim notes the 98 probably is not a candidate.

Ideally I would like to put a scrap yard engine in my garage and bring it back to life and just swap it into my vehicle. My friend is pretty good with engines, he is the fellow I bought engines from that we shipped to Amsterdam, Germany and New Jersey. He usually hears the engines run to access them, in this case the junked vehicle came into the scrap yard with an engine that was not running. A little risk there for me

I might ask him to keep his eyes open for a better candidate, for instance MY engine would be a terrific candidate

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Why not rebuild your current engine? I agree that that $100 engine is a great deal, but considering you never really know how well it was maintained, I'd much rather invest the money into a "known good" block - (your own!). I would assume, and may be VERY wrong, that removing/replacing the engine is 75% of the labor. But then again, I've never done a HG on a N* myself, so I'm not speaking from experience here.

But I will admit... I just dropped mine off last Tuesday to have the studs installed, and I've been thinking "what am I going to do if I get the "hey, your block is cracked" call! I might be in the same position...

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Why not rebuild your current engine? I agree that that $100 engine is a great deal, but considering you never really know how well it was maintained, I'd much rather invest the money into a "known good" block - (your own!). I would assume, and may be VERY wrong, that removing/replacing the engine is 75% of the labor. But then again, I've never done a HG on a N* myself, so I'm not speaking from experience here.

But I will admit... I just dropped mine off last Tuesday to have the studs installed, and I've been thinking "what am I going to do if I get the "hey, your block is cracked" call! I might be in the same position...

I did not want to lay my car up without an engine for too long, that is why I am looking for a junk yard engine. Given that I have a very good relationship with a scrap yard, I can get a rebuild candidate for a better than 'street' price... I would probably give him my engine once I rebuilt the core...

Ill report back what I find at the yard next week

Good luck with the stud rebuild, did you take it to northstarperformance in canada? How did you get it there if you did

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I found a shop local to Boston that has done several N*'s with the stud kit. I considered bringing the car up to Canada, but the cost of getting it there just didn't seem logical. I considered borrowing a friend's pickup and trailer, but then that would mean I would be near Toronto. And that means lots of strip clubs and other fun "Canada" stuff. Maybe I'd save on the HG job, but by the time I was done with the "trip" the cost would be about the same as going to the dealer! :lol:

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I hear ya! :lol:

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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  • 4 months later...

I called timesert.com today and spoke to a tech named Mike. He was very helpful and spent a lot of time with me.

My main questions were

1) When I drill the holes and instead of aluminum shavings, I find aluminum dust, should I immediately big sert the hole? He seemed to think that due to the outside diameter of the sert and the depth of the sert that I would not have a problem. He said, if the aluminum is bad, I would feel it as I torqued the new bolt if the sert let go. He is taking a conservative approach, I still feel that if I find holes that have no filings but dust, I should big sert the hole, what do you all think? By the way, there is a repair beyond the big sert that he alluded to.

2) We discussed the problem where the aluminum is not hard but dusty and soft. He said this occurs when the engine is seriously overheated and abused. We agreed that one of the reasons that the rear head seemed to go bad more often is due to the lack of cooling near the firewall. He felt that since my engine has not been seriously overheated and abused that I should be ok

3) While either he nor his company will provide head bolt torque specs, he said that the original specs were way too tight, he mentioned 270 degrees when 180 degrees is adequate. I am not sure what the current torque specs are

4) When I told him that I needed to replace the case half seal, he was not optimistic about removing the main bearing bolts telling me that aggressive locktite was used at the factory that basically ruins the threads once the bolt is removed, IF you can remove it. At this point I got sick to my stomach. I told him that the case half repair is a fairly common repair and I had not heard of many main bearing bolt problems, he acknowledged that they dont sell a lot of main bearing timesert kits. So, if I see aluminum on my main bearing bolts Ill cross that bridge when I come to it

He told me that the loctite that is provided with the kits is high temp and it swells under heat.

I found this company that does not advise the use of big serts, so the contrary advice never ends

http://www.enginebuildermag.com/Article/15...ad_repairs.aspx

Any thoughts are appreciated

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I would go with the advice of Timesert in the usage of Timeserts. I know that there have been updates on torque specs for Northstars, including yours and mine. That was some years ago and I doubt that they have changed in the last several years. I would find out what these are from GM.

I think that if there has been any corrosion in the threads that the filings will be dusty, and that even if there are some incursions clear out into the threads it won't hurt anything once the Timeserts have been installed with threadlocking and sealant. If Timesert says to ignore the filings, dusty or no, and let it go if the head bolt torques OK, that's what I would do.

In summary, I believe in going with the people who deal with the product you're looking at, and back it. This seems to me to be an inherently more sound approach than second-guessing or taking advice from others who don't back that particular product. So, Timesert for selecting and installing Timeserts, GM for torquing the head bolts.

One last thing -- watch out and make sure that the torque specs match the head bolts. A thicker head bolt will need less degrees after clampdown torque to achieve the same clamping force. So, if Timesert supplies the bolts, use their torque specs.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I called timesert.com today and spoke to a tech named Mike. He was very helpful and spent a lot of time with me.

My main questions were

1) When I drill the holes and instead of aluminum shavings, I find aluminum dust, should I immediately big sert the hole? He seemed to think that due to the outside diameter of the sert and the depth of the sert that I would not have a problem. He said, if the aluminum is bad, I would feel it as I torqued the new bolt if the sert let go. He is taking a conservative approach, I still feel that if I find holes that have no filings but dust, I should big sert the hole, what do you all think? By the way, there is a repair beyond the big sert that he alluded to.

2) We discussed the problem where the aluminum is not hard but dusty and soft. He said this occurs when the engine is seriously overheated and abused. We agreed that one of the reasons that the rear head seemed to go bad more often is due to the lack of cooling near the firewall. He felt that since my engine has not been seriously overheated and abused that I should be ok

3) While either he nor his company will provide head bolt torque specs, he said that the original specs were way too tight, he mentioned 270 degrees when 180 degrees is adequate. I am not sure what the current torque specs are

4) When I told him that I needed to replace the case half seal, he was not optimistic about removing the main bearing bolts telling me that aggressive locktite was used at the factory that basically ruins the threads once the bolt is removed, IF you can remove it. At this point I got sick to my stomach. I told him that the case half repair is a fairly common repair and I had not heard of many main bearing bolt problems, he acknowledged that they dont sell a lot of main bearing timesert kits. So, if I see aluminum on my main bearing bolts Ill cross that bridge when I come to it

He told me that the loctite that is provided with the kits is high temp and it swells under heat.

I found this company that does not advise the use of big serts, so the contrary advice never ends

http://www.enginebuildermag.com/Article/15...ad_repairs.aspx

Any thoughts are appreciated

Mike, Timesert has provided some misinformation... The original torque spec. for the headbolts was torque to a static torque value (22 ft-lbs but double check this value) plus three 60 degree passes or 180 degrees total. I think it was revised to initial static torque plus 70-60-60 or 190 degrees - nowhere near 270 degrees. 270 degrees would rip the insert out of the block or crack the water jacket... My '97 engine was overheated and when I drilled out the block, I had long spiral shavings and chips - no powdery aluminum whatsoever.

No loctite is used on the main bearing bolts - I tore apart a '98 Deville engine that I was repairing and there was no loctite on the main bearing bolts - also, there is no mention of using new main bearing bolts or threadlocker on the main bearing bolts at assembly. You do want to use a light oil on the threads or you run the risk of galling the female threads. Timesert doesn't sell very many main bearing insert kits because those threads rarely fail.

The loctite that is provided with the Timesert kits is for the Timeserts, not the head bolts. The head bolts have microencapsulated threadlocker applied to the bolts and the underside of the bolt heads.

The link advising not to use Bigserts is also BS - GM doesn't list them as a repair option but I used them when I repaired my engine 47,000 miles ago and haven't had a problem due to the Bigserts. If Bigserts are used, special oversized head alignment dowels will need to be used and they are available from Timesert.

As a side conversation, are you sure the case half is what is leaking or is it the oil manifold plate that is between the lower crankcase and the oil pan? The '98 Deville engine I worked on was leaking and when I removed the oil manifold plate, all the molded in silicone seals were beginning to dissolve. My own '96 Seville is beginning to leak oil to the ground and I inspected the leak path - the case half has very minor seepage but the main source of the leak is from the oil manifold plate between the oil pan and the lower crankcase half. A new oil manifold plate is $75 from the auto parts store (made by Victor) or $115 at the dealer.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I called timesert.com today and spoke to a tech named Mike. He was very helpful and spent a lot of time with me.

My main questions were

1) When I drill the holes and instead of aluminum shavings, I find aluminum dust, should I immediately big sert the hole? He seemed to think that due to the outside diameter of the sert and the depth of the sert that I would not have a problem. He said, if the aluminum is bad, I would feel it as I torqued the new bolt if the sert let go. He is taking a conservative approach, I still feel that if I find holes that have no filings but dust, I should big sert the hole, what do you all think? By the way, there is a repair beyond the big sert that he alluded to.

2) We discussed the problem where the aluminum is not hard but dusty and soft. He said this occurs when the engine is seriously overheated and abused. We agreed that one of the reasons that the rear head seemed to go bad more often is due to the lack of cooling near the firewall. He felt that since my engine has not been seriously overheated and abused that I should be ok

3) While either he nor his company will provide head bolt torque specs, he said that the original specs were way too tight, he mentioned 270 degrees when 180 degrees is adequate. I am not sure what the current torque specs are

4) When I told him that I needed to replace the case half seal, he was not optimistic about removing the main bearing bolts telling me that aggressive locktite was used at the factory that basically ruins the threads once the bolt is removed, IF you can remove it. At this point I got sick to my stomach. I told him that the case half repair is a fairly common repair and I had not heard of many main bearing bolt problems, he acknowledged that they dont sell a lot of main bearing timesert kits. So, if I see aluminum on my main bearing bolts Ill cross that bridge when I come to it

He told me that the loctite that is provided with the kits is high temp and it swells under heat.

I found this company that does not advise the use of big serts, so the contrary advice never ends

http://www.enginebuildermag.com/Article/15...ad_repairs.aspx

Any thoughts are appreciated

Mike, Timesert has provided some misinformation... The original torque spec. for the headbolts was torque to a static torque value (22 ft-lbs but double check this value) plus three 60 degree passes or 180 degrees total. I think it was revised to initial static torque plus 70-60-60 or 190 degrees - nowhere near 270 degrees. 270 degrees would rip the insert out of the block or crack the water jacket... My '97 engine was overheated and when I drilled out the block, I had long spiral shavings and chips - no powdery aluminum whatsoever.

No loctite is used on the main bearing bolts - I tore apart a '98 Deville engine that I was repairing and there was no loctite on the main bearing bolts - also, there is no mention of using new main bearing bolts or threadlocker on the main bearing bolts at assembly. You do want to use a light oil on the threads or you run the risk of galling the female threads. Timesert doesn't sell very many main bearing insert kits because those threads rarely fail.

The loctite that is provided with the Timesert kits is for the Timeserts, not the head bolts. The head bolts have microencapsulated threadlocker applied to the bolts and the underside of the bolt heads.

The link advising not to use Bigserts is also BS - GM doesn't list them as a repair option but I used them when I repaired my engine 47,000 miles ago and haven't had a problem due to the Bigserts. If Bigserts are used, special oversized head alignment dowels will need to be used and they are available from Timesert.

As a side conversation, are you sure the case half is what is leaking or is it the oil manifold plate that is between the lower crankcase and the oil pan? The '98 Deville engine I worked on was leaking and when I removed the oil manifold plate, all the molded in silicone seals were beginning to dissolve. My own '96 Seville is beginning to leak oil to the ground and I inspected the leak path - the case half has very minor seepage but the main source of the leak is from the oil manifold plate between the oil pan and the lower crankcase half. A new oil manifold plate is $75 from the auto parts store (made by Victor) or $115 at the dealer.

Thanks Kevin, your info makes me feel a lot better. Ill look into the oil manifold. As you know, I have been under the impression that the low oil pressure I experience is due to a bad case half seal, I do not want to do all of this work and still have low oil pressure at idle and an oil leak/burning oil smell with 10W30. I really dont want to continue to use 15W40, that is the reason I want to get into the case half seal. I also have a bad knock, and need to inspect the main, rod bearings and wrist pins.

It is possible that my oil pressure is low due to worn bearings or a worn oil pump also... I found a bulletin that speaks to low or no oil pressure and the solution is a new oil pump.

thanks

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I would go with the advice of Timesert in the usage of Timeserts. I know that there have been updates on torque specs for Northstars, including yours and mine. That was some years ago and I doubt that they have changed in the last several years. I would find out what these are from GM.

I think that if there has been any corrosion in the threads that the filings will be dusty, and that even if there are some incursions clear out into the threads it won't hurt anything once the Timeserts have been installed with threadlocking and sealant. If Timesert says to ignore the filings, dusty or no, and let it go if the head bolt torques OK, that's what I would do.

In summary, I believe in going with the people who deal with the product you're looking at, and back it. This seems to me to be an inherently more sound approach than second-guessing or taking advice from others who don't back that particular product. So, Timesert for selecting and installing Timeserts, GM for torquing the head bolts.

One last thing -- watch out and make sure that the torque specs match the head bolts. A thicker head bolt will need less degrees after clampdown torque to achieve the same clamping force. So, if Timesert supplies the bolts, use their torque specs.

Thanks Jim, I spoke to Mike at timesert about using the 2000 timesert kit and he said it was not possible for me to convert my block to the dual thread bolt head bolts, so I will be using the stock bolts, unless ARP, has a bolt that is better, I have an email out to them. There was also an article that I found about MLS head gaskets that I found interesting. It said that GM is about 10 years behind the market in using them, see this article

http://www.enginebuildermag.com/Article/14...ng_lowdown.aspx

Oh and this article kind of describes the membership here LOL, all of you Northstar lovers should read it

http://www.enginebuildermag.com/Article/14..._northstar.aspx

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I called timesert.com today and spoke to a tech named Mike. He was very helpful and spent a lot of time with me.

My main questions were

1) When I drill the holes and instead of aluminum shavings, I find aluminum dust, should I immediately big sert the hole? He seemed to think that due to the outside diameter of the sert and the depth of the sert that I would not have a problem. He said, if the aluminum is bad, I would feel it as I torqued the new bolt if the sert let go. He is taking a conservative approach, I still feel that if I find holes that have no filings but dust, I should big sert the hole, what do you all think? By the way, there is a repair beyond the big sert that he alluded to.

2) We discussed the problem where the aluminum is not hard but dusty and soft. He said this occurs when the engine is seriously overheated and abused. We agreed that one of the reasons that the rear head seemed to go bad more often is due to the lack of cooling near the firewall. He felt that since my engine has not been seriously overheated and abused that I should be ok

3) While either he nor his company will provide head bolt torque specs, he said that the original specs were way too tight, he mentioned 270 degrees when 180 degrees is adequate. I am not sure what the current torque specs are

4) When I told him that I needed to replace the case half seal, he was not optimistic about removing the main bearing bolts telling me that aggressive locktite was used at the factory that basically ruins the threads once the bolt is removed, IF you can remove it. At this point I got sick to my stomach. I told him that the case half repair is a fairly common repair and I had not heard of many main bearing bolt problems, he acknowledged that they dont sell a lot of main bearing timesert kits. So, if I see aluminum on my main bearing bolts Ill cross that bridge when I come to it

He told me that the loctite that is provided with the kits is high temp and it swells under heat.

I found this company that does not advise the use of big serts, so the contrary advice never ends

http://www.enginebuildermag.com/Article/15...ad_repairs.aspx

Any thoughts are appreciated

Mike, Timesert has provided some misinformation... The original torque spec. for the headbolts was torque to a static torque value (22 ft-lbs but double check this value) plus three 60 degree passes or 180 degrees total. I think it was revised to initial static torque plus 70-60-60 or 190 degrees - nowhere near 270 degrees. 270 degrees would rip the insert out of the block or crack the water jacket... My '97 engine was overheated and when I drilled out the block, I had long spiral shavings and chips - no powdery aluminum whatsoever.

No loctite is used on the main bearing bolts - I tore apart a '98 Deville engine that I was repairing and there was no loctite on the main bearing bolts - also, there is no mention of using new main bearing bolts or threadlocker on the main bearing bolts at assembly. You do want to use a light oil on the threads or you run the risk of galling the female threads. Timesert doesn't sell very many main bearing insert kits because those threads rarely fail.

The loctite that is provided with the Timesert kits is for the Timeserts, not the head bolts. The head bolts have microencapsulated threadlocker applied to the bolts and the underside of the bolt heads.

The link advising not to use Bigserts is also BS - GM doesn't list them as a repair option but I used them when I repaired my engine 47,000 miles ago and haven't had a problem due to the Bigserts. If Bigserts are used, special oversized head alignment dowels will need to be used and they are available from Timesert.

As a side conversation, are you sure the case half is what is leaking or is it the oil manifold plate that is between the lower crankcase and the oil pan? The '98 Deville engine I worked on was leaking and when I removed the oil manifold plate, all the molded in silicone seals were beginning to dissolve. My own '96 Seville is beginning to leak oil to the ground and I inspected the leak path - the case half has very minor seepage but the main source of the leak is from the oil manifold plate between the oil pan and the lower crankcase half. A new oil manifold plate is $75 from the auto parts store (made by Victor) or $115 at the dealer.

Thanks Kevin, your info makes me feel a lot better. Ill look into the oil manifold. As you know, I have been under the impression that the low oil pressure I experience is due to a bad case half seal, I do not want to do all of this work and still have low oil pressure at idle with 10W30. I really dont want to continue to use 15W40, that is the reason I want to get into the case half seal. I also have a bad knock, and need to inspect the main, rod bearings and wrist pins.

It is possible that my oil pressure is low due to worn bearings or a worn oil pump also... I found a bulletin that speaks to low or no oil pressure and the solution is a new oil pump.

thanks

Mike, since you have a knock, you will probably plastigage the bearings to check the clearances so you'll need to remove the oil pan, oil manifold plate, scraper plate, and lower crankcase half. Once the oil manifold plate is removed, you need to install a new one or you run the risk of leaks or no oil pressure. The case half seal leak won't cause low oil pressure but a severely leaking oil manifold plate can result in low oil pressure.

If the main bearings have the proper clearance, they can be reused if they're not damaged in any other way. The rod bearings must be replaced once disturbed. You must also replace the rod cap bolts since they are torque to yield bolts. Be sure to put the cylinder number on each rod cap, connecting rod, and piston. The rod caps are actually cast as part of the connecting rod, machined, and then broken apart in a press to create a unique break/interface pattern. That is typical for high performance engines as the break pattern resists relative movement of the cap to the connecting rod. The more I learn about these engines, the more amazed at the engineering that went into them.

It is easy to check the clearance of the oil pump. I doubt that is the root of your low oil pressure problem - I haven't seen the geroter style pumps wear out. I checked the one on my old Park Avenue and it was well within spec. I also checked the clearance on my '97 and it was within spec. Granted, neither car had an oil pressure problem though.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thanks Kevin, I can see I need to look into this oil manifold a little closer, it would be nice if that was all that was wrong with my low oil pressure at idle.

You can be sure I will be methodical with marking parts and putting them back in the same place, but thanks for the reminder.

The last engine I rebuilt was a 66 Cadillac 429 and I needed to use a ridge reamer to get the pistons out. I doubt that any ridge has been built up, its my understanding that the cylinder walls in these engines still has the honing marks in them

When the pistons go back in, do you know if its important how the ring gaps are aligned?

I know you will appreciate this article about timing the engine, you have discussed the timing procedure quite a bit, I am not looking forward to timing this engine, LOL..

http://www.enginebuildermag.com/Article/14..._northstar.aspx

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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