Northstar Timesert Kit

[AliRaza]

Anyone got a Northstar timesert kit that you may want to sell? Instead of spending $300 for a one time deal, I would like to buy it from anyone who already used it and want to sell it off. Please let me know.

Also I am planning to cjhange the headgasket without removing the engine. I know its kind of tough but doable. I think I will manage it. Anyone who has done it before and if you can share some information about what needs to be taken out specially while doing it without removing the engine. I know Bill did it once. But again I consider him as "Super Expert".

Also a copy of the shop manual availability will be the key to success. I am trying ebay and wanted to try here if someone can copy the referenced pages or want to sell the old manual???

Any feedback will be highly appreciated.

Thanks

Ali

[growe3]

Hi Ali,

Please don't shoot the messenger, but you will have a VERY difficult time attempting to do the Timesert repair with the engine in the car. With the engine out and on an engine stand, it is fairly straight forward.

You must also remove the front cover, and the harmonic balancer which is tightened down to approximately 350 ft lbs. The timing chains must be removed and then again reset, a lot of careful cleaning on the block deck surfaces, not to mention all of the drill material that will be flying around.

Without the Helms service manuals you will likely not be successful in your repairs.

I would urge you to get a set of the manuals and study what you will be up against before starting, and strongly reccommend that you remove the engine to do the work.

Good luck, George

[KHE]

Ali,

You didn't say if the mechanic tested the head gaskets with shop air through the spark plug holes and/or with a cooling system pressure tester.

If it were my car, I would want to be absolutely positive that the headgaskets were bad before I tore the engine down....

[Barry94]

I replaced my head gasket with the engine in the car. It's not an easy job.

You need lots of tools and patience.

I did the compressed air test to determine which cyl/head was at fault. With mine it was the rear head. (The most difficult to do)

As mentioned, you need the manual.

If you have little or no mechanic experience, then DO NOT attempt this on your own. I've seen guys screw up fixing a Chevy 350, and that is a much simpler engine to repair.

I'm not questioning your intelligence, just your experience.

Lots of things to go wrong.

As KHE said, be sure you know which head(s) is at fault.

If you do attempt this repair, I'll be glad to help any way I can.

Barry

[AliRaza]

Thanks guys for your concerns and also good feedback.

I have replaced a head gasket of a six cylinder before. But that was done while having engine inside the car. One of my cousin is going to help me out as well. He is a good DIYer.

If you look at my other posts :Engine OVerheating... Coolant Spilling" you can see that I tried everything and finally took the car to the dealer. He came back and told me that both gaskets are blown.

Now Barry, I would appreciate any help that you can provide. Procedures and pictures if you have any. I want to do it with engine in the car but if I can find an easier way or atleast look how to take the engine out, while I am in my garage, that will be of great help.

I would like to buy a manual and also a used timesert kit. Trying on the net and specially on ebay. Hopefully it will work out. I want to learn about the whole process completely before doing anything on the engine.

I will look for a used manual and also a timesert kit. Any ideas....

[Barry94]

Hi,

I looked at the possibility of removing the engine to do my head, It just looked like too much work. Although it is more difficult to do with the engine in the car, to me, it still seemed the best way to go.

As I think of some tips, I'll post them here.

Here are the updated Torque settings.

------------------------------------------------------------------------------------

994-99 Cadillac Concours

1995-99 Oldsmobile Aurora

1999 Marine

with 4.0 L or 4.6 L Engine (VINs C, Y, 9 -- RPOs L47, LD8, L37)

This bulletin is being issued to clarify the cylinder head tightening specification listed in the following procedures in the Engine Mechanical 4.0 L and 4.6 L sections of the appropriate Service Manuals:

Specifications -- Fastener Tightening Specifications

Cylinder Head Replacement -- Installation Procedure

Cylinder Head Installation

The torque specification and sequence for the cylinder head bolts (1--10) using J 36660-A is:

First Pass -- 40 N·m (30 lb ft)

Second Pass -- 70 Degrees

Third Pass -- 60 Degrees

Fourth Pass -- 60 Degrees (190 Degrees total)

The torque specification for the three front M6 cylinder head bolts is:

12 N·m (106 lb in)

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.

[Barry94]

Some TimeSert information.

===================================================

Time-serts are the ONLY thing to use for the Northstar headbolt holes for several reasons that have been detailed in the past in the archives...

The time-sert repair kit was developed with Time before the Northstar ever went into production. Knowing the characteristics and pitfalls of aluminum threads we realized early on that there had to be an effective repair procedure in the field for all the fasteners in the aluminum block and heads and developed the time-sert kit with time and tested and validated it during the normal course of development of the engine. The time-sert was validated on our deep thermal cycling "gasket killer" tests. The holes repaired with time-serts are better than new. Also, during prototype development there are plenty of occasions to strip bolts in the aluminum as there will often be 10 or 20 cylinder head changes on an engine on the dyno doing combustion development...so we also wanted a way to repair the engines during development and the time-sert kit that was developed worked very well.

The time-sert is a solid, one piece insert...unlike the coil that a heli-coil design uses. Since the timesert is a solid insert it can better distribute the load from the bolt into the parent metal. With the coiled slinky type of thread repair insert like the helicoil each thread supports just itself in the parent metal. Due to the threads on the head bolt being slightly irregular (we're talking minute differences but they are there in all bolts) one thread will load a little more than another and if one thread starts to pull the insert out, the adjacent threads will be overloaded and start to go and then the whole thing pulls out. With the solid time-sert insert if one thread is loaded a little more than the ohters it distributes the load on the OD to all the treads since the insert is a solid piece...not a slinky of threads. This is very important as the thread repair inserts are very hard and unyielding. If one thread is carrying more load in a conventional threaded hole , especially with aluminum threads, the thread will yield a little and then all the threads will come into alignment and the load will be re-distributed evenly. With the hard insert this will not happen and one thread being loaded a little more heavily than the others needs to be distributed over the OD threads or it will start the insert to fail.

The Northstar headbolts have a LOT of thread engagement into the block due to the load placed on them. There is a special length time-sert for the Northstar head bolts that is very long. you cannot get a heli-coil of this size that long to my knowlege. Putting a shorter helicoil into the hole will cause it to fail quickly as there is just not enough thread engagement into the parent metal of the block.

This is one of the ways that the Northstar engine (or any aluminum engine) can get a bad reputation as being "un repairable". Mechanics will try to repair a threaded hole with a heli-coil or the wrong time-sert insert , the repair will fail due to the incorrect parts or procedures and then the customer gets the explaination that the engine is at fault because the mechanic will not even know sometimes that he used the wrong procedures/parts. The correct repair is clearly spelled out in the service manual and service bulletins but still there is a serious lack of knowlege and understanding on this subject in the field

[shiden_kai]

Here are the updated Torque settings.

------------------------------------------------------------------------------------

994-99 Cadillac Concours

1995-99 Oldsmobile Aurora

1999 Marine

with 4.0 L or 4.6 L Engine (VINs C, Y, 9 -- RPOs L47, LD8, L37)

This bulletin is being issued to clarify the cylinder head tightening specification listed in the following procedures in the Engine Mechanical 4.0 L and 4.6 L sections of the appropriate Service Manuals:

Specifications -- Fastener Tightening Specifications

Cylinder Head Replacement -- Installation Procedure

Cylinder Head Installation

The torque specification and sequence for the cylinder head bolts (1--10) using J 36660-A is:

First Pass -- 40 N·m (30 lb ft)

Second Pass -- 70 Degrees

Third Pass -- 60 Degrees

Fourth Pass -- 60 Degrees (190 Degrees total)

Barry, these torque specs are out of date. The latest ones that I've been using are identical, except the 4th pass is only 45 degrees now.

Ian

[Barry94]

Barry, these torque specs are out of date. The latest ones that I've been using are identical, except the 4th pass is only 45 degrees now.

Thanks for the update Ian.

That was the current Bulletin when I did my Head.

Is there any explanation as to why the 4th pass was decreased.??

Barry

[KHE]

I replaced my head gasket with the engine in the car. It's not an easy job.

You need lots of tools and patience.

I did the compressed air test to determine which cyl/head was at fault. With mine it was the rear head. (The most difficult to do)

As mentioned, you need the manual.

If you have little or no mechanic experience, then DO NOT attempt this on your own. I've seen guys screw up fixing a Chevy 350, and that is a much simpler engine to repair.

I'm not questioning your intelligence, just your experience.

Lots of things to go wrong.

As KHE said, be sure you know which head(s) is at fault.

If you do attempt this repair, I'll be glad to help any way I can.

Barry

Barry,

Did you need to use a right angle drill when you installed the timeserts? The lack of clearance would seem to dictate a right angle drill.

[Barry94]

Did you need to use a right angle drill when you installed the timeserts? The lack of clearance would seem to dictate a right angle drill.

That would be a qualified, yes.

On the rear head, there is not enough space to use a regular drill.

I didn't have a right angle drill, so I adapted my 3/8 air ratchet. It was a little crude, however worked nicely.

Barry

[shiden_kai]

Thanks for the update Ian.

That was the current Bulletin when I did my Head.

Is there any explanation as to why the 4th pass was decreased.??

From what little I've been able to gather, the decreased angle is

designed to "help" the head bolts from pulling the threads out of

the cylinder block.

When I replace head gaskets on a warranty repair, GM will not

allow us to just install timeserts automatically. They will not

pay for that operation unless we run into problems. I have noticed

that on low mileage engines, if you are careful removing the

originial head bolts, you can get away without installing the

timeserts. And frankly, I don't care, if it's a warranty operation,

as GM just pays me if a head bolt thread happens to pull. When

it's customer pay, I insist that we install timeserts, as we cannot

come back on the customer if a threads pull on the re-install.

It's not fair to the customer.

Ian

[shiden_kai]

I didn't have a right angle drill, so I adapted my 3/8 air ratchet.  It was a little crude, however worked nicely.

Not crude at all, Barry. That's exactly what I use, even if the

engine is out on a stand. It allows you to apply nice, even

pressure, and the rotation speed is slow and easily adjustable.

Ian

[Barry94]

When I replace head gaskets on a warranty repair, GM will not

allow us to just install timeserts automatically.

That's too bad. Seems a bit short sighted.

When I originally had my head off for a burned valve, I didn't timesert the block, as I didn't know anything about timeserts.

It took a few years, however, three head bolts did pull.

I guess GM is satisfied to get the vehicle repaired and perhaps last the duration of the warranty. I would hope that many may never pull the threads, however, it's possible some will in a few years.

Time will tell.

Barry

[Poobah]

Re: Your impending head gasket project

MANUALS

I bought my service manuals from factoryautomanuals.com

The manuals were very slightly used and in excellent condition.

The check I wrote to them was for a total of $85.85, which included shipping and handling.

I hear of people getting manuals for less than this, but factoryautomanuals has been around a long time, they have a huge inventory, they give excellent service and can probably ship the manuals for your car quickly with no fooling around on your part.

They have proven to be a valuable invertment!

TIMESERT KIT

I had the head gaskets replaced in my '94 Eldo last December. I bought a Timesert kit for the job and no longer need it.

It is a genuine Kent-Moore Timesert kit for Northstar engines. It has only been used to do the one job and is in good condition. Except for the inserts, it has everything it came with including a good supply of locktite and insert oil, a sturdy steel box and a plastic-laminated instruction sheet.

If I remember correctly, the kit came with 10 inserts (you need 20 to do the whole job). I think a full set of 20 inserts costs about $60 (please confirm this).

My mechanic charged me $435 for the kit plus the additional inserts (this includes sales tax but he didn't add a mark-up).

I would sell my kit for $200 plus my cost of packaging and shipping.

That would put your cost for the kit with the full set of inserts at about $260 plus packaging and shipping.

If you are interested, I will find out the packaging and shipping cost and let you know.

It might be easiest to E-mail me on this.

In any event, I wish you the best of luck!!

[DFBonnett]

If you look at my other posts :Engine OVerheating... Coolant Spilling" you can see that I tried everything and finally took the car to the dealer. He came back and told me that both gaskets are blown.

In my mind and with my limited experience, the fact that the dealer declared both gaskets blown is troublesome. I've been messing with cars since the mid sixties and consider myself an advanced amateur, but I have yet to see or hear of an engine that blew two headgaskets simultaneously. You might wish to get a second "hands on" opinion. Perhaps others on the board might wish to comment on the likelyhood of both gaskets being blown. This is not to say that replacing both if in is bad is not a good idea, but the diagnosis is suspect IMHO.

[Poobah]

I don't pretend to be a head gasket expert, but I have been through this excercise recently and will offer the following thoughts:

Usually, head gaskets don't "blow", they deteriorate. Two common causes of head gasket deterioration are poor cooling system maintenance (less of a problem on '96 and later Northstars due to the use of Dex-Cool) and cracking of the stainless steel fire rings due to fatigue caused by a high number of thermo-cycles.

In either of these cases, if only one gasket is "blown" it is a sure bet the other one will go soon.

Given the amount of work and the cost of gaskets and other parts it takes to R&R one head, I think it would be very short-sighted to not go ahead and R&R both heads while you were at it unless you were extremely short of money and planned to pawn the car off onto some poor, unsuspecting soul soon.

Nothing is more frustrating than having to do a major job all over again a month to two later just because you tried to cheap it out.

[DFBonnett]

I agree with Poobah about replacing both gaskets if at least one is bad. That is just good sense. What I question is the diagnosis. How did the dealer know both were bad? Did both in fact go bad simultaneously? If so that is very unusual. If they didn't check both, how do you know they checked either? Are they going to do what too many places do and that is to invent a diagnosis, rip your engine apart and hurl parts it it on your nickel until they solve ( or pretend to solve) the problem?

[shiden_kai]

I agree with Poobah about replacing both gaskets if at least one is bad.  That is just good sense. What I question is the diagnosis. How did the dealer know both were bad? Did  both in fact go bad simultaneously? If so that is very unusual.  If they didn't check both, how do you know they checked either? Are they going to do what too many places do and that is to invent a diagnosis, rip your engine apart and hurl parts it it on your nickel until they solve ( or pretend to solve) the problem?

I think that you are making bad assumptions. How many

headgaskets have you replaced on Northstar engines lately?

I work on these engines all the time, and two head gaskets

going at the same time is well within the realm of

possiblities. In fact, it's usually not the "head gasket" that

goes, it's the head bolt threads in the block that "pull" out

of the block and provide no torque for the head gaskets.

Personally, I do not "put air into the cylinders" in an attempt

to figure out "which" hole is the problem. Every cylinder

head gasket failure that I've seen on the Northstar is usually

one of two things....the head gasket leaks externally, or

it leaks internally...pretty simple eh? If they leak externally,

you can visually see it, either on the outside section of

the head to block parting line, or on the inside section

in the engine valley. If the head gaskets are leaking

internally, the most common symptom is overheating

under load. Who really cares which particular hole it

is, if the external or internal leaking symptoms are there,

it's in the best interest of the customer to replace both

head gaskets, and timesert the block. That's just the

way to do things with this engine.

In any case, it's almost always the head bolts losing

their torque, not the head gasket actually "failing".

And in that case, what would be the point of only

replacing one head gasket, even if the other, for

all intents and purposes, appeared to be fine. If

the other head gasket failed soon down the road,

I as the technician would look like an idiot, as the

labour to do both heads at once is quite a bit less

then the labour to do first one head, and then the

other. This engine is time consuming to work on,

and so when you have the engine out, you fix

whatever needs to be fixed "now".

The dealership is both being smart and looking out

for the customers best interest by recommending

replacing both head gaskets at the same time.

Ian

[Ranger]

Ian,

What causes head bolts to suddenly pull loose after 80, 100, 120k or better? I understand them failing after being removed and not timeserted. Bill explained that in great detail at one time. I just don't understand what phyisics are going on (other than heating/cooling cycles) that would cause this in some engines and not others. I guess I am trying to get a handle on whether or not this is in my future and whether or not there is anything that can be done to prevent it.

[shiden_kai]

Ian,

What causes head bolts to suddenly pull loose after 80, 100, 120k or better? I understand them failing after being removed and not timeserted. Bill explained that in great detail at one time. I just don't understand what phyisics are going on (other than heating/cooling cycles) that would cause this in some engines and not others. I guess I am trying to get a handle on whether or not this is in my future and whether or not there is anything that can be done to prevent it.

I don't really have the kind of knowledge that you are looking for.

Bill would have a much better idea of what is going on. No matter

what anyone says, it's a bean counter decision to not have

timeserted the engines right from the factory. It's probably a

bit of a numbers game. What percentage will fail within the

warranty period?

My problem with that is that Cadillac stakes a large

percentage of their reputation on that engine, so why

not just go the extra mile and eliminate one weak

point on the engine.

The more you work on this engine, the more that

you see what a fine piece of machinery it is. A work

of art, really.

Ian

[DFBonnett]

I agree with Poobah about replacing both gaskets if at least one is bad.  That is just good sense. What I question is the diagnosis. How did the dealer know both were bad? Did  both in fact go bad simultaneously? If so that is very unusual.  If they didn't check both, how do you know they checked either? Are they going to do what too many places do and that is to invent a diagnosis, rip your engine apart and hurl parts it it on your nickel until they solve ( or pretend to solve) the problem?

I think that you are making bad assumptions. How many

head gaskets have you replaced on Northstar engines lately?

Ian

As you might imagine, I haven't worked on any lately or ever for that matter. My "bad assumptions" as you refer to them come from having been lied to a number of times over the years by service people, both writers and incompetent mechanics trying to cover their tracks. Not all are devious liars, but enough are to warrant a healthy skepticism regarding their grand pronouncements. My apologies if that hit a sore spot with you.

[Barry94]

What causes head bolts to suddenly pull loose after 80, 100, 120k or better?

Quick recap. I replaced my rear head about 6 years ago for a burned valve. Did not timesert the block. About 3 years ago I had the overheating under load problem. (3 pulled head bolt threads)

I know exactly when it first happened. I was stopped (long delay) in heavy traffic (on a hot day), trying to gain access to the on ramp of the highway.

Finally got on to the highway, which was clear of traffic.

The ramp enters the highway at the base of a long uphill straight stretch.

Well you likely can guess what happened when I hit the highway after being held up in traffic.

"Foot to the floor", I made a "sporting" entrance to the highway. When I reached the top of the hill, about a mile, I received the engine overheating message/air conditioning shut down, then enging hot, something, something, STOP the engine.

I let it cool and restarted and everything seemed fine. Ran great. However, it continued to heat up under heavy acceleration.

I think the combination of the second torquing on the head bolt threads and the very hot engine (prior to the highway entrance), and the long full power load up the hill simply overcame the threads.

Barry

[Ranger]

What causes head bolts to suddenly pull loose after 80, 100, 120k or better?

Quick recap. I replaced my rear head about 6 years ago for a burned valve. Did not timesert the block. About 3 years ago I had the overheating under load problem. (3 pulled head bolt threads)

Barry,

I was talking about an engine that has never had the heads touched. I agree with Ian. I'm sure it is a bean counter decision. The thing that those "suits" don't understand is that probably any Caddy owner would be more than happy to pay the paltry $100 or so that it would cost to timesert them during manufacture for the added reliability. Nothing will piss me of more than to have maintained my car meticulously and have head bolts pull on their own and have to pay $3000 for something that could have been prevented from the start for so much less. There is simply NO excuse for that in my mind. That can only hurt Cadillacs reputation. Sorry for running off but this really irritates me. I'll get off the soap box now.