Alternative to Time Serts?

[Northstar]

This looks like a pretty good product:

http://cgi.ebay.com/ebaymotors/Cadillac-No...sQ5fAccessories

[BodybyFisher]

I'd have to agree that this looks like a good product, but if one of those studs pulls, what happens then. I need to go to their site and see if they have had any problems with these studs.

The studs sticking up like that look like the dragster engines

I would be reluctant not to use timeserts but I also know that GM techs have said that timeserts sometimes dont work, with 2 inches of threads, that certainly gives that stud a lot of strength

This obviously means that the engine must come out of the car, you would never have clearance to install the rear head

[Bruce Nunnally]

I like the fact that he charges $1500 for a complete head gasket repair, and that he warranties his work.

I worry about back-yard engineering vs the factory solution, and anecdotal evidence (not one has come back yet) vs actual testing.

But I would like for this method or one like it to be successful and mitigate the issue of the expense of repairing headgaskets.

[OynxSTS]

Coolest thing I have ever seen... Good price too...

If you follow along all of the history on Timeserts there are lots of issues there too... The old posts that guaranteed a "serted" block will never fail and is stronger then the original block is not proving to be true...

Lots of people are now using "big serts" or using the long coarse kits from a 2004 and newer Northstars... other "serts" are also popping up to fill the gap... Lots of dealers have now abandoned "timeserts" and a switching to "normsert"

I like the simple "physics" of studs... all of the clamping force is perpendicular to the threads and there is none of the friction/galling between the thread and the aluminum block as they are tightened... Logically these should be much less likely to pull...

The studs are custom made for our aluminum engines... Long COARSE big threads (like the LS1/2/x engines and the 2004 N* and up blocks)

If mine blows I will be talking with this firm.

[Ed Hall]

Probably overkill but this system is what I would use if my headgasket fail.

[Texas Jim]

Better OVER than UNDER.

[Northstar]

"With the SG102 stud kit, there is a full 2 inches of coarse thread holding the heads down. The most of any Northstar repair kit. The best part? The threads are already in the block when you torque the heads down- with studs, all of the torquing is done on top with high strength nuts instead of twisting a steel bolt in the aluminum block under load. This is so much better for the engine and reduces the chance of the block cracking down to less than 0.5%"

Because of this statement I think I will try them if my head gaskets go.

[MrEldo97]

I like studs as opposed to bolts in an aluminum engine. Ran and repaired Alfa Romeo and Jaguar aluminum engines with studs for years and never had a problem.

Of course heads can be a real b*tch to get off if they're corroded to the studs (poor cooling system maintenance). If this was available when I Timeserted my Northstar

I would have used it.

[Ranger]

Hey guys, be advised that Jake is also working on solid front motor mounts as we all know that the factory mounts don't last very long. Mine was replaced last fall under warranty and is already failing. He guarantees them to last and still isolate engine vibrations. I'm waiting for one of the first threee to test. I think he is going to charge $50, but don't quote me on that.

[ted tcb]

Jake's approach to repairing HG failure is a positive step in the right direction.

He's only 4 hours from my house ... I'm considering buying an ETC simply because of his service

and reputation.

[cessnatech]

I have a 97 deville with supected head bolt threads pulled loose. Can I remove the engine thru the top or does it have to come out the bottom? The factory service manual has the alternate method of removing thru the top without the transmission. Also I've just learned of the stud kit sg102. Sounds like a good kit. Please help. Cessnatech

[BodybyFisher]

Hey guys, be advised that Jake is also working on solid front motor mounts as we all know that the factory mounts don't last very long. Mine was replaced last fall under warranty and is already failing. He guarantees them to last and still isolate engine vibrations. I'm waiting for one of the first threee to test. I think he is going to charge $50, but don't quote me on that.

I have replaced the front and left mounts so far and they are totally separated. I need to have a look at the Right Rear mount, I am sure its in bad shape if not gone.

[BodybyFisher]

I have a 97 deville with supected head bolt threads pulled loose. Can I remove the engine thru the top or does it have to come out the bottom? The factory service manual has the alternate method of removing thru the top without the transmission. Also I've just learned of the stud kit sg102. Sounds like a good kit. Please help. Cessnatech

Kevin (KHE) removed his engine from the top, but if I recall, it was not easy, I am sure he will stop by and confirm that.

We have had a few members lift the body off the engine carriage that was supported on the floor. That is probably the method I would use, support the engine carriage (with the ability to roll it out) and lift the body slowly off the carriage while I watched to make sure everything was clear. There is no question this is a big job.

[KHE]

I have a 97 deville with supected head bolt threads pulled loose. Can I remove the engine thru the top or does it have to come out the bottom? The factory service manual has the alternate method of removing thru the top without the transmission. Also I've just learned of the stud kit sg102. Sounds like a good kit. Please help. Cessnatech

The engine can be removed from the top - I did mine that way - I removed the hood support struts and the passenger side windshield wiper and then was able to open the hood 90 degrees. That way, I didn't need to remove the hood and worry about it getting damaged.

If I were going to do another one, I might try to lift the body off the powertrain but if the engine needed the case half sealed or a new oil pan gasket, the engine would still need to be separated from the trans.

As far as the studs go... I don't treat lack of comebacks as a sign of success. I like to see actual engineering tests vs. "I've never had one come back yet"

[cessnatech]

Thanks for the info KHE, I'm still getting things disconnected and trying to identify where things hook up. Also I take it you are not sold on the stud kit v. time serts. I've worked as a machinist and aircraft machanic and have had experience with heli coils. My main worry is doing the timesert and the threads still pulling out. I'll keep you posted. Cessnatech

[BodybyFisher]

Heli Coils are not as strong as time-serts. I think we will all agree here that their are times that a block can not be timeserted. Sometimes the surrounding aluminum becomes corroded deeply and the material becomes powdery its as if its resiliance has left it, I would almost want to say its become brittle and soft. I don't know what affect electrolysis has on some of these issues as the coolant becomes acidic, but I assume it has an affect on the surrounding metal.

Aren't heli-coils forbidden for aircraft engines?

Here is some interesting info on aluminum, that I did not know

http://www.usmotors.com/Products/ProFacts/modernaluminum.htm

[KHE]

Thanks for the info KHE, I'm still getting things disconnected and trying to identify where things hook up. Also I take it you are not sold on the stud kit v. time serts. I've worked as a machinist and aircraft machanic and have had experience with heli coils. My main worry is doing the timesert and the threads still pulling out. I'll keep you posted. Cessnatech

Correct - I am not sold on someone's stud service... I have Timeserts in my '97 Seville - for 38,000 miles, they have held up just fine. Heilicoils are not to be used to repair the head bolt holes in the Northstar Engine. Heilcoils will pull out upon torquing the engine the heads down. If you look at the Timersert web site, you will see the "Bigsert" description is "for when Helicoil fails"...

I like the Timesert because that is the only thread repair that was tested/validated by GM to be an approved repair. Any other methoid and YOU are doing the validation at YOUR expense...

[MrEldo97]

KHE has a good point. I like the studs as I've said but practically speaking I have over 20,000 miles and two years on my Timesert repair and it is holding up just fine. Our successes speak for themselves...

[dgaouette]

Studs don't seem like a bad deal unless you need to service the engine at a later date. As most of you know, the head bolts get stretched after torgue is applied and are a one time use part. This would imply that all of those studs would need to be removed and replaced where as the timesert is simply replace the bolt and go! Am I alone in this concern?

[KHE]

As most of you know, the head bolts get stretched after torgue is applied and are a one time use part.

WRONG. The head bolts do not get stretched nor are they a torque to yield bolt. The reason they are a one time use is die to the special threadlocker that is on the bolts. There is no practical method to apply this coating in the field so the procedures state to use new head bolts.

[dgaouette]

Thanks KHE, Idid not know this. I thought that you always used TTY bolts when using steel with aluminum head/block combos. That typically goes along with using an angle meter, not a torque wrench. Can you tell me where you got your information, I would be curious to research this further. Thanks and sorry for the mis-information!!

[BodybyFisher]

Thanks KHE, Idid not know this. I thought that you always used TTY bolts when using steel with aluminum head/block combos. That typically goes along with using an angle meter, not a torque wrench. Can you tell me where you got your information, I would be curious to research this further. Thanks and sorry for the mis-information!!

I was actually under the same impression that the bolts stretched and besides the anti galvanic coating, the bolts were stretched due to torqing and they needed replacing for that reason also. I will let Kevin respond, he has updated information that I was not aware of.

[dgaouette]

The AG coating should not be necessary if the block has a timesert installed so this would lead me to believe the the original head bolts could be reused if you timesert your block??

[BodybyFisher]

I just did a search and found these words from the GURU, I miss this guy....

Contrary to popular belief the Northstar head bolts are really not torque to yield fasteners..... The bolts will stretch very slightly (permanently) but they are good for probably 10 rundowns before any perceptable yield would occur that would render them unusable.

In fact, new bolts are run down and then loosened in the plant in the normal operation tensioning the head bolts. The pre-tensioning step actuall subjects the bolts to more tension then the final tightening step.... This is done to burnish the threads in the block as they have never seen bolts in them before the heads are installed and the head bolts tensioned. The aluminum threads need to be "worked" once before the final tensioning step so the head bolts are run down, loosened and then re-tensioned. If you started with new bolts on your reassembly then you have only done the equivalent of the first pre-tensioning step on the bolts. Use them, they will be fine. Re-using a new bolt that has been run down one time is not the same as re-using a bolt that was in the engine for 100K.......

The instructions to not reuse old head bolts is primarily because the bolts when new have a special microencapsulated coating on the threads and under the head of the bolt. The coatings act as a high pressure lubricant during tensioning and then a thread locker once installed. On a simple run down and loosening without running the engine the bolts can be "used" several times. Once the bolts see a lot of time and thermal cycling in the engine the coatings are rendered unusable again so the bolts have to be replaced as there is no repeatable means or reapplying the special coatings in the field.

If you simply installed the head with a new gasket and new bolts and pulled a timesert out and dissassembled the head the bolts are fine to use again and so is the gasket. If the head gasket was not used in the running engine and subjected to any thermal cycles it is fine. The gasket will compress permanently somewhat when torqued into place....that does not ruin it. I have seen LOTS of head gaskets run down and loosened and re-run down and continued on test fine. As long as the gasket did not stick and tear when dissassembly the gasket is perfectly fine to re-use. It has just been "pre-compressed" much as it is done in the above mentioned pre-tensioning step to condition the head bolt holes. That is done with the gasket in place so the gasket sees the compression and then relaxation in production.

With the compacted graphite gaskets it is sometimes necessary to pre-compress the gasket and even heat it during compression prior to installing it into the engine. So, simply compressing the gasket to the installed load does not hurt or ruin it. If, however, the gasket is held under load and thermal cycled in the engine it will not be reusable. That is because the thermal cycling subjects the gasket to even more load that would cause it to be deformed beyond recovery if relaxed.

Unfortunate that a timesert pulled out. A bigsert should fix the problem for sure. At least you can reuse the new gasket and bolts with no concerns.

[KHE]

The AG coating should not be necessary if the block has a timesert installed so this would lead me to believe the the original head bolts could be reused if you timesert your block??

NO - you need to use the new headbolts even with Timeserts. The threadlocker is required.