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do i really need to timesert?


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i'm rebuilding a northstar. the entire internet is flooded with the word timesert when i turn to it for help on this subject.. turns out the aluminum threads are a problem when retorqued or something. none of my head bolt threads are stripped and for the most part the bolts came out smoothly, though a couple of them had a raunchy burn out smell to them along with some black crude oil like gunk.

question is do i have to drill out these seemingly good threads and replace them with overpriced inserts for this job to get done correctly and last or will careful torque-ing suffice in this situation? the rebuild kit is like 1250 and i have plenty of other odds and ends that need to be purchased.. if i can avoid paying 400 dollars for a timesert kit i would definitely be interested in skipping that step, but not if there is a good chance that the threads blow through a week or a month after im done. i dont plan on pulling this engine more than once...

also.. if anyone has a particularly reliable and affordable supplier for caddy parts that they have delt with in the past that may help me in this venture a referral i'm sure would be appreciated by both parties

any help is appreciated, experienced help is appreciated by a guy that'll get the job done right. thanks in advance!

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:welcomesmiley: and thank you for posting.

Yes, I recommend you timesert the engine. If it were simple to pull out the engine/drivetrain and fix it later then no problem, but it is way too likely that you will have a problem down the road if you don't timesert it now.

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Good luck with your Northstar, and please keeping coming by and keep us updated on your progress. It would be great to have photos of the work as it progresses to help others along.


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I second Bruce's idea as to Timeserting the engine.

Since it is already out, it would be foolish to NOT timesert it.

There was someone on this forum that had a Timesert kit for sale recently. All you would need is the inserts.

I don't know if he still has it or not. You might also look for one on e-bay.

If I may ask, why are you rebuilding the engine?

I don't hear of many Northstars needing to be rebuilt.

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the entire internet is flooded with the word timesert when i turn to it for help on this subject.

There is a reason for that.

i dont plan on pulling this engine more than once...

You answered your own question. If you don't Timesert it there is a good chance that you'll pull a thread or two on retorquing. Even if you don't, the threads may pull down the road. Barry94 suffered that experience 10K after after doing the job before he knew about Timeserts. I'm sure he will chime in. If you are going to go through all that work, do it right the first time. It's good insurance.

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i think murphy's law applies to my entire mechanical history

when i started.. the 2468 head gasket was leaking and the harmonic balancer rubber was coming off of the metal wheel. i did a compression test before i ripped it and in addition to the number 8 cylinder having low compression (the one by the visibly leaking head gasket) the number 1 and 6 cylinders also have super low compression. it may just be the valve guides which i will look in to but the compression in each of these cylinders was about 20 percent less than the others in multiple trials, so i wanted to do rings, too.

now i know i may be proclaiming this a rebuild prematurely, but as i started tearing it down i realized just how much i hope to never have to mess with this engine again. of course i'll check it out and at the very least replace the rings, but if i can get rings, pistons, valves, seals, gaskets, bearings, a new balancer, springs, and well pretty much everything but the cam and crank shafts for just a little more than i'd pay for head/intake/oilpan gaskets valve job and a ring set etc.. i'd much rather take that route and be done wih it. like i said a visual inspection is on its way but i'm just planning for the worst because every single fluid that has come out of this engine has been in disgusting condition and the previous owner took horrible care of it... i couldn't see how a rebuild wouldn't be necessary.

oh and the engine is from a 96 eldorado.. which brings up another question - the wiring harness terminates by the front of the engine bay at the ABS modual(sp?). the harness was wrapped around and apparently got chewed up by the fan (possibly not cooling the antifreeze and causing the overheated engine?). Anyways, the harness looks rediculusly hard to change out entirely, but there are about 8 wires that are either flared out or just not there any more (in the 3 inch section of harness). i'll post a picture in a little bit, but i'd like to know if this is worth a replacement or if i should just throw some hookup wire between them and be done with it. sorry about the lenghty post

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The Northstars weak link is the head gasket. The lower end is almost bullet proof. One reason that it uses oil is the aggressive hone in the cylinders (which retains oil). Thus the rings and cylinder walls last forever. I'd bet when you get the heads off you'll still see the factory crosshatch hone pattern. What I am telling you is that you do not have to go through all that work. just replace the HG and Timesert the block. Our old "Guru" (A GM powertrain engineer) said that he has seen Northstars opened up at 250K and more and they still had the factory hone pattern on the cylinder walls. Maybe check the valves for the lower compression, but the lower end is likely just fine. Just trying to save you some time and $$$$$.

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I would say the low compression is due to the failed headgaskets... Timesert it, install new headgaskets and headbolts and drive it for another 200,000 miles...

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I have not timeserted a Northstar, but from your posts I am going to suggest something. Forget everything you know about engines. The northstar is very different. You said something about RINGS, rarely are rings a problem, as a matter of fact don't be surprised if you see the original crosshatch hone on the cylinder walls. You said, valve guides, rarely are the valve guides the problem.

When you have the engine out, you should replace the case half seal, and because you have the case half apart, you should probably replace the main bearing, rear seal, etc.

Listen to the guys here who have timeserted their engine. A few have experience burned valves, consider that as a source of your bad compression. You will need to learn everything over again, your past experience will help you, but you need to relearn.

Do you know about the torque angle method of tightening the head bolts? Replace the head bolts when you do the job.

We have a lot of knowledgable timeserters here, ask lots of questions

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If I had to do a headgasket job on a Northstar, I would look into the following.

Norms NS300L inserts - $350



I believe the 2 other repair methods have less likelihood of failure than Timeserts. The second method uses studs.

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Hi, some good information in this thread.


I originally ( In 1997) had a rough running engine.

Compression test revealed only 55 lbs compression on #5.

It was a burned valve. You could see light between the valve and the seat.

I replaced both exhaust valves in that cyl.

I did not Timesert the engine and as mentioned, the threads failed in three holes.

So, my recommendation is to definitely timesert the engine.

Those who have not usually regret that decision.

Thanks, Barry

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1970 Corvette LT-1 Coupe

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