Heli-coil, Timesert

[Ed Fenwick]

Aloha,

I sent my '92 4.9 Seville to have the head gaskets replaced. The shop owner called me today and said that the block had a heli-coil that was pulling out. I suppose that this is the same as a time-sert that you all have been talking about.

He said that after the block had a hili-coil pull out, they can't put in another. Is there no such thing as an over sized heli-coil to replace the bad one? I am told now the block is no good!!! Can this be so?

I don't think that the car is worth another motor, even a used one. Do you guys think that the block is repairable?

Thanks Ed

[JIMDTS]

They are time serts if the guy don't know the diff. I would go someplace else fast They do make an over sized time sert just for the replacement if one should happen to pull out go to timesert.com and read up..Was the block time serted before this repair?? I'm sure it can be saved just get some one who know what they are doing Only problems I can imagine is that if you already have the over sized time sert you are screwed..

Good Luck

Jim

Click on the link check out the second item down and read up

http://www.timesert.com/html/gm.html

[Scotty]

Is it possible that they guy IS using heli-coils and not time-serts and a heli-coil pulled out?

[danbuc]

Have the heads been previously removed on the engine before? If so, that might explain the heli-coil. If this is the first time the heads have been pulled off, then it's not a heli-coil that pulled out, but the actual threading from the block. I haven't heard of the 4.9 having a realy problem with this though, just the occasional N*. As far as the replacement goes, I would recommend getting that heli-coil (if that is what he says it is) pulled out, along with all the other ones that might be in there. Hopefully there's still enough material for a timesert job, if not a bigsert should work as well. If the heads had been removed once before at an earlier time, I guess it's possible that maybe one bolt got stripped, and the heli-coil was installed. You mgiht be able to get away with just replacing that one heli-coil with a new timesert, but if your going to spend the money to get that done, you might as well get all the bolt holes timeserted and be done with it. Better safe than sorry.

[Scotty]

Believe it or not, the 91 service manual recommends heli-coil repairs even on the head bolts, so its possible that one was used previously, as that was the only solution. I think the time-sert was developed relatively recently.

[Bruce Nunnally]

I have heard mechanics argue that although it might be possible to use an over-sized helicoil to repair a helicoil that had pulled out, they did not have good experience with the repair. This is the purpose of the oversize helicoils on the other hand. I guess you have to consider that if they did use oversize helicoils, then the engine had head gasket problems again 14 months from now, or maybe ran the rest of the 'life' of the car, would that be a good risk, or would you be better off swapping in a rebuilt engine now?

[Ed Fenwick]

Aloha,

Thanks for all your help guys. I will call the mechanic about the oversize tineserts. I don't think that the car is worth another engine. I realy enjoy it and it is very pretty but not worth another 6K, concidering the work to this point and then an engine too. A shame to junk it though.

Thanks again for your help. Ed

[Scotty]

Aloha,

Thanks for all your help guys. I will call the mechanic about the oversize tineserts. I don't think that the car is worth another engine. I realy enjoy it and it is very pretty but not worth another 6K, concidering the work to this point and then an engine too. A shame to junk it though.

Thanks again for your help. Ed

Ed, I don't think it will cost $6,000 to fix your car if you need to swap engines.. Look into the idea. Do you have scrap yards in Hawaii? You might get lucky and find an engine. I can get you one for about $500 and shipping would be about $500 (at least that is what it was to Amsterdam). I would see the engine personally, know the mileage and send you photos in advance. Ask what your shop would charge to swap an engine. Consider the idea, Mike

[KHE]

If it were my car, I would see what TimeSert had to offer asd far as thread repair. A time sert is stronger than a helicoil as it is one solid piece vs. a "slinky" helicoil.

A Timesert will fix the problem for good...I sure wouldn't junk the car or mess with a used engine.

[Ed Fenwick]

aloha,

Yes thanks guys. My friend found a rebuilt engine for $2900. with $400. shipping and $1600. to install. That is much more that the car is worth. He said that those prices are list and he would give me a better deal but I haven't heard what yet.

His mechanics told him that the repair is only a temporary fix but I think they were thinking of heli-coils not these timeserts. I don't think that GM would offer them if they would not do the job. Even if I go with a used engine (thanks so much Mike) I feel that $1600. is a lot to do an engine swap. I would think that he could do it in 8 hours.

If my friend is willing, I think that the timeserts are the way to go and maybe soon I can trade the car. I usually have better luck with used cars so I suppose the time has come for a troublesome one. I know more what to look for now.

Thanks, I'll let you'll, yo'all, ( you all) know what comes out Ed

[BigCat83]

Let me pose this question:

Does anyone know why Cadillac never used studs to hold the Northstar V-8 together?

The European manufacturers have used studs in their aluminum engines for decades to avoid the problems caused by using bolts. IMO, an aftermarket repair "kit" using timeserts and head studs and nuts would be a much more robust repair than timeserts and bolts.

Your thoughts?

[KHE]

Let me pose this question:

Does anyone know why Cadillac never used studs to hold the Northstar V-8 together?

The European manufacturers have used studs in their aluminum engines for decades to avoid the problems caused by using bolts. IMO, an aftermarket repair "kit" using timeserts and head studs and nuts would be a much more robust repair than timeserts and bolts.

Your thoughts?

How would studs be more robust than bolts? There is still a threaded interface into the block. The Northstar engine uses bolts because they are torque to yield bolts which provide constant clamping force. This is why the bolts MUST be replaced when removing and installing the heads.

Thread failures are relatively rare - for every one you hear about, there are millions of engines that are trouble free.

[jhall]

Hi Guys,

My two bits:

Have them install oversize time-serts to repair the damaged thread. Do NOT use helicoils. The kits are available. Search the forum under Time-sert or jhall and you should find some close-up pics of a time-sert installation on a N*

Whether studs or bolts are used (torque to yield), if the thread interface is aluminum to steel there will usually be a thread failure somewhere during disassembly.

If standard bolts or studs were used, the incidence of head gasket failure would probably be higher. There's a balance in there of performance, economy and what people are willing to pay for a car.

[JasonA]

Does anyone know why Cadillac never used studs to hold the Northstar V-8 together?

The European manufacturers have used studs in their aluminum engines for decades to avoid the problems caused by using bolts. IMO, an aftermarket repair "kit" using timeserts and head studs and nuts would be a much more robust repair than timeserts and bolts.

Your thoughts?

Studs and bolts are the same thing as far as the threads and block are concerned. Both are threaded into the block and hold for the life of the engine usually, with proper clamping force. Studs are a benefit when you take off and remove the part often, like a racing carburetor for instance. If you keep unbolting it and bolting it to the intake manifold, eventually the threads in the manifold will strip.

Come to think of it, maybe that's why the Euros use studs on their engines -- they have to take them apart all the time for repair that they figure it's easier with studs!

In all seriousness, it's relatively rare for any engine, including a Northstar, to have major work done. Timeserts and studs would be fine, but so would Timeserts and bolts. Both studs and bolts would thread into the Timesert, permanently fixing the problem. It'd be overkill to use studs because assuming your engine had a problem in the first place, the Timesert kit is essentially a guaranteed and permanent repair, so you'd never have to remove the heads again anyway.

[Ed Fenwick]

Aloha,

There just seems to be no end to this! The timesert.com site says their parts are for a 4.0 or a 4.6 engine. The mechanic is worried that it won't work on a 4.9.

I told him that a hole was a hole but he would feel better if some of you guys said that there is a timesert for the 4.9 engine or at least the other will work. Is there a problem using Northstar timeserts of the older slower engine. ('92 4.9)

Thanks guys Ed

[danbuc]

The northstar has an aluminum block, but I'm not sure about the 4.9L. I can't remember if it's an aluminum block and cast iron heads, or the other way around. If it's an aluminum block like the Northstar, they should thread in fine. If it's a cast iron block, I don't see why it would work either. The timesert is a solid piece, which should be able withstand the force needed to thread into the cast iron, but you never know. I'm also not sure if they offer the correct diameter/thread pitch timesert for the 4.9L head bolts. I would call the Timesert company, and see if they can ive you any details on whether or not they have a kit that will work with the 4.9L. I would also mention that the larger Helicoil was used. If they know their stuff, they should be able to tell you whether or not a bigsert is the solution.

[jhall]

Have a look at http://www.timesert.com/html/bigsert.html

These are for replacing helicoils that have failed.