MyBlackCar

After finally reassembling the cam tower last night, I was torquing the bolts down to spec. The top middle (towards rear) cam tower bolt would not allow itself to torque properly. The bolt spun but would not lock. To my dismay, I started hearing light metal shearing sounds. I am sure I stripped the threads in this hole.

Has anyone else make this mistake? The belt is still off, so I plan take it apart again to use Helicoils. Any other tips / things I should watch out for?

KuHL 951

You really don't have any choice at this point but to use a Heli-Coil or some type of similar insert repair. What always amazes me is how they can strip out at such a low torque value. I think too many people over the years have overtightened them just because they never checked the spec and thought it took more than 15 ft/lbs.

MyBlackCar

Agreed. I took extra precautions and torqued all of them evenly to 10 then 15 and finally 20 nm starting from the center and moving outward. I was suprised it stripped.

JimV8

Its quite amazing how easy it is to mess up. As I learned you need soft hands. Gently tighten and loosen, progressively moving to the correct tension.

FRporscheman

Are you sure you put 20 Nm and not 20 lbft?

This is one thing I could never fully accept about these cars... working on an aluminum engine is such a headache.

marky522

I would advise you use Timeserts and not Heli-coils, they can take more torque than Heli-coils can. Thats what we use at the dealership, Just sent a Boxster Head out ot have the plug hole Timeserted.

Mark

MyBlackCar

20 Nm. I only look at the bottom gauge on my craftsman wrench. It makes it easier. I will try to find some timeserts, too. Does it matter that these things are shorter than the actual length of thread on the bolt?

MyBlackCar

Quick update after diassembling my cam tower for this bolt:

The bolt thread edge flattened! This caused the bolt to thin the threads on the head. The buildup of chips at the bottom of the blind hole stopped the bolt upon reassembly which lead to the stripped threads. God must hate me.

Anyhoot, I am now making it a habit to test each bolt upon reassembly on a critical component. Tapping a hole in an aluminum bar and testing each bolt is well worth the effort compared to taking apart 1/4 of the engine. If you can, definitely check bolts before they go back into critical components.

944J

just use a slightly longer bolt! I did this on one of mine and the longer bolt fixed it... the longer bolt works for all kinds of stripped bolt issues, recently did it on my jeep brakes... (beats paying $100 for a new hub)

FRporscheman

How does a long bolt solve the problem of a stripped hole?

jacksonrw

we have all done it
hang in there
i just rebuilt an engine i use and had to succumb to using heli coils where high torque was no needed...the guy before me did a real sloppy job..

you will survive and so will your engine

did you try to re-thread hole?

944J

not much longer, but I don't remember, the holes where it screws into is actually much longer than what is used by the bolt, try going up 1/16" or 1/8". I wouldnt really know unless I took my bolt out...

Tom M'Guinn

A helicoil should work just fine for that. I use 'em all the time. Just keep the metal flakes out of the head/engine.

MyBlackCar

I have a timesert kit ready to go. I just machined a guide for the drill. I am now awaiting new bolts from Pelican.

Luis de Prat

I think using new bolts is a must. When I did the cam cover on the S2 I used new bolts and no problems.

It's a cinch compared to the 2.5 liter cam towers, no doubt, but notorious for stripping bolts just the same.