Engine/Transmission (1994 - 1998) Broken head bolts

[bkroupa]

I had a reputable shop bump my timing to 16, run the valves & retorque the head about 10k ago. One of the heads bolts broke while being tightened & was replaced.

10k later I noticed my overflow bottle had a higher level than normal . Turns out two more head bolts had broken sometime after being retorqued. Has anyone else has head bolts break? Hindsight is 20-20, I wish I would've gone with studs with the retorque... ... ... ... ... ... ... ... ...

I'm going back with studs & o-ringing the head, it's a bit overkill for my rather mild combo & driving style.

 

[Kernel]

I just read in a thread not long ago (can't remember where) and been told that it isn't necessary to retorque a head that has never been off. I can't remember what the specs were but the head bolts have a certain pressure/torque rating that can easily be reached, they "stretch" so to speak and with unnecessary tightening they will break off. I thought of and brought the issue of checking the head bolts up with my trucks and always got the same answer: "Naw, leave it alone. " Has the head ever been off on your truck, did you get unnecessary tightening or get them too tight? Don't know a reason why they would spontaneously pop off other than they were ready to break but just didn't at the shop like the one did and through the heating/cooling/vibration process of the last 10 thousand miles finally gave up.



Scott

 

[JGK]

I think all the action in the last few years over twins, o-ringing, studs, etc. has got people over-reacting. Now some are thinking they need to do as bkroupa did and retorque a "stock" head setup. Unfortunately, he's discovered what happens when you "fool with mother nature"



I say leave these things alone (like head bolts) until they have failed or you've modified them. These engines are built to go 360K miles in stock form. They're tough. The old adage of not fixin' it if it isn't broken has merit.



Bkroupa, my recommendation is to get a set of studs and replace the stock bolts one at a time in the same order as specified in the manual for originally torqueing the head. Torque them to manufacturer's spec, then retorque if the mfr. recommends it. Then leave them alone until you pull the head and do an o-ring job. Maybe you can get the shop to help out, but I'd be inclined to steer clear of them.



FWIW,

-Jay

 

[bkroupa]

That's why I posted. If you feel you need to be concerned about your HG, go ahead & replace the bolts with studs as you retorque.

I believe my truck would have been fine if I had left it alone.

I don't blame the shop, they only did what I asked. I was very pleased with the MPG & performance with the timing change.