Later results of an over torqued cylinder head?

What are the later results of an over torqued cylinder head? Warping or stripping later vs then?? A friend borrowed a torque wrench to re-torque his head after having questions about the fist wrench. I showed him that I always check my Sears Micro wrench with my Ward?s Pointer type wrench. When he returned the Micro wrench, I asked how did it go? He replied,? they were all too tight?. I replied, ?did you re-torque them? and he said ?No?! Now I?m curious as to what damage he might cause. Thanks, jow

Re: Later results of an over torqued cylinder head?

Don't know if it can cross from automotive engines. But from working on cars over torquing the cylinder head can crush head gaskets, warpage, and at worst case, crack a cylinder head. This is the same for bolt sequence. Gets even more critical when you deal with aluminum cylinder heads (like outboards).

Re: Later results of an over torqued cylinder head?

I suppose it really depends upon how much over torque specs the bolts are. You don't give that information. A pound or two in 20 foot pounds (240 inch pounds) won't make a vast difference but 5-10 pounds will.

It has never happened to me but I suspect that if you compress the head gasket too much, it will lose resiliency and not rebound on cooling, leading to leaking and damage.

And, of course, at some point, being that the head bolts are in aluminum, they will strip. Again, I don't know at what torque this will happen.

If all bolts are equally tight and over torqued, I don't think that head warping would happen though.

Ultimately, I also suspect that a lot of backyard repairmen don't bother to use a torque wrench and just tighten "grunt" tight. I know, when I first started, I was like that: Too tight was just right. Now, I trust the engineers and the torque wrench, although, if there is a range I still tighten to the maximum specification.