Willie

iTrader: (1)

Aluminum heads on a rebuilt engine. Fired the engine up and ran it up to temperature (about 200 degrees). Let it cool down afterwards. Is one thermal cycle enough before getting dirty again to retorque the head bolts? Or should I cycle it a couple more times?

I am using head gaskets that do not require retorquing, but I plan on checking the torque anyways (can sleep better knowing they are all uniformly torqued). I also have a friend who just fired up a fresh engine with aluminum heads and he drove it about 25 miles before checking the head bolts. He said FIVE were slightly loose. So I figure I should check.

JeffC1500TBI

hmm.. I was wondering the same thing.. I just had my engine rebuilt.. haven't put it in yet.. but I now have edelbrock aluminum heads and I was looking at the instructions that came with them and they say to bring it up to temp and then after cooling to retorque.. if this is so that means I have to remove valve covers to get to the bolts right?

Willie

iTrader: (1)

Valve covers, rockers AND exhaust manifolds. It's a lot of work to get to the bolts but I would rather be safe and sorry, especially with aluminum heads. So if your Edelbrock instructions say one thermal cycle is sufficient, I won't do any different. Any more opinions?

Willie

8Mike9

Hmmn, never used Al heads, but never re-torqued castiron ones.

My personal opinion would be that it's not needed...I don't think the factory is doing it..not just GM, but think of all the Al headed engines out there now. They seem to be okay.

JeffC1500TBI

apparently there some gaskets that do not require retorque.. I don't know what type the builder used on mine.. I know they are baby blue color if that means anything as far as brand /type..

irocbsa

Fel-Pro

JeffC1500TBI

any other opinions?

Hellraiser

I wouldn't worry about it, they really shouldnt need to be re-tourqed.... assuming they were torqued properly the first time with decent fasteners. I've never had a new head gasket fail on a SBC, nor any other engine with aluminum heads because they werent retorqued. I'd say if this is a race car it might be worth the trouble, but if its your daily driver your fine.

RB83L69

Manufacturers turn out millions of cars every year with aluminum heads, and not a single one gets retorqued after its initial run-in... think about it... would you, as a mfr, design your new cars such that the very first thing your customer had to do the first time he drove it was to turn back around and take it back to the dealer and have them tear it down far enough to tighten a bunch of bolts at your expense? I don't think so.

You'll be fine, if it was assembled correctly, to the right torque, on every bolt; i.e. after the first time of going around the engine and tightening to spec, if the builder went back around the torque sequence again and checked to make sure that every bolt was still at spec. That's all that the factories do, and they all seem to get by without too much trouble.

a73camaro

A sealant was used on the threads of the cylinder head bolts (or should have been ). That torque was established with a "wet" sealant. Now the sealant has dried after a thermal cycle. I believe that the dried sealant would give false torque readings. Plus you have a chance of breaking the seal and causing coolant to leak into the engine.

Guest

Fel-Pro

No retorque needed. Ive never done a retorque with head bolts on a SBC. Studs and other engines is another story entirely.

Matt87GTA

I second all of that (or am I thirding or fourthing it? ...... hehe).

ronterry

I thought it came down to the bolts. In fact I did a head job on a quad 4, and the new bolts stated that these are TTY or torque to yield bolts, and do not need re-torquing.

BTW: I never re-torqued the head bolt in the past, then again I never recycled the bolts either(this might be a valid point to re-torque).

Ron

a73camaro

I'm doing 11.01 at 122 with recycled head bolts (this is with 13.5 to 1 pistons). No head gasket failure.

I do find that 1 out of ten bolts have detectable stretch.

Guest

Usually those bolts break if used more than one time, thats more than likely why they say they dont "need" retorquing, they actually cant handle it.

I have seen some bolts that the mfg. recommends retorque because the bolts sometimes need it, besides the head or gasket needing it.

ronterry

So far what I've learned on this post is: If your loosing sleep then do it, but If you've done your fair share of head bolts / valve lash for the season there's a lot of reasons & testimonials not to.

Ron