Question about retightening engine fasteners after rebuild

[lil hoodlum]

I recently had a 327 sbc rebuilt and installed in my 1968 C10. Is it normal for the bolts/ engine fasteners to need to be retightened?

I ask because it seems that all of my bolts loosen up a little bit and I have been tightening them down for the past 2 weeks. Example: header bolts, intake manifold bolts, oil pan bolts, timing chain cover bolts, water pump bolts, carburator to intake manifold bolts, etc.

Should I keep tightening them until they no longer "loosen up" or maybe use some loct-tite?


Another question. How many foot pounds of torque for aluminum cylinder head bolts? I checked them at 65 foot pounds and they are tight, no clicking of the torque wrench.

[cadillac_al]

I don't think any of those will need tightening again except for the header bolts. The oil pan gasket may be sensitive to over-tightening depending on the gaskets in there. The engine looks picture perfect, very nice. Do you have 2 vents on the passenger valve cover? Any special reason for that?

[James the III]

Stage 8 header locks will stop the header bolts issue..

[homemade87]

Probably what you are seeing is the gasket material is compressing after several heat cycles . It is possible to damage a gasket if you keep tightening it . If it were me would thread lock the bolts and torque them to spec and call it good .

The header bolts is another story . They always seem to loosen because of the extreme heat cycles they go thru . The other fasteners may or may not have loosened up a little but the thread lock will ensure they stay in place .

[TJ's Chevy]

The intake bolts loosened a bit on my 305 v6 after I installed fresh gaskets. When the engine was stone cold I retightened and haven't touched them since. Same with the manifolds.

I agree with the thread locker idea for sure.

[GASoline71]

What bolts did you use for the cylinder heads? Reused the stock bolts? ARP? GM?

Gary

[toolboxchev]

Originally Posted by TJ's Chevy

The intake bolts loosened a bit on my 305 v6 after I installed fresh gaskets. When the engine was stone cold I retightened and haven't touched them since. Same with the manifolds.

I agree with the thread locker idea for sure.

X2 on the intake and exhaust manifolds. Not so much on the intake. I have not touched my oil pan or other areas.

Very nice looking engine by the way.

[lil hoodlum]

Originally Posted by GASoline71

What bolts did you use for the cylinder heads? Reused the stock bolts? ARP? GM?

Gary

Hi Gary, to answer your question, the head bolts used were new Felpro ES72856. I had to dig out my receipts to see what was used.

I am curious does it matter what brand of head bolts used as to whether to retorque them?

[lil hoodlum]

Originally Posted by James the III

Stage 8 header locks will stop the header bolts issue..

I do have the stage 8 locking header bolts installed. Have not installed the lock washers and clips at this time.

[Ironangel]

I've had to retighten my aluminum intakes once after a couple of heat cycles and they're good after that. Valve covers, oil pan, and timing cover, get at least two re-snugs after the initial installation torquing procedures. Depending on what gaskets get used the headers will require at least one retightening regardless of what kind of fancy bolts you use. Heres a Nascar trick I picked up off this forum and so far it's proved positive. Wrap your header bolts in teflon tape and "Wallah!" They wont back out until you put a wrench on them! ~Ghostrider~ PS. I've never had to retighten or retorque head bolts and I attribute that to always using new head bolts with this stuff on the threads... http://www.jegs.com/i/Permatex/775/5...FQ-2wAode0UAjA

[homemade87]

Most performance builds will require the head bolts to be re torqued if using a composite gasket after a couple heat cycles . Not so much because of the bolts but because of the gasket gets compressed and seated . Not really needed on a standard build or if using a multi layer steel head gasket . Aluminum heads expands more and if using composite it might be a good idea to re torque . If running a iron head I would not worry about it so much on a standard build .

[lil hoodlum]

I was able to go by the machine shop who did my rebuild today. They said I do not need to re-torque the head bolts because of the gaskets used.

The FelPro one are torque-to-yield? Not really sure what that is all about. So am considering purchasing some ARP head bolts and swapping them out and calling it done.

['63GENIII]

Ive never used a torque to yield on a SBC but then again, Ive never run aluminum heads on a Small Block either. I have used them on an aluminum head Mazda engine and it had to be the weirdest torque procedure ever. Snug bolts in the proper pattern to 16 lbs then go through the pattern twice turning all bolts 90 degrees on each pass. Torque procedure done. I had to really pay attention while torquing that head down.

Now the iron head '97 454 the I just built was also TTY bolts. I had read in a few places that the TTY were not to be reused. My machinist said the could. I took his advice. Torque spec and sequence were the same as earlier Big Blocks. No problems so far. Permatorque gaskets as well.

Far as I know, all LS engines are TTY as well. Not sure what the reasoning is for different bolts for the same applications though. Maybe someone here can explain the uses for TTY vs traditional torqued bolts?