[tinman386]

I put my oil pan on along with intake and valve covers last fall. I had to take the oil pump back off to repaint it do to moros and their crappy paint job. when i went to take out the bolts they were quite loose almost no effort to take them out. so i went around and double checked everything else while i was at it. they were all loose or atleast needed to be tightened. the bolts i used are ARP's polished stainless bolts. did these bolts stretch and is that why they need tighted? The motor has never been installed yet just sat in storage and the bolts were loose. If its not bolt stretch then what could it be? I dont want to have issues if they come loose again once the motor is in and end up with leaks.

[crash70rs]

Did it have a cork type gasket? If so the gasket may have shrunk in storage.
The bolts should not "creep" (elongating from a load, i.e. being tight) at all. A least I wouldn't think so.

[curtis73]

That's very typical. The oil pan and valve covers are made from wimpy stamped steel so you can't torque them like other bolts. What would happen is the stamped steel would deform and compress the gasket just under the bolt which would cause massive leaks between bolts. The secret to getting them to seal is to just snug them so the stamped steel remains flat and provides unifom pressure along the rail. When the gasket relaxes it often means loose bolts.

[Blazin72]

A bolt will stretch while tightening it. That is what causes the tension to hold the component in place. This is what you are accomplishing when you are torquing a bolt, using a predetermined force (torque) to set bolt stretch (and therefore tension). However, a bolt should not continue to stretch any more once you've stopped torquing it. It should hold its tension. Over torquing, fatigue, vibration, the gasket relaxing or component deformation (both as previously mentioned) could be causes for a bolt to loosen.

[tinman386]

I have edelbrock's aluminum valve covers i know they arent flexing thats why i bought them so i could torque the crap out of them and not pull or stretch the metal. The oil pan is fairly thick and i daw no sign of mushrooming around the holes. so it must be the cork gaskets i used relaxing or shrinking. hopefully they are done doing that now that i torqued the heck out of all the bolts again. even my intake was loose but not the water pump so it must have been a gasket thing. thanks guys that awnsers alot.

[jimfulco]

Cork gaskets shrink, especially early on in their life. I always re-tighten mine after a week or two, then again after a few months. Check them again after a year or so just to be sure.

This assumes the engine is being run fairly regularly. Yours probably did the first weeks worth of shrinking while it was just sitting in storage.

[Vortech 4.3]

Originally Posted by tinman386

I have edelbrock's aluminum valve covers i know they arent flexing thats why i bought them so i could torque the crap out of them and not pull or stretch the metal.

you don't know much about aluminum.

[Ambassador of 'Pane]

I agree it is probably the cork gaskets, but you are also right that SS bolts stretch. They are just fine for things like valve covers and oilpans, I'm using SS screws for just that as well, but stainless steel doesn't have enough carbon in it to be tempered and hardened and are therefore comparable to a grade 2 bolt.