C2 small block oil pan bolt torque

[Gary B.]

inches


Gary

[Leif A.]

Re: C2 small block oil pan bolt torque

80 in/lb is the correct torque spec for oil pan bolts.

[Gary B.]

Re: C2 small block oil pan bolt torque

Maybe the question I really should have asked is, is bolt torque of a gasketed junction independent of gasket stiffness and/or thickness?

Gary

[Joe L.]

Re: C2 small block oil pan bolt torque

Maybe the question I really should have asked is, is bolt torque of a gasketed junction independent of gasket stiffness and/or thickness?

Gary

Gary------


Check the Mahle gasket package for installation instructions. It may specify a different torque than OE specs. As I recall, the Fel-Pro one piece gasket does so. If an other-than-OEM torque is specified, use that.

By the way, later GM small blocks used a one piece oil pan gasket that is similar to the Mahle and Fel-Pro one piece gaskets for earlier small blocks. The GM torque spec for those gaskets is 200 lb/inches for the corner bolts and 100 lb/inches for the remaining bolts. However, those later applications also used full length oil pan rail reinforcements.

As far as deformation of the oil pan rail surface at the bolt holes goes, that's going to occur regardless unless the full-length rail reinforcements are used. The later small block reinforcements won't work on pre-1980 small blocks due to the change of the dipstick tube location. However, suitable reinforcements for pre-1980 small blocks might be available in the aftermarket. Of course, the use of such reinforcements would significantly deviate from originality.

[Bill B.]

Re: C2 small block oil pan bolt torque

Gary,

I had just purchased the Fel-Pro OS 34509 T one-piece blue neoprene oil pan gasket set (came with longer bolts & star locks supplied) for my 1970 small block. The tightening torque for the smaller 1/4" x 20 rail bolts were 8 ft. lbs (10.7 Nm) and for the 4 larger 5/16" x 18 end bolts, 18 ft.lbs (24.3 Nm).

As I recall, the gasket had metal eyelets at each bolt hole, (Fel-Pro calls then "torque limiters") so the tightening torque specs were unique to this particular gasket design, as Joe L. had stated above.

I did not notice any visual deformation of the pan rails, perhaps owing to the metal eyelets, but was difficult to visually discern.

[Gary B.]

[Gary B.]

Re: C2 small block oil pan bolt torque

I just got off the phone with Mahle technical support and they said to use the GM bolt torque values. Also, although some Mahle oil pan gaskets have compression limiters at the bolt holes, like the Fel-Pro gasket that Bill mentioned, the Mahle one-piece OS32458 gasket that I used does not.

Gary