Reinstalling intake manifold

I have a volvo 740 GLE 16 Valve. I had to take the intake manifold of
to take out and replace the oil trap. I do not know how tight the bolts
on the manifold need to be. I do not have a tourque wrench. I tigtened
it up intell it felt tight. I do not think I have any leaks. Although
how tight does it need to be? How do I know if I made it too tight? Do
I have to worry about empansion of the intake? For example, if it is
too tight and the intake expands will it crack?

 

That is what I'd worry about. I think it is more of a problem with exhaust
manifolds, but the difference in expansion between the aluminum head and
iron manifold has caused a lot of broken manifold studs. I don't know the
torque for the B230F, but the Haynes manual says 7-11 ft-lbs for the B28 V6
engine. That is a very low torque.

Mike

 

You need to get a torque wrench to make certain you have the head
tightened correctly. To get the specs, you need a manual. You should
be able to get both at a chain auto parts store for under $25 total.
Have someone drive you to one.

Incidentally, some heads have a specific sequence that the bolts must
be tightened in. You should loosen all the bolts until there's no
tension on them, then tighten to the specified torque in the specified
order (if there is one).


Gary

 

I think the general sequence for tightening bolts is to tighten the
center two bolts opposite each other and then go outward, top and
bottom. Do not put the final torque on the bolts until they are all
snugged in first.

 

IIRC the 8 valve specs 15 lb-ft torque on the intake bolts. Some of them
are tricky to get a torque wrench on though so I just use a standard
wrench and estimate, snug but not so tight as to strip out the soft
aluminum.