I just ran a torque wrench over my intake manifold, since it has been maybe 200 miles since I put it on, maybe a little more. They were quite loose. What about the head bolts...should I retorque those as well. I tried just one that was easiest to reach, and it didn't move too much when I set the torque wrench on the highest allowable setting (70 ft/lbs). Now that I think about it, I probably should not have done that. Now one bolt is 5 ft/lbs or so tighter than the rest. :16suspect
Retorquing is fine (and expected by moost hot-rodders). I'd suggest using the recommeded sequence and no more than 5Lb/Ft than original torque (but at least as much as you originally torqued them to).
I used a fel-pro gasket on my 250 6 cylinder back in March. Retorqued it in June when I had the engine out of the '74. Haven't touched it since and still running fine 12,500 miles later.
the intake ALWAYS needs retorque... because its aluminum and it will expand and contract more than the heads will.. intake should be torqued initially.. and then about 50-250 miles later... and then rechecked at about 500 miles... i have rechecked head bolts before.. and never had one loosen.. so i usually dont worry about them
Of course, header and exhaust bolts ALWAYS need retorquing after 100 miles or so then every 500-1000 after that (it seems) until theyve seated well.
What I don't understand is why don't brand new cars from the factory ever need the manifolds and stuff retorqued?
todays gaskets Most of todays cars ues gaskets with built in torque stops. Most of their gaskets are the high quality brand....the Cadillac oil pan gasket is reusable just like a lot of trans pan gaskets.
They have been heat cycled already during testing at the factory, so they prolly retorque things a few times. I dont know for sure though. Earl Branham should be able to tell you
I do know that new cars use 'torque to yield' bolts, that do not require retorque. These bolts twist when proper torque is applied, and keep the torque at a constant level, not needed retorqued. Downside is, that they are not reusable.
I have to disagree with that Earl....It is a waste to have to change bolts every time you change the head gasket. Any torque-to-yield bolts as well as other bolts can be checked for distortion.....Simply lay the bolt on a machined straight edge,If you have any gap between the straight edge and bolt....That bolt is weak. A person may have to buy a complete set of TTY bolts to get one,if that's the case...I would change all bolts.
hrd; I am saying what Ford recommends in their overhaul and rebuild manuals. I guess that is because the bolts may be unreliable, and not have the tensile strength they had on the first torquing. The small block head bolts are too small to begin with, and with a good wringing on the first torque, they can be very fragile. I had one break when I replaced the heads on my car, and it was a bear to get out. And as you said, I had to buy a whole set of bolts to get that one. Not a bad thing, as the others were probably just as bad. Great discussion. Take care, Earl
