intake manifold bolt torque question

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pjc360

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I have a 300hp crate 360 magnum engine and i'm running a dual plane edelbrock rpm air-gap intake manifold on. I had my intake manifold bolts torqued to 20 ft lbs. I just found out that the spec is 12 ft lbs.
I have been running this intake torqued to 20 ft lbs for about 6 months or so, but I hardly drive the truck the motor is in. Maybe have put 3000 miles on it in that 6 months. I hope I didn't hurt the engine. Tonight I loosend all the intake manifold bolts and tommarrow I will torque them to 12 ft lbs.
Anybody know if 20 ft lbs could cause major damage? I don't have any oil in my coolant or coolant in my oil.
 
Wont hurt a thing. I think 12 is a little light. I believe you were right on, IMO.
 
if it is a aluminum intake...you need to check it ever once in awhile anyway...as they have a habit of loosening up...
 
12? Really?

I didn't realize it was that low. I think I ran the ones on my 5.2 to 18...and cuda is right...the vertical bolt arrangement is known for loosening up...just like small block Fords
 
20 was fine and being that they were at 20, you should re-torque them to 20.

I agree with bOb shingler (post #5). Putting them to 12 now is asking for problems.
 
When I read the OP post I was going to add that you didn't have coolant in the oil, but probably will now.
I see that got covered already. :)
 
Here's a torque chart from Moparts that says 35ft lbs. I tried it on my last build this summer and at about 30ft lbs I could feel one bolt start to loose the treads. They were not grade 5 which was the issue. I would say with an aluminum intake 25 to 30 should be good but make sure you have good fasteners.
 

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I have not ran the engine since loosening the intake manifold bolts. If I torque them back to 20 ft lbs I should be good to go then right? I have tons of intake manifold gasket sets laying around fel-pro, bought them up when I worked at a parts store and got 30 percent off. I could easily change the gasket again, but since I have not ran the engine since loosening the bolts I was thinking it would be ok if I torqued it back to 20 ft lbs.
 
pjc360 said:
I have not ran the engine since loosening the intake manifold bolts. If I torque them back to 20 ft lbs I should be good to go then right? I have tons of intake manifold gasket sets laying around fel-pro, bought them up when I worked at a parts store and got 30 percent off. I could easily change the gasket again, but since I have not ran the engine since loosening the bolts I was thinking it would be ok if I torqued it back to 20 ft lbs.
Click to expand...

One would hope, but I don't think anyone wants to be the one that say's it'll be fine and then be wrong.

Personally, I would give it a go with retightening and watch it close for awhile.
 
20 ft lbs of torque just doesn't seem like all that much too me. I torqued them to 12 ft lbs of torque, then went and torqued them to 20 ft lbs, 20 ft lbs of torque from 12 ft lbs is only 3 more small pulls on my torque wrench. When I change the intake manifold gasket in the future I will torque them to 15 ft lbs. and call it good there.
 
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