intake manifold bolt torque question

[pjc360]

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.

 

[RustyRatRod]

Wont hurt a thing. I think 12 is a little light. I believe you were right on, IMO.

 

[70aarcuda]

if it is a aluminum intake...you need to check it ever once in awhile anyway...as they have a habit of loosening up...

 

[txstang84]

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

 

[bOb shingler]

I think you screwed up when you loosen them up. the gasket is no longer compressed.

 

[FrostyMopar]

I just do them up til they're tight....this is bad isn't it?

 

[1968FormulaS340]

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.

 

[TrailBeast]

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.

 

[RustyRatRod]

I think you screwed up when you loosen them up. the gasket is no longer compressed.

This ^^^^^^^

 

[RustyRatRod]

I just do them up til they're tight....this is bad isn't it?

I found out the hard way when I just recently did some head work on my Ranger.

 

[blewbyoutobad]

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.

 

[txstang84]

LA vs. Magnum-different bolts, different arrangement, different torque spec.

 

[pjc360]

so 20 ft lbs is ok and not too tight?

 

[pjc360]

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.

 

[TrailBeast]

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.

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.

 

[pjc360]

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.