Check your intake manifold bolts

[HEMIMANN]

When she starts to sputter @ idle, it's time. Still haven't reached the point where the screw gaskets have compression-set solid. It has to occur sometime. Then I guess it's a new manifold, unless there's some aftermarket o-ring you can glue on.

@wildone

 

[Wild one]

When she starts to sputter @ idle, it's time. Still haven't reached the point where the screw gaskets have compression-set solid. It has to occur sometime. Then I guess it's a new manifold, unless there's some aftermarket o-ring you can glue on.

@wildone

New Mopar gaskets are expensive,so i've been using the Felpro's instead,and so far they don't seem to be to bad,but they still need the occasional retorque too

 

[HEMIMANN]

New Mopar gaskets are expensive,so i've been using the Felpro's instead,and so far they don't seem to be to bad,but they still need the occasional retorque too

Rick, isn't it the screw gasket that is compressing?

 

[Wild one]

Rick, isn't it the screw gasket that is compressing?

There's no gasket on the bolts Brian,they use a self contained steel washer,so that leaves the manifold o-rings and the manifold itself as the only things to be compressable

 

[RedSRT4Me]

I just had to tighten my 6.4 manifold as that pita 219b popped out of nowhere

 

[HEMIMANN]

There's no gasket on the bolts Brian,they use a self contained steel washer,so that leaves the manifold o-rings and the manifold itself as the only things to be compressable

Ok - when you replaced was it because you couldn't tighten the screw enough to seal the intake gaskets any longer?

 

[Wild one]

Ok - when you replaced was it because you couldn't tighten the screw enough to seal the intake gaskets any longer?

If the manifold has some heat cycles on it,i usually install new o-rings,as the ones around the oil fill tube and pcv tube usually go hard. The actual intake o-rings will stay semi pliable,and could be re-used,but i figure if i'm changing the 2 around the pcv and oil fill i might as well replace them all

 

[grizzstang]

Retorqued mine on Saturday.

All about a half turn loose or so.

It was running great so no noticeable difference I can feel.

 

[HEMIMANN]

Retorqued mine on Saturday.

All about a half turn loose or so.

It was running great so no noticeable difference I can feel.

Even at idle? That's where a lean A/F ration is really noticeble. Mine sputters and stumbles.

Btw, my son's theory is the plastic intake manifold is dishing out (deforming) under the screw heads.

 

[Wild one]

Even at idle? That's where a lean A/F ration is really noticeble. Mine sputters and stumbles.

Btw, my son's theory is the plastic intake manifold is dishing out (deforming) under the screw heads.

That's always been my theory as the intake is the only thing in the equation that can actually change shape.At only 9 ft-lbs i highly doubt the bolts are stretching,and the aluminium heads definitely aren't changing shape at that torque spec

 

[mdc1990zr1]

That's always been my theory as the intake is the only thing in the equation that can actually change shape.At only 9 ft-lbs i highly doubt the bolts are stretching,and the aluminium heads definitely aren't changing shape at that torque spec

I wonder if someone could machine a bar that would go under the intake bolts to help stop the deformation and spread the load. Kinda like the way Chevrolet did on the old time valve cover bolts.

 

[Wild one]

I wonder if someone could machine a bar that would go under the intake bolts to help stop the deformation and spread the load. Kinda like the way Chevrolet did on the old time valve cover bolts.

I've kicked that idea around for awhile now,but i don't have access to a mill,so it's only been an idea so far

 

[HEMIMANN]

Yeah I thought about using hardened washers to more equally distribute clamp load under the screw head. Screw heads deflect a fair amount and promote unequal load onto the substrate.

 

[grizzstang]

Even at idle? That's where a lean A/F ration is really noticeble. Mine sputters and stumbles.

Btw, my son's theory is the plastic intake manifold is dishing out (deforming) under the screw heads.

Even at idle. I changed the oil early March and ran it with the hood open and it was smooth.

I ran it again after I retorqued the intake on Saturday and I didn't notice any difference.

I haven't driven it yet so maybe I will notice it more then.


I wish someone would have stepped up and made an aluminium intake for the Hemi but the only ones I have seen so far require a Supercharger, which would be nice, but pretty expensive.

 

[Wild one]

Even at idle. I changed the oil early March and ran it with the hood open and it was smooth.

I ran it again after I retorqued the intake on Saturday and I didn't notice any difference.

I haven't driven it yet so maybe I will notice it more then.


I wish someone would have stepped up and made an aluminium intake for the Hemi but the only ones I have seen so far require a Supercharger, which would be nice, but pretty expensive.

The early 6.1's had an aluminium intake manifold

 

[Grams]

Not a MoPar Hemi…. but a similar problem existed on an irrigation pump engine we had…the plastic manifold held down by metal bolts would slowly loosen up and start leaking about every other month.

The Fix was created by the DEI hire we had: Install a spring-washer on top of a flat washer. It never did it again.

 

[mdc1990zr1]

I thought someone did make an aluminum one but it was pricey

Not a MoPar Hemi…. but a similar problem existed on an irrigation pump engine we had…the plastic manifold held down by metal bolts would slowly loosen up and start leaking about every other month.

The Fix was created by the DEI hire we had: Install a spring-washer on top of a flat washer. It never did it again.

that is my feeling on the exhaust manifold bolts. I always thought that if you could put a spring between the nut on the bolt and the heat shield, it would allow the bolt to stretch and cool without being confined by the heat shield securely/tightly fastened by the outermost bolt. Or just taking the heat shield off all together should prevent the bolts from snapping. Just my theory.

 

[04fxdwgi]

Them cheezy shields aren't what is causing the bolts to snap. It's the manifolds warping and due to the short length of the bolt protruding from the head, limiting most of stretch and flex, they snap.

That is why resurfacing the OEM manifolds, after they warp, will also stop the bolts from snapping because they won't warp again.

 

[Grams]

That’s a repair I’m facing. The other day a visitor (who used to own one of these hemi’s) …drew my attention to outside the truck …at the rt wheel…immediately after a cold-start.
CLICK….CLICK…CLIck…CLick…Click…click…click…. cli.. …..

“Hey! You gotta exhaust-manifold leak… Probably broken bolts! That’s what My old Hemi did Too! It happens all the time to Hemis…”, he said.

I’ve got it scheduled into the shop …who also confirmed they usually belt-sand or machine the manifold before re-installation for the fix. They’ll do the work while I’m an a camping trip next month. (Using the 2500 to pull the RV to Utah and back)

 

[inuyasha-rules]

Not a MoPar Hemi…. but a similar problem existed on an irrigation pump engine we had…the plastic manifold held down by metal bolts would slowly loosen up and start leaking about every other month.

The Fix was created by the DEI hire we had: Install a spring-washer on top of a flat washer. It never did it again.

Had to do the same thing to my brothers Buick. Original plastic intake warped and was leaking coolant, 1st replacement one of the bolt holes cracked on the second round of torque (can't remember the numbers, but it was progressively higher each pass) so the second replacement I put a washer and spring washer under each bolt.