Warped exhaust manifolds

[DanAR]

I’m sure if I guy went through the old threads enough I could find the answer to this but the threads seem voluminous. Cast iron exhaust manifolds have always been subject to warping as long as I can remember. I got an exhaust tic from one in my first car, a 64 Sport Fury in the late 60s. A lot of the time it was due to manifold bolts loosening and backing out - sometimes simply retorquing the bolts would take care of it. If not then, matching the manifold, adding a gasket (most manufacturers did not use them) or some red, high temp RTV solved the issue. But I keep reading about seized and broken bolts when I read threads on the RAM bout warped manifolds. That’s new to me. If a bolt breaks and clamping force is lost on a portion of the manifold I can understand the manifold warping. But why are the bolts breaking. Are they just plain using weak bolts? Over- torquing during assembly? What’s going on here?

 

[danielmid]

Are they just plain using weak bolts?

Yes on purpose

Over- torquing during assembly?

No

What’s going on here?

Manifold flanges are thick cast, heads are aluminum. Manifolds hold heat and warp. Bolts are the fuses in the system and snap before pulling threads out of the heads making things much much worse.

 

[Wild one]

Yes on purpose

No

Manifold flanges are thick cast, heads are aluminum. Manifolds hold heat and warp. Bolts are the fuses in the system and snap before pulling threads out of the heads making things much much worse.

Even when heads were cast iron,manifolds gave static. My Dad used to braze up FE Ford manifolds in the late 60's/early 70's as they were prone to cracking/breaking,and 352/360/390 FE Ford F100/150's were the predominant truck in our local farm community back then

 

[DanAR]

Do they use gaskets on the manifolds or are they mounted bare to the heads?

 

[danielmid]

Do they use gaskets on the manifolds or are they mounted bare to the heads?

Yes they use manifold gaskets. They're okay as far as OEM go, even come with a small heat shield for the lines running over the vale covers.

 

[Mb7640]

Do all rams have this issue? Im at 45k had since 10 miles and I do not have this issue as of yet. Should I just replace with shorty headers now?

 

[DanAR]

No, I’m sure the incidence of broken bolts is a fairly small percentage and like any auto forum, things get magnified out of proportion to real world experiences. But it apparently isn’t a rare event either. I’m just trying to better understand the mechanics of what causes it. I’m surprised RAM/Dodge didn’t just change over to Heli-coiling all the exhaust bolt holes in the heads and go up 1/16” larger in diameter with higher strength bolts. It’s not an uncommon thing in the aftermarket world. RAM seems to take its long, sweet time in initiating fixes to repetitive and aggravating issues Like rear window leaks, delaminating leather dashes and the hemi tic.

 

[Mb7640]

No, I’m sure the incidence of broken bolts is a fairly small percentage and like any auto forum, things get magnified out of proportion to real world experiences. But it apparently isn’t a rare event either. I’m just trying to better understand the mechanics of what causes it. I’m surprised RAM/Dodge didn’t just change over to Heli-coiling all the exhaust bolt holes in the heads and go up 1/16” larger in diameter with higher strength bolts. It’s not an uncommon thing in the aftermarket world. RAM seems to take its long, sweet time in initiating fixes to repetitive and aggravating issues Like rear window leaks, delaminating leather dashes and the hemi tic.

I understand maybe when I go get my oil changed next week I will ask the dealer how many of these they see and go from there

 

[Allamand]

2012 Ram Hemi with just over 100k, add me to the list of broken manifold bolts.. good times

 

[EdGs]

2012 Ram Hemi with just over 100k, add me to the list of broken manifold bolts.. good times

Welcome to the BEMBC! Lots of members in this club......lol