Heat riser question

[Jim Yergin]

The exhaust on my car started to make more noise. I discovered that the heat riser shaft was lose and, after pulling the manifolds, I could see that the heat riser plate was off the shaft because the screws holding it on had sheered off. The shaft had pulled out of the rear hole in the manifold and that was where the exhaust noise was coming from. I was also missing the rear side bushing in the manifold. This was a replacement heat riser I had installed last year. I drilled out and retapped the screw holes in the shaft, installed a bushing, and reattached the plate. I then followed the advice on the heat riser section of the tech portion on this site and spot welded the plate to the shaft. My question is, what caused the screws to sheer off?

My other question is probably a dumb one but does anyone have any tips on reattaching the exhaust pipe to the manifold. I cannot get it back on tightly and it leaks. I replaced the gasket and losened the entire system from the frame all the way back to the tailpipe to give me some flexibility in fitting it to the manifold but it just won't pull up tightly.

Thanks.

Jim Yergin

[oldmopar]

No real idea on the screws maybe because the bushing was loose the flapper valve was bounced around and that damaged the screws. As to the exhaust have you tried 2 gaskets

[Normspeed]

Jim, do you think the flange plate on the exhaust pipe may be warped? I had one like that, kept burning out gaskets. Finally a few months ago I made up a short piece of pipe to slip inside where the pipe bolts to the manifold. I made it a tight fit using a tailpipe expander, put in a fresh gasket using the Permatex red high temp gasket sealer and it has not leaked since.

[Rodney Bullock]

Jim, my flange is warped so I used the dounut shaped packing crush gasket. I fits in the exhast flange and you tighten the bolts, this action crushes the packing between the to flanges and seals everything. My heat riser did the same thing. It started to back out all I did was push it back in, this is some threads ago. I never had a problem with it since, It's funny though when that thing comes out it makes an awful noise. What makes the little screws shear:confused: no idea however it does happen.

[Jim Yergin]

Norm and Rodney,

Thanks for the suggestions. I was thinking of taking Rodney's approach. Rodney do you remember what size ring you used?

Jim Yergin

[Rodney Bullock]

Your right Jim there are a couple of sizes, I don't know the one I used however when you go to purchase it You will be able to eye ball it.

[Jim Yergin]

Rodney, I followed your suggestion and got a donut exhaust gasket. It appears to be working. Nice to have the car running quieter again. Been sunny and fairly warm here the past couple of days and have been driving the car to work.

Jim Yergin