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8v92 exhaust system
Hi Guys,
Its time for new exhaust pipes on the old 8v. I have the old pipes off (5 inch turbo to muffler and 2-3 inch from manifolds to turbo wye). I have decided to have a local custom exhaust shop fabricate them. In looking at google images of 8v92’s as well as my own system it seems all of them have a flexible bellows on the 3 inch to the turbo wye on the left side only. The right side is rigid with no bellows. Is there a reason for this? Is there any reason a bellows could not be installed on the right as well? Thanks for any insight into this.
Jeff
Jeff and Lindsay
91 Marathon XL -
72 Replies
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Jeff, I’ve heard that these parts are very difficult to find. I assume that’s why you’re looking at having them made. Sorry I can’t help with your question, but I hope you’ll follow up with us if you have some made. Mine aren’t leaking yet, but look pretty gnarly. It’s definitely on my radar.
Jeff and Lindsay
91 Marathon XL -
Chad,
I have had no luck finding the parts through regular parts suppliers or aftermarket sources. My next step was to contact Prevost or Detroit. I just decided that it would be easier to have them fabricated. My original plan was to have them made out of 304 stainless but in my research i found that it would not be practical. The tubing was no issue but the 5 Detroit flanges are not available off the shelf in stainless. The 5 inch turbo flange would have to be turned out of stainless billet. I didnt even get to what it would take to fabricate the wye to manifold flanges. (Looks like flares but probably Detroit spec dimension.)
It was challenging finding the correct components but i have them all now. My next step is to build plywood jigs off of the old assemblies so there are no fitment issues. I will post with photos and part numbers when its complete along with rough costs. If you think you would like to do the same thing we can compare dimensions and if the same i can take my jigs back to my guy and have him fab the pipes for you. Jeff
Jeff and Lindsay
91 Marathon XL -
I forgot to mention, when the exhaust guy looked at the old pipes he said that they were not aluminized. Something about inside out or outside in corrosion. He suggested that aluminized would be a huge improvement in longevity and that stainless may not be worth the additional cost and effort. I read a very old post on another forum by Jon stating 10 years on the 8v pipes. Are the Detroit or Prevost pipe assemblies aluminized? Im guessing no from findings.
2005 XL Thompson Coach
Rarely tow anything behind us.
Sold: 1993 Liberty that we loved for 12 years. -
For heavy duty exhaust contact this company, employee owned and the leader in custom wet and dry exhaust.
This is fairly easy to remake when you have the old still available.
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Thanks Al. I should have spoken up sooner. They probably would have been able to get the proper parts in one shot. I thought i was taking the easy path! Wrong again.
2005 XL Thompson Coach
Rarely tow anything behind us.
Sold: 1993 Liberty that we loved for 12 years. -
Jeff what did you do with your exhaust system? My Muffler is in need of replacement.
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The time has come to do a little work to my exhaust system. Exhaust manifolds, pipes, muffler, exhaust manifold gaskets, nuts, clamps etc etc. I have a couple pretty bad exhaust leaks where the manifold bolts to the head which should give me more boost if i can seal everything up correctly. I was going to wait until after the January Bus Rally in Quartzsite, but what the hey, let’s do it now.
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Today i got almost everything out except the exhaust manifolds, and the Y pipes and adapter. Going to clean, rebuild, and paint before i reinstall. The muffler was heavily rusted and not connected the the Bellows pipe. You can see the muffler flange up inside the bellows pipe.
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Darn Mike
That looks like way to much fun. NOT
Chuck
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Thanks Chuck, I am taking my time, especially witht he exhaust manifolds. I have been soaking the nuts with penetrating oil for a week or so. I have a couple pretty bad exhaust leaks, the gasket is completely missing in some areas.
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Mike, do yourself a favor and have new exhaust manifold studs, nuts on hand. Also high temp sealant. I may be wrong, but I seem to recall if you back one out (or break one and have to extract it) coolant will follow. I think I drained some coolant down first. In putting on new gaskets we found a cracked manifold (actually broken) that had to be replaced. We have functioning pyrometers on each side and they are inserted into taped ports into the manifolds. While you have your muffler out look over your radiator very closely especially in the lower corners. We did and found serious deterioration, and had to replace ours. I was told the pipe leading to the muffler is flex pipe because of the flexing movement of the engine under load. Not sure if that is true. Good luck.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Good info John, Thank You. I am guessing the studs are going to come out due to the heavy rust on the nuts and studs. I have spare studs and Nuts ready but no sealant, do you know what sealant is recommended? Is there a torque spec for the studs? Hard to locate info like this from Detroit. I am prepared to check for cracks and flatness on the exhaust manifolds also. I can resurface them if needed.
Here is where I bought the studs, nuts, gaskets
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Mike if nuts or studs give any problems try a can of freeze off works well ,and good luck
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Good idea, Thank you. I am going to wait until Saturday to attempt the Exhaust Manifold removal, meanwhile after work this week i can keep cleaning.
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The best penetrating solution are
1. 50/50 acetone- dextron
2. Kroil
3. P B Blaster
Might be worth considering
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