[Chevelle]

Looking for some help on 3512 Cats. I am having a recuring problem on my turbos. A major leak occurs at the outlet side of the turbos around the "slip joint" going into the cast iron exhaust "rams horn" on both turbos. Kind of hard to explain in writing. Anyway, I am looking for anyone that may have knowledge in this area as Cat mechanics have twice failed to make a correct repair. Any one that can help, post up and we will get in touch by phone.

[Jorge Lang]

Has this been a consistant problem? There a number of factors that can cause this. Excessive back pressure, mating flanges that are not true, exhaust overhead supports that are too rigid, etc. Let me know I would be happy to assist you.

[K1W1]

Hi,

I have extensive experience with this exact problem.

Cat used to use a stainless steel bellows and 4 half flanges to connect each turbo outlet to the pot in the middle, they went away from this in the mid 1990's, replacing this with two fixed rings and a centre piece with rings on each end not totally dissimilar to Piston Rings. These all leaked like sieves no matter if they are in boats or trucks.

I have retro fitted the bellows off the D 398 to a set of engines to cure this and have had custom made ones to remedy it on another pair of engines where the housings were a different size to the 398's

Cat have now gone back to using the bellows type arrangement on the Series 2 engines I am using now.

If you send me a PM with your e mail addy I will give you the name of the guy I deal with at Pantropic in Ft Lauderdale who helped me out with the parts in the past.

I don't have a drawing of your setup but I could draw one from memory if you wanted to see the difference.

Here is the page out of the parts book showing the current setup.

[Ken Bracewell]

K1W1,
Thanks for the reply. When Tyler told me that he was going to post this problem on the Forums I was sure that he'd find someone with some expertise!
Best,
Ken