Any complaints about switching to Chevy SB donuts? - Diesel Forum

roots · 08-31-2005, 11:10 AM

Hi All.

I'm getting ready to take apart my up-pipes (again) to plug a bad exhaust leak. After reading some previous posts by those who have made the switch to the Chevy SB exhaust flange gaskets, I am debating whether to switch too. To those who have done it, how has it worked out for you?

I'm planning on removing the downpipe and getting at the bolts from below, using extensions and a swivel joint (i.e. NOT removing the turbo). Any tips/tricks/notes of caution? I still remember how painful this was the lst time...

This job realllly sucks, but I'd rather not cough up the $495 the local dealer quoted to do it.

BTW, if anyone knows of a good diesel machanic in the SE PA/ N DE area, I'd love to hear from you!

wilson61 · 08-31-2005, 01:50 PM

i also like this information for a 99 date of 1-28-98 so it is the early type so what parts do i need it looks like everything for mine is different [img]/ubbthreads/images/graemlins/blush.gif[/img]

golfer · 08-31-2005, 05:32 PM

The SBC donuts will leak too...

Take out your uppipes and take them to a local muffler shop...have them expand the ends of the pipes so that they are back to 2" OD

When the uppipes leak the movement between the pipes and the collector will "etch" the pipes, effectively shrinking their OD.

tip~ install the clamps before they are expanded, otherwise trying to slip the clamps on can be a major PITA.

while you are in there check your manifold to head for leaks; look for sooty areas and if they are suspect, a gasket may be needed there as well.

Uppipe and/or manifold leaks lose as much power as a boost leak on the compressor side of the turbo.

...and yeah...doing uppipe donut R&R sucks [img]/ubbthreads/images/graemlins/tongue.gif[/img]

take care~

Dave

cbuttre835 · 08-31-2005, 05:41 PM

I had what Golfer describes done; it takes a meaty expander as the uppipes are thicker than standard exhaust tubing. your standard wrench type expander won't budge the stuff. We tried a mechanic's grade one (either a Mac or Snap On, that's all the guy uses) and it didn't do squat.

Mine came out kind of 6-sided. but the shop did it for free, took like 30 seconds once I explained what I wanted done.

Still seal up OK, but if they'll let you go back, get them to stretch it a little and then rotate it 1/12 turn and stretch again. ought to come out a little rounder.

clamgulch · 09-01-2005, 02:49 AM

Someone else posted a different suggestion for expanding the pipes and I tried it and it worked perfectly: Use progressively larger sockets in a bench vise that are a snug fit inside the pipe, get out a hammer and start whackin' that eroded area until it expands.
Crude but it worked really well and was perfectly round when I was done with the erosion/scarring only half as deep. It'll do for now.

Also, here is a hint- with the tranny out, the up pipe work is a snap, so if your tranny is going to be coming out at some point, plan ahead and take care of the donuts then. You may have to do them now as well, but do them again with the tranny out and buy yourself a few years of ignoring them. After all, ignorance is bliss...

Fat Diesel · 09-01-2005, 03:49 PM

Has anyone priced the new up pipes from the stealer?

Long0 · 09-02-2005, 01:46 PM

[ QUOTE ]
Has anyone priced the new up pipes from the stealer?

[/ QUOTE ]

I just purchased some a couple weeks ago. $38.00/each - Plan on installing as soon as my truck comes back from the tranny shop

Andy

Fat Diesel · 09-02-2005, 02:23 PM

Cool. Thanks Andy.

Andy in Morgan Hill.