engine and drivetrain Welding header to center res...thoughts and opinions wanted

[vintage_car]

I'm getting a new header...finally. The header doesn't have a 3 bolt flange to bolt up to my existing center resonator. It has a slip fit jacket that has to welded onto the center res. I know my muffler shop can weld up a 3 bolt flange no problem, but I was told that the bolting the header to the center res. created more stress on the header and potential leaks? I was also told to have the header welded to a rigid bracket on the transmission, making the engine, tranny and header all one piece and letting the exhasut take the flex of the engine. Is all this true and the wa it needs to be done? My current header doesn't have any sort of bracket between the tranny and the header, so where do I tell the muffler shop to put this bracket? The other issue I have is if I need to pull the engine, or drop the tranny it makes it nearly impossible since the header is now welded to the center res. Am I missing something? What are your thoughts on this?

[jerry]

by rigidly attaching your header to the transmission you are merely moving the likely crack initiation site further down the exhaust pipe. you won't entirely eliminate the resonance that the exhaust tube will experience. i would opt for ease of disassembly first. ideally, you want to dampen or attenuate vibration, not merely relocate it (which is what hard connections do). using rubber mounts is one method to attenuate the vibration. i'd opt for the welded on flange or alternatively, don't weld the slip fit but merely clamp it together using a hightemp material as a gasket.

disclaimer: these are my observations/recommedations based on doing many failure investigations on tubing on aeroengines.

[Steve73tii]

From a little recent experience with the stock setup and the faq / CCA tech tips, my guess would be you probably want a stock-like connection to the gearbox.

There is a short bracket bolted to the back of the trannie then a separate ~8-10" bracket attached to that through 2 rubber shock mounts. The downpipe or header is attached to the long bracket with a U-bolt. For a larger diameter header, it would be fairly easy to modify the longer bracket or fab a new one and use a bigger U-bolt.

Also, I don't know if it's possible to flare the end of your header or weld on a flange, but being able to detach the exhaust at the transmission is a huge help in accessing the driveshaft/guibo and shift linkage.

Just my $.02.

Steve

[merlin]

I say you need to keep a bolt up flange there, as you work on the car from time to time you need to remove the exaust. Also if you were to hang the center res or another part of the exaust on the ground you want it to break at a good spot. I would run a sopport bracket off the trans like stock and not worry about it. The muffler shop should beable to flair the end of the exaust like the stock unit. Just bring them an old flange to use.

Sam Schultz

LaValle's Import Restorations

[colorobo2002]

but I was told that the bolting the header to the center res. created more stress on the header and potential leaks?

I think that headers end up cracking because when swapping in a header, people don't put the support bracket on rear of the tranny. THAT is what causes the fracturing. Sometimes one may need to alter the support bracket to fit the exhaust, but it's worth the trouble.

I had a welded up header on my car and absolutely HATED it. As well as a few '02s I'd worked on. A friend had a header w/ no rear support and kept welding the fracture like it was routine maintenance on his car. It's such a pain to get in there and do repairs w/ a welded up exhaust/center resonator. If I were you, I'd get the rear support, all the hardware and the flange, bring it to the muffler shop and get them to make the system work as close to a stock layout as possible. Either install it on your system as best you can right now, or give the shop pictures from realoem.com or copied from the factory manual. Even if it's more trouble/cost now to get the system put together this way, it's worth it. The next time you have to remove your quibo, or shifter components, or tranny, or centerbearing, or replace tranny seals you'll be glad you did.

disclaimer: these are my observations/recommedations based on doing many un-scientific investigations on welded up headers and stock configurations on 2002s.

[DukeRimmer]

Mine has two e21 flare joints welded in, no cutting needed for complete removal of entire exhaust.

Disclaimer; this driver cares not one whit about performance. It's an econo-car. Solex one barrels rule!

[BigDog]

From the header, have a collector bolted on so that you can still separate the exhaust system at the back of the header.

Next peice should be one of those flexible stainless wire mesh do-dads in the size that's appropriate for you (I use 2.5" personally). This will allow vibration from the motor to not shake your teeth out as you drive down the road.

Good luck!

-------------

BigDog

'76 2002 Ireland Header + Custom 2.5"/2.25" by Exhaust Specialties Racecraft

[Delia]

I'm no expert, but I seem to recall where someone was using a larger diameter, flexible, spring and ball-type connector from an early 80s VW Rabbit GTI mounted between the header and the center resonator.

Otherwise, the header should be fixed to the transmission using a factory bracket. As I recall, on the stock setup, there is a brass or copper ring gasket that helps manage the flex and/aligment/exhaust leak difficulties between the "Y" pipe and the center resonator.

I'm not a fan of headers for the street, but I'm from Michigan and they always rust through somewhere at the collector...

Delia