Welding Collectors?

[Peter Olliviere]

I have been working on a problem with the header pipes on my RF exhaust system. The pipes keep leaking at the entrance to the collectors. I have removed them, plasma coated them and used high temp sealer but I still get some leakage at the joint. My question is, if I weld the pipes to the collectors can the headers still be removed as a unit? The other side of the same question is what have others done about this problem?

Peter

 

[Mike Dozier]

Peter

You might get away welding a couple of the pipes....
but no chance of welding them all and getting them back on the car.

Do the collectors have tightening tabs or just a slip fit?

MikeD

 

[Peter Olliviere]

Mike,

Thanks for the input. The pipes only have one tab per collector and that tabdoes not pull the pipes togeather it just serves to keep them togeather. I have a couple of pictures that I need to resize before posting so that the problem can be seen clearly.

My other throught is to weld new tabs on that allow me to pull the pipes into the collectors with some tension on them.

The welding idea came from viewing other pipes that seem to have been welded.

Peter

 

[Paul Thompson 'Hooligan']

Hi Peter

I have no experience with RF, but have taken a GTD exhaust off without splitting the system down. Roy has a crossover system and hates assembling it, especially if it had been sealed well with no leaks, so, we have on occasion removed it complete.

We have to remove all exhaust mounting bolts and silencer support mounts. Remove both rocker covers. (might get away with one).

Then, by lowering and moving toward the block on one side, the other can be 'sprung' slightly to allow it past the head with no rocker cover fitted. You need two people and need to be careful not to clout the rocker gear during the process.

Actually - thinking about it again.... As I recall Roy's TFS heads have 1/4" adapters permanently fitted to the exhaust ports, that are in turn drilled and tapped with a slightly wider bolt pattern. These enable the large exhaust ports to not be compromised by the narrower standard header bolt arrangement and also save the alloy heads from repeated bolt removal as the adapter plates are steel.
It might be the extra 2 x 1/4"that makes this possible on Roys......

Also - noticed that your collector inlet has a large'ish inlet diameter, giving rise to a gap. Do you use jointing paste? - as with most of these deisgns, if they are blowing, they also probably draw in some fresh air during the normal cycles and that in turn could affect your Lambda measurements / fuelling...

Just a thought. (nice finish on the pipes..!)

 

[Mark Clapp]

Harbor Freight Tools has an inexpensive exhaust expander tool that I've seen advertised for around $8-10 and comes in three sizes. It is actuated with a regular wrench. You could use it to slightly expand the header so a tighter fit is acheived. Just go to harborfreight.com and put expander in the search box to see them. Also NAPA sells an exhaust sealer called Acoustic made for this application.

 

[Jac Mac]

Peter ,
Had a similar problem with a race car that developed a backfire on overun due to a leak in that area. Made a mandrel out of 2" bar stock with one end turned down to the ID of the primary pipe for approx 1.25". Where this turned area ends machine a smaller dia approx 1/4" long x 1/8" smaller than the primary pipe ID.The turned area to suit the PP ID will now be 1.00" long. Now wobble this to expand each primary pipe until it is a slip fit in its respective collector ( GO EASY, IT DOES NOT TAKE MUCH )

Jac Mac

 

[Peter Olliviere]

Thanks for the input from all those that responded, I think I have a solution. I intend to get the right size expander and increase the size of the pipe slightly. I will then coat the inside of the collector with WURTH EXHAUST ASSAMBLY PASTE before inserting the pipes. It seem that this stuff was designed to seal slip joint in exhaust systems and will harden and completely seal the pipe under engine heat.

Peter

 

[Big_Si]

Another option that I've seen used here in the uk is to weld tabs on to either side of the point and use stiff springs to hold it all in place and seal. Kind of like the systems you see on some bike exhausts.