slip fit on header pipes

[t walgamuth]

I have noticed folks using some sort of sealant on slip joints in the exhaust system. How important is this and what can happen if not sealed, please?

[olddog]

If not sealed, it will leak exhaust gasses that will get in the passenger compartment and make your clothes stink of exhaust. It is possible to become ill and even pass out if the gasses get thick enough, which is not likely with the open cockpit. However I wouldn't bet that it is impossible, if the wind and speed were just right.

Having dealt with this, it is my opinion the builders who sell this should be shot. Do yourself a favor and weld flange plates on your pipes. Make gaskets out of soft aluminum.

Yes I tried copper RTD and several other things suggested. They were temporary fixes at best. Some may fit tight enough to seal, as there are people who claim they got them sealed up. I had no such luck.

[t walgamuth]

Thanks Olddog!

I was wondering it it might affect performance...?

[kevins2]

Tom,

This is what ERA recommends:

https://www.amazon.com/Walker-35959-.../dp/B000CQDL94

If you use it, wear disposable latex gloves because it is a tar-like substance. It cleans up easily with mineral spirits. When I last used it, I looked on-line for information on how long to let it set up before starting the car but didn't find anything so I let it cure for a couple of days. When you first start the car, it will smoke a lot but that dissipates quickly.

I agree with Olddog - actually, not that they should be shot, but I think his point is that slip fits are a pain in the ass and are troublesome.

Kevin

[t walgamuth]

Thanks Kevin!

[olddog]

Originally Posted by t walgamuth

Thanks Olddog!

I was wondering if it might affect performance...?

If you are running fuel injection, and your O2 is before but close to this joint, or if the O2 is down stream of this joint, then any air getting sucked in will make the O2 read lean. This would happen on deceleration, for sure. If enough air was sucked in it would cause popping in the exhaust. Mine did.

As for "being shot," that is for shock affects only. I wouldn't actually sign the papers if I were King.

[t walgamuth]

Originally Posted by olddog

If you are running fuel injection, and your O2 is before but close to this joint, or if the O2 is down stream of this joint, then any air getting sucked in will make the O2 read lean. This would happen on deceleration, for sure. If enough air was sucked in it would cause popping in the exhaust. Mine did.

As for "being shot," that is for shock affects only. I wouldn't actually sign the papers if I were King.

Yeah, my o2 sensor is about 2' down from the four slip joints and I do occasionally get popping in the exhaust. It also seems to run rich until very warm.

I don't see how a flange can be mounted on mine as the four slip joints are all up against each other. That guy who did my roll bar could probably do it though....his welding is a thing of art.

[hauss]

The motorcycle world has a lot of good solutions for slip fits with no leaks . Do not shoot the MFGS.Guide them in the right direction.

[t walgamuth]

Originally Posted by hauss

The motorcycle world has a lot of good solutions for slip fits with no leaks . Do not shoot the MFGS.Guide them in the right direction.

Hi Hauss. Thanks for your comment. Sorry but I don't understand your second sentence. Would you expand it a bit please?

[hauss]

The manufactures need to be shown better designs.

[t walgamuth]

ahah!

Thanks Hauss!

[ront49]

My 2004 BDR has the slip on headers and like earlier stated, they suck! Very poor design at best. Tried to weld on new spring hooks with poor results but that's my fault. They rattle and leak and the design does not allow flanges to be welded on. I had two Pro/Custom welders recommend I just replace the headers and side pipes. OUCH!

[t walgamuth]

I'll try the cement I guess.

[olddog]

Originally Posted by t walgamuth

Yeah, my o2 sensor is about 2' down from the four slip joints and I do occasionally get popping in the exhaust. It also seems to run rich until very warm.

I don't see how a flange can be mounted on mine as the four slip joints are all up against each other. That guy who did my roll bar could probably do it though....his welding is a thing of art.

Whichever (side Pipe or Header) set of pipes are the female, the flange plate is tack welded to the end of it, such that the ends of the pipes are flush with the plate. Then the slip fit (male) has a flange plate slipped onto it. Then slide them together. Make sure everything fits correctly on the car, with the plates bolted together. Once everything is aligned, tack weld the plate to the male pipe. Now disassemble. The male pipes are sticking through the plate. Cut them off flush with the plate. Now carefully weld the pipes to the plates by short beads and skipping around so not to heat warp anything.

If the flanges would come too close to something, then the plates would have to be slid one way or the other. Then the trimming pipes would have to be altered.

My pipes required different diameter holes, as the female pipe is larger in diameter than the male. The tighter the fit the less welding. My plates bolt together via 8 bolts (four corners and one in the center of each side), and they are 3/8" thick plates. Any coatings have to be stripped where you are going to weld to prevent contamination. I had to relocate my hydraulic clutch line, as the plates being 1/2" closer boiled the fluid.

PS
The original design had a couple tabs that bolts went through to keep them from falling apart. I cut the tabs off and ground it smooth. Looks as if they were never there. Also the plates have to be flat (where the gasket will go), when you are done. A lot of file work, so a belt sander would be better. Better yet mil them flat if you can.

[t walgamuth]

Thanks for the detailed description of how to do the bolt on flanges. I believe pipes going to the motor are male and the pipes going to the muffler are female. Did you do this yourself or hire it done? Any estimate of the time involved?

Seems like someone who has the skills and tools could do one in a half day? $3 to 400 per side maybe?

[olddog]

I had a local machine shop make the plates. I provided the pattern (drawing) for the holes and sizes. No recall of how long it took them to get the plates to me, but seems like maybe a week.

I had to clean off ceramic coatings, before welding. Also cut off the tabs and grind. Seems like a few hours.

My son welded the plates on for me. Tacking them and installing and aligning everything, then tacking the other plate took the longest. Seemed like 3 hrs.

Then disassemble and weld it, a couple more hours.

I started out thinking I could file the plates flat. I wasted a couple hours. Well, I had it pretty good, but I am obsessive. So I took them into work and used the belt sander to get them looking professional.

I sanded everything I could reach, but could not clean all the plates. They were shinny clean when starting but the welding discolored and there is slag and what not. I likely spent 2-4 hours on that.

I then soaked the plates in a weak acid, being careful not to dip them up to the ceramic coating. They soaked a day or so. Once they were shiny all over from the acid I neutralized the acid and applied a ceramic paint. Another day for the paint to dry.

Put them on and then followed the paint instructions on heat cycling to cure the ceramic paint.

All in all I think I spent a couple weeks on it.

I also did some other things. I changed to studs in the head to hold the headers on. I had to custom grind many of the washers so they hit flat on the header, as the original welds that connect the flange to the pipes was too close to some of the bolt holes. I didn't want to grind the welds flat, as they are ceramic coated. So, I opted to remove metal from the washers to make everything fit properly.

[olddog]

One more thing I recall. The plates have a substantial area of metal between the 4 pipes. It's kind of a x shape with the curves from the 4 large holes. Once that plate is welded on, it's a PIA to get paint on it by trying to shoot between the pipes. It might be better to put the paint on that side of the plate before attaching and welding. That would have eliminated the acid dip, as you can reach everything else to sand. I did not weld on that side of the plate, as you cannot weld all the way around it.

[olddog]

You asked about costs. I used a mild steel for the plates. It seems like it was between $100 and $200 for the plates. Mostly labor. If you had stainless side pipes and headers. The plates would need to be stainless as well. I doubt the stainless verses mild steel would be a significant difference.

Other than the cost of fasteners and paint that was it for me. I think you should be able to have it done for $400 or less, but I never priced it. I already had the aluminum that I made the gasket from.

PS
If you actually paid someone to be as anal as me you would pay $1.5K. Most professionals can do things much quicker than me, but not to my level perfection. Admittedly, I waste time making things look good that you would have to disassemble to see I did it. I also waste time deciding how to best do something. This is why I would never try to do this for a living.

[olddog]

Oh yea I had the 4 holes for the pipes Tapered about 2/3 depth into the plate. That allowed the weld to go deep into the plate and be welded from the gasket side of the plate. The side of the plate that has no pipe sticking out. You have to fill more metal on top but it makes a nice strong weld.

[t walgamuth]

Sounds like you did an excellent job! My pipes off the motor are stainless, the muff and its collectors are painted steel. It makes it worth thinking about using clamps.