Assembling TC Exhaust system

[Bryan Boyle]

Picked up a mild steel TC exhaust system (since I'm going to remove the OEM one to finally drop the oil pan to reseal it to attempt to cut down on the anti-rust treatment of the rear frame...) from the header to the muffler...and, in slipping the parts together "just to see", I notice that the fit of the pipes is, um, a bit loose.  OK.  Now, I have the stainless band clamps to attach the cross pipe to the header, then a clamp for the muffler to the cross pipe...but, even tightened down...there is a lot of slop.  Maybe I'm overthinking it, but, to me, everything should be nicely snugged up to minimize leaks, right?

So...without overengineering the solution...how?

Figure there are some who've run into this.  My thoughts?

1. Liberal application of Firegum (or equivalent over here) to the male end and just honk the clamp down as much as possible to attempt to compress the mild steel female side of the joint.

2. Cut short slots 180 degrees to each other, maybe the thickness of the slot about 1/16" at the end, liberal firegum on the male side, honk down.

3. Weld in situ?  Nah.  Then I'd be getting out the sawzall every time I wanted to pull it down and replacing pipework.

FWIW, a liberal application of a combo of Kroil, PB Blaster, and drizzling a 50/50 mixture of acetone and ATF on the OEM header nuts resulted in 8 loose nuts (I know, go ahead and chuckle...) and no backed-out studs in the head.  Didn't even use any persuasion with the blue wrench (It can't be stuck if it's melted, right?), but did use a shorty ratchet handle (to limit the torque), a good 6-point socket from my snap-on kit, and steady pressure to turn the nut.  If you rush...that's when bad things happen, and I did NOT want this to turn into a 'damn, I have to pull the head to replace studs because I used the 3' breaker bar...'

Thoughts welcome...

[BDA]

If you have to have your car inspected, they will probably want your exhaust system to be leak free (we don't want you to get asphyxiated from the exhaust gasses, right? - don't try to argue that the "leak" is behind you and therefore inconsequential). Without seeing the looseness of the fit, I would vote for taking a hack saw and cutting a slot in the larger diameter and drilling a small hole at the end of the cut. A slathering of heat resistant orange RTV and some good hose clamps should finish the job.

My headers are similar (it's a two into two into one setup). The "one" that the two go into is cut with the holes at the end of the cut to ensure a crack doesn't form there. The are a decent fit so not much RTV was needed but it all works.

[Bryan Boyle]

I found the below over in the UK...like your idea about slotting (and relieving the stress with a stop drill at the end of the cut); using something like this (and slathering the inside with a coating of either the high temp RTV or exhaust paste) could be a solution, no?

FWIW, the OD of the header outlet is 1.75" (same as the muffler end) so this would work (had to go to the UK to find this since the conus pipes seem to be a 2" minimum...)

Additional thoughts?

[jbcollier]

I always use heat on header/manifold nuts.  It's the only way to guarantee you won't break a stud.

How loose is loose?  Sounds to me to be a manufacturing error.  If it is "that" loose, use shim stock to take up the slack and then use high temp silicone to seal.

[BDA]

Those would certainly work. I think it depends on the quality of the fit. Those would certainly accommodate a larger misfit. They would be WAY overkill for my application.

Those stainless steel hose clamps are pretty strong. The guy who built my Spridet race car (a LONG time ago) used them to bind the leaf springs and they never broke.

Another suggestion might be to visit a muffler shop to see if they can help improve the fit.

[Bryan Boyle]

Probably guilty of overthinking the thing (a constant failing of mine).  Thanks, both of you, for your insights.  Will report back at some point after I get the system together after doing the oil pan sealing work.