Frustrating Exhaust Leak, Early Turbo

[Nashfan]

I have a exhaust leak between the up-pipe of my turbo and the lower exhaust that seems to defy all "normal" remedys.
heres a picture of it from a while ago. What I've attempted to do about it is put another clamp on, and a S.S. heavy duty band clamp... all three tightened a few times!! Its not working! This connection normally seals by carbon build up and now that I have EFI, it doesnt get enough carbon most of the time to seal up/or stay sealed. The next time the turbo and exhaust comes off, I want to do something that is permanently leak proof, and still looks kinda sorta stockish from the engine compartment side. What are some of the non-stock exhaust clamping methods that have been done? Any one?

[61SuperMonza]

I would try a lap joint clamp. This will give more clamping force due to more surface area. They won't distort the pipes like a standard exhaust clamp.
NORM

[Nashfan]

I hunted for quite a while to find that type of clamp that would fit. Unfortunately, the ones I found were not stepped and were for squeezing the o.d. of the larger tube down to clamp on the o.d. of the smaller tube. One of these was a little too big to tighten up, the other was the next size down, and although I could get that one on, when I tightened it enough to "clamp" the tube, it distorted badly and still leaked. Do you know the part number of the correct lap clamp? One thing I have not tried, is an actual exhaust pipe sealant, like this stuff https://www.amazon.com/Blue-Magic-8024- ... B000BOAZM8

Anyone brave enough to try something like this??

[61SuperMonza]

I would check out totalflowusa.com. They should have what you need. They exhaust sealant will work as well but it's a pain if you have to remove the pipes at a later date. Hopefully they will have what you need.

[Nashfan]

Thanks for the link!! I checked it out, they do have the clamp size I wasn't able to find before in a lap joint style. It will be interesting to see how this works out and how the turbo responds!!

[61SuperMonza]

Good deal, hope this works out well. Keep us informed.

[Deadwolf]

Best turbo response would be a welded pipe, but that is difficult in the area you have and then will almost always require cutting to remove. I wonder if you could cut it and put in more of a donut gasket like what comes out of the exhaust manifolds.

[nirvairna]

Is there room for a v-band fitting? You might have to add an extension to one of the pipes to get it to work.

v-band fitting.jpg (21.39 KiB) Viewed 3187 times

You can get them in smaller sizes such as 1.5"
https://www.amazon.com/Stainless-Exhaus ... B08GJ4Y59L

[Nashfan]

Deadwolf- the late type turbo exhaust does use a donut type, and they are prone to leaking also. Nirvairna- the issue with a v-band clamp is the same as with a welded triangle flange in that the heat collar and engine compartment shrouds have to be put on first, and the mount for the turbo, then the v-band is welded on. It is extremely difficult to take apart later that way. The only thing that is nice about the stock set-up, if the lower pipe gets stuck on the up-pipe (from over tightening or whatever) the lower pipe can still be cut off, which is what I've had to do the past few times. Theres barely enough room to put a v-band or welded triangle flange in the stock location, and I think if I went that far, it would make a heck of a lot of sense to have a custom one made that has the attachment point lower and redo the heat collar and shroud parts to make it easy to take apart... build strategic splits into the shroud holes so instead of one piece for the top and another for the bottom, maybe they are three piece for the top and bottom, with a heat collars that are split also.
As hard as it is to get the turbo and exhaust pipe off (even when the lower part comes off like it should), this might not be a bad idea anyways! I'm probably going to a custom exhaust at some point anyways, its clear that the stock set-up isnt that great for best flow anyways... its kinda like a kinky hose with too large of a nozzle (turbo housing a little to big), and is a major source of pinging. Modern turbo exhaust systems are way different than what we have!! they guarantee that the turbo is they main restriction, and before that is as free flowing as possible!!
I'm going to try the lap joint clamp thing first, I just havent ordered it yet.

[pcarney]

I just finished installing Clarks Deluxe exhaust kit and a local club member (Rex) suggested using a lap band clamp like you are trying to use. I found one in stock at my local Napa Auto store. It was about $10. No wait and no postage.

[Nashfan]

Well, I went ahead and ordered the clamp, and it should be in this Tuesday- its going to be interesting for sure to see how this works out!!

[Nashfan]

Today I put the clamp on... the clamp size that works is 2" lap joint clamp. It is difficult to get this clamp on correctly,
Something hits before the clamp is slid in far enough for both diameters of tubing and clamp to match. It looked like it was the bolts were hitting the down pipe, but I could tell that it would be hard to reach both clamping nuts even if I did shorten the bolts and move the clamp some more. As badly as the pipe was leaking this time I figured it would be impossible for the new clamp to seal worse than the 2 u-bolt clamps did. The leak that was present this time was way worse than the picture, and 2 u -bolt clamps were used! The joint was not round, and one thing that was clear, the new clamp was going to apply much more even pressure at the joint. Havent had a chance to test the boost yet, but the engine did sound different.
I guess I will find out tomorrow when I stand on it!!

[Nashfan]

I got a little boost test in today, sheezus that was fun! Normally when I do this, I pound it first gear and can get between 10 and 15 psi, and then when I shift 2 second it can go over 20. It just has not been like that lately and seeing that giant black streak on the turbo inlet pipe suggests that it was the cause of it. Todays test consisted of flooring it at 3000 rpm in second and made it 18psi at 6000 rpm, and from past experience, it seems about right, given the way I hit it. Car pulled really strong, but after looking at the data logger, seeing that the air fuel ratio was getting too rich ( 10.7-10.5) past 4500, I think I need to bump the timing a little more in the upper rpms, maybe 2 degrees more. All in all, the lap joint clamp was a pretty easy way to take care of that problem!!

[Nashfan]

I thought I would update this post a little. The lap joint clamp worked pretty good for a while, but then began leaking again and really went downhill to the point of not making any boost. Last winter I had some other work to do on the car and decided I was going to take care of that leak once and for all!! Stove pipe cement!!! I found some stuff at the hardware store that cost less than 10.00, is designed for metal to metal joints and is good up to 2000 degrees! The car is back on the road now, and wow!!! nothing like having a well sealed turbo exhaust! sheezus it boosts quick now! Much of the problem seemed to have been that the pipe joint normally wont fully seal until it carbons up, but with EFI it spends a lot of time cruising along running at or near stoich, and wont make enough carbon to fill in the gaps. Aint going to run into that problem now!!

[Beers]

Stove pipe cement? Like RTV for exhaust joints!

Very cool, sounds like it did the trick