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Header exhaust leaks

If Peninsular doesn't have a fix, i would start with having some braces welded from flange to flange. Then checking for & surfacing like he is saying.

Hummer headers dont have the braces, but they can expand between flanges and not distort. Because the ports are not tied together by a pipe that can expand linear between them.
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The headers are coming off. I will check them for straightness and decide what to do from there.

I emailed Peninsular with several questions about the header leak issue and the possibility of replacing them.
 
I don't know. Just dreaming of a high temp spring washer. Would putting some spacers like stand offs allow a longer bolt that might stretch or act like a spring to thermally grow and not clamp so hard and allow a little movement but cool and shrink back to clamp cold ???? With Lock washers to stay tight?
 
Yesterday, I took the headers to the machine shop. They are going mill them removing the least amount of material as possible. They also suggested using 3/16-1/4in hardened steel washers to distribute the force of the header bolts. We talked about copper exhaust gaskets with the embossed O-ring around the ports too. I have a question into a supplier to see if they make them for 6.5.
 
I just picked up the headers from the machine shop. They couldn't mill them because there wasn't enough material to work with.

I talked to Peninsular and instead of building all new headers, they can cut off the old flanges and weld on new thicker flanges using a jig to keep everything in place. Now I'm waiting to hear back from them too on this solution.

I did hear back from the place selling copper gaskets. They didn't sell them for the 6.5, but they gave me their supplier info and I waiting to hear from them. In the mean time, I did find solid graphite gaskets to fit the 6.5.
 
See if Peninsular will remake the headers with a 3/8" thick single piece flange. That will most likely solve the leakage problem as each runner will no longer be able to "squirm" around its port as it heats, expands, cools, contracts.
 
@3bals Not good that your first reaction was to laugh... Am I confused? Didn't they build them when they sold you the engine and turbo?

Husker6.5 said:
See if Peninsular will remake the headers with a 3/8" thick single piece flange. That will most likely solve the leakage problem as each runner will no longer be able to "squirm" around its port as it heats, expands, cools, contracts.
Click to expand...

I would say this and connecting the ports together like big block gasser headers do. The only reason hmmwv headers don't need it is because they all swoop down and then connect.
Hummer and van exhaust manifolds with center mount turbos are connected from port to port directly where it contacts the head.
 
I'm not sure it's Peninsular's issue, since it's been 3 years since the headers were fabricated and how do I prove they made a mistake and not the installer or the fact that I wrapped the headers prior to use. Also the people (machine shop guys) have years of experience of building drag race car and tractor/truck pull components said that connecting the ports wouldn't help, as most of the people end up cutting the connection to eliminate movement.

Peninsular always used just RTV and no gasket and they claim that they have 170-190 sets in use with no problems.

I'm thinking I'll follow the idea of thicker flanges (7/16-1/2in) being welded on. I'm undecided on using a gasket/RTV, just a gasket or no gasket and just RTV.
 
All the regular manifolds I've done over the years went on clean and dry, and only if it leaked (way rare) did it get a gasket- but that is cast manifolds.

On the steel hummer headers, I only delt with maybe 15 installs. Most of them get the regular felpro gaskets I mentioned.

I forgot it has been 3 years already- yeah, kinda hard to push that.

Most headers do not need the ports connected, but with the design on yours, I can't see how they are not. Stainless steel (almost all types) expand massively, ESPECIALLY PIPE.

Iirc 316 is .04 factor, meaning your header is trying to expand 1/16" in length. Between that and the vibration, I can't see how rtv is viable. And you cant compare hot rods to rv. Hotrod is constantly getting checked, tweeked, things getting tightened,etc. Your rv should be like that spinning cooker- set it and forget it.

If you haven't snapped any locking retainers, and they obviously stayed tight, you just need a simple gasket. Copper gaskets are great and have there place, but idk about them here. The copper is ductile, yes. But once it flattens out, it will just keep getting malled by the vibration. Just my guess, I never used copper on a 6.5- paper always worked as long as bolts aren't coming loose. The paper can handle expansion and contraction. When the SS expands it will squish the copper more, but what about when it contracts, Won't it leak then?
 
In hindsight, maybe I should have stayed with the stock exhaust manifolds, but there wasn't much room for the bigger turbo on the side. I'm thinking I would have had to add onto the doghouse cover and cut more of the floor out, thus reducing passenger space.

My thoughts were to have a more powerful/reliable RV. Not so much. It's been a PIA since I chose the P400 and related accessories, no matter where I bought it. Maybe I should have just put in a reman, drive it til it dropped then scrap it. I would have been money ahead, but now I'm stuck with the money pit.
 
I know you are getting frustrated but you still made the very best decision by going with the p400. I would think the thicker solid flange and like @Will L. said fel-pro paper gaskets should fix the problem.
 
Getting frustrated?

Let's see,

1. It took forever to get the engine, transmission and related parts shipped in.
2. The transmission arrived broken in shipment and took weeks to get a different one.
3. The transmission that was sent was for a 4X4 truck, not a motorhome.
4. No transmission was available for the motorhome application.
5. I had to research where to have the best reman done to my Transmission. Even though I really didn't need a new or reman transmission, as the old one worked fine. My thoughts were with more power it would be better.
6.The shop doing the work kept changing techs, instead of keeping the guy that I knew was good on the project. Of coarse there was poor communication between the different crews, so things got missed.
7. When we finally got it leave on our trip, the radio didn't work, we could smell something hot, then the transmission started shifting funny, which caused us to abort the trip after 6oo miles and limp it home with a coolant leak, an exhaust leak, an oil leak (turned out to be a ripped gasket on the IP mount), disconnected radio wires, miss aligned transmission fill tube with a torn grommet and fried transmission wires from being too close to the exhaust, causing the shift issues.
8. The second time out, just a shorter trip to check things out. After 200 miles one of the rear brake calipers hung up causing very hot conditions, that if I wouldn't have caught it, probably would have started a fire. (got towed home) The installer was told to replace the brakes. They only replaced the pads.
9. Finally got to go on the trip we wanted to, but had to take it back on return for an exhaust leak and other issues.
10. The next year we thought we were ready to go, but had an issue I thought was a wheel bearing, but turned out to be a brake issue that still hasn't been resolved.
11. Then we had another oil leak that caused me to stop every 100 miles to put in 1-2 quarts to make it home the last 1500 miles. It turned out to be loose bolts holding the turbo to the custom mounting bracket which allows the oil to return into the crankcase.
12. 190 miles from home the alternator shaft broke on the new alternator that only had 9000 miles on it. causing another tow home. Thanks to an upgraded AAA policy didn't cost anything. I fixed this myself.
13. Now back to the shop before we take off again to fix the brakes, exhaust leak and other small issues with the drive train. Small camper issues I could do myself, before we take off again. Now it's 2017, the first trip was in 2015.
14. After about 700-1000 miles I noticed an exhaust leak again and on the way down a 12,000 foot pass in CO. in low to keep the engine and brakes cool, I stopped to cool things off near the bottom and couldn't move the shifter out of low. I let it idle and cool for about 15 min before I could move the shifter. The shifter issue turned out to be a melted shift cable cause by a broken bolt on the turbo to manifold connection.
15. Here we are.

That's it in a nutshell, the quick version.
 
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