Vanistan exhaust: retorque, leaks, etc.

[chachi]

i've had this exhaust on for 10k now. frankly, it's always leaked. i could see carbon scoring and feel the air coming out of the band clamps at 5k and it's only getting worse. Chris (aka tencent) says it has to be retorqued at some point and i have had at least one owner tell me that the 80ftlb is insufficient and he went up to 110. after failing oregon deq for insufficient back pressure, i'm looking for options. there are kind of a ton of bolts to torque on this thing and at least one of the clamps appears to be unreachable without removing a lower band clamp. all clamps are looking rusty, some on the verge of being problematic and some that will almost certainly be in 10-20k. is getting it fully welded an option? anybody with any long term experience with this exhaust that can give me some insight into their experiences?
_________________
'74 transporter panel
'91 vanagon carat NAHT

[bluebus86]

[chachi]

clamps i'm referring to are the wide band clamps, there are four, tightened by two nuts each. but there are points in the exhaust where pipe ends are inserted into flared ends of other pipes and then secured with bolts as well. the band clamps are the most obviously problematic locations but i'm also wondering about the pipe-into-pipe locations as well. do they need to be retorqued? chris is chris corkin(sp?) of vanistan, the designer/retailer of this exhaust. i would like to think exhausts shouldn't move but you have all metal surfaces heating and cooling, expanding and contracting...i can't imagine band clamps that are only keeping seal with tension (there does not appear to be any internal sealant nor has any been mentioned by chris or my installer) would be consistently tensioned. the consistently worsening physical appearence of the exhaust is bearing this theory out.
_________________
'74 transporter panel
'91 vanagon carat NAHT

[Ahwahnee]

[bluebus86]

oh, aftermarket, yikes near 2 grand and it leaks from the get go? maybe something got bent, or missaligned???? these clamsp you refer to, are they over slip fit pipes to seal them?

I wonder if some thin heat proof gasket material could be wrapped around the innner pipe, then outer pipe with crushed over it?

seems this moght be simular to the aftermarket pipes used on bug motors?


could a wider band be sued with two sets of clamps?


the photo supplied in other post link is not clear enough for me to see the joints well that your refering too.


can you supply photo of the leak points? maybe a different clamp is needed??

are the clamped joints need to move to allow for thermal expansion, contraction? if so it will be tough to seal them, short of a welded bellows, it the joints must move


good luck
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022

[hdenter]

I've had one for about 15k and it has been a challenge to keep sealed up. The band clamps have been my issue and it keeps coming loose at #4 as well. I purchased mine used and had to source a couple nuts and bolts and head studs. Considering that there very few, if any, complaints about the system, I'm going with operator error on my part. RMW now sells the system with the cat and muffler welded together eliminating one clamp and I'm sure the tailpiece could be welded to get rid of that one. The performance it has brought out weighs the need to tighten it up every once in a while. I've though about having it welded up, would just need to make sure that those last sections can still be removed as one unit without having to cut it off.

Good luck!

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[bluebus86]

[chachi]

here's the worst offenders, and you can see the clamp that is hard to reach in the top of this photo.

_________________
'74 transporter panel
'91 vanagon carat NAHT

[bluebus86]

ok, I see. maybe a flange can be weld on if the joint needs to be removed ever? can the clmap on the upper one be rotated to give better access? could it be maybe the bolt holes in the clamp have been too much enlarged, causing the bolts to not snug up enough by pulling in the clamp tight around the pipe? if clamp wont snug up tight around pipe, maybe a secondary piece of sheet metal can be sandwhiched around the pipe, under the existing clamp? you may even be able to wrap sheet metal around joint more than once, so you have a mor continuois wrap of metal around the pipe, held in place by the existing clamp?


good luck
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022

[hdenter]

I can't offer dino #s, but uphill onramps are easier to get to highway speeds on and modest hills in 4th gear that used to take a floored peddle can be crested without fully mashing it now. This is on my 1.9 work van that weighs 5k.

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[SLIKROC]

I have the same problem. I've tightened them so many times it's crazy. Trouble shooted with RMW. Here is what they told me. Buy new clamps, apparently mine are stretched out and can't be tightened any further. Tighten the bolt side only. I'm assuming to 80ft/lbs. I bought new clamps but have not installed yet. All clamps are now the straight ones with no step. RMW told me they have changed all to that style as they seem to work better. I have the same new motor as the OP. It's too bad the clamps are loose. It can't be good for the Oxygen sensor and I doubt I'm getting all I can from that new motor. Maybe the copper nut is the answer. I may try that when I install the new clamps. Any other thoughts on this issue?

[90Doka_Guy]

I had the system on mine for about a year and I had problems with it sealing also. Mostly at the band clamp joints. I tried new clamps and re-torqued a few times but was never able to get it fully sealed. My next plan of action was to buy some ceramic sealant and use that on the clamps. Never got around to it though, I sold the exhaust before I gave the sealant a try.
_________________
-'87 Westy
-'90 Tintop
-'90 DOKA

[photogdave]

I've never had a problem. Re-tightened clamps once after initial install, as per instructions, and no issues since.
However, it is easy to install the system slightly wrong by unintentionally reversing a bracket or two. Ask me how I know!
I wonder if that could potentially lead to a problem with sealing?
_________________
89 Syncro GL Westfalia 2.1 WBX/WBXaustSS

My Westy Movies:
photogdave On Vimeo
photogdave On YouTube

Stop dead photo links! Post your photos to The Samba Gallery!

[thatbaldwinlife]

Tell me more about failing Oregon DEQ? I have this same exhaust sitting in a box waiting to go on to my new RJE 2.2L I am picking up tomorrow and need to go to DEQ almost immediately as my tags are expired. How did they test backpressure?
Little concerned now about leaks and after spending $1600 on an exhaust, this seems a bit worrisome. Not liking the rusting clamps too. For this price, everything should be stainless.
nate

[bluebus86]

[thatbaldwinlife]

What if a 1" or so slit was cut where the pipe slides over the other pipe, allowing the band clamp some room to squeeze the pipe down? Seems like it is trying to compress a round tube onto another round tube with no where to go. I am going to put hi temp sensor safe RTV on mine joints when I assemble.

[bluebus86]

put a tightly rolled sheet of stainless springly sheet in two hose clamps, have a couple wraps around, make it a bit larger diameter than the exhaust pipe, maybe make the role about three four inches long. then slip this assembley over the pipes (exahust dissassembled), slide the roll out of the way on the pipe, and reassemble exhaust, then slide roll,over the pipe joint, and tighten down both the clamps on the roll ends. no seem, clamped tight.

now alternatly you might be able to roll the springy stainless sheet metal roll on the pipe with the exhaust inplave, installed on motor, but access for wrapping and installing the dlamps may be difficult. lot easier to roll up the metal and put on the clamps on the roll while on the bench, off the pipe, than try to wrap it around the pipe in place.


I have found this type of wrapped splice sealing method to be effective only use highest quality, strong temp resistant clamps.

good luck
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022

[chachi]

thanks for your comments, bluebus. i am slowly coming to the conclusion i may have to pull the motor to gain sufficient access. not stoked.

back pressure test was just part of their usual sniffer routine. my tags are up and i knew i was going to have to have the mixture tweaked on my rje to get through, but i wanted to see what i was going in with. i blew a 1200+ hydrocarbons, so, warning, don't tune your rje before you go through DEQ. but i had already failed back pressure, he had to put the sniffer in a long funnel to get the HC reading.
_________________
'74 transporter panel
'91 vanagon carat NAHT

[msewalson]

Chachi, did you install the exhaust system yourself? Also, dropping the engine is not necessary to tight one of those band clamps. Lastly, have you talked with Chris regarding these issues? I would hope so because I know Chris takes pride in his products.

The exhaust I have on my Subaru conversion is manufactured by the same company that manufactures Chris's exhaust and uses those same band clamps. I haven't had any issues with mine since installing it a few years ago.

Matt
_________________
87 Syncro w/EJ22

[CdnVWJunkie]

Those slip style band clamps are used on every big rig and commercial bus going down the road. Tried and true units. Of course, like anything else available now, quality varies from brand to brand. The non-stepped, or straight units- getting 100% alignment between the pipes is imperative to correct sealing. If both mating surfaces are clean and alignment is proper then no sealing products should be needed.