I have the same problem with my exhaust as well on my RCR and my next step was to add the washers as you suggested. Will let you guys know the outcome when I get my straight pipes back from being welded.I think I would put a couple washers between the block and motor mount on both sides to see if that would buy you the needed clearance..
I half expect that raising the engine will only rotate the pipes to the rear and not have any effect.
Will an RCR be able to accept a new mount under the gearbox ? Build one to suit !!
Good point just made me realize that adding the washers between the block and the motor mounts will just misalign the ZF gearbox dog ear mounts and the cross-support brace. On an RCR chassis you have the 2 holes in the upper support that accept 2 bolts through the dog ears of the gearbox upper mounting plate. Not much wiggle room. I do have 2 mounting tabs with bushings on the bottom of the bellhousing which line up well with the cradle of the chassis, I just need to fabricate and weld L type brackets with bushings for through bolts to complete the motor mounting process. The problem is in the design of the bundle of snakes supplied by RCR. I believe the solution (if any) should probably be within the bundle of snakes. Just need to gain a 1/8-3/16" gap between snakes and chassis support.I half expect that raising the engine will only rotate the pipes to the rear and not have any effect.
Will an RCR be able to accept a new mount under the gearbox ? Build one to suit !!
In addition to the rotation you mentioned, It will also lift the pipes up the amount that you shimmed. I have already played with this on my own car. Yes, there will be a slight misalignment with the transaxle support, but you may have enough compliance in the bushings. If not - well modifications are in order..I half expect that raising the engine will only rotate the pipes to the rear and not have any effect.
Will an RCR be able to accept a new mount under the gearbox ? Build one to suit !!
I am using the same set up on my RCR and am having issues with leakage between the pipes and collectors. I tried several times using copper sealant and still leaked slightly. Got tired of reinstalling these headers. I finally purchased 8 more of the tabs and am having a fabricator weld them on the inner side pipes and collectors (between the two banks) so I can pull all 8 pipes in fully to the collector flanges. I think that will limit any movement between them and along with sealant It should work. It is going to be a tight fit but I think that is my only solution. Did you have any issues with exhaust leakage? I am also very close to the dog bone with my headers. (I reversed the collectors in photo 2 to show how close the tabs are. I think with modification, or offsetting them, it should work)So my exhaust headers just barely clear the crossmember. In fact, one of them is ever so lightly resting on it and the other has a tiny clearance (maybe 1/32"). You can see in the pix that the part that is interfering is the "thinner" diameter and where the collector slips over the header tubes is just touching the outside edge of the crossmember.
Would it be a good idea to put something in between there to reduce the likelihood of the pipes wearing through? I thought perhaps a strip of heat shield fabric (the kind that is woven ceramic with a silver coating on one side)? Or even thin strip of pine door shim? The idea being that the middle layer of the sandwich would wear before the pipes. The other side of doing that is that it puts more pressure on the pipes which, for now or not under much if any force resting there (at least not when cold).
I've got about 500 miles on the car so far with it this way and so far it doesn't seem to be an issue. I also can't tell if there is any movement back there between the Prothane engine mounts and the stiff bushing holding the ZF in place.
Any thoughts/suggestions?
Thanks for the feedback. I had a feeling that the leakage would be a general issue with other builders. I had them sealed and then tested them again a few days later and they leaked just slightly. I think stabilizing all the pipes with the tabs and sealing them should do the trick. We will see. I'll keep you posted.If those are "single slip" connections to the collectors, you'll likely always be challenged in getting them to seal. You need double slip connections and even then they sometimes leak enough to cause O2 sensor misreading. I've been surprised on one of my cars on how challenging it is to keep the outside air from sneaking into the exhaust and causing the EFI to run rich. I'm in the process of moving the O2 sensor upstream now as I just can't stop a V band connection from leaking air in.
Sounds like a good idea if you are adding washers to the mounts.Thinking about this for a day, when I get to the shop, I’ll see what I can do about building a couple offset bushings for the transmission / upper cross member, all the 40s I’ve worked on had the steel x member and there were no clearance issue , I’ll keep you posted
Thats a thought not much material to remove, I'm thinking just enough material just by removing the RCR logo should do it!In addition to the rotation you mentioned, It will also lift the pipes up the amount that you shimmed. I have already played with this on my own car. Yes, there will be a slight misalignment with the transaxle support, but you may have enough compliance in the bushings. If not - well modifications are in order..
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Frankly speaking, there is a LOT of material in the RCR dog bone and I wouldn’t be afraid of milling some material off of it to clear the headers.
Thanks for the feedback. I had a feeling that the leakage would be a general issue with other builders. I had them sealed and then tested them again a few days later and they leaked just slightly. I think stabilizing all the pipes with the tabs and sealing them should do the trick. We will see. I'll keep you posted.