RVM Downpipe Problems-Help-already searched!!
 

To try and keep it concise here goes: Picked up a RVM DP off ebay. Hand carried the thing down to Phoenix/Tempe when I was at a seminar recently and had it Jethot coated. Hoping to do this one time and do it right.
Anyway I finally get down to starting the job this past Sunday-pulled the precat. Previous owner had installed a gutted precat. He left the top two studs in and used bolts in place of the lower two studs/nuts. Nuts came off fairly easy...had to work at the bolts a little while. The freakin' DP to MP nuts were a trip---I literally used my legs to apply pressure--maybe not a wise thing to do but they loosened a slid off easily after that.

I was able to get the DP on over the two upper studs as I wanted to check fitment even though the studs are going to need to come out as I have four new ones that I want to use (along with new gasket that ran me $80) and the threads on one of the them look pretty bad.

So I'm trying to get the thing off so I can start working on the two studs and I find that the MP end of the DP is jammed up against the bracket that connects the precat brace to the underside of the car. So after working it a little I was able to get the thing back out but find that I have another problem.
I won't be able to get the OEM nut for the lower right stud on because of the bend in the pipe!! I know probably no biggie for most but nevertheless I some how expected this to be easier than the fuel filter...


So my questions are:

-Anyone have experience with RVM DP's?

-If so what did you use as fastening devices?

-Anyone run into similar problems with the precat bracket being in the way and how did you resolve that?
I figure simply removing it would work but I was hoping to use it with a modified type of brace to help support the DP/Cat. Any suggestions?

-Any recommendations on mixing in a bolt with three studs in the other locations?

Thanks for the assist.

Yes I have the same one problem.
I had to cut a piece of the pipe to make sure i can get nuts there.
but still have't installed it (i needed a new gasket) so really can't tell you how it fits now
another good way to get thru this is to use hex bolts that have a round head or use longer studs+spacer

I think I have that dp. was on the car when i got it. that stud is not installed on mine either. actually that stud appears to be broken on mine.

Get some really good quality alloy steel 'socket head cap screws'. The heads are smaller than the OEM nuts. Cheap hardware store versions may not handle the heat + loads, so I bought 316 stainless versions from www.mcmaster.com.

Dave

Thanks for the input guys. What size socket head cap screws would I need to go with.
I think length is 10mm but what about "thread size"?

Actually, I think it's M10(x1.5 thread) x 40mm length. I used Mcmaster.com's #91292A216.

Dave

Dave,

Thanks for the part #.
Did you use washers with the cap screws??

Thanks again!

one more thing...

I just tried installing a new stock cat and found that the studs in the stock cat do not align with the holes in the downpipe. You have to either enlarge one of the holes or somehow remove the studs from the cat and use a nut and bolt.

Another reason why I hate cheap knock off ebay parts...

Hey Alberto:
Get one of those Unibit drill bits, and progressively enlarge the holes. I have one if you need it.

Bob (in Va.)

That's just what happened with my RX7store downpipe. (Except I paid more). Probably the same batch of bad parts. I was able to exchange for the Pettit part - unfortunately you're going to have to grind the holes out and hope the flange is flat enough to not leak.

Dave