69 510 l20b exhaust y pipe

[510revisited]

Ok, since im on a roll for creating topics, heres another one. I know, im just FULL of dilemmas. Here goes. 69 510 with an l20b swap done by previous owner. Im at the stage where id like to completely redo my exhaust. Manifold to tip. Reasoning is the y pipe collides with the block, causing it to not allow me to tighten the manifold/pipe flange enough, and therefore causing a leak. Or its warped. The exhaust also hits the body at the trans crossmember, and rattles like a snake in the rear subframe. I just want new. Now, the shop i took it to isnt capable of recreating a new "y pipe" because, well hes a

just an ass (yes i know, get a second opinion).

 

My question is this.. i know the swap has been done for many years, so there has got to be a y pipe off another l20b equipped vehicle that would make the exhaust not hit the block. Or do i need to get fancy and have something fabbed by someone who can actually fab. The rest of the exhaust is easy. I will take pics for clarity. Thanks for the help.

[datzenmike]

The Y pipe should be no where near the block. If poorly made it's more likely to hit the transmission that it has to bend around.

 

 

L16 and L18 had a 4 into 2 pipe manifold with a 2 into 1 down pipe. L20Bs are all 4 into one manifolds and a single down pipe. There were no L20B Y pipes.

 

If you use an L16/18 manifold and Y pipe on an L20B, everything should work however the L20B will position the exhaust 3/4" higher. Usually there is enough room for the pipe to be 3/4" higher at the front.

 

You could just use an L20B manifold and single down pipe and join it to your 510 exhaust system.

 

 

I have an L20B 710 with an L16 4 into 2 manifold. The modified down pipe is from a 240sx that has two pipes down under the floor and join there and then back and join to the stock exhaust.

 

 

I found this in a wrecking yard thrown out with a lot of other new but unsold inventory that was scrapped. I think I spent $10 for it. Previously Mklotz70 had given me a Y pipe flange so I removed the 240 sx flange and put the other on and with a bunch of fittings I welded it on and made my own gasket.

 

 

The 240zx uses the same transmission shape as the 510 so the bends are in the right place to clear the steering box and transmission. It doesn't just bolt together. I had to make that pair of pipes slightly smaller diameter to fit up into the manifold. I'm not at all a fan of the 4 into 1 L20B manifold and much prefer the L16 'cast iron header'

[510revisited]

So your saying, essentially i can make a single pipe down pipe. Oval on one end, round on the other. I agree. The exhaust shouldnt be touching anything at all. However i assure you it is. This swap was done by the p.o... The shittiest part is the muffler shop guy tried to talk me out of doing it "my" way 

[datzenmike]

Trust what you want and be willing to pay for that. True you may be wrong but it's a learning process. As for muffler shops... some benders are artists!!! others are arses. Anyone can bend pipe but the better ones have an eye for it. Ask a shop who they would recommend see if the same name keeps coming up. Ask their customers how it worked out.