Exhaust pipe touching block.

[LenRobertson]

I'm back working on my L20b/dogleg transplant into '72 510. Bolted the exhaust down pipe up to the manifold, and the pipe is touching against the lower corner of the block at the bell housing face where the tranny bolts to it. I checked the pipe on my 200SX L20b, and while it is very close to touching, there is a tiny bit of clearance. Maybe I'm worrying about nothing. Maybe this pipe is touching the block on lots of Datsuns, But it seems the heat transfer from the exhaust to the block and transmission isn't the most desirable thing. The down pipe I'm using is a heavy two-into-one style, so heavy I think it may be a casting. The spot where it touches is only 4 1/2 inches down from the exhaust manifold. No chance of bending it over. I thought about heating it and dinging it in with a hammer, but if is cast, I don't think that will work.

 

So bolt it up touching and don't worry, or maybe get a different pipe? Or something simple I'm not thinking of?

 

Len

[mike]

Ive got the same issue in my wagon, it will clunk if it diesels when I shut it off... Sounds awesome and chicks dig it :lol: I tried tweaking it out of the way when I swapped heads and now Ive got an exhaust leak at the collector. Truthfully, it wasnt that bad and didnt happen very often. I thought about the heat thing but I dont really know how much of an issue it would be on the bell housing, it will take a hell of a long trip or maybe a healthy day at the track to heat soak an entire tranny housing to the point causing damage.

 

I think the best solution would be to build, or have built, a new collector with a bend in it for clearance. Until then run it as is.

[LenRobertson]

Ive got the same issue in my wagon, it will clunk if it diesels when I shut it off... Sounds awesome and chicks dig it :lol: I tried tweaking it out of the way when I swapped heads and now Ive got an exhaust leak at the collector. Truthfully, it wasnt that bad and didnt happen very often. I thought about the heat thing but I dont really know how much of an issue it would be on the bell housing, it will take a hell of a long trip or maybe a healthy day at the track to heat soak an entire tranny housing to the point causing damage.

 

I think the best solution would be to build, or have built, a new collector with a bend in it for clearance. Until then run it as is.

 

Thanks Mike. I suspected I was worrying about a non-issue. I'm amazed how many things I've run into on this swap that don't quite fit and have to be dicked around with. Probably everyone else has more or less the same experience. I guess that is part of the fun.

 

OT - I guess I never got back to you on those seat tracks and head rests. I would like to have them, if you haven't dumped them already. I don't know when I'll hit the Big City again, maybe next Sat. if the weather holds out.

 

Len

[mike]

No problem on the rails and headrests, theyre sitting outside under my awning. Give me a call when you roll into town.

 

On the exhaust, make sure your exhaust mounts have plenty of give/are installed correctly so that it can move with the engine. Otherwise that flange will be the weak point if it starts to flex. I "lucked out" when I got the wagon and all the exhaust mounts were broken or rotten.

 

Random thought... I forgot to check on that 710 out at P&S to see if it had the same exhaust manifold/flange as a 510, those and 610s came with the square port heads and L20s... it might be something to look for next time you see one in the yard.

[dryheat]

Same problem on my wagon. I used ball peen hammer to slowly/carefully adjust the exhaust pipe to remove the interference. No leaks and plenty of clearance now.

[Gary]

the heat from exhaust to block wont hurt anything :) the only bad thing about it is if it might rattle and get annoying

[Mini-L320]

You can Heat Wrap it. With Header Wrap. I had a problem with my downpipe coming 1/2 inch close to my Clutch Line so I used Header Wrap on it just incase.

[datsunaholic]

It hits because you're probably using the L16/L18 exhaust and piping, right? The L20B is taller, so you've pulled the exhaust up and now it hits. Had the opposite problem with my old KC, had a L18 with the L20B exhaust and it was so low it hit speed bumps. It finally, um, "clearanced" itself.

[LenRobertson]

It hits because you're probably using the L16/L18 exhaust and piping, right? The L20B is taller, so you've pulled the exhaust up and now it hits. Had the opposite problem with my old KC, had a L18 with the L20B exhaust and it was so low it hit speed bumps. It finally, um, "clearanced" itself.

 

Yeah, I believe that is the problem. The only L20 manifold I have had a broken stud. I tried to blow it out with a torch, and screwed it up pretty good. Since I didn't have the right pipe to bolt up to it anyway, I gave up on it and used the original L16 manifold and pipe. Since freezing weather will be here soon, I'll probably just toss together what bits I have to get it running. Even though I won't be driving the 510 this winter, I dream of making a few laps around my driveway before the snow flies.

 

Len