Walker Y-Pipe Oil Pan Clearance on 350

[RWBeringer4x4]

hi V8 gurus,

I’ve had a heck of a time installing some new Dorman 2” exhaust manifolds and the walker Y-pipe 42087 on my V8 conversion. This is well tread territory, but it isn’t cooperating.

First - the Dorman manifolds took some considerable grinding at the bolt flanges to even get the bolts to fit, and then even more at the PS exhaust flange as it conflicted the block.

Now, I’ve been having issues getting the Y-pipe to line up. First, the walker 42087 pipe was too wide by about 1” to fit the manifolds. I was able to “massage” the pipe to get the flanges in line. However, it was still contacting the oil pan when everything was tightened down.

Next, with the manifolds loosely bolted to the 350,I tightened on the pipe, then torqued down the manifolds. After a few tries, I managed to get everything bolted down, but there is only about 1/8” of clearance at the corner of the oil pan at the crossover:

Clearance beyond this corner seems ok - about an inch:

I am running the heat riser spacer on the passenger side:

Just wondering how tight that corner usually is. As long as it’s not touching, am I ok or will this transfer too much heat to the oil?

 

[RWBeringer4x4]

Bump for any insight - key question is just - is 1/8” air gap between oil pan and exhaust over a short distance asking for trouble or is it probably alright?

I could try “pulling” the pipe over (maybe ratchet straps or a hammer?) but if it’s not necessary I won’t mess with it.

 

[shawnfj40]

I would say that so long as they don't make contact you should be OK. Obviously the more space you have the better because of heat transfer.

 

[RWBeringer4x4]

Yeah, I don't want them rubbing, obviously, I'm just curious of the other folks who ran them, if they're always that close. Not sure how much the Y-Pipe will move in relation to the engine (could it flex into the oil pan?)

I'm gonna tag @Cdaniel and @Texican if they're still on here, as I think they ran these at one point (found some old threads). Not sure if Texican's on here anymore. @bikersmurf are you running one of these?

If I could get the damn thing to bend/flex from where it currently is to the passenger side by about 1/2" I'd be golden - but that pipe is tougher than it looks.

 

[coonassjohn]

You could remove it and take it to a muffler shop to be re-bent to your needs.

 

[RWBeringer4x4]

You could remove it and take it to a muffler shop to be re-bent to your needs.

I may have a shop bend up the rest of my exhaust - that that’s the case I may definitely ask them to do that (or just build a new Y-pipe). Just figured this would be the “easy” way - and maybe it still is, if the fitment I’m seeing is normal.

 

[coonassjohn]

Good idea. The shop can compensate for any issues along the way. I found a good shop to do mine and it worked out fine and looks and sounds great and wasn't that expensive.

 

[bikersmurf]

I made my own, but researched extensively. I've seen some to suggest that it wouldn't be terrible, but I'd not run it that tight.
I settled on a good fingers width (big hands) and header wrap at the tightest point. This seems to be inline with factory design... rather than what some are getting away with.

 

[bikersmurf]

Would a spacer on the other side solve the issue?

A muffler shop could likely fix the issue... but it can be hard to find one that'll build what you want for less than your first Born.

In these parts, buying J pipes, a muffler, and a 7' length of pipe (3' left over) was at least 1k less than what a muffler shop would charge. The shops here have limited competition and all charge a large fortune for exhaust work... been told dual exhaust for a Chevelle starts at about $1500... I didn't bother getting quotes for mine since it was so custom, and I wanted it built in a very specific way. The routing was very tight in many spots.

 

[Cdaniel]

Still lurking. Not sure why you're running into fit issues, but here's pics from mine

 

[RWBeringer4x4]

Would a spacer on the other side solve the issue?

A muffler shop could likely fix the issue... but it can be hard to find one that'll build what you want for less than your first Born.

In these parts, buying J pipes, a muffler, and a 7' length of pipe (3' left over) was at least 1k less than what a muffler shop would charge. The shops here have limited competition and all charge a large fortune for exhaust work... been told dual exhaust for a Chevelle starts at about $1500... I didn't bother getting quotes for mine since it was so custom, and I wanted it built in a very specific way. The routing was very tight in many spots.

Another spacer might help...but the issue is that the point that it’s tight is literally the pivot point - so a 1” change at the manifold probably wouldn’t make a huge difference (but this might be all the difference I need).

I talked to a shop around here little while back, they wanted about $400 for everything after the Y-pipe which seemed reasonable (expensive but certainly not $1500). The key is getting it there (so I just drive 10mi with open headers? There is a shop literally a quarter mile from me but I haven’t had a chance to ask if they do exhaust yet, and what it might run.

Still lurking. Not sure why you're running into fit issues, but here's pics from mineView attachment 1641765 View attachment 1641765 View attachment 1641767 View attachment 1641768 View attachment 1641769 View attachment 1641771

Thanks @Cdaniel - you, and your glucosamine thread have saved my butt a number of times. I believe last I cried for help you had moved on to a sandrail project - done yet?

Definitely looks more clear than mine - but if you don’t mind another question - it still looks pretty tight right at the passenger side corner of the oil pan right where it starts to bend under and cross over - Do you have a ballpark size of the gap?

It’s weird - if I could literally mount it in a press holding the downpipes where they are now vertically, but pull the whole thing 1/2” to the passenger side, I’d be golden. The bend seems just slightly off where it should be.

 

[Cdaniel]

That's the beauty of ih8mud. Such a collective resource of info.

Best estimate of that gap at the corner of the pan where the pipe bends is 1/4 inch. It's close, but doesn't bother me. I figure GM brain trust used it for decades, it must be okay

 

[RWBeringer4x4]

Ok, maybe mine’s not as far off as I thought...I’d say I’m closer to 1/8” but I was expecting it to fit with at least a finger’s width. Maybe I just had lofty expectations...

 

[Cdaniel]

Ok, maybe mine’s not as far off as I thought...I’d say I’m closer to 1/8” but I was expecting it to fit with at least a finger’s width. Maybe I just had lofty expectations...

My 1/4 estimate is probably optimistic, so....

Not getting my grubbys on and crawling under there with the calipers.

 

[RWBeringer4x4]

Certainly not asking you to go that far, I think you’ve at least confirmed that what I’m seeing is pretty normal.

I may jump under there with a set of calipers just to take a measurement in case anyone stumbles on this thread in the future - should be easy with the grill and radiator out.

 

[RWBeringer4x4]

So, by feeler gauge I’m at almost exactly 1/16, maybe a touch less.

 

[Cdaniel]

How thick are the donut gaskets? Should be close to 1/2

 

[RWBeringer4x4]

They look about like yours I'd say - they're FelPro 8194's. Similar to this:

Fel-Pro Gaskets 8194 Exhaust Pipe Flange Gaskets, Donut

 

[Cdaniel]

A couple of these might help
1964-81 Chevrolet Small Block Exhaust Manifold Heat Riser Spacer | eBay

 

[bikersmurf]

For $400 I'd go for it.

Materials alone:
J pipes $27 x 3
SS Muffler $80
7' - 2" pipe $35
Y Collector $25
Clamps & hangers $25
Misc supplies $15
Total +/- $220

Vs $400 and no labour.

I drove mine a similar distance at 7 am with only about 8" of pipe on each side... 10.25:1 compression. Trip was fine. Loud as can be. After I found out the alternator bearing was screaming... and I couldn't hear it.