vapor lock

[sweatybetty]

i read what seems to be quite a few threads where vapor lock seems to be the problem. has anyone thought that the fuel line runs right down the transmission tunnel just a few inches above the exhaust pipe for 4-5 feet. seems sitting in traffic this might be a perfect place for vapor lock to start. has anyone ever tried wrapping the exhaust or some type of shield around the fuel line in the trans tunnel? just some thoughts............

[Chickenman]

Unless I'm mistaken, the stock Fuel lines all run down passenger side of chassis no where near the exhaust system.  Edit: I think you're looking at the Evap canister purge line from the Evap Reservoir  tank. That line does run down the left side in the engine compartment and then crosses over the transmission tunnel to the passenger side. But that  line getting hot won't affect anything. 

Here's a picture of stock Fuel pipe routing viewed from the rear. They don't even attach to the tunnel, but rather to the bottom of the floor pan and all on the Passenger side. Well away from the exhaust system.

Edited April 16, 2016 by Chickenman

[sweatybetty]

all the lines on my car (72) are in the upper right side of the tunnel. the "cutout" for the exhaust on that crossmember is also on the right side ill post some pics later

Edited April 16, 2016 by sweatybetty

[Chickenman]

Curious. Now you have me thinking.

I've don't recall ever seeing a  240/260/280 Z with the exhaust cut out on the right side ( Passenger side ) of the car..... at least not from the Factory. V8 conversions and aftermarket " Dual Pipe " cross members don't count.

It doesn't make sense as all of the exhaust goes down the left side and then tucks up under the driveshaft and then muffler exits on the Left side ( Driver side ) . Exhaust would have to cross over at rear and that's not factory routing. Factory mounting for muffler is in left rear corner and the gas tank is also offset mounted to the right side on all of the 240/260/280Z models. . 

I wonder if some one put your cross member  bracket ( with the exhaust cut out ) on backwards?  They will fit both ways. 

Factory parts manuals show exhausts system going down Left hand side of car all the way from front to rear. On all years from 1970 thru 1978.

Edited April 16, 2016 by Chickenman

[Chickenman]

I believe that Nissan may have moved the fuel lines on later years up into the right side of the transmission tunnels for safety reasons. A little more protection from road debris.  Hard finding pictures of all of the various years. But still all on the passenger side. 

 

 

[Chickenman]

Delete. Double post.

Edited April 16, 2016 by Chickenman

[sweatybetty]

1 hour ago, Chickenman said:

I wonder if some one put your cross member  bracket ( with the exhaust cut out ) on backwards?  They will fit both ways..

 i found that the right rear wheel bearings and spindle pin have been changed, so that is entirely possible. but, the exhaust was run down the right hand side.

 

Edited April 16, 2016 by sweatybetty

[Zed Head]

Just a reference.  The majority of Z owners use the factory exhaust routing, left of the drivetrain.  Picture from 1970, they're all like this.

[sweatybetty]

mine is has a 1/72 build date. what are "later" years?

[sweatybetty]

2 hours ago, Zed Head said:

Just a reference.  The majority of Z owners use the factory exhaust routing, left of the drivetrain.  Picture from 1970, they're all like this.

that drawing makes perfect sense. the guy i bought the car from bought it from a tweaker, so who knows? i will put the crossmember the way it should be and go from there. but, my original question still stands. can heat build up in the trans tunnel contribute to vapor lock, if the lines are in the tunnel?

[sweatybetty]

4 hours ago, Chickenman said:

Unless I'm mistaken, the stock Fuel lines all run down passenger side of chassis no where near the exhaust system.  Edit: I think you're looking at the Evap canister purge line from the Evap Reservoir  tank. That line does run down the left side in the engine compartment and then crosses over the transmission tunnel to the passenger side. But that  line getting hot won't affect anything. 

Here's a picture of stock Fuel pipe routing viewed from the rear. They don't even attach to the tunnel, but rather to the bottom of the floor pan and all on the Passenger side. Well away from the exhaust system.

what year is that car?

[Chickenman]

1 hour ago, sweatybetty said:

that drawing makes perfect sense. the guy i bought the car from bought it from a tweaker, so who knows? i will put the crossmember the way it should be and go from there. but, my original question still stands. can heat build up in the trans tunnel contribute to vapor lock, if the lines are in the tunnel?

I would say no. Much higher temps develop in engine bay. Most cars run the fuel lines down the tunnel and have no issues with Vapor Lock or Fuel Percolation. It's an issue on the Z cars related to the exhaust manifold being directly under the Intake manifold.

Edited April 16, 2016 by Chickenman