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Temp readings FYI


siteunseen

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Goofing off today I took some measurements on my 280 with the aluminum fuel rail. It goes up and down 20 degrees every few seconds. I guess that's when the excess dumps after the fpr opens up?

Anyway the car was 80 degrees cold in my garage before starting. The higher numbers are of course after a quick romp.

Fuel rail room temp...

20190915_163803.jpg

Hot closer to the return hose...

20190915_171621.jpg

Front of head...

20190915_171749.jpg

Rear...

20190915_171803.jpg

#3 header runner...

20190915_171921.jpg

Head at room temp...

20190915_163945.jpg

Oh yeah (don't tell my Mom) but here's my next purchase. @JLPurcell didn't you buy something similar to this? Thanks for any advice. Cliff

Screenshot_20190915-162544_Facebook.jpg

 

Edited by siteunseen
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Your 280z is a 76 isn't it? Your intake manifold is the 75/76 variety that doesn't have the webbing between ports. My 75 has a heat shield though that attaches to the underside of the intake manifold. I can't see a heat shield in your photos. If there isn't one, you might reinstall, or locate one and install.

If that doesn't cool your rail, you could also wrap your headers or shield them with something like what I used for my 240z manifold.

heat shield material

 

 

Edited by jonathanrussell
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This post has me thinking. (And that's a dangerous thing.) I noticed that in my fuel injection conversion, the car runs fine at first, and it acts up after it gets warm. I currently have the system dead-headed.

I'll try insulating it first, and then if it still acts up, I'll add a return to the fuel rail.

Thanks for the inspiration, @siteunseen.

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On 9/15/2019 at 6:54 PM, siteunseen said:

Goofing off today I took some measurements on my 280 with the aluminum fuel rail. It goes up and down 20 degrees every few seconds. I guess that's when the excess dumps after the fpr opens up?

Anyway the car was 80 degrees cold in my garage before starting. The higher numbers are of course after a quick romp.

Fuel rail room temp...

20190915_163803.jpg

Hot closer to the return hose...

20190915_171621.jpg

Front of head...

20190915_171749.jpg

Rear...

20190915_171803.jpg

#3 header runner...

20190915_171921.jpg

Head at room temp...

20190915_163945.jpg

Oh yeah (don't tell my Mom) but here's my next purchase. @JLPurcell didn't you buy something similar to this? Thanks for any advice. Cliff

Screenshot_20190915-162544_Facebook.jpg

 

 

Yes, Just on the other side of the TAXA Tiger Moth trailer in my garage. 

IMG_0405.JPG

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On 9/15/2019 at 3:54 PM, siteunseen said:

Goofing off today I took some measurements on my 280 with the aluminum fuel rail. It goes up and down 20 degrees every few seconds. I guess that's when the excess dumps after the fpr opens up?

Are you sure that your heat gun isn't catching some of the head and it's cooling passages?  The FPR would have a steady flow through it, it doesn't pulse like the thermostat does.  The thermostat has a chunk of wax in it that melts and solidifies over and over.  That's why it pulses.  The FPR has a spring and a diaphragm that just move based on vacuum and fuel pump pressure.

If you put a piece of cardboard behind the rail and measure again it might stop pulsing.  If it does pulse it seems more like a fuel pump thing, with the flow rate changing.  Maybe a voltage pulsing causing the fuel pump to pulse.  Who knows it might actually go all the way back to your alternator/regulator.  Maybe it's dying or engine RPM has it on edge.

Edited by Zed Head
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