Ceramic Coated headers/extractors

[Murph]

Yep, fuel system recirculates. That only keeps fresh fuel in the main lines though, not the lines to the carbs, or in the carb bowls. After 5 minutes of turning it off the carbs are that hot you can't touch them. Go for a 10min drive and they are cold again, whereas without the heatshield they'd remain hot.

I can get a small thermo fan for nothing, so I might gave that a whirl, see how it goes.

[260DET]

OK if the carb bowls are getting that hot do an additional heat shield. Looks like you could fit one under the carbs.

BTW how do you get such good pics?

[Murph]

An aditional heat shield to give some more protection around the top of the carbs would help for sure. The fuel bowl is pretty well protected as is though. You can see how high it comes a bit better in the attached pic. An additional layer of some sort of insulating material on the heat shield should also help.

One thing I have noticed is that when I get this vapour lock problem, I get some overflow from the fuel bowls. Would that point to the fuel boiling in the fuel bowl?

Pics are taken with a Kodak DX3900. Not the greatest digicam ever, but it does seem to produce quite sharp images with the flash on at night. That pic above was scaled to 33% then slightly sharpened.

[260DET]

Yes the heat would expand the petrol in the bowl and may cause the engine to flood. Hard to hot start? Flattening the accelerator when its cranking over could help.

You reckon your car gets hot? With the turbo the paint under the bonnet of mine blistered, before some al heat shields were added and the bonnet vented.:classic:

[260Zed]

I had similar probs. Although mine don't seem as bad as datto-zeds, mine would never die, just hesitate. Also wasn't as severe on hot restart. I have electric RX7 fuel pump, recirculating fuel line, etc. I have a non-vented hood and round top SUs. I was experiencing a hesitation only after engine got to working temperature and was a hot day 35C+, and only after car had been at idle (set of lights etc).

Fuel pump - didnt fix

Ceramic coating - helped but didnt completely solve.

Insulated fuel float bowl - helped

Insulated rubber fuel line from rail to carb - Huge difference

With all these, the problem is gone in normal driving condidtions. (Yeah even in our summer). I'm currently looking at ways to insulate the fuel rail without having it look pig ugly (a la foil wrap etc).

I'll post pics of the bay when I get them back. The only visible insulation is the pipe around the fuel line. But looks suprisingly good! :classic:

A thing to note is that I do not have a heat-shield of any type! (Only a 6mm closed-cell foam with aluminium foil backed insulation on float bowl.)

BTW The coating cost me about $200 AUS.

Jet Hot in comparison are about $240 i think inc postage to Vic.

Hope this helps mate.

Luke

[Murph]

260DET: Geez! I don't even want to think what it would be like with a turbo under there.

Originally posted by 260Zed Fuel pump - didnt fix

Ceramic coating - helped but didnt completely solve.

Insulated fuel float bowl - helped

Insulated rubber fuel line from rail to carb - Huge difference

Hmmm never thought of that, but it makes sense.....I'll try insulating those lines tomorrow. I did notice it gets rather hot. Being black and with a much larger surface area than the metal lines would make them significantly hotter. What material did you use to insulate them?

[260Zed]

The lines were the last thing i did. I used a expanded nitrile rubber pipe insulation. Commonly used round hot water systems. Usually called Armaflex or Superlon. I got mine thru work cheap, but you should be able to pick it up for bout $6-7/mtr. Fire retardant, good resistance to fuels/oils, I'm trying to find it in the right size for the fuel rails, to cover them indervidually, rather than slap a big one over it all.