Hey guys, I have an 84 camaro berlinetta with the 305 LG4 stock set up. The car is getting vapor lock during our hot arizona summers and I just purchased a 3/4 inch wood heat spacer for my stock carb. After I order it I started to worry that it might be to tall for the under-hood clearance. Does anyone know how tall I can go with a spacer before I run out of room? Thanks

 

That's about all that will fit.

About vapor lock, do you know what kind of fuel pump you have? The factory pump had 3 lines going to it, supply from the tank, output to the carb, and a smaller return line to the tank. If your pump has been replaced with a "standard" pump with only supply and output, that's at least part of your problem. Some 3rd gens also had a dealer-installed anti-vapor lock kit that included an in-tank electric pump. If yours has that, and the in-tank pump has failed, vapor lock is even more likely.

 

If it's truly vapor lock (the fuel pump is not pumping fuel to the carb because vapor has formed between the pump and the tank) then a carb spacer won't help. For obvious reasons.

If it's a fuel boiling issue, in that fuel is getting to the carb but is boiling in the bowls and causing a rough, rich condition after a hot soak, then cooling the carb AND the fuel pump/lines may help. Assuming the stock style fuel system with return is functioning correctly.

Next time it hot soaks, check the temp of the fuel pump and carburetor. You'll probably find that the fuel pump is just as hot or hotter than the carb. If you can duplicate the issue in the driveway, spray some water on the fuel pump to quickly cool it and see if it immediately (or pretty quickly) clears.

A spacer for the fuel pump may help it keep cool. Also insure that your fuel lines are still in the stock position and not picking up too much heat from the exhaust. They should be relatively cool after a hot soak. Some headers route the exhaust too close to the stock lines (like my hedmans). I've installed some insulation around my stock fuel lines on my 87 SC along with a thin wood spacer at the fuel pump and it has helped but not completely eliminated the occasional 'loaded up' idle I get for a few minutes after soaking.

You may want to try a phenolic spacer for the pump. I used some 1/4" plywood but my mech pump well is dry (not bored to the cam lobe) and I only use it as a return 'regulator' for an electric pump.

 

Hey thanks guys for the advise. I havent changed out the spacer yet but will next week so I will see if it does the trick. The fuel pump is new but its the stock (3 line) replacement and it was doing it before the pump was switched out. Also I heard GM had some fixes for vapor lock like the electric fuel pump in the tank and as far as I know this car doesn't have one since there is no fuse for it in the fuse panel. THe more I think about it the more I think its fuel boiling in the carb. Back in the late 90s I had an 83 berlinetta with the same motor and it never had an issue but it had a 1/4 inch wood space so I am hoping my new spacer will do the trick. I got a 4 hole spacer and they say they are good for low end torque so if anything the performance boost will be good. Thanks again!

 

I had a crab where the floats were set too low and the car would suck them dry and act like a vapor lock. Had to pull the car apart and reset the level. This was a stock rebuilt replacement for a 1972 Camaro I had. If the carb has been replaced, might want to check that as well.