604 help!!!

[leeroy]

Carb is sweating... High RPM miss. Problem has been going on for a couple of weeks. Just replaced old carb with new Willys, still same result. Any thoughts?

[jedclampit]

Valve springs!

[leeroy]

Thanks Jed... They checked good but I will change them anyway..

[Egoracing]

Only time I have seen a carb sweat was when there was a high alcohol content to the fuel, valve springs would have nothing to do with it. What kind of fuel are you running? The one I say was a track buying pump gas and mixing alcohol in to get the octane up and putting coloring into the fuel to make it look like race gas and they were selling it as Sunoco Blue. It burned up several motors and all cars had carbs condensing on the fuel bowls and main body and the engines were missing.

[leeroy]

sweating is most noticable on the spacer. sprayed starting fluid around it last night to check for leaks.. could not determine that there was a leak. We use sunoco race fuel, pumped directly from the barrel at the track...

[noral54]

missing

your too rich on top end lean out about 3 jet sizes front and back ,the warmer the ambeant temp the worse it will get.

[leeroy]

Found that the pick-up in the distributor was bad, hopefully this was the cause of most of the problems, i will keep the jet change in mind once we get some practice laps this weekend. thanks for the suggesstions.....

[SRXSRULE]

Pick-up coils get overlooked a lot .

Very easy to check. Pull the cap and rotor, unhook the two wire connector going to the module. Hook up a DVOM to the two wires coming from the pick-up coil and set your meter to A/C volts. At normal engine crankinng RPM the pick-up should put out 700-1100 mV. I perfer to stay above 900mV and anything under 700mV will cause problems. Eric

[leeroy]

This pick up looked very very bad, with rust/corrosion. I will definately put it on the things to check list from now on. I did notice when I fired the engine with the new pick up the timing was off a little. I guess this is normal...?

[jedclampit]

Only time I have seen a carb sweat was when there was a high alcohol content to the fuel, valve springs would have nothing to do with it. What kind of fuel are you running? The one I say was a track buying pump gas and mixing alcohol in to get the octane up and putting coloring into the fuel to make it look like race gas and they were selling it as Sunoco Blue. It burned up several motors and all cars had carbs condensing on the fuel bowls and main body and the engines were missing.

I believe the high rpm miss was the problem at hand, and it was not unreasonable to postulate that weak valve springs, on any engine, especially a 604, could be at fault.

Cars running on VP, CHP fuel sweat the carb.

[Egoracing]

I believe the high rpm miss was the problem at hand, and it was not unreasonable to postulate that weak valve springs, on any engine, especially a 604, could be at fault.

Cars running on VP, CHP fuel sweat the carb.

I agree with that, It has been recently that I have started to see the alcohol mixed fuel and it seemed to be at more than one track and it had the exact issues, Missing and the carb was sweating so bad it was puddeling in the intake.