What Carb spacer to run and Holley carb issue.

[ZZ4CutlaSS]

Been looking for a carb spacer but have no clue what to buy. My engine is a ZZ4 with a dual plane intake and 770cfm Holley carb. Two summers ago when the engine was running I was having issues with it dumping fuel into the take when engine was shutoff after engine was at operating temp. My garage also would smell like gas so I would remove the air cleaner and could see fuel dripping into the intake. My guess it that the carb is getting to hot and it starts to boil over. And also it would start hard due to flooding. So my theory is a carb spacer will help keep the carb cooler. Any tips on a spacer or my carb issue will be appreciated thanks.

 

[carguy1959]

I think you need to check the float level in your carb, or the "needle and seat" need to be replaced...

 

[ZZ4CutlaSS]

I think you need to check the float level in your carb...

Thanks but thats the first thing I went after and its fine. Seems like pressure is building in the fuel bowls and only does it when at opperating temp.

 

[ZZ4CutlaSS]

Should of mentioned carb has only 5,000 miles on it and has had the issue since new. I took it apart and inspected the needles and seats and no issues found.

 

[565bbchevy]

The best insulating spacers I have used are phenolic made by Jomar Perf. in MI. also wood spacers work good but are not that strong, I've had those crack around the bolt holes. Since you have a dual plane you would have to use a 4 hole or 2 hole (2 long oval holes so the divder is still sealed) an open spacer will affect the performance of a dual plane. Aluminum spacers do nothing for insulating heat.

 

[ZZ4CutlaSS]

The best insulating spacers I have used are phenolic made by Jomar Perf. in MI. also wood spacers work good but are not that strong, I've had those crack around the bolt holes. Since you have a dual plane you would have to use a 4 hole or 2 hole (2 long oval holes so the divder is still sealed) an open spacer will affect the performance of a dual plane. Aluminum spacers do nothing for insulating heat.

Thanks for the input. Does my issue sound heat related to you?

 

[Bonnewagon]

If it is heat related a spacer is probably not the answer and could cause other problems. Usually when a carb boils over it is caused by the EFE (heatriser) valve being stuck shut. That diverts all the exhaust from one bank through the middle of the intake and out the other bank and that roasts the carb, boiling fuel. I see you have headers, so that's probably not it, unless the manifold is open to the exhaust crossover in both heads and is getting overheated anyway. In that case block-off intake gaskets would cure that and in extreme cases the passageway could be blocked with molten aluminum.

 

[ZZ4CutlaSS]

If it is heat related a spacer is probably not the answer and could cause other problems. Usually when a carb boils over it is caused by the EFE (heatriser) valve being stuck shut. That diverts all the exhaust from one bank through the middle of the intake and out the other bank and that roasts the carb, boiling fuel. I see you have headers, so that's probably not it, unless the manifold is open to the exhaust crossover in both heads and is getting overheated anyway. In that case block-off intake gaskets would cure that and in extreme cases the passageway could be blocked with molten aluminum.

Thought of that too but my heads don't have a exhaust cross over port casted into them.
http://www.summitracing.com/parts/NAL-1 ... /?rtype=10

 

[ZZ4CutlaSS]

Think I will give this one a try to see if it helps.
http://jomarperformance.com/catalog/pro ... cts_id=206

 

[565bbchevy]

I would say if the fuel is actually boiling over in the carb because it is too hot then you would have driveabilty problems like it won't start after you shut it off after driving awhile, stalling or hesitation. As long as you have checked the float levels correctly, made sure there are no sticking needle and seats, your fuel pressure is not too high or unregulated with too strong a pump. make sure you have done all these before buying a spacer. But regardless a good insulating spacer will always help keep the carb cooler.