Raising the floats on a holley

[mopar367]

Hi there, I currently have a 600 holley vac secondary on a built up 440 .455 mopar purple cam, 8.8 compression engine. Torker intake 906 heads. The engine runs great bottom end acceleration to about 60 or 80 kms. At higher speeds over 80 km, when I kick it down doesn't feel right, plugs say it is running lean. Whiteish colour and clean.

I currently can't afford to buy a big 750 or 850 carb for it. So I adjusted my holley a bit, I raised the floats a half turn.I also turned the idle adjustment screws out a bit, and backed off the timing. My question is, is it ok to raise holley floats to get the engine to run rich? Does it work well? I did a few hard runs after the adjustments and plugs seemed darker to me. What is your take on this?

 

[bm02tj]

screw bigger jets in but you will run out of air at higher RPMs with a 600 on a 440

 

[Photon440]

Raising the floats raises the level of fuel in the bowls, you'll run richer.

 

[Meep-Meep]

I'd leave the floats where they belong and change the metering plate or add a block. Also don't forget to check the primary side. You might go up one size there too. Contrary to popular belief a larger CFM carb does not run richer and it can actually run leaner if the application is not right. The 600 should work fine, and probably very well for general street driving to 4500-5000 RPM.

I have the exact same cam in my 440 but with 10:1 CR and it's runs great. Curious to know what your cranking compression PSI is. Mine is 190 PSI.

 

[coloradodave]

Raising the floats raises the level of fuel in the bowls, you'll run richer.

Not true. Listen to Meep Meep. Increase the secondary metering plate size (or jet size if it's been converted to a metering block) and make sure the float level is set correctly. If you're unsure how to do this go to the Holley tech site.
I will agree that if you raise the floats high enough to run rich, you are puking fuel into the motor and run the risk of washing your cylinder walls with gas. NOT a good option...

 

[Cranky]

The only thing you'll do by raising the float level is make the float lever higher and too high will cause fuel to slosh into the carb like Dave mentioned but if you think you're running the bowls out of fuel at high rpm, raising the level can get you a bit more rpm before they run dry but I doubt that's happening. If you are running the bowls out of fuel, it'll act like someone turned the key off. One way to find out what's going on is to install a fuel pressure gauge. Thing is, that only tells you your PSI at high rpm and not volume but it's still a good indicator as to what's happening....

 

[67 coronet]

listen to meep and colorado.a 600cfm carb will pull a street 440 to about 4700 rpms safely(by the math).just adjust your seconday plate or jets as stated to get it right.

 

[Photon440]

Not true. Listen to Meep Meep. Increase the secondary metering plate size (or jet size if it's been converted to a metering block) and make sure the float level is set correctly. If you're unsure how to do this go to the Holley tech site.
I will agree that if you raise the floats high enough to run rich, you are puking fuel into the motor and run the risk of washing your cylinder walls with gas. NOT a good option...

You are correct; NOT a good option. I hadn't said that it was, but perhaps it was implied. Your clarification was better worded.

 

[joshb1983]

my floats are way to high..gas keeps seeping from the adjuster screws..i think the seals are bad..

 

[67 coronet]

my floats are way to high..gas keeps seeping from the adjuster screws..i think the seals are bad..

you are correct sir.if leaking fuel from adjusters,seals need replaced minimum.poss indication of needing a full rebuid.

 

[mopar367]

Thanks for the great advice guys. I think I may adjust the jetting. Since I backed my timing off a few degrees, it actually cured the problem I was experiencing. I wouldn't say it was pinging , maybe very slight pre detonation at higher RPM. Maybe that caused my plugs to read the way they did. But like mentioned above, 600 cfm is good until 4700 rpm. That is good for me because I hardly ever take it over 5000 rpm.

Meep-Meep your question about my engine with the same cam as you, I am unsure of the cranking compression of the cylinders. My friend has a compression tester and I will eventually check, Ill let you know. The engine sure runs hard though. I just grin from ear to ear when those cherry bombs start trumpeting when passing an old person hehehe. Especially on the 2-3 shift pure music

 

[tallhair]

Thanks for the great advice guys. I think I may adjust the jetting. Since I backed my timing off a few degrees, it actually cured the problem I was experiencing. I wouldn't say it was pinging , maybe very slight pre detonation at higher RPM. Maybe that caused my plugs to read the way they did. But like mentioned above, 600 cfm is good until 4700 rpm. That is good for me because I hardly ever take it over 5000 rpm.

Meep-Meep your question about my engine with the same cam as you, I am unsure of the cranking compression of the cylinders. My friend has a compression tester and I will eventually check, Ill let you know. The engine sure runs hard though. I just grin from ear to ear when those cherry bombs start trumpeting when passing an old person hehehe. Especially on the 2-3 shift pure music

I don't find this funny at all .. but that's just like my opinion man, but still wtf?

 

[daredevil]

Glad youre getting it sorted out. Running rich just washes your rings and causes premature wear.

 

[mopar367]

I don't find this funny at all .. but that's just like my opinion man, but still wtf?

Sorry, didn't mean to offend anyone. What I mean is anybody driving slower and in a lame quiet 4 cylinder car . Especially a prius