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Anything around 4 psi is OK for the Holley. It sounds like your problem is not enough gas is getting to the carb? Filters? lines from tank?
Filters are new as are the fuel lines. Tank is about 9 months old. I am not sure what the regulator is set to from the factory but I thought I remembered 2psi from somewhere. I will look to see if I can open it further.
It looks like your vacuum is low. Here is a good chart that may help you. I'm not sure what size Holley you put on but that may be your problem. Remember that you only have a 239 cid engine with 6:1 compression ratio (assuming that you haven't changed anything). Any vacuum loss is a problem. Go back to your original carb and see if the stumble goes away.
I'm not sure what type of advance Jim Linder put in for you (mechanical, vacuum or some combination). Did you tell him about the 4 barrel carb before you ordered the distributor? What is your initial timing?
Picked up a Mr. Gasket fuel pressure gauge and I have 2 lbs. I have adjusted it up to 3.5 and much more has is flowing. I'll try to static time it tomorrow. And see if that helps the stumble
Pete, Thank you for the chart that is helpful! I got the mechanical advance distributor from linder I told them what I had. The carb is the smallest thing holley makes so I hope size isn't the issue. I would try an old carb but I don't have one. When I bought the truck the holley was already on it. The whole truck ran pretty well after I put on the linder distibutor until the old electric fuel pump went out. That points to the fuel system and possibly timing since I fiddled with that a little also. My vacuum is a little low but rpms m to have more effect than anything so I would like to make it idle a little smoother before I panic about bad rings or something like that.
My vacuum is a little low but rpms m to have more effect than anything so I would like to make it idle a little smoother before I panic about bad rings or something like that.
Yes, but remember that chart is for 600 RPMs as Ross noted. Your carb would have to be too big for a stock flathead as Holley no longer makes a carb small enough for a stock flattie. Even so I think that your timing (initial or advance) may be the issue. Jim Linder at Bubbas might be able to help. Charlie Price at Vintage Speed is also a good source of info on carbs.
Understood. I was have problems where the idle would be 600 for a few seconds then 800 then 600. It is likely I will have some other issues to deal with soon but for now I need to truck to run so I can justify more money spent.
Pete, the Holley 390 cfm is made just for flatheads. It may not make a huge difference on a stock engine, but it's better than 3x2's which are common enough.
John, which regulator do you have? If it is a round one with pressure settings on the lid, usually made by Spectre, they are crap.
Pete, the Holley 390 cfm is made just for flatheads. It may not make a huge difference on a stock engine, but it's better than 3x2's which are common enough.
John, which regulator do you have? If it is a round one with pressure settings on the lid, usually made by Spectre, they are crap.
Ross,
I didn't see the 390 listed on Holley's site but they have changed things around significantly and I may have missed it. Yes, 390 cfm looks to be about right. I just don't know what John has. I still think that timing is his most likely problem.
Pete, the Holley 390 cfm is made just for flatheads. It may not make a huge difference on a stock engine, but it's better than 3x2's which are common enough.
John, which regulator do you have? If it is a round one with pressure settings on the lid, usually made by Spectre, they are crap.
I have the Holley 12-804 which should be for 1-4psi. I am not entirely happy with it as it is weeping a small amount of fuel despite several attempts to reseal. If there is a better choice I am all ears. I may just be able to eliminate it since I do not think the pump will produce more than the 8lb Holley limit
It's been a busy day but no love from the ford. I have timed the thing 9 ways to Sunday. All put the distributor in the same position. I have adjusted and readjusted the floats I have done the same with the needle valves. The engine runs no better. At times it was worse but never better. This truck ran convincingly well 6 months ago but not now. I guess the only thing left is to rebuild the carb again but I did that 8 months ago so I can't imagine what could have gone wrong in that short amount of time. Starting to think MegaSquirt.
MegaSquirt's no panacea. Where is the reg leaking? If out of the dome, the diaphragm is ruptured. Holley sells a rebuild kit with new springs for $10 at O'Reilly's, p/n 12-807. I'd keep a spare. If it's just weeping at the connections, keep tightening, cleaning the seats. It'll stop.
If you have the throttle stop screw set too far closed, and are adding fuel thru the idle mix screws, it will idle OK but run poorly off-idle. Try opening up the throttle plate a little, and re-adjusting the mix screws leaner.
MegaSquirt's no panacea. Where is the reg leaking? If out of the dome, the diaphragm is ruptured. Holley sells a rebuild kit with new springs for $10 at O'Reilly's, p/n 12-807. I'd keep a spare. If it's just weeping at the connections, keep tightening, cleaning the seats. It'll stop.
If you have the throttle stop screw set too far closed, and are adding fuel thru the idle mix screws, it will idle OK but run poorly off-idle. Try opening up the throttle plate a little, and re-adjusting the mix screws leaner.
I'm pretty sure it is leaking at the bottom connection and not a lot as far as I can tell.
Forgive my lack of nomenclature but are you referring to the Primary idle speed screw (with the spring)?. If so it is backed almost all the way out to keep the idle lower.
08-12-2014, 11:10 AM
