Norwood

[GregWeld]

Old pumps and new fuel.....


Good to replace it and ANY old rubber fuel line. Had one buddy chasing a fueling issue - replaced pump TWICE -- turns out the insides of the 50 year old factory rubber lines (that connected the steel lines) had failed and was acting like a check valve.

Any more - I only use PTFE lined braided if I need a wobble point.

[GregWeld]

BTW - I'm no carb guy -- but I thought that the air bleeds (not to be confused with idle fuel adjustment screws) were there to overcome big azz cams that just couldn't be tamed with the idle screws. Since we know that carbs work via vacuum (actually low pressure in the ventures) -- any source of vacuum (air) leak is going cause you to have to fatten the idle screws and is going to also cause a higher idle.

Might just try to plug them temporarily and see what happens to the response and idle adjustment??

[Sieg]

Originally Posted by GregWeld

Old pumps and new fuel.....


Good to replace it and ANY old rubber fuel line. Had one buddy chasing a fueling issue - replaced pump TWICE -- turns out the insides of the 50 year old factory rubber lines (that connected the steel lines) had failed and was acting like a check valve.

Any more - I only use PTFE lined braided if I need a wobble point.

E10 may have finally gotten to it, we'll see.

There's no OEM rubber on it, the tank to hard line is the oldest, I just replaced the rubber line between the fuel pump and hard line which was installed at the same time and it appeared OK just a little hardened.

Originally Posted by GregWeld

BTW - I'm no carb guy -- but I thought that the air bleeds (not to be confused with idle fuel adjustment screws) were there to overcome big azz cams that just couldn't be tamed with the idle screws. Since we know that carbs work via vacuum (actually low pressure in the ventures) -- any source of vacuum (air) leak is going cause you to have to fatten the idle screws and is going to also cause a higher idle.

Might just try to plug them temporarily and see what happens to the response and idle adjustment??

The only vac leak I know of would be from the baseplate and spacer and I checked those surfaces with a straight edge. This carb has no vac ports. PCV and gauge vacuum come off the intake manifold behind the carb.

The idle bypass valve is what I don't have a good feel for yet. Holley tech said the there's no relationship between fuel screws and this circuit? But when you open up that valve it creates a lean idle similar to a vacuum leak.

Being patient......should have the pump in two days.

Yes...........Fast EZ-efi would be nice but way too simple and............

[GregWeld]

When I say vacuum leak. I mean ANYWHERE air is allowed into the engine. I don't just mean a bad seal.... The air bleeds are technically a "controlled" vacuum leak... As is a PCV etc.

[GregWeld]

Sitting at Boise airport since Alaska canceled the sun valley flight "due to weather". Right! It was clear blue skies and u could see for miles. Oh well.

[DaleTx]

Sieg.... sounds like your getting closer to resolving the tuning issues with your new carb

Here is a link to a thread I ran across that has some discussion about tuning the Holley HP Ultra carbs that could be helpful.

http://www.ffcars.com/forums/17-fact...carb-idle.html

[Sieg]

Originally Posted by DaleTx

Sieg.... sounds like your getting closer to resolving the tuning issues with your new carb

Here is a link to a thread I ran across that has some discussion about tuning the Holley HP Ultra carbs that could be helpful.

http://www.ffcars.com/forums/17-fact...carb-idle.html

Thanks Dale, I can definitely relate to those posts, especially j.b.goode's.

Holley tech told me the transfer slot exposure is supposed to be .025 even though the manual which is relatively detailed makes no reference. That's where I set them and it results in a fast idle and the idle bypass valve is relatively ineffective in controlling idle speed. The motor has been weak/flat/stumbles/bogs when engaging the clutch which says lean. Just haven't been able to find that crisp and meaty response right off idle yet.

I'm going to retain the primary transfer slot spec and back the idle down with the secondaries and see what it gives me. It's about time to say screw the rules and tune by response!

The upside is off idle performance is pretty strong, trailing throttle in corners is good, roll on's into the secondaries near seamless. The pump cams and squirters even feel close but I will test +/- alternatives just because.

I'm close, another decade should do it at my current rate.

Disclosure: In no way do I feel this carb is at fault. .......it's me

[Sieg]

Originally Posted by GregWeld

When I say vacuum leak. I mean ANYWHERE air is allowed into the engine. I don't just mean a bad seal.... The air bleeds are technically a "controlled" vacuum leak... As is a PCV etc.

Nit-Picker!

The air bleeds AND that idle bypass valve.

If the carb isn't getting adequate fuel pressure at idle would that impact the idle circuit function?

[GregWeld]

Originally Posted by Sieg

Nit-Picker!

The air bleeds AND that idle bypass valve.

If the carb isn't getting adequate fuel pressure at idle would that impact the idle circuit function?

I don't think it would affect idle at all.