Hello,

I would like to say I am a classically trained carter / edelbrock tuner using metering rods which is the same concept as the Holley Power Valeve, just applied mechanically different to the enrichment circuit, but no one trained me... I just sort of figured the Carter stuff out over time.

I am now tuning a typical Holley carb; it's a 4 Bbl with the typical primary side metering block, primary jets, and secondary side jets / metering block.

In the primary metering block in the power valve used for enrichment circuit.

The power valve has a stamped vacuum rating on it , like 6.5 etc.
Does the # printed on the 6.5 PV mean that at 6.6" of hg up to say 14", 20 " or 30" hg of vacuum there is no enrichment, and when the PV vacuum signal falls below 6.5" vacuum the enrichment begins?


Thanks Holley sages!!!

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You are correct!

Lou

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Home of Slant6-powered fun machines since 1988

That is correct. When the power valve opens it allows fuel enrichment through the power valve enrichment channel (PVCR).

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Thanks Guys

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Another Question:

Do you guys find that the power valves themselves to be inconsistent?

I Tried some trailer towing and found that tuning the part throttle load / cruise to be virtually impossible
I thought I got a handle on tuning this thing, with primary jets and PV, when I went to other PV's it was rich down low (low demand/ high vacuum) then when I swapped it for a lower value valve it got worse! More lean on low vacuum!

Got out the mighty vac and tested the valves.. they seem inconsistent compared to their stamped markings.

At this point I am not sure if I should try futzing more with it some more or just buy an Edelbrock Performer 500 CFM and be done with it@#!!

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I feel this is an inherent problem with Holleys, and is why I mostly hate them and do not use them. The power valve is a major design flaw as it is pretty much on or off and makes a big mixture change. Maybe on a V8 they are calibrated/optimized better, but I expect everyone just lives with these things and doesn't care about fine drivability or MPG. On a related note, EFI will always be better at fine tuning, but requires much more expense and knowledge.

Lou

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Home of Slant6-powered fun machines since 1988

I have gotten the driveability fair enough and can be "lived with" properly on my Carter 500's and 750s with just a few quick hours of futzing.

I think then I will go ahead and buy the new eddy or in the worst case Steal the one off of the (non-running for the time being) '64 Dart and reimburse myself later.


Yes If I just floored it last nite with the Holley it was fine, but there was a vast desert of part throttle leanness that was not cool, going up hill adding throttle with the trailer going to 17's AFR? WTF?

I never had that issue with the 'ole Eddy / Carter, Even if I tuned it somewhat badly.




Thanks,

Greg

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And you already knew the answer!

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I just thought it would tune up as easy as the Edelbrock did.
You know, I thought maybe I was doing something wrong, This car already had the carb on it so I wanted to try to use it, but no good now that I have the AFR gauge on it.

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