700 double pumper on a road car

Blue · Post by **Blue** » Fri Aug 29, 14 11:39 am

Interesting, that's not been my experience.

dustymopar · Post by **dustymopar** » Fri Aug 29, 14 11:47 am

Indeed, all of the Holley 4150 rebuild kits that have past through my hands come with the Red umbrella's - some were used and some not depending on the style / age of the bowl.

Guy · Post by **Guy** » Fri Aug 29, 14 12:07 pm

GJUK wrote:I will lob this 750 vac sec Holley I have bought on

I meant the bowls off of the 750 vs he has, sorry for any confussion

Pete wrote: I believe the fuel inlets are handed, so whilst a Primary bowl may bolt on, it will not work in practical terms.....I stand to be corrected..........

Unless they are dominator bowls which are ambidextrous

GJUK · Post by **GJUK** » Fri Aug 29, 14 2:15 pm

dustymopar wrote: My money is still on the needle valve

Yeah this is brand new though, was replaced with the kit.

GJUK · Post by **GJUK** » Fri Aug 29, 14 2:17 pm

dustymopar wrote:Indeed, all of the Holley 4150 rebuild kits that have past through my hands come with the Red umbrella's - some were used and some not depending on the style / age of the bowl.

Maybe I have some in the box still

...

dustymopar · Post by **dustymopar** » Fri Aug 29, 14 2:35 pm

GJUK wrote:Yeah this is brand new though, was replaced with the kit.

I know you did Jon, it's quite possibly OK although I would since you problem just relates to the Sec bowl I would be tempted to put the old one back in to eliminate it.

I put a brand new cooling system stat in once, got a couple of miles from home and the motor overheated. The Mrs brought another spare from home (same rating) and drove home on it without any problem. The new one is still at the end of the common about 50 yards from where I thew the damn thing

GJUK · Post by **GJUK** » Fri Aug 29, 14 2:47 pm

dustymopar wrote:
GJUK wrote:Yeah this is brand new though, was replaced with the kit.
I know you did Jon, it's quite possibly OK although I would since you problem just relates to the Sec bowl I would be tempted to put the old one back in to eliminate it.

I put a brand new cooling system stat in once, got a couple of miles from home and the motor overheated. The Mrs brought another spare from home (same rating) and drove home on it without any problem. The new one is still at the end of the common about 50 yards from where I thew the damn thing

I hear what you are saying. the needle does seem to stick at the top a little, that said all that would cause is NO fuel. not barrels of the stuff.

I might just stick a webber 45 on the car :p

dustymopar · Post by **dustymopar** » Fri Aug 29, 14 3:16 pm

If the valve is not fully seated on closing the fuel would still trickle in. I'm sure you'll sort it out

GJUK · Post by **GJUK** » Fri Aug 29, 14 3:17 pm

dustymopar wrote:If the valve is not fully seated on closing the fuel would still trickle in. I'm sure you'll sort it out

But it does fully close - you can test this while blowing in to the carb and gently raising the float. You hit total resistance.

GJUK · Post by **GJUK** » Fri Aug 29, 14 3:24 pm

GJUK wrote:
dustymopar wrote:If the valve is not fully seated on closing the fuel would still trickle in. I'm sure you'll sort it out
But it does fully close - you can test this while blowing in to the carb and gently raising the float. You hit total resistance.

Added to this the float gets stuck to the bottom, when you try to raise it up it catches on something and is quite stiff to release. That said once free it goes up and down of its own free will.

I'm just wondering if that spring it doing its correct job or anything at all for that matter

dustymopar · Post by **dustymopar** » Fri Aug 29, 14 3:33 pm

Take a pressure gauge and blow into it, I'm sure as hell I can't push 4,5 or 6 Psig...... At greater pressure any seating problem will reveal itself. Try it, if I am wrong, then I'm wrong

GJUK · Post by **GJUK** » Fri Aug 29, 14 4:13 pm

point made.

GJUK · Post by **GJUK** » Sat Aug 30, 14 11:33 pm

I checked and there is a ball bearing in the base of that float bowl. I do have a red 'stopper' though but it would not fit in this carb.

GJUK · Post by **GJUK** » Mon Sep 01, 14 9:02 pm

Back to the car.

Page 16 of this thread, amazing

I now have a known working 750 Vac Sec on the car, setup and taken off a 400 big block which was of okay spec, similar to mine.

Started first time, no leaks, back on the mechanical pump and regulator sticking at 5 psi.

took it out, went well apart from if you floor it.

The car bogs the pops a huge flame out of the scoop. Blink and you'd miss it but it was at least 1ft tall. Quite impressive but scared the Bananarama! out of the people around me and myself

No booster flooding, no dripping, no stalling no issues other than the bog and fireball.

My thanks to Philph for the carb.

So, how does one fix the fireball issue? Running lean?

Timing is spot on at 17 idle and 37 at full in at 3100 rpm.

[Carb details]

It's listed as 750 vac sec 3310-S. It 's been fitted with 72F and 76R jets with a 8.5 power valve and size 32 shooters. It also has a quick change cap for the spring in the vac sec po

Thank you.

Jon

John · Post by **John** » Mon Sep 01, 14 9:13 pm

Definately sounds lean, sounds like you need mighty Mick to pop round again

Failing that you should now be able to go through the carb tuning sticky

Bigger primary jets and bigger front shooter