Valve float?

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Re: Valve float?

Post  Mark Miller on May 2nd 2017, 11:18 pm

rmk57 wrote:
Mark Miller wrote:IMO sounds like it's running out of fuel[fuel pump]more then likely put a good electric pump on it and try again.Mechanical Pump might be ok for street driving but not enough for the track.The 11.95 run was a good ET but 107 MPH is low for the ET maybe running out of fuel?


All four of my passes were at 107 mph even the 13.46, which was the first and the worst.

What should the mph be for high 11's ? 113- 115 or so?

Overall I'm happy with the first outing with it. I was hoping for mid-12's. When I got the 11 second slip I was very surprised just because of the way it was running.

I really wanted to try and stay away from an electric pump just because of the racket they make, but if it is a fuel issue I may have to. It is a street car.

For what it's worth this what I did to my M60882 pump. Drilled and tapped -8 inlet and -6 to the carb.


http://www.460ford.com/forum/37-engine-tech/129644-carter-172gph-pump-still-exists.html

I would say mph should be in the 111-112 mph range at least for a 11.9 pass.I remember my cousins 74 Comet with a 351 Cleveland was running consistent 12.30's@108 mph years ago.

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Re: Valve float?

Post  Scott Foxwell on May 3rd 2017, 7:54 am

rmk57 wrote:
Scott Foxwell wrote:I think that Carter pump is a 120 gph but even still, should be plenty of fuel pump. You have 1/2" feed line so that's good. Is your fuel tank sumped? Is it 1/2" all the way inside the tank, or is there a restriction there?
X2 on getting the points gap to .016-.017 but I don't think that's your problem. Sounds like valve springs or fuel. Carb is small but again, not the problem. I'm leaning toward valve springs. Do you know anything about the springs on the heads now? Assuming it's a flat tappet? Need to somehow get a spec on the spring and then check seat pressure.

I did modify the carter pump by enlarging the inlet/ outlet ports to -8 and -6. Originally it came with 1/4" pipe. No the fuel tank is not sumped, just an original 57 Ford tank.
I did weld in a new 1/2" pipe bung and it is 1/2" all the way inside the tank and 1/2" to the pump, then -6 to the carb. I had about 8-10 gallons of gas in it when i was racing it,which is less than 1/2 tank.
As far as ignition I dont think it's the problem either. I may be picking up a an MSD 8477 distributor tonight just to get rid of the points anyway. It has a a MSD 6al-2 box and a MSD blaster 2 coil.
The only thing I know about the valve springs is what Iv'e read here and the other 460 site. There brand new Edelbrock 75cc heads, and I did put .030 shims in already, which may bump up the pressure to 130? I bought the heads used but they were brand new, never fired on a engine.
1.975 installed height
120 closed 330 open
1.160 coil bind
The cam is a solid flat tappet, 590/600 233/244 @ .050. Scotty from Reincarnation speced it for me, i'm really happy with it.
I would check the springs if you can. If they do have ~130 on the seat that should be enough to push past 6000 pretty easy. Everything else sounds pretty good. Does it ever backfire through the carb? LIke said...read plugs...might just be lean and running out of fuel regardless of the delivery system. Carb is a bit small.
3600+ lbs running 11's...it's making decent power.

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Re: Valve float?

Post  rmk57 on May 3rd 2017, 11:33 am

I'm going to get a couple springs checked at my local builder and if they are questionable get them all checked and replace the .030 shims with .060 shims.
I checked a couple plugs at the end of a run in the pits and they looked ok to me. Light grey, mostly white porcelain, no signs of any leanness or fouling. My jetting is at either 82/86 or 84/88, forgot to write it down.
It's never ever backfired through the carb. It falls off before my 2-3 shift and then really noses over at about 200-300 feet before the finish line. From the 1000 ft to the timing marker I'm only picking up 8.5 mph.

It is making decent power, 1.60 sixty foot with only Caltracs and a stock suspension. I think once it's sorted out 11.60's-70's should be realistic.

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Re: Valve float?

Post  supervel45 on May 3rd 2017, 12:51 pm

https://www.quickfueltechnology.com/carburetors/street/ss-series/ss-series-carburetor-750cfm-annular-booster.html

Are you sure you did not get an E-85 carburetor with those jets? The Holley 9379 750 annular is 68P 81S 6.5PV Primary Power Valve only.

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Re: Valve float?

Post  rmk57 on May 3rd 2017, 1:42 pm

supervel45 wrote:https://www.quickfueltechnology.com/carburetors/street/ss-series/ss-series-carburetor-750cfm-annular-booster.html

Are you sure you did not get an E-85 carburetor with those jets? The Holley 9379 750 annular is 68P 81S 6.5PV Primary Power Valve only.

My bad.... 74/84 5.5 P/V

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Re: Valve float?

Post  supervel45 on May 3rd 2017, 1:52 pm

^^^^^Much Better, those first jet sizes actually do equal out to E-85 Jets if you don't count air bleed sizing, LoL


Last edited by supervel45 on May 3rd 2017, 1:58 pm; edited 1 time in total

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Re: Valve float?

Post  supervel45 on May 3rd 2017, 1:57 pm

I guess check your valve springs and go from there. You are border line in 3-4 areas and they may all be stacking up together.

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Re: Valve float?

Post  rmk57 on May 3rd 2017, 2:50 pm

I picked up almost new MSD 84771 distributor yesterday with all the extra pieces it comes with, I just have to buy the trigger cable for it.
Should rule out any ignition problems. I was never really happy with the points part of it anyway and Iv'e had mixed results with Pertronix conversions.

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Re: Valve float?

Post  supervel45 on May 3rd 2017, 3:03 pm

I think the MSD is a great idea. I would still grab a fuel pressure gauge. I am with the other guys, those mechanical pumps by them self leave a lot to be desired. If those valve springs are real weak for some reason, I personally would just replace them.

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