Valve float?

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Valve float?

Post  rmk57 on May 1st 2017, 11:04 am

I went out to my local track for the street legals on Friday for the first time and had mixed results. My first pass was a 13.46 @ 107 mph, some tire spin. My second pass was a 11.95 @ 107 mph. The rest of my passes were low 12's but all at 107 mph. The car just seems to hit a wall at around the 1000 foot mark. I have my shift light set at 5600 rpm and it never came on once. I don't have a proper tach just an msd shift light with the digital rpm readout on the side. Just by the sound I doubt it's getting to 5000 rpm.

The engine is a
502 c/i. Scat rotating assembly.
Edelbrock 75cc heads with .030 shims installed.
One of Scotty's cams, .600 lift 233/244 @ .050, solid lifter.
Weiand Stealth, QFT 750 cfm, annular.
MSD 6al2 with points triggering the msd box.
2 inch headers, 3 inch exhaust.

The car is a 57 Ford Custom. With me in it it's 3660 lbs.
C-6, 2600 stall, 3.70 D/L, MT drag radials.

The ignition could be part of the problem, but not the major problem. The points are new Blue Streaks and should be able to go to 5600 rpm.
I guess my question is do you think I could shim a bit more? Could the valve springs be toast now?

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Re: Valve float?

Post  rmcomprandy on May 1st 2017, 11:38 am

rmk57 wrote:I went out to my local track for the street legals on Friday for the first time and had mixed results. My first pass was a 13.46 @ 107 mph, some tire spin. My second pass was a 11.95 @ 107 mph. The rest of my passes were low 12's but all at 107 mph. The car just seems to hit a wall at around the 1000 foot mark. I have my shift light set at 5600 rpm and it never came on once. I don't have a proper tach just an msd shift light with the digital rpm readout on the side. Just by the sound I doubt it's getting to 5000 rpm.

The engine is a
502 c/i. Scat rotating assembly.
Edelbrock 75cc heads with .030 shims installed.
One of Scotty's  cams, .600 lift 233/244 @ .050, solid lifter.
Weiand Stealth, QFT 750 cfm, annular.
MSD 6al2 with points triggering the msd box.
2 inch headers, 3 inch exhaust.

The car is a 57 Ford Custom. With me in it it's 3660 lbs.
C-6, 2600 stall, 3.70 D/L, MT drag radials.

The ignition could be part of the problem, but not the major problem. The points are new Blue Streaks and should be able to go to 5600 rpm.
I guess my question is do you think I could shim a bit more? Could the valve springs be toast now?

It might be valve float ... does it go past that RPM in the lower gears ...?
Whether or not you have enough room to coil bind will determine whether or not you can shim them more.

I would look at the points floating, also. Do you know somebody with a distributor machine ...?

Personally, I think you also need more carburetor with that set-up.

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Re: Valve float?

Post  rmk57 on May 1st 2017, 12:59 pm

It never hit the shift light once during the burnout or 1,2,3 gears. I forgot to mention I had Scotty recurve my distributor for this combo. I just read through 5 pages of "custom black birds" issue with crappy valve springs with Edelbrock heads. I may try a Pertronix point conversion to rule out points bouncing.
The carb may be a bit small but it's all iv'e got for now, so it's staying.

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Re: Valve float?

Post  rmcomprandy on May 1st 2017, 3:03 pm

rmk57 wrote:It never hit the shift light once during the burnout or 1,2,3 gears. I forgot to mention I had Scotty recurve my distributor for this combo.  I just read through 5 pages of "custom black birds" issue with crappy valve springs with Edelbrock heads. I may try a Pertronix point conversion to rule out points bouncing.
The carb may be a bit small but it's all iv'e got for now, so it's staying.

Is that a single spring with a flat damper ...?
If so, you may need a better spring; which to use, will depend upon the installed height required.

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Re: Valve float?

Post  STR-LGL-70 on May 1st 2017, 5:16 pm

What are you using for a fuel pump? What size lines/filter?
This is also a potential issue that could make it lay over on top end.
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Re: Valve float?

Post  supervel45 on May 1st 2017, 6:41 pm

I'd loose the points and be looking for a bigger carburetor, among the other things mentioned.

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Re: Valve float?

Post  rmk57 on May 1st 2017, 7:47 pm

supervel45 wrote:I'd loose the points and be looking for a bigger carburetor, among the other things mentioned.

Funny enough, I found a deal on a MSD 84771 distributor.

I agree, it could use a bit more carb, but this ones going to have to do for now.

I had a Mighty Demon 850 V/C on it for a while and the difference in throttle response from it

to the Quick fuel is like night and day.

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Re: Valve float?

Post  supervel45 on May 1st 2017, 9:07 pm

Like said before check your fuel system. A fuel gauge you can see through the windshield at WOT is very helpful and while you are at it maybe a vacuum/boost gauge you can see also, to see were you are at in that department also in regards to your carburetor size.

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Re: Valve float?

Post  supervel45 on May 1st 2017, 9:25 pm

Be sure your point gap is around .018". I went through this bs for almost a year with a dual point with one set running a MSD 6AL box popping at 5,500Rpm with .022" gap. Went to 7K like lighting at .018".

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Re: Valve float?

Post  rmk57 on May 1st 2017, 9:47 pm

supervel45 wrote:Be sure your point gap is around .018". I went through this bs for almost a year with a dual point with one set running a MSD 6AL box popping at 5,500Rpm with .022" gap. Went to 7K like lighting at .018".

I checked my point gap at the races and it was set at .020. The car really isn't missing like ignition miss fire, no popping, it's more of a gradual nosing over and not gaining
any rpm. I have my shift light set at 5600 rpm and it never lite up once during at four passes.

I have a Carter mechanical fuel pump, I think it was rated at 140 gph, not sure whether they even make them anymore. 1/2" fuel line going to the pump and -6 from the pump to the carb.

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Re: Valve float?

Post  supervel45 on May 1st 2017, 10:06 pm

Knock that gap down to .016" to .018" just to rule it out. Seriously it made a world of difference on my deal. A gauge on a WOT pass is about the best way to see whats going on in the fuel pressure department and is also cheap and easy. Rule out the easy/cheap stuff first has always seemed to work for me. You may want to make a pass and shut it off and check your plugs also.

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Re: Valve float?

Post  rmk57 on May 1st 2017, 10:17 pm

supervel45 wrote:Knock that gap down to .016" to .018" just to rule it out. Seriously it made a world of difference on my deal. A gauge on a WOT pass is about the best way to see whats going on in the fuel pressure department and is also cheap and easy. Rule out the easy/cheap stuff first has always seemed to work for me. You may want to make a pass and shut it off and check your plugs also.

Valve spring shims are cheap, but not easy. Yes, I should look into a fuel pressure gauge. I was getting all my info from a post from years ago. Guy had the same heads and basically the same cam profile and the same symptoms as mine. He shimmed them .060 and it cleared his top end no rpm issues. I'm thinking I may have the same problems.

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Re: Valve float?

Post  supervel45 on May 1st 2017, 10:22 pm

You could check your installed height, pull one spring and have it tested to see where it's at rate wise and go from there. Just an idea.

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Re: Valve float?

Post  cool40 on May 1st 2017, 10:48 pm

You can check the spring seat psi on the head. LSM has a great tool for the job.
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Re: Valve float?

Post  Mark Miller on May 1st 2017, 11:25 pm

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?

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Re: Valve float?

Post  rmk57 on May 1st 2017, 11:54 pm

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

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Re: Valve float?

Post  Scott Foxwell on May 2nd 2017, 8:23 am

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.

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Re: Valve float?

Post  zbob on May 2nd 2017, 9:16 am

hiya, I am not a big time engine builder or anything like that. however I have a edelbrock headed 466 car similar to yours. times too. I can tell you what I had to do to get from 13.4s to 12.8s and the best of 12.6 at 110.
.....car weighs 3360 me in it. 75c heads also. 327 gears with 26 inch tires, works out to 350s with 28s. I had a 750 carb too. stock type timing chain, carter fuel pump too. stock gas tank. mostly 1/2 lines. some not.
....well guess what. 850 proform carb, cheapest 850 to be had!.....double roller timing chain, holley blue pump, still not mid 12s. fuel cell rear sump, swore I had a ignition miss.....next I replaced all the fuel lines with nice sweeping curves no 90 corners etc. voila! high 12s. I since changed the cam and now hit mid 12s.
...along the way I replaced the edelbrock valve springs with new ones, arp rocker studs(edelbrock ones were a little wobbly when changing springs) and a set of better push rods.
ask me what I think did it? mostly the fuel cell and the lines. but every little thing moved a step closer/ fwiw zbob

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Re: Valve float?

Post  rmk57 on May 2nd 2017, 10:28 am

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.

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Re: Valve float?

Post  supervel45 on May 2nd 2017, 11:08 am

Not sure on the Carter pumps but on the Holley pumps with 1/4" fittings are 80 GPH and the 110 and 130 pumps are 3/8" NPT. Holley made a 170 GPH pump with a AN-10 inlet and -8 AN, not sure if they offer it for the 429/460 though.

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Re: Valve float?

Post  rmk57 on May 2nd 2017, 11:51 am

supervel45 wrote:Not sure on the Carter pumps but on the Holley pumps with 1/4" fittings are 80 GPH and the 110 and 130 pumps are 3/8" NPT. Holley made a 170 GPH pump with a AN-10 inlet and -8 AN, not sure if they offer it for the 429/460 though.

They dont offer that pump anymore and haven't for quite awhile. I drilled and tapped mine for an-8 fittings which should bring it up to to the 170 GPH specs or close.
I figure my engine is putting out around 520 flywheel hp., so this pump should be up to the task.

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Re: Valve float?

Post  supervel45 on May 2nd 2017, 11:58 am

Maybe but, I'd still put a fuel pressure gauge on it to verify.

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Re: Valve float?

Post  rmk57 on May 2nd 2017, 12:10 pm

supervel45 wrote:Maybe but, I'd still put a fuel pressure gauge on it to verify.



Would a wideband sensor be able to tell me anything like whether the motors leaning out from lack of fuel pressure?

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Re: Valve float?

Post  supervel45 on May 2nd 2017, 12:16 pm

It would tell you the A/F ratio... Could be lean jetting in the carburetor among other things besides a fuel supply issue from the gas tank sump forward.

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Re: Valve float?

Post  supervel45 on May 2nd 2017, 12:19 pm

What did the spark plugs look like after a pass?

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