Valve spring recommendation

I just checked my springs tonight and all have around 145-150 at the seat. I keep chasing a miss and  it sounds like valve float up stairs. I first started with new ignition box, rebuilt the distributor, new coil and wires. Rebuilt carburetor. Checked fuel pressures and volume. I guess springs can still test ok and be weak. I’m lost at what to do. Heads are ported doves with 2.25/1.76 valves.

64galaxie wrote:I just checked my springs tonight and all have around 145-150 at the seat. I keep chasing a miss and  it sounds like valve float up stairs. I first started with new ignition box, rebuilt the distributor, new coil and wires. Rebuilt carburetor. Checked fuel pressures and volume. I guess springs can still test ok and be weak. I’m lost at what to do. Heads are ported doves with 2.25/1.76 valves.

How far "upstairs" are you talking about ...?

Did all the spark plugs look even and dry?

Might want to do a compression test just to rule that out.

The big CompCams hydraulic flat tappet like yours are only wanting 125 on the seat, assuming your's is a HFT?

Any miss at idle or just high RPM?

Ballast resister anywhere, good voltage at the coil?

Ignition switch and wiring all good?

Check for vacuum leaks?

You sometimes just have to eliminate possibilities until you find it.

Upstairs at around 5500, but sometimes it acts the same way when tipping in the throttle just to pass.

Just called Bullet cams. They said 130 off the seat and 380 open would be plenty.

If you have a magnetic pickup distributor look into the polarity of the wires being backwards. Seems like I have heard of some that were not made right from the factory. Also they can get crossed on install.

It's a long shot but you since you were into the distributor I thought I'd mention it. My memory is fuzzy but, there may even be an airgap clearance to the reluctor wheel. Hey found it.

https://www.460ford.com/threads/duraspark-dist-rotor-pick-up-air-gap.161600/

Did you pin out all the main body air bleads and main well bleeds on the metering blocks, to make sure they were clear, when you rebuilt the carburetor, assuming it was a Holley?

That's plenty of pressure for a hyd. cam and then some.

Springs are 495 open

64galaxie wrote:Springs are 495 open

495 open, I'd check to make sure the cam and lifters are'nt eating each other alive! Seems a bit much for a HFT cam.

Went back over the valve adjustment, nothing wrong there. No metal in the oil. Checked polarity of the pick up wires. Checked ohms of pickup wires. Have found nothing. Runs bad starting at 3000 rpm’s under a load.

Float levels set properly? Any way bad/contaminated gas could have entered the picture?

Double check your firing order.

Bad MSD or ignition box.

Dave De wrote:Bad MSD or ignition box.

He said he replaced it with a new one. I agree that does not mean it is a good one.

I replaced a bad blue chip Dura Spark II box once with another blue chip box and it advanced my timing 6 degree's. Yes the timing was checked and set correctly before the first box went bad.

I "assume" he checked his timing after the swap?

Electric Tachometers can cause problems too.

Timing set at 39 locked

39 degrees locked while tipping in at a low rpm may be too much. 39 degrees is rather high but consistent with D0VE, D3VE, and D0OE heads. Ignition boxes dont like electronic noise. Adding an electrolytic capacitor to the main power line will help clean the power up. Even if its not the problem its good to do.

https://www.summitracing.com/parts/msd-8830?seid=srese1&gclid=CjwKCAjwo7iiBhAEEiwAsIxQEXOu8bHCwmNfLynTlgbIBlFnBvSXJpfJschU1AfdWH89pHaqMkrRWBoCEDsQAvD_BwE

Did you check the fuel pressure under load with a gauge, driving?

Sock still on pickup and clear, with enough fuel in the tank to keep it covered?

Brass inlet filters removed from float bowls?

Yeah checked fuel pressure while driving

It certainly sounds like an ignition or electrical current issue to me.

64galaxie wrote:Upstairs at around 5500, but sometimes it acts the same way when tipping in the throttle just to pass.

When I hear that I usually think fuel problem related to the accelerator pump system, at least the tip in part.

Squirter needles missing, or stopped up shooter nozzle/nozzles, bad umbrella or check ball, ect., if the floats are correctly set.

Your deal from other posts not in this thread make me think the car has been running fine with no changes made and the problem just appeared out of the blue?

If that is the case and the carburetor was rebuilt properly, along with the floats re-adjusted properly, clean or removed inlet fuel filters, along with tight throttle shafts, good base gasket, and all is good with the rest of the fuel system, as well as good fuel in ample tank supply, I think you can move on to ignition or other possible mechanical issues.

PS: On Holley floats and others, the black foam floats can get fuel logged and be heavy and not meter correctly. The brown plastic and brass floats can leak and get fuel inside of them and do the same. Most people can easily miss that if they don't pull them out to check.

If you get too frustrated with it and think it's an ignition problem, I would almost be temped to stab one of these in and run a hot wire to it, and see if it went away. If it did, then pinpoint the problem, fix it, and keep it in the trunk for a backup. Just a thought.

https://www.karlkustoms.com/product/kppjm6506/?attribute_color=Blue+Cap

Not a bad idea

Does your ignition box have a Rev Limiter and are you sure your Tach is good showing the right RPM?I had a Tach go bad once and the rpms were off bad with it!!

Changed tach too. Lol. I have thrown a bunch of parts at it

supervel45 wrote:If you get too frustrated with it and think it's an ignition problem, I would almost be temped to stab one of these in and run a hot wire to it, and see if it went away. If it did, then pinpoint the problem, fix it, and keep it in the trunk for a backup. Just a thought.

https://www.karlkustoms.com/product/kppjm6506/?attribute_color=Blue+Cap

Even those still require about 10 amps of current going through them.
On some cars that usually requires using a relay in the ignition circuit.

rmcomprandy wrote:

supervel45 wrote:If you get too frustrated with it and think it's an ignition problem, I would almost be temped to stab one of these in and run a hot wire to it, and see if it went away. If it did, then pinpoint the problem, fix it, and keep it in the trunk for a backup. Just a thought.

https://www.karlkustoms.com/product/kppjm6506/?attribute_color=Blue+Cap

Even those still require about 10 amps of current going through them.
On some cars that usually requires using a relay in the ignition circuit.

^I should of expounded better. I meant run a completely new "hot" wire to the battery, for a test run.

For safety it would be best to "run" it in the car with a on/off switch, even just to test.