[SScott]

THANK YOU in advance!

My car pings (sounds like valve float) under acceleration no matter what I do. I have it so retarded now it smells pig rich. My only guess is bad valve springs or something is wrong with my cam. I really don't know.

I have a 306 with a 144 supercharger and stick with 3:73's in a fox mustang.
New locked MSD dist. and digital CD.
Ford Racing B-303 roller (224/480), new (cloyes double) timing set, straight up.
Cobra GT40 heads with 1.7 crane RR.
All new 750 DP with proform body, quickfuel base and plates. 72/84 blocked rear PV.

The only thing hooked to vacuum is the brakes.

I have tried 3 distributors, with and without the blower, timing from way advance to way retarded. I also tried a different carb.

Any ideas of what to look for next or try?

Thanks again!

Scott

[RWENUTS]

What's a locked distributor?
Sounds like to much timing!

[ap72]

What's "way advanced" mean? And is your carb properly boost referenced?

You'll need about 30 degrees timing and a correctly referenced carb with a functioining PV system.

[SScott]

Originally Posted by RWENUTS

What's a locked distributor?
Sounds like to much timing!

The distributor does not have an advance mechanism now.

Originally Posted by ap72

What's "way advanced" mean? And is your carb properly boost referenced?

You'll need about 30 degrees timing and a correctly referenced carb with a functioining PV system.

It did the same thing with a single plain intake and with the belt removed, I have tried both.

It seems to me like too much advance but I have turned the distributor to retard it so far it will barely run and still get the pinging sound like if you were to take off in 4th gear. I have 10:1 compression by the way on 93 pump gas.

Thank you so much!

[ap72]

Then it sounds like a mechanical issue, not tuning. How's your oil pressure? Is it coming from one cylinder?

[cobalt327]

Originally Posted by SScott

The distributor does not have an advance mechanism now.



It did the same thing with a single plain intake and with the belt removed, I have tried both.

It seems to me like too much advance but I have turned the distributor to retard it so far it will barely run and still get the pinging sound like if you were to take off in 4th gear. I have 10:1 compression by the way on 93 pump gas.

Thank you so much!

I'm afraid you're going to find that 10:1 CR and boost w/only 93 octane isn't going to be enough octane.

That cam doesn't require a locked out timing, although for diagnosing things it's not going to hurt- but once you're up and running, use an advance curve.

It may take using an MSD BTM (Boost Timing Master) ignition box to retard the ignition by the amount of boost the blower is making. That's much safer and will give the most performance.

Have you verified TDC? Absolutely no chance of cross firing between the plug wires or because of a fouled distributor cap? Has the rotor phasing been checked? Prolly not the problem because you've tried several distributors, but might be worth checking just the same.

You mentioned valve springs. If the valves were floating or bouncing, etc. the performance will be way off but I'd not expect it to be detonating- IF that is in fact what you're hearing. But I would for sure be wanting to closely inspect the springs to be sure there are none broken!

[SScott]

Originally Posted by ap72

Then it sounds like a mechanical issue, not tuning. How's your oil pressure? Is it coming from one cylinder?

Now that is a good question. I have good oil pressure. 40 at idle but do not know how to tell if the sound is only coming from one cylinder.

Originally Posted by cobalt327

I'm afraid you're going to find that 10:1 CR and boost w/only 93 octane isn't going to be enough octane.

That cam doesn't require a locked out timing, although for diagnosing things it's not going to hurt- but once you're up and running, use an advance curve.

It may take using an MSD BTM (Boost Timing Master) ignition box to retard the ignition by the amount of boost the blower is making. That's much safer and will give the most performance.

Have you verified TDC? Absolutely no chance of cross firing between the plug wires or because of a fouled distributor cap? Has the rotor phasing been checked? Prolly not the problem because you've tried several distributors, but might be worth checking just the same.

When I can ever get it all worked out I do plan on race fuel before I go to the track. Maybe I should try some now to see if that is what is up?

New cap and rotor and each distributor had one too. I know I need to install the MSD timing tape as opposed to the setting timing at idle and that is on the todo list. I have a Crane HI6R with boost retard but I have not installed a MAP sensor yet and I do plan on more work on the carb when I am ready to fine tune, I have been too worried to do anything else until I narrow down the pinging. When I installed the heads, I put viton seals in even though I was told the heads were fresh from a machine shop, I wish I would have had all the springs checked. If this sounds like a valve spring issue I do not mind buying the comp cam replacements that have the same diameter.

Thanks!!!

[cobalt327]

Originally Posted by SScott

Now that is a good question. I have good oil pressure. 40 at idle but do not know how to tell if the sound is only coming from one cylinder.


When I can ever get it all worked out I do plan on race fuel before I go to the track. Maybe I should try some now to see if that is what is up?

New cap and rotor and each distributor had one too. I know I need to install the MSD timing tape as opposed to the setting timing at idle and that is on the todo list. I have a Crane HI6R with boost retard but I have not installed a MAP sensor yet and I do plan on more work on the carb when I am ready to fine tune, I have been too worried to do anything else until I narrow down the pinging. When I installed the heads, I put viton seals in even though I was told the heads were fresh from a machine shop, I wish I would have had all the springs checked. If this sounds like a valve spring issue I do not mind buying the comp cam replacements that have the same diameter.

Thanks!!!

You can make a temporary timing tape yourself.

I wouldn't expect the springs (unless broken) to be so weak that the engine won't even come up off idle w/o losing control of the valve train- but I suppose anything's possible. I would recommend the springs be inspected carefully, though. A broken damper can even cause problems.

In any event, if you plan on revving the engine anywhere near the redline it's capable of, using the correct valve springs set to the correct installed height is a must.

Have you readjusted the hydraulic lifter preload? Often guys will mistakenly bottom out the lifter's plunger when looking for zero lash because the books all say to twirl the p-rod between the thumb and fingers instead of jiggling the p-rod up and down. More on valve adjustment here. The page was written w/Chevy engines in mind but except for the firing order the procedure holds true for your Ford.

Some more valve train points to check. I apologize for all the links but it's the only practical way to cover so much ground in a single post.

Have you had a chance to do a leak down or at least a compression test on it yet? Has the vacuum at idle been checked- and note the needle behavior as well- as in is it steady or rhythmically jumping or "wandering"? Here is a vacuum gauge reading guide, this is another one.

[SScott]

Originally Posted by cobalt327

You can make a temporary timing tape yourself.

I wouldn't expect the springs (unless broken) to be so weak that the engine won't even come up off idle w/o losing control of the valve train- but I suppose anything's possible. I would recommend the springs be inspected carefully, though. A broken damper can even cause problems.

In any event, if you plan on revving the engine anywhere near the redline it's capable of, using the correct valve springs set to the correct installed height is a must.

Have you readjusted the hydraulic lifter preload? Often guys will mistakenly bottom out the lifter's plunger when looking for zero lash because the books all say to twirl the p-rod between the thumb and fingers instead of jiggling the p-rod up and down. More on valve adjustment here. The page was written w/Chevy engines in mind but except for the firing order the procedure holds true for your Ford.

Some more valve train points to check. I apologize for all the links but it's the only practical way to cover so much ground in a single post.

Have you had a chance to do a leak down or at least a compression test on it yet? Has the vacuum at idle been checked- and note the needle behavior as well- as in is it steady or rhythmically jumping or "wandering"? Here is a vacuum gauge reading guide, this is another one.

What a plethora of valuable information! Thank you very much! I love cheap DIY! The timing tape wiki is great! The damper is a new SFI unit from Summit, I have factory crane roller rockers that are pedestal mount so I don't have a lot of room for adjustment. I have not done a compression check but I will check that and I am a vacuum idiot, I will look into that and getting a vacuum gauge.

Thank you!!!!

[zildjian4life218]

Have you ever thought about running E85 with that high compression and a super charger?

[Mr. P-Body]

If you turned the distributor every "which way" and the symptom doesn't "change", it's NOT "spark knock". It sounds like detonation to me. That is, too much static compression for the octane being used.

I would suggest you put about a 50/50 mix of 110 "race gas" and 93. If it STILL does it, I don't know what to tell you... But if it stops, it IS detonation.

FWIW

Jim

[cobalt327]

Originally Posted by SScott

Now that is a good question. I have good oil pressure. 40 at idle but do not know how to tell if the sound is only coming from one cylinder.


When I can ever get it all worked out I do plan on race fuel before I go to the track. Maybe I should try some now to see if that is what is up?

As Mr. P-body has said, trying some extra octane will be something well worth doing. What you do not want to do is load the engine until the cause is known. Because if it IS detonation, that can take out the pistons, cylinders and damage the bearings- as I'm sure you know.

Keep us posted.