52 8rt engine pings going up hill

[john mullen]

I have a 52 8rt .030 over with Eddlebrock heads, 3x2 setup, SU1-A cam and Bubba ignition.the timming is set dead on the mark. it starts and runs very well. it just pings like hell when its up to opr,temp (180)as you go up a hill or go throttle up. I have tryed timming it all over the place (no)help the carb setup is vintage speed end carb bases and center carb set up kit 48main jet in primary carb,the number on the power valve is ground off so i dont have a clue what it is It realy does run good til 180 deg and then PING PING PING .iTS DRIVING ME NUTS any help????

[Vergil]

Running lean contriutes to pinging as does high compression and bad or low octane gas, hot air into the caruretors is not as good as cool air when you mention pinging. I would try a good, higher octane gas and then richen it up a little. You mentioned you tried different timing settings so won't mention that. If and I say if the cam gear, cam or crank gear are keyed or drilled off to where the cam is advanced and increased the dynamic compression it doesn't help your problem either. My opinion and I'm sure there are better opinions than mine.


Vergil

[Ed Pitts]

What do the sparkplugs look like after a run? Ed

[Ol' Ron]

The first thing i'd do is check the static compression 150/160 is about normal with 8.5Cr and a long cam.
Next is a simple test of the distributor. Using a timing light , disconnect the vacuum and check the advance at 2000 RPN, this should be about 20/22 degrees. Now with no load on the engine connect the vacuum. The timing should advance to 26/28 degrees. Under these conditions it should run on 87 oct. gas.
Now having a lean mixture will cause this and with the new gas reading plugs is pretty useless, so we use an A/F meter. Good luck. Welcome to tuning a flathead.

[john mullen]

Cam is degreed straight up.I checked the marks during assyat TDC all good. Bubba ign has no vac advance its gm centrifical conversion. Spark plugs ash brown w/some black speceled spots otherwise look good. I tryed fuel up grades and oct booster .it helped some but no cure . Ill try the fatten up fuel. how about power valve any recomendations??

[Ol' Ron]

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Have you checked the timing?? Why not use the vacuum??

[Ronnie]

Originally Posted by john mullen

Cam is degreed straight up.I checked the marks during assyat TDC all good. Bubba ign has no vac advance its gm centrifical conversion. Spark plugs ash brown w/some black speceled spots otherwise look good. I tryed fuel up grades and oct booster .it helped some but no cure . Ill try the fatten up fuel. how about power valve any recomendations??

What type of dist? A modified chevy or a chevy Mallory?

[jack orchard]

if'n it was my engine and it has Ford 94 carbs, i would try 50 jets in all carbs, 5.5 power valve in primary carb, block power valves in secondary.carbs. if using a modified chevy distributor, you can use Standard Motor Products VC24A vacuum advance. 8* advance-all in at 16" vacuum. good for 1-3 MPG. Should be stamped B1 on part. Hook it to manifold vacuum. Rock Auto sells for $ 15.58. Summit also sells it and adjustable ones. Also wait to see what the distributor and carb experts have to say...best of luck...jack

[flatjack9]

As Ron said, check static compression. Start with the basics.

[BUBBAS IGNITION]

Originally Posted by john mullen

I have a 52 8rt .030 over with Eddlebrock heads, 3x2 setup, SU1-A cam and Bubba ignition.the timming is set dead on the mark. it starts and runs very well. it just pings like hell when its up to opr,temp (180)as you go up a hill or go throttle up. I have tryed timming it all over the place (no)help the carb setup is vintage speed end carb bases and center carb set up kit 48main jet in primary carb,the number on the power valve is ground off so i dont have a clue what it is It realy does run good til 180 deg and then PING PING PING .iTS DRIVING ME NUTS any help????

John,

Lets assume this is my fault ( at least for a minute) I have sent you the " Bubbas Spark Knock" repair kit . Its six springs and i would suggest removing the lightest spring and replacing it with the heaviest from this selection. Then test drive the car and adjust as needed.
I usually use two different weight springs to allow the engine to have 24 degrees of timing at 2500-3000 rpm. That may be too quick for your application. I shipped these springs to you today....let us know how it works. Just remove the rotor ( 2 screws) and change one spring at a time then testdrive until perfect...

[36tbird]

Now that's service!

[1952henry]

Bubba, you're a good guy!

[Walt Dupont--Me.]

Originally Posted by flatjack9

As Ron said, check static compression. Start with the basics.

My static compression on my 276 in my 40 is 160#, I've always had ping problems. I finally welded the slots in the stock crab to get 17* total. There is no end of the RPM. Even with that and the middle grade gas I half to screw retard down about half way. That's what you call to much compression. In 35yr's I've blown one head gasket and broke one 2rd piston ring on account of pinging. Walt

[Richard in Florida]

Originally Posted by BUBBAS IGNITION

I usually use two different weight springs to allow the engine to have 24 degrees of timing at 2500-3000 rpm.

I love ya, Bubba, but there's that 24 degrees again!

Here's a quote from JWL's book on the subject:

"I have often been asked why a Flathead engine needs 5 degrees (approximately) of advance to run correctly at 600 RPM and needs 20 degrees of spark advance (approximately) to run correctly at 2000 RPM but does not need more advance, such as 30 or 40 degrees of advance, to run properly at 4000 or 5000 RPM."

He then goes on to explain why the above is true. Beg, borrow, or steal a copy of his book, and look at the bottom of page 17 and the top of page 18.

All of our (Ol' Ron) on-the-road testing has shown that JWL is correct for just about any streetable flathead.

[john mullen]

Bubba. I will say this , the dist you sent realy woke my engine up and I love it. thank you for the spring comming my way. Your customer service is incredable to say the least. I am a old skool tuner and know not to change more than one thing at a time .I will try the springs first and then follow up on all the other tips and suggestions .Thanks to everyone who posted.... John

[BUBBAS IGNITION]

Originally Posted by Richard in Florida

I love ya, Bubba, but there's that 24 degrees again!

Here's a quote from JWL's book on the subject:

"I have often been asked why a Flathead engine needs 5 degrees (approximately) of advance to run correctly at 600 RPM and needs 20 degrees of spark advance (approximately) to run correctly at 2000 RPM but does not need more advance, such as 30 or 40 degrees of advance, to run properly at 4000 or 5000 RPM."

He then goes on to explain why the above is true. Beg, borrow, or steal a copy of his book, and look at the bottom of page 17 and the top of page 18.

All of our (Ol' Ron) on-the-road testing has shown that JWL is correct for just about any streetable flathead.

Richard ,
I think you are misunderstanding my point here. In your example the 5 intial plus the 20 = 25 degrees.

On our distributors i usually use a #24 distributor cam this is 24 degrees of mechanical advance , set the timing on the pin and you have 26 degrees give or take a degree or two. With a brass bushing as a stop its usually less than that.
So in reality we are saying the same thing.
Our Bonneville flathead has been dynoed and we made the maximum wot horse power at this 24 degree setting.
Thats where we will run it at Wilmington next weekend with the ECTA group for a land speed record.

Just for you and ole Ron i will set the mag at 16 degrees for one run and post the changes ....

[Richard in Florida]

Originally Posted by BUBBAS IGNITION

I think you are misunderstanding my point here. In your example the 5 initial plus the 20 = 25 degrees.

I don't think that's what JWL meant at all. He was talking about a maximum of 20 degrees BTDC.

If you rotate your distributor in your engine so the mechanical advance mechanism maxes out at 20 degrees BTDC, then the maximum advance will be 20 degrees BTDC regardless of WHAT the idle (initial) advance turns out to be. Initial advance is simply what the springs and weights add at idle to whatever the advance mechanism's "zero" or starting point is.

Think of the mechanical advance range as an arc that you can slide around the outside of the 360-degree pulley.

If that mechanical advance range arc is 20 degrees long, and you slide it around on the pulley so the maximum advance end of it is at 20 degrees BTDC on your pulley, then the minimum advance end of that 20-degree arc will end up at O degrees (TDC) when the engine is NOT running.

If you slide the arc some more so the maximum advance end of it is at 25 degrees BTDC on the pulley, now the minimum advance end of the arc at 5 degrees BTDC on the pulley.

In other words, the position of the advance arc determines MAX advance and STATIC advance.

With typical springs, the advance mechanism will add a few degrees at idle. This is the INITIAL advance.

BUT regardless of the initial advance, the MAXIMUM mechanical advance will stay where you set it.

[Richard in Florida]

Originally Posted by BUBBAS IGNITION

Our Bonneville flathead has been dynoed and we made the maximum wot horse power at this 24 degree setting. That's where we will run it at Wilmington next weekend with the ECTA group for a land speed record.

I will be rooting strong for you, and I hope you take plenty of pictures.

A minor point, though. I have no doubt that 24 degrees BTDC is giving you what you want for Bonneville, but I'm gonna take a wild guess and say that's not exactly what I think of as a streetable engine! NO FAIR!

[john mullen]

So Richard are you saying i need no more than 20 deg total timming ???

[Ol' Ron]

My two cents. Seting up a street engine with more than 20 degs advance is a bad idea. Let the Vacuum advance add 6 or 8 degrees then you have the engine properly TUNED FOR STREET.
We set the stockcar uo on a dyno. Add 12 HP. took it back to the track and it couldn't get out of its own way.

PS
If your not running a vacuum advanve your running a race engine.