Hello, I am a first time poster.
I just built a 460 from a 76 Lincoln.
I made a newbee mistake in choosing components.
I used 10:1 KB hypereutectic pistons.
I also used a Comp Cams RV type cam for low end torque.
Timing is set straight up, as per the cam card.
The problem is, even with 93 octane gas, it pings.
The ignition timing stock calls for 10* BTDC, and it pings like crazy.
I set the ignition to 0* (TDC) and it pings much less.
I hooked up the EGR to the spark port and the pinging is mostly gone.
Nice to know that EGR helps.
I know what I did wrong...
The high compression along with the RV type cam are making very
high cylinder pressures (dynamic compression).
I think this has to do with the early intake closing point of the RV cam.
I read that retarding (i think) the cam timing will help shift the intake
valve closing point later, this bleeding off some compression.
Another thought was to buy a cam with some more overlap to bleed
off some compression. What do you guys think is a better fix??
I admit I also chose too high of a compression ratio pistons.
I used stock replacement McCord graphite composition head gaskets.
Are there stock type gaskets that are a bit thicker.
I don't want to get into copper shim type gaskets.
Thanks for any ideas you may have.

--Doozer in Buffalo

 

You need to get a timing light on it and see how much total advance it has and how quickly it comes in. What heads are on it ? I wouldn't run a egr with that set up.

Welcome to FTE !

 

It is a stock '76 Duraspark dizzy, so it has the slow advance curve.
Heads are '76 Lincoln heads. I removed the air injection bumps
in the exhaust ports for better flow. Eliminated the smog pump.
I can just tell that this motor is way to sensitive to detonation.
I will check total advance, but I believe the pinging starts way
before the mechanical and vacuum advance come in the full way.
Why no EGR? It helps suppress detonation. It doesn't take away
any power. Seems beneficial to me. Just wondering if I should:
1. Change from the RV cam to a high overlap cam.
2. Retard the cam timing. I have multiple keyways on my timing sprocket.
3. Lower the compression some with different head gaskets.
4. Something else??

Thanks-
--Doozer

 

Do you have a 700cfm carb or bigger? It might just be lean...

 

Carburetors meter fuel and air, and try to maintain a given air to fuel ratio. There are power valves, air bleeds and accelerator pumps that make the mix richer at times, but in general carbs try to maintain the air-fuel mixture close to stoichiometric.
Almost any size carb will work on any size engine (within reason). You can run an 800 cfm carb on an 302 engine or a 600 cfm carb on a 460 engine. As long as there is adiquate vacuum signal at the venturi to draw fuel, it will work. If the carb is reall small (like a 600 cfm on a 460 engine), the vacuum signal at the venturi will be pertty strong, and a rich condition may occur, but nothing serious.
The carb is the stock Motorcraft 4 bbl 4350 model. It has the Holley bolt patern and the Quadrajet bigs and littles throttle plates. I have actually ran this carb on a Chev 350 once, and it ran real nice.
Thanks for the reply on your thought that the carb is too small, but I believe there are other issues. Plugs look like it is burning well.

--Doozer

 

Ok, are the JETS big enough? Those carbs were designed to run lean at idle & cruise, but dump the fuel at wide open throttle for passing, etc. Emissions control. The EGR returns any unburned fuel to the intake. If it runs better with an operational EGR, I would assume you have a lean condition. Retarding the cam timing may help a little bit, but it will mostly just raise the rpm of the powerband. You can only move the ignition timing so much. Ford built engines with 10:1+ compression & didn't put monster cams in them. Alright, I won't bother you anymore. Good luck.