Engine ping/knock

[Anonymous]

I have a 1966 FB Mustang with 200/C4. My problem is with the distributor advanced to where it runs the strongest its also pings/knocks like crazy.
When I retard it to get the ping/knock out it drops way down in power.
Engine has been modified as follows:
Clifford 264H cam and lifter kit
Clifford six into one header with center port divider into 2.5 inch pipe with Dynomax muffler.
Clifford 2 barrel adaptor with Weber DGES carb.
Jacobs electronic ignition with Ultra coil
Head is ported and polished with 1.75 intake valves. Surfaced .0007
Stock distributor w/vacuum advance
Chevron Supreme for go juice
Can anyone help me?

Don Metzger

 

[Guest]

Can of octane booster maybe?

 

[BIGREDRASA]

If you're running the stock Loadamatic dizzy with your current setup, that might be your problem.

 

[rbohm]

8) a vacuum leak and /or a lean mixture will also cause detonation, especially when combined with timing too far advanced.

 

[Anonymous]

If you're running the stock Loadamatic dizzy with your current setup, that might be your problem.

Don't have a Loadomatic it a dual advance type.

 

[Anonymous]

8) a vacuum leak and /or a lean mixture will also cause detonation, especially when combined with timing too far advanced.

I don't think there is a vacuum leak but maybe I am too lean. The plugs look really clean. Are you familiar with with the Weber DGES carb? How would I richen it up?

 

[Anonymous]

Your Jacobs ignition is going to go a long way in helping keep the plugs clean. I installed an MSD box, and my plugs don't foul out anymore on my dual quad Corvette which has a tendency to run rich.
I had the same problem last summer and found out my vac advance was not functioning. It sounds like a distributor issue. What is your timing set at? What is your timing with the vacuum hose connected? Is most of your timing coming from the initial setting? If so, it is likely to ping on acceleration. The vac advance will retard the timing under load.
You may need to check the vacuum can and make sure the advance mechanism is functioning. The problem with swapping out distributors, is that you do not necessarily know how they are curved. They may have been rebuilt, and what specs were they re-curved to? You may need to tune the distributor. Distributors from cars with emission controls wree set up differently. The following site has some good tech articles on ignition. (most geared to V-8's but the ignition is applicaple)
http://fordmuscle.com/archives/engine.shtml

 

[rbohm]

8) a vacuum leak and /or a lean mixture will also cause detonation, especially when combined with timing too far advanced.

I don't think there is a vacuum leak but maybe I am too lean. The plugs look really clean. Are you familiar with with the Weber DGES carb? How would I richen it up?

8) you are running lean. the plugs should be a golden brown for proeper combustion. since i think you are lean through out the rpm range, swapt o a larger main jet, say about 3 sizes should get you closer. after that you may need to tune the air corrector jets, but we can cover that later.

 

[Anonymous]

I was wrong about the plugs. The last time I checked them was just after I put the engine back together. I must not have had enough miles on them yet as they had not accumulated any deposits on them.
I checked them yesterday and they are as you described they should be.
Sorry for the misinformation.
I recieved another tip from a web site yesterday that one of the members turned me on to. It involves backing off the adjustment in the vacuum diaphram on the distributor. Since the ping only occurs when I put my foot in it at higher revs I'm thinking the vacuum advance is just pulling too much. I'll try that today and post the results.

Thanks

 

[Anonymous]

The distributor I bought from Autozone has the hex key adjustment in the nipple. When you adjust the spring tension, you are adjusting the threshold when the vacuum will start moving the diaphram/advance mechanism. As I understand it, it does not limit the amount of vacuum advance, only when it starts advancing. So if you tighten the spring, it will require more engine vac before it starts advancing. This should only help during part throttle pinging when engine vac drops momentarily. If you have pinging continuously at wide open throttle where you already have very little engine vacuum, then you have too much initial and or centrifugal advance. Some of the adjustable vac advance cans for V-8 engines also include a stepped cam that can be installed to actually adjust and limit the amount of total vacuum advance.