pinging/knocking under load

[Anonymous]

Havn't been around in a while but I think you guys may still be willing to help me out. My 200 pings/like crazy when under a load (anything past half throttle or so or up big hills). I checked everything I know, including spark plugs, fuel-air mix, and advance. I suspect pre-ignition, but I'm not sure. I know the vac advance is working, but I don't know whether it is working to the correct degree and I donno how to check that. I'm still playing around with stuff to try to get a good set up but nothing seems to be working....any ideas? Is it common to have pinging due to the suffocating log intake and 1 brl carb? Sorry fo so many questions but thanks for the help.
Kyle

 

[Anonymous]

My I6 200 with an Autolite 1100 and a load-o-matic distributor runs great at speed but I have never been able to get it to idle. It would help diagnosis a lot if you told us what kind of engine, distributor, and carb you are running.

Right off I would guess that your engine has timing problems. Maybe your vacuum advance isn't working? Two things to try

1 - get out your timing light and put the car running in park. Pull on the throttle cable and see if the timing changes. It should. If it doesn't then that says your vacuum advance isn't working, assuming you only have vacuum advance like I do in my load-o-matic.

2 - Also, you can disconnect the vacuum hose from your vacuum advance canister and apply a vacuum to it, I did it by mouth but it tasted pretty bad. The diaphragm in mine was busted I guess cause the lever didn't move at all when I applied a vacuum to it.

-Dan in Atlanta

 

[LaGrasta]

Two suggestions that worked for me. Be sure your oil is topped off and retard until it stops. The timing marks and light seem to only add to the confusion. I made it as fast as I could and drove it over and over around the block retarding it until it stopped pinging. To this day, that's where it's set. Keep us updated.

 

[Anonymous]

It's timed at 6 bTDC (stock specs) and I already checked the advance. I just don't know how much it should advance (maybe its advancing too much?). I am running the stock 1967 set-up (200, autolite 1100, everything bone stock). I am curious as to what the advance should be and how to check that. I have the idle set now somewhere near 575-600 and I played around with the fuel air mix a bit. With my current set up the pinging seems to have dissipated somewhat (maybe in my head ), however its still is there. thanks for the quick reply,
kyle

 

[ludwig]

I have a bone stock 200 with Pertronix. I had to fiddle with the fuel/air and the timing for a while. It would still knock under load even after I had everything on the numbers and up to spec.
I switched to mid-grade gas and the knock went away completely without adjusting anything.

 

[Anonymous]

I tried other fuel grades and still trouble...not worth the $$ if it doesnt fix my prblm.

 

[Hot 6t Falcon]

Kyle,

Have you tried de-carbonizing it?

Go to Wal-Mart and get a can of Sea-Foam combustion chamber cleaner. Follow the directions on the can - basically pour it in a hot engine while its idling- let it set for an hour. and start it. It will SMOKE UP A STORM!!!

Then put your tranny in low gear and full throttle the car up to about 30 or 35 mph and then de-accellerate (no brakes) to about 15 and full throttle again to 30 and back again. Do that about five times. Watch the rearview mirror to see if you have a big cloud of crap coming out the tailpipe... If you are carboned up, this may clean it out enough to stop pinging for a while.

You might do the wide open throttle bursts first, and then again after the sea-foam to really clean the combustion chambers out.

Good luck

 

[Anonymous]

Nope, haven't tried that...35 mph in first gear sounds a little steep though ...maybe I'll try it out.
Kyle