Engine chatter at heavy throttle

[cooltech]

I maybe worried about it maybe something simple to take care of. But since I changed the timing
belts and oil, coolant at freeway speed 65mph. when I give it a heavier throttle to pass someone
I can hear a chatter or pinging same when pulling a hill does not happen in 1st to 3rd only in 4th or 5th
rechecked the belt marks are still right on resinked the carbs. have not tried higher grade fuel Is there
anything I can do or check too make it go away.

 

[dan filipi]

Maybe you got some bad gas?
Could try filling with Premium to see if it helps.
I'd run 8 oz ATF in each tank. The mix will also help clean the carbs.

 

[AApple]

Sounds like either crappy fuel, or the ignition timing is off, or possibly the engine is running a bit hot?

 

[joedrum]

id sure check the belt timing as it could be one tooth off on one side ....soulnt have changed attitude from the work you done ...but atf is good all the time to use ...if you changed thermostat ...could be upside down maybe ....hmmmm good luck

 

[Ansimp]

I know you said that you re checked the timing belt instal, but it does sound like the timing is out.

 

[slabghost]

Check your vacuum advance for leaks.

 

[cooltech]

where is the vacuum advance at

 

[slabghost]

Right rear of the motor. Just inboard of the fuel pump. Look for the canister and hose.

 

[mcgovern61]

Check your intake manifold O-rings, you might be pulling a vacuum on a leaking O-ring which will show up at the highest vacuum (dropping your throttle to pass someone at higher RPM).

 

[dan filipi]

What I'm aware will cause ping (preignition/detonation) are,

Bad gas.
Low octane.
Timing too advanced.
Vacuum leak.
Carbon in cylinders causing a hot spot which ignites the mixture too early.
Overheated engine, can be violent.

I've never experienced valve timing out of time causing it but I suppose so.

 

[joedrum]

hmmmm thats interesting ...yea it could be quite a few things ...

 

[AApple]

What I'm aware will cause ping (preignition/detonation) are,
Bad gas.
Low octane.
Timing too advanced.
Vacuum leak.
Carbon in cylinders causing a hot spot which ignites the mixture too early.
Overheated engine, can be violent.
I've never experienced valve timing out of time causing it but I suppose so.

Add to this list a lean fuel mixture...which could also be caused by a vacuum leak, but a vacuum leak would normally only cause a lean problem on the cylinder closest to the actual leak. :wave:

 

[slabghost]

Let us know what you find.

 

[mcgovern61]

But since I changed the timing belts and oil, coolant at freeway speed 65mph.

Sorry I missed this one, you changed your coolant. Do you notice that the temp is any higher than it was before? (Hotter engine will cause pinging)

Just to ask, (just so that I do not make any assumptions) You did use a 50/50 mix and not straight coolant?

 

[cooltech]

yes I changed the coolant with a 50/50 mix and pulled the air out
on my rides it has not ran hot runs a little below half way up
being digital when it gets one mark passed the half way point
the fan comes on and cools down thanks for asking.

 

[n2ppn]

Is the noise a "chatter" or more of a "pinging".... pinging is detonation, chatter can be a bad primary chain or other things... I assume it only makes this noise when under load, and in higher gears?? but not when at steady throttle...

If it is a "pinging" noise try the fresh premium fuel in the tank first (easiest and quickest of all tests), if it goes away, you had bad gas.... if it doesn't, then start looking at the other fuel/vacuum suggestions others have given.

If noise is NOT a pinging (sounds like the shaker ball inside of a spray paint can, or marbles being shaken in a glass container) one, then you might need to look into the engine/transmission/drivetrain for the source of the "chatter" noise.... Good luck and keep us posted on your results....

 

[cooltech]

nzppn it is more of a pinging than a chatter does it on flat ground or hills with heavy throttle
at steady cruz does not happen I will try the gas first after I run the gas out first they are
changing the fuel here to the summer grade I will get it at another station

 

[toytender01]

I would try the gas and ATF. It could just be the DALLS, you know how they are. :smilie_happy: :smilie_happy: :smilie_happy:

 

[cooltech]

thats what I am thinking that it is fuel we really do have bad fuel in Oregon it is unregulated
going to put good fuel in it and atf to clean the system out

 

[DaveO430]

My 83 I would do that unless I ran premium fuel. Nothing at all was wrong with it, it just pinged on hard accel. I have read of other 83s pinging, no real explanation for it, some just do. I thought about putting an adjustment screw in the advance to keep it from advancing as far but never got around to it.
Simple job, I did it to another advance unit I had just to see if I could. There is a plastic plug in the end and after getting it out there are already threads to put a long 5mm screw in.