Engine Pinging Issues

[Posi]

Lumpy, for the Howell conversion the knock sensor is removed. The conversion should run on 87 octane and I would say mine works pretty good with it. In my opinion, the AMC 258 i6 / 4.2l does not run very well with the top end ignition timing above 28 degrees. Per the instructions, a Nutter by-pass is done where the computer does not control the ignition.

Thinking out loud here, you can remove the knock sensor, and do a nutter bypass to the computer and pass SMOG, but you can't lock down the weights that is hidden under the distributor plate? To run computer timing, you need the knock sensor which already is there.

Howell sells the kit with and without computer timing. However it's easy to setup computer timing on your own especially if the knock sensor is already there Don't know all the laws in CA, is there something I'm missing?

 

[Lumpy Grits]

Posi-I know of at least 2 folks that tried the nutter deal here. They failed SMOG.
When the 'puter was put back in the loop-They passed.
I saw one printout-That showed much higher emissions w/o the puter than with. This was a couple of years ago.
Also-Don't forget our CJ's are held to a lower emissions now-Than when they were made ......
PRK wants to get rid of every car that runs a carb--
LG

 

[Torxhead]

When one does the FI conversion, and especially with the 4.0 head swap.
Do you run the OEM spec'd AMC/Jeep spark plugs or change to a different heat range?
LG

Per the instructions a different set of spark plugs is recommended which is the Champ RFN14LY. I have tried them and thought they were just too hot and went back to the Auto 985s. If pinging gets to be a problem, I will research these more. Nothing is mentioned about the head swap, although I am quite happy with the big cap conversion. Prior to the conversion, I was able to pass smog with the Nutter by-pass.

 

[Lumpy Grits]

What made you feel the Champs were to 'hot'?
Those Champions you listed were OEM factory for our '7s', and the 985 is the Autolite version.
LG

 

[Torxhead]

What made you feel the Champs were to 'hot'?
Those Champions you listed were OEM factory for our '7s', and the 985 is the Autolite version.
LG

Putting the two side by side the Champ plug did appear longer as a hotter plug would be. I did previously check a cross reference chart also. I guess I am more partial to the Autos anyway. For me getting the f.i. conversion to stop pinging was to back off the initial timing and tinker with the vacuum advance adjustment.

 

[Lumpy Grits]

Was there any difference in the amount of ping'n, with the Champs vs Autolites?
LG

 

[Torxhead]

Lumpy, at the time I did test other spark plug heat ranges and looked at the burn deposits, I was not having any ping issues when I did the comparsion. I would like to suggest using the larger of the air cleaners that was suggested in the Howell instruction manual as I have had a rich fuel burn code sent as the smaller ones got a little dirty.

 

[Lumpy Grits]

What type of air filter element do you use?
X2 on larger A/F, for airflow.
LG

 

[hole]

IIRC I remember reading using a RC9(??) plug being recommended by the guys at Hesco for pinging

 

[thundley57]

I solved my pinging problem. Since my dist had a little more slop in it then I was comfortable and I wasn't sure what mods (if any) the PO had done to the advance springs, I purchased a new Cardone dist which did have slightly less slop and I'm assuming the factory spec centrifugal weight springs as well as the factory spec vacuum diaphragm. I tested the new diaphragm against my old diaphragm and noticed that the new one took quite a bit more vacuum before it started opening and approximately 25" before it would open completely. This is with the pre-load screw turned all the way in. After turning the screw all the way it would not even begin to open until 10" of vac or so. My old diaphragm started opening and went full open at significantly lower vac values depending on the adjustment screw setting. I run the vacuum advance on ported vacuum which achieves a maximum of 15" during cruise.

Anyway, installed the new dist, adjusted the base timing down to 6 deg and absolutely no pinging now and the performance seems to have improved. Time will tell how the fuel economy has changed if any but I'd rather give up a little economy then deal with pinging and lower performance.

Thanks all!

 

[Lumpy Grits]

:ty: For the update.

LG

 

[slomo]

I already use premium fuel 92 octane and add a dose of StarTron Enzyme Fuel treatment which claims to "cure & prevent ethanol problems". Gasoline here in CA is 10% ethanol most everywhere. I will try the oil to the dist shaft.

Torxhead, it sounds like you have resigned yourself to the fact you're going to have some ping in certain operating conditions, is this true? Mine isn't terribly bad in fact if I'm driving with the windows open I have to lean forward closer to the firewall to actually hear it. Maybe I should quit worrying about it? I know it is probably slowly and steadily causing damage though.

I'm going to try retarding the timing back to 6 deg to see if there is any improvement and maybe try experimenting with different strength centrifugal advance springs. Does anybody know where to buy spring kits for the stock motorcraft dist?

Since you have to run that ethanol fuel, I would install a fuel/water separater filter unit. Our Jeeps are NOT designed for ethanol fuel. You'd be surprised how fast that water piles up in your tank. Those warm evenings and cool/cold nights are a killer. Here's a link below. Something with a clear bottom cup so you can drain it.

https://static.grainger.com/rp/s/is/image/Grainger/4ZNX2_AS01?$mdmain$

Saw a youtube video. Guy took a mason jar of 10% ethanol fuel. Placed it in front of a fan in his shop. It immediately started sweating and turning cold, inside the jar and out. You could see the water droplets it was pulling from the air inside the fuel.

slomo

 

[thundley57]

Since you have to run that ethanol fuel, I would install a fuel/water separater filter unit. Our Jeeps are NOT designed for ethanol fuel. You'd be surprised how fast that water piles up in your tank. Those warm evenings and cool/cold nights are a killer. Here's a link below. Something with a clear bottom cup so you can drain it.



https://static.grainger.com/rp/s/is/image/Grainger/4ZNX2_AS01?$mdmain$



Saw a youtube video. Guy took a mason jar of 10% ethanol fuel. Placed it in front of a fan in his shop. It immediately started sweating and turning cold, inside the jar and out. You could see the water droplets it was pulling from the air inside the fuel.



slomo

Thanks slomo, I'll check it out.


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

I only run prem in mine.
As long as the timing isn't to far advanced(3-4*) from the factory setting, I've never have any ping issues.

LG

 

[slomo]

Was wondering if anybody runs their AMC 258 i6 / 4.2l I6 engine with no vacuum advance at all? I can't seem to get an annoying ping to go away which occurs at higher rpm's 2200 - 2400 and when pressing the throttle (loading the engine) while at normal cruise. At normal cruise with maximum vacuum there is no ping but as soon as I step on the gas a bit it starts.

I've read all of the timing articles that I can find on this forum and a few others but the only way I can get it to go away is by removing and plugging the vacuum to the vacuum advance diaphragm. Initial timing is set at 8 degs BTDC.

I've tried running on ported vacuum and manifold vacuum, tried adjusting the diaphragm pre-load from all the way in to all the way out and everything in between. Inspected the centrifugal weights which seem to be in good condition and have tested the advance diaphragm with a vacuum pump which has smooth operations

I would think that with the lower vacuum during engine load would drop the vac advance and prevent the pinging? Do I need to install stiffer springs on the centrifugal weights and or somehow limit their travel? Is there any harm in running with no vac advance or does it only affect fuel economy?

Have you upgraded/improved your grounds yet? Is your ignition fed from a relay for full battery voltage? Do you have a brass terminaled cap and rotor? How about some low resistance per foot plug wires? Clean plugs? Firing each cylinder cleanly? No oil in the cylinder issues? Have you graphed your mechanical timing curve and your vacuum advance curve? Are you running ethanol fuel????????? If so you will have a ton of water in your tank. If you have to run ethanol, you better install a fuel/water separator. Try some of these things and see what you get. Good luck to you.

slomo