Distributor??? Lavoy, help!

[ggfossen]

Lavoy,

This morning, I started the 420 to move it out of the shop, and under it's shed.

It started well, and ran well. It has been running well, but has, occasionally, simply died. I assumed that was because I'm still having to clear rust from the sediment bowl, and that it was clogging, and starving.

This time, when I reached the shed, it began to run extremely roughly. It was kicking back into the carb enough to blow off the breather cap. The kick backs were accompanied by extremely hard and deep knocks in the bowels of the engine. Then it died.

It would restart, but continued with the rough business.

I pulled the distributor, and cleaned the advance mechanism as well as I could.

I replaced it, and with advancing the spark (I think "advance," I turned the distributor clockwise) perhaps 4 or 5 degrees, it would run relatively well at low speeds, but not at working RPMs.

I can't think of anything else by spark problems in that it seems to be firing, every few revs, way too early, and kicking back on the crank.

Am I in the right ball park thinking it is the distributor? Do I need a new one? Do you have them? How much?

Gary

[Lavoy]

Nothing new available as far as the whole dist, but there should be nothing bad that is not fixable. Re-time the engine with a timing light in case the dist slipped a little and screwed it up. Replace points and condenser if you have not already done so. Copper core wires, not carbon? Coil is good and wired correctly? Plugs okay, maybe faulty if new? Just a few things to check.
Lavoy

[ggfossen]

Lavoy,

I replaced points and condenser when I was trying to clean the advance mechanism. The plugs and wires are new, and the wires were suppose to be copper.

It was running well before this happened, but the was a distinctive hardness to the exhaust tone.

In pondering it, I may have been slightly off on the timing, and then the advance system finally worked loose from the rust, and moved the whole nine yards in the wrong directions. I may also be that a crack appeared in the cap, or something as mundane as that.

When I last had it going sort of smoothly, I pulled one plug wire (not without a slight shock), and it ran very poorly, but it ran. Both cylinders appear to firing.

I will tinker with it some more this PM. Too damn cold this morning. Besides, I have oak to plane into useable stuff.

I am a little concerned that the hard ponding may have damaged something internally, but I guess I will know if I get the distributor working properly.

Problem is, I have the damn thing pointed the wrong direction in the shed, so the front of the engine is not nearly as accessable as it should be.

I guess all things work out in the end??

Many thanks,

Gary

[Jimmy in NC]

Gary-

Just be glad it's in the shed. I normally get calls when the tractor is about a half mile from the road down in a bottom.. and rain is forecasted for the next 3 days...

You'll get it figured out though..

Jimmy in NC

[ggfossen]

Lavoy,

I messed with the timing, and it started easily enough. I have it running well on both high and low ends, but, when I apply power other than very slowly, or if I put it under load, I get a hellacious crack from the front part of the engine. I continues until the rpms level out. I think something is busted in the governor? Does that make sense? It seems like it's kicking back into something on the inside??

I did ease it back into the shop. I'm letting it cool down before I start tearing off the front end.

My oak planing project got put on hold.

Gary

PS: I'm not getting notifications when a new message is posted in the thread. Has there been problems with the program? I'm messing with a new virus/spam program, and that could be the problem.

--------------------------

I just pulled the front off. I can't find anything broken in the governor, but the cross shaft (the one between the yoke and the throttle attachments) is not smooth. It seems to be a bit catchy. I wonder if that might cause some sort of problem? I'm wondering if, maybe with the timing off a bit, and if it happened to kick back at just the right moment, if it might bend the fork shaft??

I did, however, manage to drop the little washer into the crank case. Removing the pan is in the wind for tomorrow regardless of what else I have to do to it.

[Lavoy]

Gary,
The cross shaft is always a little rough, if you take the spring off, it is smooth, don't know why.
The noise you are hearing isn't detonation like the timing is too far advanced?
Did you get the camshaft retainer bolted in, or have they come loose? Main bearing caps on correct? Kind of grabbing at straws here.
Lavoy

[ggfossen]

Lavoy,

It sounds awfully hard for detonation. I have to pull the pan to dig out the cantankerous little washer, so I will check all the caps. I will also check the cam shaft retainer.

I suspect I did something stupid, but I am puzzled because it ran really well for about 2 hours of run time, maybe three.

It may be a combo of things. Spark advance springs working loose for openners.

It seems to happen only when being accelerated, or when under a load.

Perhaps I don't have the governor set correctly?

I'm still not getting email notification on new additions to the thread.

Gary

[Lavoy]

Gary,
Check your profile, and make sure you have the feature enabled. Even so, I would not doubt that your spam program is knocking them out, mine does, and I no longer get notifications either.
Lavoy

[ggfossen]

Lavoy,

Yes, I have the software switch "on," but I've been messing with different virus/spam programs. I now have BitDefender, and it has a lot of conflicts with Earthlink. I'm back on Earthlink, but still no notification.

I sent you a couple emails about parts.

Gary

[hunter41mag]

Gary,

If you get detonation hard enough it can sound like someone taking a sledge hammer to the side of the block.

Like Lavoy said make sure your timing is correct and if I remember right they are two marks on the flywheel that are close to each other. So make sure you have the correct mark for timing the distributor.

A few other items to check are:
Fuel, make sure it is not contaminated and of good quality.
Spark Plugs, make sure they are the correct ones (not a hotter plug).
Intake Leak, would run ok until under load than be to lean and give detonation (I had this one happen on a small gas engine and drove me nuts until I found it).

Don
Eastern PA
440 IC

[ggfossen]

Don,

I will re-work through all those points.

I just pulled the front off the machine. I think the clunk may have been the weights of the governor being ticked by the cam gear. I found fresh marks, and it could be the result of the machine having been run without the necessary washer/bushing between the governor and the block. That coupled with a hell of a lot of gunk being removed may have loosened things enough to cause the governor to jump back and forth causing at least a part of the problem.

I just emailed Lavoy for parts. I will put a kit in governor, and take it from there.

On your list the only possibility, aside from timing, might be an intake leak, but I doubt it.

I don't have a timing light, but...I will have.

Thanks for the input.

Gary

[ggfossen]

Dan and Lavoy,

I may be all wet on my conclusions. I dropped the pan, fished out the bushing, put it where it should be, and I can't make the governor weights contact the cam gear. It could be happening, but it appears not.

Back to detonation. I have to go on the web, and read up on just what it is.

Gary

[hunter41mag]

Gary,
Detonation in short is the air/fuel mixture ignites before it should. Think of the piston moving up and in normal operation the air/fuel mixture is ignited right before top dead center and the piston only needs to move up slightly and than starts moving down as the pressure from combustion really increases.
In detonation it ignites way early and the piston is trying to move up against the rapidly increasing pressure from combustion. This really plays hell on the upper cylinders, especially pistons/rings.
The air/fuel mixture should not ignite until the spark plug sparks from the triggering of the ignition system (points/coil) and at the correct # degrees BTDC.
In a gasoline engine the combustion temperture is hotter when there is a lean fuel mixture and combustion tempature is cooler when there is a rich fuel mixture. So if the engine is running in a lean condition the cylinder/head gets hot and than ignite the air/fuel mixture just from the heat (especially any carbon deposits) and way BTDC, thus detonation.
Or if the base timing is advanced to far BTDC will also cause the same load knocking noise.

I hope this helps.

Don
Eastern PA
440 IC

[ggfossen]

Don,

Something occurred to me as I munched on a bad lunch.

I've been having a problem with residual rust and such slowing the fuel flow. If that were to happen about the time other things were happening, the situation would be exacerbated with low fuel flow possibly leading the a lean mixture. Coupled with the spark advance unit slowly working loose in the distributor, that could lead to a problem.

I have, of course, encountered spark knock, or pinging, but never a detonation so heavy as I was hearing from the John Deere. I'm hoping that there was no internal damage.

The hopeful part is that it did continue to run well when not under load, so I don't think anything serious was done.

I do have to get a light to make sure I'm timing it correctly.

I'm not sure, when turning the distributor, which direction is advance, and which is retard. I assume that moving the distributor towards, or into, the direction of rotor rotation, is advancing the spark? The distriburtor body in a clockwise direction?

GAry

[ggfossen]

And the plot...thins. I think I may have stumble onto the real problem. The adjustment nut and screw from the #2 exhaust valve came completely out, and that valve was able to open only very slightly with the nude rocker arm, and probably for far less time than necessary. Pressure would have remained in that cylinder and, on the next intake cycle, all hell broke loose.

Yes, I did it, or didn't, depending on how one views it. Yes, I'm looking for some cold crow.

As I am not completely sure if this is the chicken, or the egg, I will continue with rebuilding the governor, and messing with other stuff, but I think it all started with the rocker arm.

Gary