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Ford 8n/Cletrac Crawler Engine Bogging

P

paul25g

Member
Hi guys,
I apologize ahead of time for the lengthy post, but I'm trying to give as much detail up front as I can.

First of all, this is the first 8n engine that I've messed with. I'm not a mechanic, more of a tinkerer. So with that in mind, here's what I've got.

I put a 1950 8n front mount distributor engine on a 1947 Cletrac HG undercarriage.

mvphoto85224.jpg


The 8n engine came in trade on another project I was working on. It had supposedly been rebuilt by the previous owner, but of course, I'd take that with a grain of salt. However, the engine was painted up nicely, had a new intake/exhaust manifold installed, new starter, new alternator, etc. It came with the wrong carb, so I got a correct original TSX241 that was rebuilt by a guy who is known to be a reputable rebuilder of these Marvel Schebler carbs.

When building this machine, I went ahead and converted to 12 volt and put in a new wiring harness. I've also put on new Autolite 437 plugs, new plug wires, new distributor cap, new points, condenser and rotor. The coil that came on the motor measures 2.5 ohms resistance, so my understanding is that was already a 12 volt coil, so I did not replace it. Timing has been set according to the manual and valves have been adjusted.

I finally got the engine installed and have gotten it started up. After some initial adjustments, I've gotten it to the point that it starts reliably. The issue I'm having is that the engine is bogging down under any amount of load.

The results of a dry compression test are:

Cylinder 1- 110psi
Cylinder 2- 110psi
Cylinder 3- 105psi
Cylinder 4- 112psi

The pic shows the plugs after running it around in front of the barn for a little while. As you can see, the plugs for cylinder 1 and 4 are very sooty compared to 2 and 3.

mvphoto85225.jpg


I know bogging down can be a symptom of a bad governor, so I unhooked the governor to carburetor rod and ran a piece of wire straight to the carb so that I could control it by hand and it's still bogging down and a bit slow to react when going from idle to full open throttle. Not sure if this is a good test or not, but to me, it seems to show that even if the governor was part of the issue, there's still another problem.

First gear and reverse allow movement with some bogging, especially when steering as steering with this crawler is like pushing on a brake to turn right or left, second gear is worse and it will barely move in 3rd. Same results if the gas cap is removed so it's not a plugged tank vent.

So I guess I'll start with two questions. First, any idea of that is causing plugs 1 and 4 to look so different from 2 and 3? Secondly, based on what I said above, any idea of what could be causing the bogging with the governor disconnected?

I'd appreciate any ideas and just let me know if you need any additional info, thanks!


This post was edited by paul25g on 11/28/2021 at 11:33 am.
 
I think you should just give up on it! I'll give you 300 bucks for it delivered to my garage!
Actually, what a fantastic looking hybrid!!!
 
That is a sweet looking machine.
I had an HG crawler that had a poor engine.
Wish I had kept it and done something like that.
 
Look for a leak on the intake side,that could cause a lean on the two cylinders.(new doesn't mean
good)
 
He paid me over a hundred plus shipping for the adapter for it so I don't think $300 will buy it LOL.
 
(quoted from post at 14:55:06 11/28/21) Check your plug wires to verify that you have the correct firing order.
Click to expand...

Checked plug wires and they are in the correct order...1,2,4,3
 
(quoted from post at 14:53:52 11/28/21) He paid me over a hundred plus shipping for the adapter for it so I don't think $300 will buy it LOL.
Click to expand...

Ha, you got that right Kirk! And thanks again, that adapter was the piece that let everything come together!!
 
(quoted from post at 14:35:25 11/28/21) Look for a leak on the intake side,that could cause a lean on the two cylinders.(new doesn't mean
good)
Click to expand...

The only place that can happen is where the carb attaches to the manifold, isn't it?
 
Manifold leak can be at the carb or where it bolts to the block or can also have a hole rusted into it so it leaks
 
(quoted from post at 15:55:52 11/28/21) Manifold leak can be at the carb or where it bolts to the block or can also have a hole rusted into it so it leaks
Click to expand...

Ok, thanks! There is a new gasket where the carb bolts to the manifold and I put on two new exhaust gaskets where the manifold bolts to the block. The manifold looks new and there wasn't any rust on it.
 
Does choking it hurt or help it?? Do you have a good blue/white spark that will jump a 1/4 inch gap or more at all 4 plug wires?? If you pull the carb drain plug do you get a good steady flow of gas that will fill a pint jar in under 3 minutes and 2 is even better. When was the last time you serviced the air cleaner and dumped the water and mud and fill it with fresh oil?
 
You are obviously more than just a tinkerer. Have you checked the point gap and timing? Point gap should be .015.
 
(quoted from post at 16:26:02 11/28/21) Does choking it hurt or help it?? Do you have a good blue/white spark that will jump a 1/4 inch gap or more at all 4 plug wires?? If you pull the carb drain plug do you get a good steady flow of gas that will fill a pint jar in under 3 minutes and 2 is even better. When was the last time you serviced the air cleaner and dumped the water and mud and fill it with fresh oil?
Click to expand...

So far I've been running it with the intake air tube off, so the air cleaner isn't in play. I'll have to test your other two suggestions and report back, though I should have mentioned that the fuel shutoff is new too and the screens are clean.
 
(quoted from post at 16:37:22 11/28/21) You are obviously more than just a tinkerer. Have you checked the point gap and timing? Point gap should be .015.
Click to expand...

Thanks Jim, just not completely comfortable when it comes to diagnosing engine issues. Yes, point gap was set to .015 and timing set per the manual.
 
But is that point gap the same at all 4 lobes of the distributor?? Seen more then one distributor that was bad and the point gap was not the same at all 4
 
(quoted from post at 17:03:53 11/28/21) But is that point gap the same at all 4 lobes of the distributor?? Seen more then one distributor that was bad and the point gap was not the same at all 4
Click to expand...

I'm pretty sure I checked on multiple lobes, but I can check again to be sure.
 
A few years back I worked on a front mount 8N and found half the lobes didn't open the points to the 0.015 but the other half did. Ran poor at best and was hard to start. Replaced the distributor and it fired up so fast I could not get my hand off the start button fast enough and had more power then it had had in years
 
(quoted from post at 17:47:21 11/28/21) A few years back I worked on a front mount 8N and found half the lobes didn't open the points to the 0.015 but the other half did. Ran poor at best and was hard to start. Replaced the distributor and it fired up so fast I could not get my hand off the start button fast enough and had more power then it had had in years
Click to expand...

I'll try to get a chance to take the distributor back off this week to check.

Is it likely that the differences in the plugs and the bogging down are related or am I looking at two separate issues?

One thing that I've wondered about is if the previous owner got the cam gear timing right. Not sure what the symptoms of a mistimed cam gear are, but I'm running out of ideas on what the issue may be. Thanks!
 
(quoted from post at 18:24:36 11/28/21)
(quoted from post at 14:53:52 11/28/21) He paid me over a hundred plus shipping for the adapter for it so I don't think $300 will buy it LOL.
Click to expand...

Ha, you got that right Kirk! And thanks again, that adapter was the piece that let everything come together!!
Click to expand...

I was wondering about that. The adapter sure didn't look home-brew

TOH
 
It doesn't look like two plugs are even
firing. When running, short each plug
with a screwdriver. If no difference in
sound or running, they are not firing.
Could be destributor, plug wires crossed,
plugged intake manifold or intake to
center block port plugged, center exhaust
valves not opening. Or???
 
(quoted from post at 08:52:37 11/29/21) It doesn't look like two plugs are even
firing. When running, short each plug
with a screwdriver. If no difference in
sound or running, they are not firing.
Could be destributor, plug wires crossed,
plugged intake manifold or intake to
center block port plugged, center exhaust
valves not opening. Or???
Click to expand...

Thanks Roger, I'll try shorting the plugs over the weekend and see what happens. Plug wires are definitely not crossed, I've checked that.
 

In situations like this never trust the new ignition parts. Try switching plugs, wires around and old parts back in. With # 1 and 4 plugs looking like they do, it hard to believe it is running as it should.
Also could the drive train be binding up and causing the problem?
 
I still say it looks overly rich....screw the main power adjust in a half turn, one turn, experiment a bit.
 
I'm thinking Roger may be onto something. Seems to me that if Cylinders 1 and 4 plugs are looking the same and 2 and 3 are looking the same, maybe this is only running on two cylinders. That would explain a lack of power. I checked spark with the plugs out and all 4 were working, but didn't check with the plugs screwed in. Won't have a chance to look again until at least the weekend, but that's where I'll start. If two of those cylinders aren't sparking they I'll have a direction to track down the actual problem. Thanks all!
 
(quoted from post at 13:48:52 11/30/21) I'm thinking Roger may be onto something. Seems to me that if Cylinders 1 and 4 plugs are looking the same and 2 and 3 are looking the same, maybe this is only running on two cylinders. That would explain a lack of power. I checked spark with the plugs out and all 4 were working, but didn't check with the plugs screwed in. Won't have a chance to look again until at least the weekend, but that's where I'll start. If two of those cylinders aren't sparking they I'll have a direction to track down the actual problem. Thanks all!
Click to expand...
f you mistakenly thought that distributor turns CW and installed wires 1-2-4-3 accordingly, then 1 and 4 will fire and 2 and 3 will not.. :idea:
2lZHsz4.jpg
 
(quoted from post at 11:52:21 11/30/21)
(quoted from post at 13:48:52 11/30/21) I'm thinking Roger may be onto something. Seems to me that if Cylinders 1 and 4 plugs are looking the same and 2 and 3 are looking the same, maybe this is only running on two cylinders. That would explain a lack of power. I checked spark with the plugs out and all 4 were working, but didn't check with the plugs screwed in. Won't have a chance to look again until at least the weekend, but that's where I'll start. If two of those cylinders aren't sparking they I'll have a direction to track down the actual problem. Thanks all!
Click to expand...
f you mistakenly thought that distributor turns CW and installed wires 1-2-4-3 accordingly, then 1 and 4 will fire and 2 and 3 will not.. :idea:
2lZHsz4.jpg
Click to expand...

Thanks for the graphic JMOR! I don't think the plugs wires are hooked up incorrectly. The distributor cap is numbered just as in your pic and wire from 1 on the cap goes to the cylinder up by the radiator and works its was back from there....#2 on cap to cylinder 2, etc

I will triple check it though to be sure!

This post was edited by paul25g on 11/30/2021 at 11:39 am.
 
Just confirmed that plug wires are running from the number on the distributor cap to the corresponding cylinder understanding cylinder #1 is closest to the radiator.
 
(quoted from post at 19:05:55 11/30/21) Just confirmed that plug wires are running from the number on the distributor cap to the corresponding cylinder understanding cylinder #1 is closest to the radiator.
Click to expand...
he important part is that they are CCW, since that if they are CW in order, the cylinder #1 & 4 will fire just fine but #2 & 3 wont. I have never seen a cap that had all 4 numbered, all I have seen only have the #1 or none.
 
(quoted from post at 08:45:13 12/01/21) Here's a pic of the distributor cap I used...
mvphoto85333.jpg
Click to expand...
ell, I guess I have beat that to death! It was such a perfect match to your problem. Too bad that it wasn't the answer. Be sure to let us know the solution.
 
(quoted from post at 07:19:51 12/01/21)
(quoted from post at 08:45:13 12/01/21) Here's a pic of the distributor cap I used...
mvphoto85333.jpg
Click to expand...
ell, I guess I have beat that to death! It was such a perfect match to your problem. Too bad that it wasn't the answer. Be sure to let us know the solution.
Click to expand...

Will do JMOR and thanks again for your input....you're right, that would have made perfect sense and been an easy fix....I'll let you know what I eventually find...thanks!
 
Bingo....even though the inline spark tester showed spark at all cylinders, timing light shows cylinders 1 and 4, the ones with the sooty plugs, aren't firing. Now, gotta figure out why...
 
Sooty says it is running to rich. If it where me I'd replace then China made plus with some NGK3112 plugs
 
'timing light shows cylinders 1 and 4, the ones with the sooty plugs, aren't firing. Now, gotta figure out why'

OK so here is a completely off the wall hypothesis. New manifold, correct?

Suppose the manifold somehow ended up with the intake passages way to small. This would cause the mixture to travel at a higher than normal velocity through said passages. Since gas in injected into the air stream as a mist rather than vapor by the carburetor and gas being much heavier than air, when the mixture gets to the ends of the manifold and makes that hard right angle turn going into the engine, the heavier gas droplets are thrown against the ends of the manifold, and like in a centrifuge, some of the gas gets separated from the air stream. When the center cylinders are taking air that separated gas collects in the outer cylinder ports. When the outer cylinders are taking air they take it all.

Result:
Extra rich mixture on outer cylinders, extra lean on the inner cylinders.

Although it is not a likely scenario, I have done some metal casting and had some mold failures and core failures, so am of the opinion that it is within the realm of possibility.
 

I suppose this is entirely possible.

But, my understanding of an induction timing light clamped over the plug wires is that the timing light flashes when it senses the electricity in the plug wire. Since its not flashing at all for cylinders 1 and 4, doesn't this mean that something more towards the distributor isn't doing what its supposed to in order to provide spark to those cylinders? In other words, regardless of the fuel/air mixture, I'd have to have spark regardless, which I don't seem to for those cylinders.

As I said earlier, not a mechanic, just trying to understand if this is what the timing light is showing.....thanks for the help!
 
It has been my experience that when using a timing light if the spark plug is fouled the light will not flash. Those plugs had to be firing at some point or they would not be covered in black soot, they would just be wet. For an experiment you could swap the outer plugs with the inner plugs. Then it may be that the engine will run a little while on the outer cylinders, or it may not start at all. If it runs and the timing light flashes o the outer plugs and not on the inner, that would add credence to my hypothesis. Otherwise, it blows the theory all to heck.

Of course you could have just gotten lucky and got some bad plugs.
 
(quoted from post at 19:25:26 12/01/21) It has been my experience that when using a timing light if the spark plug is fouled the light will not flash. Those plugs had to be firing at some point or they would not be covered in black soot, they would just be wet. For an experiment you could swap the outer plugs with the inner plugs. Then it may be that the engine will run a little while on the outer cylinders, or it may not start at all. If it runs and the timing light flashes o the outer plugs and not on the inner, that would add credence to my hypothesis. Otherwise, it blows the theory all to heck.

Of course you could have just gotten lucky and got some bad plugs.
Click to expand...

That'll be my first check when I get a chance....put new plugs in 1 and 4 and test again with the timing light. If I get no flash, I'll look towards the distributor.
 
You have cleaned those plugs since you took the photo of them haven't you? If so, your timing light test would be accurate.
This might be off base, but you mentioned how the P.O. had painted the engine. He didn't get paint down in the spark plug holes did he?
 
Great point to check for paint in the plug holes, but they were clean. Put new plugs in cylinders 1 and 4 and timing light shows they are running now. Didn't get a chance to do anymore than that. This weekend I'll try to get the carb adjusted and test the bogging/no power issue.....hopefully this will take care of it but will report back on how it goes.....thanks for all the suggestions!!
 
Ok, new updates and observations. As I mentioned earlier, replaced plugs 1 and 4 and now the timing light is showing that all cylinders are firing. So I set the carb to initial settings and started the motor to let it warm up. Initial settings that I used were both main mixture screw and idle mixture screw turned out 1 full turn.

After letting it warm up and trying to begin idle mixture adjustment, I knew it still didn't seem to be running right. So took the carb air cleaner tube off and noticed a little gas spill out. Also noticed that idling at the initial carb settings mentioned above, that a little gas is spitting out of the carb air inlet.

I'm sure this is what was causing plugs 1 and 4 to foul....not sure why it also wouldn't have been fouling 2 and 3. I guess the big question is, what would be causing gas to spit out of the carb air inlet side at idle?

Valves are adjusted on the compression stroke, though not necessarily at TDC.....would this be part of the problem?

This post was edited by paul25g on 12/05/2021 at 10:22 am.
 
(quoted from post at 12:17:14 12/05/21) Ok, new updates and observations. As I mentioned earlier, replaced plugs 1 and 4 and now the timing light is showing that all cylinders are firing. So I set the carb to initial settings and started the motor to let it warm up. Initial settings that I used were both main mixture screw and idle mixture screw turned out 1 full turn.

After letting it warm up and trying to begin idle mixture adjustment, I knew it still didn't seem to be running right. So took the carb air cleaner tube off and noticed a little gas spill out. Also noticed that idling at the initial carb settings mentioned above, that a little gas is spitting out of the carb air inlet.

I'm sure this is what was causing plugs 1 and 4 to foul....not sure why it also wouldn't have been fouling 2 and 3. I guess the big question is, what would be causing gas to spit out of the carb air inlet side at idle?

Valves are adjusted on the compression stroke, though not necessarily at TDC.....would this be part of the problem?

This post was edited by paul25g on 12/05/2021 at 10:22 am.
Click to expand...
djust valves as close as possible to Top Dead Center.
 
(quoted from post at 13:53:18 12/05/21) Paul, disconnect the exhaust pipe at the manifold, and test it. Let us know the results.
Click to expand...

Jim,

Removed exhaust pipe and that nearly eliminated the spitting from the carb intake, but there is still just a little.

Hard to tell for sure, but seems like the exhaust is sort of moist.....leaves a little bit of sheen on the side of the block.
 
Hi guys,

I'm wondering if this could be a manifold with an internal casting issue, as someone mentioned earlier. Is there a good way to test this manifold for internal leaks?

Not sure if the hole circled in the pic is supposed to be there or not.



Thanks!
mvphoto85634.jpg



This post was edited by paul25g on 12/10/2021 at 09:09 am.
 
Good question, I don't have a manifold to look into. I'm sure someone does though.
What I was after with disconnecting the exhaust pipe was to see if there may be a blockage causing a lot of back pressure. Had that happen years ago. Datsun pickup had been rescued from the ocean. Put a used engine in it and it wouldn't rev up much past an idle and had a lot of vapor coming out of the carburetor. Turned out to be a plugged up muffler.
 
'I'm wondering if this could be a manifold with an internal casting issue, as someone mentioned earlier. Is there a good way to test this manifold for internal leaks?

Not sure if the hole circled in the pic is supposed to be there or not.'

That does not look good to me. Since you have the manifold off, cover the carburetor inlet with duct tape, lay the manifold down engine block side up and fill the intake ports with water. If after a few minutes the water level goes down, pour out the water watching for water coming out of the exhaust ports. Water will leak much slower than air and there being no differential pressure between intake and exhaust, give it some time.
 
Thanks Jim!

Even though there was much less spray coming from the carb intake when I removed the exhaust, there was still a little. The exhaust was brand new, but I know there's a chance that something could have gotten in. I ran a wire through it and have tapped with a rubber mallet, but didn't get anything. Guess I could try to flush it with water from the hose.

That hole circled in the pic might supposed to be there, not sure. But was just wondering if there's a chance something else on the inside might be bad and if there's a way to test.

Thanks for your input!
 
That does not look good to me. Since you have the manifold off, cover the carburetor inlet with duct tape, lay the manifold down engine block side up and fill the intake ports with water. If after a few minutes the water level goes down, pour out the water watching for water coming out of the exhaust ports. Water will leak much slower than air and there being no differential pressure between intake and exhaust, give it some time.[/quote]

Thanks Dean! Don't have the manifold in front of me, but if I remember correctly there are 6 ports. I believe the outside ports are exhaust for cylinders 1 and 4, the next two in are the intake for cylinders 1 and 4 and finally the two inner ports act as both intake and exhaust for cylinders 2 and 3....Do I have that right? So are you saying just pour the water into the intake ports for cylinders 1 and 4....since the ports for cylinders 2 and 3 are both intake and exhaust?
 
(quoted from post at 14:30:12 12/10/21) Ports are front to back:
exhaust #1
intake #1, #2
exhaust #2
exhaust #3
intake #3, #4
exhaust #4
Click to expand...

Great, thanks!! I'll try the water test tomorrow and see what happens
 
Did the water test and within a few seconds, water was pouring out of the manifold exhaust outlet and showing in the exhaust ports. Looks like a bad manifold....I'll order a new one and hope that I've finally tracked down the problem!
 
(quoted from post at 12:23:43 12/11/21) Did the water test and within a few seconds, water was pouring out of the manifold exhaust outlet and showing in the exhaust ports. Looks like a bad manifold....I'll order a new one and hope that I've finally tracked down the problem!
Click to expand...
t wouldn't be the first time....see the light thru the hole.
vqL945P.jpg
 
Got a replacement manifold installed and this thing is running like it should now!!! I even took it through some swampy areas that my 850 wouldn't stand a chance in, and this thing just zipped on through like it was nothing!

Now I just have to decide if I'm going to keep it, but its been a fun project!

Thanks for all the help guys!
 
(quoted from post at 17:53:00 12/17/21) Got a replacement manifold installed and this thing is running like it should now!!! I even took it through some swampy areas that my 850 wouldn't stand a chance in, and this thing just zipped on through like it was nothing!

Now I just have to decide if I'm going to keep it, but its been a fun project!

Thanks for all the help guys!
Click to expand...

While youare debating keeping it just drop it off here and I will keep it cleaned up and exercised for you ;-)

Dan
 
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