Compression Testing Dry Wet Marvel Mystery Oil 1951 Ford 8N

[bradleydavidgood]

 

[Hobo,NC]

My guess rust build up on valve/valve seat. Oil will help if you can get it to run it should ware/beat the rust off.. Are hope it does.

 

[bradleydavidgood]

My guess rust build up on valve/valve seat. Oil will help if you can get it to run it should ware/beat the rust off.. Are hope it does.

Yea, I think that's a good guess. I'm going to do many days of MMO with longer cranks and see if that improves it any. Then determine what to look into about valves.

Thanks!

 

[bradleydavidgood]

2nd day of cranking, compression testing, and Marvel Mystery Oil.

Promising results

 

[Jim.ME]

2nd day of cranking, compression testing, and Marvel Mystery Oil.

Promising results

I don't see that told whether or not you have the throttle wide open when doing the compression tests. It should be if it is not.

 

[soaked]

Agree with Jim.

And why no oil info, or did I miss it?

Is oil pressure showing on the gauge? A nice oil pump on 12 volts (230-240 rpm) with plugs out should prime itself, and show (ticking needle) around 8-12 psi, or more.
Was the old oil changed? Any water, cooland, gas in it? Was it reading above the full mark on the dipstick?

Gotta be nice to the crank/ bearings/rods after their 20 year nap, its likely there're parched.

 

[bradleydavidgood]

I don't see that told whether or not you have the throttle wide open when doing the compression tests. It should be if it is not.

I think it's in the middle. I'll put it all the way up. That should improve the numbers.

Thanks!

 

[bradleydavidgood]

Agree with Jim.

And why no oil info, or did I miss it?

Is oil pressure showing on the gauge? A nice oil pump on 12 volts (230-240 rpm) with plugs out should prime itself, and show (ticking needle) around 8-12 psi, or more.
Was the old oil changed? Any water, cooland, gas in it? Was it reading above the full mark on the dipstick?

Gotta be nice to the crank/ bearings/rods after their 20 year nap, its likely there're parched.

Good idea. I'll record the oil pressure gauge tomorrow. I haven't looked at it.
I'm also going to crank it a little longer tomorrow on each repetition.
No gas. The hood is off.
No coolant. I drained that out the lower hose today and ordered new hoses and a 180 degree thermostat along with some other things I can't remember right now, but basically I am refreshing everything that wears.
I also ordered coolant.
I received my 12V EI parts and I'm going to start that soon...but that's another thread.
Just saying there's that work before I start it. And I really want to go many days with this routine of cranking without starting and MMO soaks until the numbers level out and then more days after that. I ordered a gallon of MMO and I may use the whole thing. 20-25 years is a long time and since it was professionally rebuilt, I want to break it back in/clean it up gently and be patient.
I've got plenty to do in the mean time and more parts on the way.

Thanks!

 

[Jim.ME]

Good idea. I'll record the oil pressure gauge tomorrow. I haven't looked at it.
I'm also going to crank it a little longer tomorrow on each repetition.
No gas. The hood is off.
No coolant. I drained that out the lower hose today and ordered new hoses and a 180 degree thermostat along with some other things I can't remember right now, but basically I am refreshing everything that wears.
I also ordered coolant.
I received my 12V EI parts and I'm going to start that soon...but that's another thread.
Just saying there's that work before I start it. And I really want to go many days with this routine of cranking without starting and MMO soaks until the numbers level out and then more days after that. I ordered a gallon of MMO and I may use the whole thing. 20-25 years is a long time and since it was professionally rebuilt, I want to break it back in/clean it up gently and be patient.
I've got plenty to do in the mean time and more parts on the way.

Thanks!

Count the number of gauge pulses on the first cylinder you do. Stop when the gauge stops going up on each pulse. Go the same number of pulses on all the cylinders.

 

[bradleydavidgood]

Count the number of gauge pulses on the first cylinder you do. Stop when the gauge stops going up on each pulse. Go the same number of pulses on all the cylinders.

OK. I was just doing it on each one until it stopped climbing. I thought that was acceptable.

 

[Jim.ME]

OK. I was just doing it on each one until it stopped climbing. I thought that was acceptable.

4 to 6 compression strokes is a commonly stated guideline. Same number of strokes gives you an idea of how near alike the cylinders are performing.

You also need to be sure the battery is performing at the same level for all cylinders. excess cranking can reduce battery performance without keeping a good charger on it.

 

[bradleydavidgood]

4 to 6 compression strokes is a commonly stated guideline. Same number of strokes gives you an idea of how near alike the cylinders are performing.

You also need to be sure the battery is performing at the same level for all cylinders. excess cranking can reduce battery performance without keeping a good charger on it.

OK sounds good.

After cranking today I was still at 93% charge.

And after each day's session, I put it on a maintainer and it is back at 100% next day.

Thanks!

 

[Hobo,NC]

Google this

what does the first pulse of a compression test tell you

Most folks think rings rings rings all they know is rings rings rings and oil seals rings. To get a good hit on the first pulse the cylinder needs to be at the bottom of the compression stroke. I am not gonna spend much time trying to get the piston at BDC. I am going to test each cylinder 3 times I am going to use the best first hit of each cylinder as my guild to how well each cylinder seals. All the other hits the next 3 hits tell me how well the valves are sealing.

Yes, oil will greatly improve poor sealing valves this is overlooked because its got to be the rings. There are no doubt in my mind the valves have accumulated some surface rust.

I think you have done all you need to do till you can get some fire in each hole. By all means make sure you have oil pressure while spinning the starter.

 

[bradleydavidgood]

Google this

what does the first pulse of a compression test tell you

Most folks think rings rings rings all they know is rings rings rings and oil seals rings. To get a good hit on the first pulse the cylinder needs to be at the bottom of the compression stroke. I am not gonna spend much time trying to get the piston at BDC. I am going to test each cylinder 3 times I am going to use the best first hit of each cylinder as my guild to how well each cylinder seals. All the other hits the next 3 hits tell me how well the valves are sealing.

Yes, oil will greatly improve poor sealing valves this is overlooked because its got to be the rings. There are no doubt in my mind the valves have accumulated some surface rust.

I think you have done all you need to do till you can get some fire in each hole. By all means make sure you have oil pressure while spinning the starter.

Thanks!

 

[bradleydavidgood]

Seems to be coming around....

 

[soaked]

Seems to be coming around....

Fantastic oil psi!
Compression on a fresh rebuild is
120 - 125 psi.

Clone or 241-B carb?

If you leave the short #1 plug wire out of the loom, the other 3 will be super easy to determine. So no foul ups on 3 & 4.

 

[Hobo,NC]

It would be cool if they made nitrile shocks, you never know where those tractors have been.

 

[bradleydavidgood]

Fantastic oil psi!
Compression on a fresh rebuild is
120 - 125 psi.

Clone or 241-B carb?

If you leave the short #1 plug wire out of the loom, the other 3 will be super easy to determine. So no foul ups on 3 & 4.

Good to hear!

I think the carb is TSX-241B original. I ordered a kit from YT and it's on the way.

Here is a pic of the carb brass plate:

What loom? Do I have a loom?

I have all the wires marked 1-4 when I took them off so I was just going to follow that for the install of the new ones. How could I mess it up doing that?

Thanks!

 

[bradleydavidgood]

It would be cool if they made nitrile shocks, you never know where those tractors have been.

It's pretty clean actually there ha. I don't mind dirt and manure just don't want chemicals in the hands all the time and I work on vehicles constantly. Plus my finger tips crack if I get chemicals on them.

 

[soaked]

Spark plug loom

This reads 1151, meaning December 1951, yours prolly has a 2, im guessing, in front of 51.
Edit:
Woops 11 is November, not December