59ab compression numbers

42Ford M-H

42Ford M-H

Senior Member
Just looking for some confirmation on my thinking. From reading a bunch of threads I "think" i have a good idea on whats going on.

My last trip last fall ended up coming home on a flatbed. Started running really rough, couldnt get it started again after i stopped. Of course it was dark and raining so just called the flatbed. Got it home from the flatbed and it started right up. Long story short, after swapping may parts it was still running rough. Was chatting with a buddy the other day over he asked if i had checked the compression... I said nope.. Motor doesnt smoke at all.

Well... After checking the numbers
Engine was hot, took it for 10 minute drive.
plugs out, cranking over quickly for 5 compression strokes.
All cylinders were between 80-86 psi compression
put maybe half a teaspoon of oil in the first cylinder made no difference.
forgot to block the throttle open half way thru testing. Tried it again with throttle open/choke off, made no difference that I could tell. If it did it was maybe 1-2 pound difference? so i left it close to keep everything consistent.

Motor still sounds like its missing on occasion.

so my thinking is
more than likely the valves? Did I put in enough oil to have a decent test?
Motor doesnt smoke. Is 80-86 PSI low for a stock 59ab? from what I've read, I think so?

Sorry for the long winded thread. Looking for ideas on what to do next. I'd really like to just drive it this summer and save any big projects for this coming winter if possible.

Thanks in advance for any feedback.
 
I took a look at your post, I think we may have different issues. But im going to keep an eye out on your thread to see how it goes. Here are my plugs, I've actually wondered if im running lean. I'm going to try the 2 fingers over the carb @ 1200 rpm trick. I've seen comments by folks that you can't really judge by looking at plugs unless you do some correct tests.

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Your compression is not great, but good enough that it shouldn't cause a problem running. I assume you've checked the coil and condenser, the usual suspects. If it's running bad, try pulling the choke on to see if it helps.
 
I've replaced coil, condenser and points. Condenser and coil tested ok with but i tried it anyways. Not that its not possible one of the new parts isnt bad. I was nervous about the compression numbers. I didnt want to keep chasing parts if the problem was in the engine. Which is why I posted here :)
 
Those plugs look pretty good to me,,,,,,reasonably clean ,,,I think .
Even though the compression is not all it should be,,,,I don’t think the rings are an issue,,,,or the guides.
No oil on them at all .
How are your valves sealing,,,,,they might be a little marginal,,,,,no way to tell really,,,other than using a vacuum gauge and reading it .
If you pull the heads,,,that will show how they are sealing,,,,,but that’s a lot to do just to check .
Vacuum gauge will tell the story .

Tommy
 
Plugs look ok , check exhaust , plug wires ,fuel .were any plugs a different color ? Do you have a vacuum gauge ? Look for a steady vacuum reading , if one cyl is not working as hard as the others youll get a unstable reading . When was the last point gap check , dist cap check . Have it running at night or dusk , get a mist spray bottle and mist the plug wires , start in the back . Check your vacuum lines ,wiper motor vacuum line , dist vacuum line all good and not leaking ? Fuel pump screen clean ?
 
Or if you are still looking how about the fuel side. Old fuel in tank. Filter if fitted due a clean. Mech fuel pump ok? Carb ok? For me your plugs look fine. Compressions a little low but all even. The vaccum gauge will tell you if valves are suspect.
Best of luck.
Phil NZ
 
To me, if you have consistent numbers across the board - then you don't have one cylinder with issues - rings or valves . . . they're all working about the same. My guess is that it has something to do with fuel and the fuel pump/carb or the ignition system.
 
I drove my original '51 Ford for thirty years with compression like yours with no problems other than less than stellar performance.

I finally got tired of it three years ago and put in a new engine.
 
Napa Coil IC7 oil filled, I believe I left the resistor in under the dash. And measured 4.5 volts at the coil. Also replaced the condenser with one from Napa. I can check voltage again and try another condenser. I believe I could take out the resistor, but that the coil would just run "hotter".

Took for a drive last fall and it started running like crap within 10 minutes.

I swapped the points the other day, no change other then at high RPM's. The old points spring tension was weak. I believe they were floating at high rpms. Not that I ever drive it like that. This was just a quick blimp of the throttle.

Throttle response is always pretty snappy.

I'll check Vaccum and for leaks. And check for arcing plug wires. Never heard of the misting water trick.

Right now if i start it up and keep it around 1200 ish rpms you can hear 1 maybe 2 cylinders cutting in and out. When it get's hot it gets worse.

Sounds like the compression isnt great, but not the reason I'm having issues. So I'll keep chasing parts. It's always started hard after running for awhile. I always chalked it up to not "knowing" the trick. Like one pump and turn over or 1/4 throttle kinda stuff. Figured after 75+ years its just finicky.. sounds like maybe its the lower compression numbers.
 
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You may have to try several new condensers until you get a good one. A member over on the H.A.M.B. decided to chase down the ongoing condensers problems that are common these days. Upon taking several apart, he found that there was no real connection between the lead and the condenser works. They were just crimped together and expected to have good continuity. They will even test good, but fail immediately while running due to the vibration present. Even new Echlin's for NAPA are suspect these days.
 
I saved my old one, it actually has ford imprinted in the casing. It tested ok? I also have another new Echlin in the box. Maybe I shouldnt have replaced both the coil and condenser at the same time. Maybe I swapped one problem for another. Hard to say... It's almost a good thing that its running rough almost all the time. Makes me feel like if I change a part and it goes away immediately, rather then having to drive it down the road and possible get stuck somewhere.

On a side note I've been thinking about adding a fuel pressure gauge. Just for easier troubleshooting.
 
Denny,
That is great to hear,,,,,it makes sense too .
No wonder the new condensers are crap,,,,,,,no permanent connection to the lead .
I was wondering how a new condenser could fail in just a few days .
That news makes complete sense to me .

To be honest,,,,I guess that makes a Tubman condenser even better .
At least they are quality,,,,and built correctly!

Tommy
 
Lots of things could be going on. The rub connection on your dist. (the little pole that leads in to the points) could have and internal short or resistance. The resister contacts under the dash could have excessive resistance, take the wires off, sand the contacts and nuts. Your ign. switch contacts in the little box on your switch could have resistance and need cleaning as well as the wires going to the switch and away from it. Resistance and the circuits has a tendency to heat up and get worse when current is engaged.
 
I've noticed in my trials that if the fuel system isn't perfect, the flatty won't be either. A good fuel pump and carb working properly, that's key for my '35. I'v chased this problem and finally got it right myself. Your plugs look great and I'm going along with Phil G and suggest the fuel area to look at. These engines are so simple yet so finnaki ! Hope you get it running right!
 
After lots of troubleshooting i finally found the problem. Shutoff valve on the bottom of the tank was full of crap. Bouncing are just right would cause it to plug. Fuel pressure gauge would have made it quicker to find.
 
42Ford M-H said:
Just looking for some confirmation on my thinking. From reading a bunch of threads I "think" i have a good idea on whats going on.

My last trip last fall ended up coming home on a flatbed. Started running really rough, couldnt get it started again after i stopped. Of course it was dark and raining so just called the flatbed. Got it home from the flatbed and it started right up. Long story short, after swapping may parts it was still running rough. Was chatting with a buddy the other day over he asked if i had checked the compression... I said nope.. Motor doesnt smoke at all.

Well... After checking the numbers
Engine was hot, took it for 10 minute drive.
plugs out, cranking over quickly for 5 compression strokes.
All cylinders were between 80-86 psi compression
put maybe half a teaspoon of oil in the first cylinder made no difference.
forgot to block the throttle open half way thru testing. Tried it again with throttle open/choke off, made no difference that I could tell. If it did it was maybe 1-2 pound difference? so i left it close to keep everything consistent.

Motor still sounds like its missing on occasion.

so my thinking is
more than likely the valves? Did I put in enough oil to have a decent test?
Motor doesnt smoke. Is 80-86 PSI low for a stock 59ab? from what I've read, I think so?

Sorry for the long winded thread. Looking for ideas on what to do next. I'd really like to just drive it this summer and save any big projects for this coming winter if possible.

Thanks in advance for any feedback.
Click to expand...
Have you tried removing all plugs and reconnecting the HT wire to each one, with a good earth, and crank over the engine to check the condition of each spark?
 
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