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farmall m wont start

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castle55

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We have a 1948 farmall m that ran great until it needed a valve job, head was reworked,new valves,ect. Block cylinders piston looked good.Head was off for 3 months. reassembled and now have real low compression on 3 cylinders. I think we have narrowed it down to stuck rings. soaked them with sea foam and marvel oil,hotter plugs,and anti fouler plug adapters but cant keep the plugs from fouling long enough to keep it running. Has anyone seen this before?
 
(quoted from post at 08:42:06 09/30/14) We have a 1948 farmall m that ran great until it needed a valve job, head was reworked,new valves,ect. Block cylinders piston looked good.Head was off for 3 months. reassembled and now have real low compression on 3 cylinders. I think we have narrowed it down to stuck rings. soaked them with sea foam and marvel oil,hotter plugs,and anti fouler plug adapters but cant keep the plugs from fouling long enough to keep it running. Has anyone seen this before?
Click to expand...

Did you correctly set the valve clearance gap when you reinstalled the head?
 
Yes the gap is set @.017 and I did a compression test with the valve train and push rods out and no change in compression 60-60-60-90. I don't think it has enough seal to even draw the fuel mixture in on the intake stroke. plugs are oil fouled.I did have it humping on a couple cylinders, but it just sputters out..I think if I could get it to run long enough to heat up that the rings would expand so the sea foam and marvel mystery oil could clean them up. what do you think?
 
#1 you used the wrong mix to free up the rings. #2 did you spin it over with ALL the plugs out to clear the cylinders before you tried to start it?? #3 what you should have used to free up the rings is good old AFT and let it sit a day or 2.
 
I did spin it with plugs out before I tried to start it and tried to start it several times since.
I did have it hitting on a couple of cylinders but it just wont keep running. I will try the ATF today.
I think that the thin MMO and sea foam just runs by the rings anyway.
 
(quoted from post at 13:50:45 09/30/14) and I did a compression test with the valve train and push rods out and no change in compression 60-60-60-90.
Click to expand...

What does this mean??
 
The seaform is a abrasive type of stuff so that did not help any at all. ATF will soak down by the rings and clean/free them up.
 
(quoted from post at 12:15:41 09/30/14)
(quoted from post at 13:50:45 09/30/14) and I did a compression test with the valve train and push rods out and no change in compression 60-60-60-90.
Click to expand...

What does this mean??
Click to expand...

Means that he eliminated the possibility of valve adjustment being the issue with low compression.

If you take the rockers and pushrods out, the valves are always 100% closed. It's not something a mechanic would normally do, but it is a valid way to eliminate one possibility.
 

My point exactly. His compression test is meaningless.

He says it ran good before so that means something is put together wrong............

Until we know what was taken apart and such it will be tough to give any good answers.
 
we were pushing snow and it started popping and missing losing power so we parked it. It would not start after that.We replaced the coil cap rotor points condenser plugs, rebuilt the carb,and then found we had low compression, sent the head in for a valve job and they found a couple cracked valves and the rest could not be ground again so it got new valves and seats. It has good spark and is in time as can be without it running. carb spits fuel while cranking, I don't think it is sucking it all the way to the valves compression 60-60-60-90
 
(quoted from post at 20:41:43 09/30/14) we were pushing snow and it started popping and missing losing power so we parked it. It would not start after that.We replaced the coil cap rotor points condenser plugs, rebuilt the carb,and then found we had low compression, sent the head in for a valve job and they found a couple cracked valves and the rest could not be ground again so it got new valves and seats. It has good spark and is in time as can be without it running. carb spits fuel while cranking, I don't think it is sucking it all the way to the valves compression 60-60-60-90
Click to expand...

These are static timed so you are in time or not!

Sounds like you better check valve timing too.

Maybe check firing order as well

Your description of the failure does not indicate valves, compression, etc.
 
If its spitting fuel back out of the carb, then something is not right. For the fuel to go backwards, one of the intake valves has to be open, so Im wondering if you torqued the head gasket down to the right specs, in the correct order, or the valves are set too tight, or something.
 
I would agree you need to start with valve timing, then static ign timing. Also, compression test with no valves operating would not tell you anything worthwhile.
 
It sounds to me like those valves are adjusted wrong. Start completely over and adjust them per the manual. It seems like the adjustment is backwards on some of them or something. Only other time I have had an engine do something like that is when I left the distributor clamp loose and the distributor rotated way out of time (car).
 
Okay FIRST they parked it because it started not running well SO IT WASN'T "OKAY" WHEN PARKED. I'm thinking valve timing, adjustment or something messed up in the relationship between the cam, the crank and the distributor. I think I'd be rolling it over by hand and making sure valves are opening and closing in sync with the crank. Train of thought it maybe the cam gear did something or maybe even the cam or the distributor drive committed harry-carry. Does it have live hydraulics?
 
Yes it does have live hydraulics and I thought it might be a timing issue but the tdc mark lines up both valves shut on #1 cyl. the rotor points at #1 tower on the cap. also lined up the lone single notch to the timing pointer and the clutch grease zert was centered in the hole. the timing was done by tdc #1 both valves shut set to .017 rotated motor 1/2 turn set #3 turned 1/2 to tdc set #4 turned 1/2 set #2 how do you know if a gear jumped or a woodruff key broke/bent short of removing the whole front end?
 
Have you tried to pull start the tractor? This would get the engine to roll over a little bit faster and you would have more electrical power for the ignition system, instead of the starter robbing some of the battery power.
I thought the proper way to adjust the valves was to put the engine at TDC for cylinder #1. Adjust both valves on #1 and one valve in cylinders 2 and three, and then rotate the engine one revolution to get #4 to TDC and adjust the remaining valves.
Your tractor started to spit and sputter while plowing snow. Maybe that is the problem you are still looking for.
SDE
 
I'm going to give the ATF a couple days to soak and then I will gap the valves your way. book say's .017H (hot)?
I'll try a loose.017-.018
 
Bring No1 piston at the radiator to TDC on the compression stroke. Counting from radiator adjust valves 1-2-3&5. Rotate the engine one full turn and then adjust valves 4-6-7-8. Adjust them cold and add .002" to the hot setting.
Hal
 
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