MF 150: Distributer Cap, Rotor Button, Condensor

[crowbar032]

I have a 1968 MF 150 with a gas engine and about 2800 hours. It's all original. For whatever reason the past three years, this tractor goes through 2-3 tune up kits a year. I put the new parts on and it runs great for a couple of hours at PTO speed then it starts missing. The spark plugs and wires are not the issue. Check the points and they have slipped. Reset the points, it runs good for a couple of hours then starts missing. After this happens a couple of times, the distributer cap contacts are fouled. I talked with the former owner of a Massey dealership who now runs an independant tractor repair shop. He told me the whole distributer assembly is worn out which causes it to "wobble" moving the points and burning the contacts in the cap. Has anyone else had a similar issue? Does this even sounds plausible? How hard is it to convert to an electronic ignition and how expensive? Or is this a complete engine overhall moment? I hate to do a complete rebuild as the engine doesn't smoke or use any oil. I'm just at a dead end.

 

[MasseyWV]

Which gas engine do you have, the Continental Z-145 4 cylinder or the Perkins 3 cylinder?

 

[crowbar032]

Which gas engine do you have, the Continental Z-145 4 cylinder or the Perkins 3 cylinder?

It's the Continental Z-145 four cylinder gas engine. It still has the soft valves in it so I add lead additive to the gas.

 

[Dieseltech]

If distributor shaft is loose may be time for new bushings in housing so points will stay in adjustment. If not loose may need a small amount of lube on camlobe to slow point rubbing block wear.

 

[MasseyWV]

It's the Continental Z-145 four cylinder gas engine.

Based on the description you provided, it's very likely that the distributor bushings and/or shaft are worn, thus causing the problems you're experiencing. The distributor shaft should not have more than .002 inch of side to side play. It's also possible that the timing advance weight springs are damaged.

You could purchase a rebuilt replacement distributor, or have your existing distributor rebuilt by a distributor repair shop or possibly even a local machine shop. The part numbers for your distributor are as follows:

Massey Ferguson Part Number: 194059M91
Delco-Remy (GM) Part Number: 1112-644

Exploded-view parts diagrams and a complete list of part numbers for your distributor can be found at AGCO Parts Books

 

[Jerry/MT]

I have a 1968 MF 150 with a gas engine and about 2800 hours. It's all original. For whatever reason the past three years, this tractor goes through 2-3 tune up kits a year. I put the new parts on and it runs great for a couple of hours at PTO speed then it starts missing. The spark plugs and wires are not the issue. Check the points and they have slipped. Reset the points, it runs good for a couple of hours then starts missing. After this happens a couple of times, the distributer cap contacts are fouled. I talked with the former owner of a Massey dealership who now runs an independant tractor repair shop. He told me the whole distributer assembly is worn out which causes it to "wobble" moving the points and burning the contacts in the cap. Has anyone else had a similar issue? Does this even sounds plausible? How hard is it to convert to an electronic ignition and how expensive? Or is this a complete engine overhall moment? I hate to do a complete rebuild as the engine doesn't smoke or use any oil. I'm just at a dead end.

It's very plausible.

The bushing and shaft often get worn and then you really can't set the dwell (or points gap) because the shaft wobbles. On my Delco, the shaft/bushing radial tolerance is 0.002".

The distributor on our TO-30 was so bad that with the points closedand applying a radial load on distributor shaft the points would open to 0.030". It had obviously been worrn for some time and then suddenly started running like a three legged dog. I had the distributor shaft turned and rebushed and advance re-curved (as long as it was being worked on) and have had no problems after that.
So the person you talked gave you the right general advice. Get the distributor refurbed by someone who knows how to do this. Auto electric shops that can do this are getting scarce. I live in the West and had an outfit in Portland, OR do mine (The Philbin Group - Philbin Manufacturing and Philbin Rebuilt Products). If you have a small lathe and a press and the associated skills, you can do it yourself. You make sur ethe shaft is trully round and then make the bushing ID to fit the shaft and the OD to fit distributor housing.

There's another issue on some of these Continental engines; cam thrust plate wear. it caases the distributot shaft to move up and down as the cam moves fore and aft due to the distributor drive gear design and damages the cap and rotor. The fix is to replace the cam thrust plate. It's not impossible to have both problems on an older engine.

 

[crowbar032]

What is the best way to find out if it's the shims or the shaft or both? The guy I talked with said a new distributor was $800 and an electronic one like he used was $150. $650 will buy a lot of other tractor stuff. Will I be able to tell by feel using my hand or will I need some special tool? Or is this one of those jobs where you just replace the shims first and hope it's not the shaft.

Thanks for the help, I really appreciate the feedback.

 

[MasseyWV]

What is the best way to find out if it's the shims or the shaft or both? The guy I talked with said a new distributor was $800 and an electronic one like he used was $150. $650 will buy a lot of other tractor stuff. Will I be able to tell by feel using my hand or will I need some special tool? Or is this one of those jobs where you just replace the shims first and hope it's not the shaft.

Thanks for the help, I really appreciate the feedback.

You can generally tell if there is excessive distributor wear (side to side or up and down) by using your hand. It's best to have the distributor removed to check it.

 

[Jerry/MT]

What is the best way to find out if it's the shims or the shaft or both? The guy I talked with said a new distributor was $800 and an electronic one like he used was $150. $650 will buy a lot of other tractor stuff. Will I be able to tell by feel using my hand or will I need some special tool? Or is this one of those jobs where you just replace the shims first and hope it's not the shaft.

Thanks for the help, I really appreciate the feedback.

You can check for cam trust plate wear by removing the cap and rotor and watching the top of the distributor shaft while you crank the engine. (if you want to get fancy you can hook up a dial gauge) If it moves up and down the thrust plate is worn and needs replacing. you have to do this installed on the engine since the cam bevel gear and for and aft motion lifts the distributor shaft.

Eight bills for a replacemnt distributor is nuts! I had mine done about 5 years ago for $100 plus shpg. Look at Yesterday's Tractors web site and see what their parts guys want for for a rebuilt distributor. I'm sure it's way less tha a $800. Check for auto electric shops in your area and get a quote from them for a rebuild of your distributor. A replacement distribuor with EI for $150 could be deal but you can buy a Pertronix for under $100 and put that in your existing distributor. The shaft/bushing wear is not that critical when you use EI's solid state switching. I wouldn't recommend this option however except as an iterim fix.

Unless your made of money, I wouldn't give anybody $800 for a tractor distributor. Look at all the alternatives before you decide.

 

[crowbar032]

Eight bills for a replacemnt distributor is nuts! Unless your made of money, I wouldn't give anybody $800 for a tractor distributor. Look at all the alternatives before you decide.

MasseyWV came through with a website that I can get a remanufactured on for $175 plus $75 core charge.

Thanks for the advice.