My 1966 Massey 135 Tractor (Pics)

[MasseyWV]

While I have the front of the tractor torn apart, I'm sorely tempted to go a bit further, by removing the front axle support bracket, so I can sandblast and paint it. It would also give me an opportunity to inspect and/or replace the front axle pivot bushing.

However, removing the front axle support bracket would require removing the complete front end assembly, and I'm not sure if I want to go that far just yet. Perhaps it would be better for me to wait until I give the lower half of the engine a complete overhaul at a later date.

Decisions, decisions.

 

[MasseyWV]

Last night, I finally got around to removing the valve guides from the head, using a special tool I made for my air hammer.

The tool was made by tack welding a bolt, that was cut and ground to the proper size, to an old pointed chisel air hammer bit that I wasn't using. The valve guides were pressed out from the top to aviod being jammed by carbon deposits, and came out easily. Note that it was done without heating the head.

When the time comes to fit new valve guides, I will have the machine shop do it, because the valve seats must be precision-ground whenever the valve guides are changed.

 

[MasseyWV]

Here are some of the parts I've recently cleaned and sandblasted. I'll give them a final sanding by hand, before priming and painting them.

 

[Jerry/MT]

I've managed to make some progress while tinkering with the Massey 135 to begin getting it back into shape. I say tinkering because that's all I'm really doing for now because I plan to eventually do a full restoration so doing too much right now would likely be a waste of money.

So far, I've taken all of the front sheetmetal off so I can begin to straighten it out and have easier access to the engine as I work on it. I also removed the rear fender with the heavily dented/mangled corner and have come a long way towards hammering it back into shape. Getting the rusted screws and bolts out was a challenge, but I managed without too much difficulty, except for one of the retaining bolts that held the rear fender mount in place, which was stuck and required some persuasion to get out of the hole so I could remove the fender.

It was long past time for an oil change so I replaced the old oil with 6 quarts of Valvoline SAE 10w40 along with a new oil filter. The old oil, aside from needing changed, showed no signs of moisture or other contaminates so it looks like the engine is ok, aside from needing the valves adjusted, and a new set of valve seals... for now.

Speaking of the engine, it smokes (light blue oil smoke) on startup and idle until it gets hot, so I'm planning to change the valve seals while I have the valve cover off to adjust the valves. Granted, the oil control rings could also be stuck from carbon buildup, but I'm hoping that valve seals takes care of most of the oil smoke until I tear it down for a rebuild during the restoration.

The shop manual hasn't arrived yet but in the mean time, does anyone have any experience with adjusting the valves and/or changing the valve seals in a Continental Z-145 engine? I hear the Z-134 uses the same heads so it should be applicable as well.

The fact that the engine only smokes at start and low power is due to the guides and/or valve seals on the intake valves being worn. At high manifold vacuum (like idle to somewhere off idle) the there will be a large pressure differential between the open intake valve and the upper part of the head where the valve springs and stems are located. This literally sucks oil down the valve stem. At WOT, the differential goes to near zero and very little oil will get down the valve stem. Between Idle and WOT the differentil gets smaller and at some point it will not beable to draw oil down the valve stem. As the engine warms up, some of the clearances get smaller and less oil wil be drawn down but usually at idle you see some signs of smoke.

Usually with a loss of oil control by the rings, the engine smokes across the power range.

 

[Jerry/MT]

Today, I made a trip to a local Massey Ferguson dealer, and purchased a number of different parts, including valve seals, assorted gaskets, nuts/bolts, and a new "replacement" hood latch to replace the ugly monkey-rigged hood latch that's on it. I also bought some stabilizer bars and a handful of spring pins.

Another interesting item I purchased for just $10, was an original owners manual for the Massey 135. I had already bought a reproduction of the owners manual, but couldn't resist the opportunity of owning an original.

After finally receiving the shop manual, I was able to confirm that the Continental Z-145 4 cylinder gasoline engine only has valve seals on the intake valves, but I purchased two sets of valve seals so I could also place them on the exhaust valves if desired.

I don't think you want to put valve seals on the exhaust valves. They'll probably melt! the exhaust valves get pretty hot.

 

[MasseyWV]

The fact that the engine only smokes at start and low power is due to the guides and/or valve seals on the intake valves being worn.

I agree. Removal, cleaning, disassembly, and inspection of the cylinder head revealed that both the valve stems and guides were indeed worn beyond tolerances. The wear was likely caused by excessive valve lash that was allowed to go without adjustment for an extended period of time, perhaps even for the life of the tractor.

As the rocker arm strikes the top of the valve stem, excessive valve lash increases the angle and force of impact, which causes the valve stem to ride against the valve guide, causing normal wear to accelerate.

 

[MasseyWV]

I don't think you want to put valve seals on the exhaust valves. They'll probably melt! the exhaust valves get pretty hot.

Retrofitting the exhaust valves with valve seals, would require the use of special valve seals (made of Viton or Teflon), designed to take the heat of the exhaust valves.

While I remain undecided about whether or not to retrofit the exhaust valves with valve seals, I'm strongly considering the possibility of retrofitting umbrella type valve seals on the intake valves, in addition to the existing o-ring type valve seals, for better oil control. I could have the tops of the intake valve guides machined to accept positive type valve seals, but I think it would be overkill for this application.

Valve Stem Seals Materials/Designs: Engine Builder

 

[Jerry/MT]

Retrofitting the exhaust valves with valve seals, would require the use of special valve seals (made of Viton or Teflon), designed to take the heat of the exhaust valves.

While I remain undecided about whether or not to retrofit the exhaust valves with valve seals, I'm strongly considering the possibility of retrofitting umbrella type valve seals on the intake valves, in addition to the existing o-ring type valve seals, for better oil control. I could have the tops of the intake valve guides machined to accept positive type valve seals, but I think it would be overkill for this application.

Valve Stem Seals Materials/Designs: Engine Builder

So what material were the seals you bought earlier and said you were going to use on the exhaust valves.

I also noticed your compression number and they were very high. I believe your engine is 6.5 CR so it should be closer to 125-130 psi compression for a new or rebuilt engine. I saw dry numbers of 155 psi and 160 wet. (I presume those are raw numbers and have not been adjusted for ambient pressure at the time of the compression test.)That's really high compression if your engine is in fact a 6.5 CR machine, and with those numbers I'm wondering why you felt you needed to rebuild the engine? There appear to be carbon deposits on the combustion chambers from the pictures, that may explain those compression pressures. There can't have been any valve leakage and the rings must be really good to get those numbers. Any comments to explain those compression pressures? Was there any sign of pre-ignition on the plugs or was the timing retarded to reduce pre-ignition?

 

[MasseyWV]

So what material were the seals you bought earlier and said you were going to use on the exhaust valves.

I bought stock o-ring type intake valve seals at the tractor parts store, and a set of 8 umbrella type Viton valve seals for the intake and exhaust valves from a local auto parts store, just in case I decided to use them. Since they would be retrofitted, I had to know the diameter of the valve stems and the inner clearance between the valve springs and guides, to select valve seals which would work.

The umbrella type valve seals only cost about $15 so I went ahead and bought them so I would have them on hand if needed. I'm always working on something, so even if I don't use them now, they will eventually be used.

I also noticed your compression number and they were very high. I believe your engine is 6.5 CR so it should be closer to 125-130 psi compression for a new or rebuilt engine. I saw dry numbers of 155 psi and 160 wet. (I presume those are raw numbers and have not been adjusted for ambient pressure at the time of the compression test.)That's really high compression if your engine is in fact a 6.5 CR machine, and with those numbers I'm wondering why you felt you needed to rebuild the engine? There appear to be carbon deposits on the combustion chambers from the pictures, that may explain those compression pressures. There can't have been any valve leakage and the rings must be really good to get those numbers. Any comments to explain those compression pressures? Was there any sign of pre-ignition on the plugs or was the timing retarded to reduce pre-ignition?

I agree that the compression readings (raw) were a bit higher than expected, and heavy carbon deposits could have been the cause. I was using one of those cheap compression gauges to perform the test, and haven't checked it for accuracy yet, so the numbers may have been off by a few PSI. At the time, I was mainly looking for consistency among the cylinders, so the exact PSI values were of less concern to me, unless they were inconsistent or extremely low.

Rebuilding the lower half of the engine may or may not be necessary, but I won't know for sure until I eventually pull the oil pan to inspect it. Granted, the compression was good for all the cylinders, but many other things (bearings, etc...) could also need attention.

The spark plugs were heavily oil fouled, but there were no indications of preignition or detonation. The tops of the pistons and cylinder walls look great, which also rules out preignition and/or detonation. As far as I know, the timing was stock, but I hadn't checked it yet because I wanted to address the oil buring problem first.

 

[MasseyWV]

I also noticed your compression number and they were very high. I believe your engine is 6.5 CR so it should be closer to 125-130 psi compression for a new or rebuilt engine.

According to the shop manual (looking at it now) for the Continental Z-145 engine, the compression ratio is 7.1 to 1 (not 6.5 to 1), and the compression for all cylinders should be between 145-160 PSI for a warm engine cranked at 150 RPM. However, the shop manual didn't specify if the compression values were wet or dry, so I'm assuming it means dry.

Now that I think about it, oil combined with carbon, was likely the main cause for the higher than expected compression readings, and would also explain why there wasn't much difference between the wet and dry compression readings. The higher than expected compression readings could also mean that the lower half of the engine is in great shape, despite the problems with the upper half of the engine, mentioned previously.

In any case, I plan to perform another compression test after I've reassembled the cylinder head, and get the engine running again. I could be wrong, but I believe I'll see a greater difference between the dry and wet readings, but judging by the condition of the pistons and cylinder walls, I don't expect to see much change from the previous compression readings.