Compression check on WD45?

JEK1

Member
I have a Allis WD45 1955 that I have had for 15 years and use it about 20 hours a year. The machine runs real good and strong. It does smoke a bit when cold but tends to go away when warmed up.

Today I ran a compression check on all engine cylinders and got like 145 PSI out of every one. That is way more than what I would have expected. Does that sound right for wd45?
 
WD-45 gas cranking compression is 130 psi as per A-C specs. The D-17 engine was 145 psi. So, it either has D-17 pistons/sleeves or maybe M&W pistons/sleeves. On a side note, WD-45 LPGas pistons were the same as D-17 gas pistons/ sleeves. Anyway, a WD-45 was kind of a tiger anyway, but when they were up-rated to this compression they were really mean for their size !!!
 
To me that says you have an engine that tis still in good shape. If I where you I would try a quart of ATF in 5 gal of gas and see if the smoking when cold goes away because that could be as simple as rings sticking or carbon build up
 
Probably the best thing that could happen is to hook it onto a plow or disc and work it for a couple of hours. Maybe hook a loaded wagon or trailer behind it and go for a 20 mile drive at full throttle. I have a feeling the spark plugs could be changed to one heat range hotter for the way it gets used ?? Like AC Delco 46-S instead of 45-S ??
 
Just to let you know I have found the NGK 3112 plugs work a whole lot better then the champ and AC or auto lite plugs do. I run them in my ford and A/C tractor and they have made a big difference as to how quickly they foul or not. I have a WD45 that would foul plugs and it has yet to foul the NGK3112s I put in
 

Even though the engine never had valve seals, a set installed on the intake valves will probably eliminate the smoke at start-up..and they are cheap..
 
Not many repair manuals give the compression pressure of an engine but rather recommend comparing the pressure between cylinders.
However, the WD-45 "Owners" manual shows a compression pressure of 125 PSI for the gas engine.
Based on that, I would say the stock pistons have been replaced with something like D-17 or LP gas.
I bet she "barks" very nicely!
 

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