WD45 Engine Update - Success!

Back in October I started a thread about a miss I am hearing in the engine of my WD45. Here's a link to that thread for anyone who might want to read it again: (http://www.allischalmers.com/forum/forum_posts.asp?TID=130424&KW=Dave%28inMA%29&PID=1078377&title=wd45-engine-diagnosis-needed-update-nov-3#1078377) 

Edited by Dave(inMA) - 06 Mar 2017 at 5:34pm

As Steve said takes special tooling to grind rocker arms. they need to have a curve to them not flat. Machine shop that does engine work such as valve grinding etc will have the proper equipment to do this.

It often takes 4 or 5 strokes to get to the full compression pressure on the compression gauge. Making it in two looks fine to me.

Gerald J.

It takes a good eye and a real steady hand.

I think a new WD45 had 130 PSI compression. Mine with M&W pistons makes 145, the other one with kit from Tony 150. The propane engine made 190 on the best cylinder. It is 4&1/8 bore with flattops. My rough calculations say 10 to 1 ratio.

Hmmmm....based on that input (thanks, guys) it sounds as though my engine is a little weak! Though maybe I should re-do the test as I only measured through 2 compression strokes. I had understood that I should read the psi on the first compression stroke, but now I've read information that says to spin the engine until the reading peaks.

Edited by Dave(inMA) - 27 Jan 2017 at 2:19pm

Thanks, Dave. I agree - I've always understood that consistent readings are more important than the actual number. But I have read differing advice on how to conduct the test, though most sources are saying to spin the engine until the reading maxs out. So, just for fun, I'm going to do it again following that advice. 

Very normal wear on this age engine and certainly renewable. Depending on whether your're better with a file or grinder you can do them by hand if you're needing to save a little money. The best way to do it of course is to have ground by the head shop. I did my 45 by hand, taking my time, and it's been 5-6 yrs. now and no problem at all. But Joe and I think alike and pinch our pennies, Joe because he has money, and me because I have none. LOL The condition they are in, you really do need to resurface them. You'll get a better valve adjustment, more power and it will run smoother. PM me if you have any questions.

That's what I'd do too.   You've got nothing to lose and everything to gain.  Just slow and careful...kinda like your first date.....

The compression looks just great, they are all within spec.  Once you get it running, do it again cold and then get it up to temp and do it again.  Then come back and tell us what you have.  Should be just a little drop, but they should all be within 10psi.  That is acceptable.  At least it is to me and the way I learned......

Today I pulled the rocker arm assembly, took photos, and disassembled it so I could grind the rocker arm pads. After studying the pad shape a LOT, I used the side of a fine wheel on my bench grinder - all eight done in about 5 minutes using light passes rotating the arm against the wheel. Reassembled the rocker arm assembly and re-installed it. I've set the clearances to 0.013 cold....I believe the spec if 0.012 hot. Once all the fluids are back in the old girl, we'll see how it sounds!

Thanks, Dave. I'll reset them.

After you've run it a bit it's always a good idea to readjust the valves. You think you have them even and doggone if there won't be one or two loose. I've developed a way to do it that is very accurate, so if you're interested PM me and I'll get back to you. Explanations can take up a lot of room. Congratulations on getting it running. Yahoo!