1949 Moline R proper engine timing to adjust valves

[Tybowers87]

Original starter motor was rebuilt and cranks it over the correct clockwise direction

 

[Fritz Maurer]

I'm confused with your terminology. If the crank and cam were not disturbed, I don't understand how the timing can be off.

Only way the cam. timing can be off at this point is some mechanical failure causing the tractor to be parked in the first place.

 

[Butch(OH)]

Don't get lost in some exact proceedure for that particular engine or it won't run because that is folklore. There are multiple ways to set the valves the only difference being how much you have to turn the engine to get it done. Each valve is basically open 1/2 a turn every other turn and closed for a turn and a half so there is a long duration when the lifter is on the base circle and clearance can be set. Perhaps the easiest to remember way is that at NO time are both valves on a cylinder fully open. If one valve is fully open the other one must be fully closed and the clearance can be set. When we had a drag car that had to have the valves set every run we simply turned the engine until one valve was fully open and set the other one on that cylinder. then do the other valve on that cylinder following down the head in order. Because we had a remote starter button this was easier than trying to find TDC and following some book proceedure and accomplished the same end. To check cam timing after you have set the valves turn the engine until #1 exhaust valve is beginning to close. Turn slowly until the intake just begins to open and the exhaust is not quite closed and stop. The piston should be at or very near TDC.

 

[Texasmark]

My valve adjusting procedure is different because it always has been hard for me to find TDC. What I do is remove the spark plug or injector and start turning the crankshaft one way or the other depending on access available to a device and connecting point. I then watch the valve train for a rocker arm to relax. I rock the crankshaft back and forth maybe +/- 10* and if the rocker didn't rise, insert the feeler gauge, check gap compared to spec., if out adjust and move on to the rest of the rockers repeating the process.

Has always worked for me and I find it pretty simplistic. If you can line up the valve train per the manual, have at it and good for you. I just found it was too much trouble to follow the manual. I've been working on my engines of numerous types/pieces of machinery since about 1955 and must be doing something right as I don't recall ever having to put something "in the shop" because I couldn't fix it. There was one hiccup however....some buddies and I thought we could overhaul the next door neighbor's 1949 Mercury flat head V8. The problem was, we didn't realize that you needed to grease things up when going back together with new parts.....that was an exceptions and a one time event....hello Lubriplate 105.

 

[used red MN]

Original starter motor was rebuilt and cranks it over the correct clockwise direction

Thanks for that clarification!

All I can figure is has to be in the valve timing since the distributor, crank and cam were never removed

This means you have verified that the valves are set correctly per recommendations here?

If the crank and cam were not disturbed, I don't understand how the timing can be off.

Only way the cam. timing can be off at this point is some mechanical failure causing the tractor to be parked in the first place.

I agree the crank and cam cannot come out of time just setting.

Upon trying to fire it, the exhaust manifold is sucking air in.

The “vacuum” is a constant suction or pulses?

 

[Tybowers87]

Kind of a special moment, was told that the moline’s lights never worked when my dad was growing up he was born in 1956. New wiring harness and headlights. She has working lights again

 

[used red MN]

Kind of a special moment, was told that the moline’s lights never worked when my dad was growing up he was born in 1956. New wiring harness and headlights. She has working lights again

That’s great, good to get a positive response from a project. Any more info on the engine problem.

 

[Tybowers87]

So after listening to folks advice we simply focused on getting cylinder #1 to TDC. Pretty easy to see the high crown of the piston through the spark plug hole. Adjusted intake valve to .012 and exhaust to .018. Then moved on to cylinder 3 per firing order. Interestingly the half turn on the crank which is what the manual says to do, definitely didn’t put that piston all the way up in the cylinder, so im thinking that might have been the issue. As each cylinder took more than a simple half turn

 

[T.R.K.]

In your picture you have the side cover off. If the piston is all the way up, 1/2 turn of the crank will put it all the way down. You should be able to see the connecting rod go from all the way at the top to all the way at the bottom.

 

[Tybowers87]

that’s correct, why I removed the covers to be able to exactly see what’s going on in the crankcase. And pulled spark plugs to verify that piston was at TDC on compression stroke for each cylinder before setting valve tolerances. However I can say it took more than a just a half turn of the hand crank to get the piston completely up in the cylinder. That’s where I think my issue was.

 

[Tybowers87]

I actually was thinking about it and have a theory now. From trying to unstick the engines all 4 pistons we did the old pour penetrating oils down all 4 cylinders and let soak for weeks. Well being impatient lead to some jumping on the hand crank handle. Even a jack. I’m thinking the bracket on the crank pulley for the hand crank handle is probably bent slightly or wore out. So the half crank hand theory is now more a 3/4 crank since it’s been used and abused.

 

[wore out]

I actually was thinking about it and have a theory now. From trying to unstick the engines all 4 pistons we did the old pour penetrating oils down all 4 cylinders and let soak for weeks. Well being impatient lead to some jumping on the hand crank handle. Even a jack. I’m thinking the bracket on the crank pulley for the hand crank handle is probably bent slightly or wore out. So the half crank hand theory is now more a 3/4 crank since it’s been used and abused.

Since it's a conventional 4 stroke in-line engine with a "single plane" crankshaft the pistons reach TDC, in firing order, every half-turn of the crankshaft, that's simply the way it is, it's passed time for you to accept that as fact.

 

[Tybowers87]

100% agree now that I’ve discovered my lil gremlin

 

[Janicholson]

100% agree now that I’ve discovered my lil gremlin

The turning of the crank for TDC on each cylinder must subtend 180 crank shaft degrees. 3/4 turn is not going to work. Wore out is correct!!!
It does not matter where the crank handle starts to turn the snout, the end point must be opposite that location. 180degrees. Jim

 

[Alan K]

If the valves are not being held open it should start regardless. Per the YT tune-up spec listing for Molines you are using the wrong spec. It shows .012”H for the intake and .014”H for the exhaust for R series Molines. Might not hurt to drop down to the Moline forum and ask for someone to verify this. My apologies Tom if you are knowledgeable on Molines.
YT Moline tune-up specs

I just did my cousins ZA. I remember seeing there were two different specs for the R and the Z engines, mainly the older ones. Don't remember why they had different settings but that might be what the .012 and .014 settings were for.

 

[molinegb]

Crank motor by hand until #1 intake valve closes. Crank another 90 degrees. That is TDC.