1949 Moline R proper engine timing to adjust valves

[Tybowers87]

Working on a 1949 Moline R and have been going through the engine. All 4 pistons stuck. After getting the pistons unstuck head blocks and valves redone, new piston rings. Replaced about everything, cap, rotor, wires, plugs, carb rebuilt, generator rebuilt, new voltage regulator, wiring harness. Followed the Manuel for setting the valves watching cylinder #1 intake open then close go half turn on crank. Set intake to .08 exhaust .10. Then per book half crank same in each cylinder per the firing order. Upon trying to fire it, the exhaust manifold is sucking air in. Has to be an issue of valve timing as the crank and cam were never out, or distributor. Head blocks and valves were all gone through. Anybody have any suggestions here?

 

[JOCCO]

There is a Moline colum further down on the page.

 

[rustred]

Working on a 1949 Moline R and have been going through the engine. All 4 pistons stuck. After getting the pistons unstuck head blocks and valves redone, new piston rings. Replaced about everything, cap, rotor, wires, plugs, carb rebuilt, generator rebuilt, new voltage regulator, wiring harness. Followed the Manuel for setting the valves watching cylinder #1 intake open then close go half turn on crank. Set intake to .08 exhaust .10. Then per book half crank same in each cylinder per the firing order. Upon trying to fire it, the exhaust manifold is sucking air in. Has to be an issue of valve timing as the crank and cam were never out, or distributor. Head blocks and valves were all gone through. Anybody have any suggestions here?

Sounds to
Me like u are not adjusting the valves properly. The piston has to be on top dead centre on the compression stroke in order to adjust that cylinders valves. Even if you feel for compression coming out the plug hole then feel the piston with a wire or something till it’s at TDC. That’s that engine with the sideways valves. As I always say an engine is an engine , but the procedure is still the same.

 

[Tybowers87]

Does the timing marks on the crank and cam being matched up designate TDC as well? Is .08 intake .10 exhaust valve clearance acceptable? For a totally cold engine. Once you adjust valves in cylinder 1 do you then adjust cylinders in there firing order 1-3-4-2. Leave the crank alone, or follow book instructions of doing a half crank turn each time

 

[rustred]

Yes once u have #1 cyl. Valves set then 1/2 turn to #3 to TDC. And set them valves and continue the same with 4 and 2.

 

[rustred]

Yes once u have #1 cyl. Valves set then 1/2 turn to #3 to TDC. And set them valves and continue the same with 4 and 2.

You can only set one cylinder’s valves at a time when following the firing order procedure.

 

[rustred]

And a good idea to feel the piston at TDC. To make sure that’s where it is. The other way is to watch number three’s running mate’s valves and have them on the rock. But to keep things simple for u , just feel the piston.

 

[scootergmc]

Honestly I don't know much about Molines that aren't Olivers, but those valve clearances you posted don't look right. Take a look here (and I don't know if it's the same engine series):

https://forums.yesterdaystractors.com/threads/cold-valve-lash-on-a-z.780751/

 

[rustred]

Yes would be the same. He is correct.

 

[used red MN]

Does the timing marks on the crank and cam being matched up designate TDC as well?

Hello Ty, welcome to YT! Alignment of the cam and crank gear timing marks does not necessarily indicate TDC, although in many engines it is part of the design, I can’t answer for this application. Do you know the back history of the tractor, so basically you know it ran when parked? If so that would indicate the timing of the gears is correct as far as you know. I assume the manual shows you the timing marks for TDC. To check for correct cam timing you can use the “rock” position on the valves. Turn the engine until the exhaust valve on number 4 cylinder is closing. As it nearly closes the intake valve will start to open. When the movement is even between the two valves the crankshaft should be within a couple degrees of the TDC mark and number one cylinder will be on TDC of compression. Since your following a manual I assume it shows you or you know number 1 cylinder is closest to the radiator. And the valve set procedure you used is correct as it should be when placed in a manual. In a 4 cylinder, 4 cycle engine one of the 4 cylinders fires every 180 degrees of revolution of the crank. This completes 4 cylinder firing events, one for each cylinder in two turns of the crank and again completes 4 cycles for each of the individual cylinders.

 

[Tybowers87]

Grandfather bought it brand new in 1949 from a local dealer, only tractor we ever bought new LoL. Been on the farm ever since, they used the heck out of it then sat around in barns and garages since the early 1980s. In my entire life I’ve only ever seen it run maybe 10 minutes. Decided tired of seeing the old girl sitting there love to be able to have it run and drive again.

 

[tom upton]

Looks like your off by a decimal point on both? But maybe just a typo? In my opinion the the sure fire way to set valves is simply- turn engine in normal direction of rotation until the exhaust valve starts to open or exhaust pushrod starts to come up on the particular cylinder you are adjusting, at this point set clearance on the intake. Then continue to turn engine until intake on same cylinder has fully opened and gets close to being fully closed again then set your exhaust valve. Takes a little more turning of engine, but this way you dont get mixed up. This method will ensure you are on the base part of the lobe on the cam. Great to see someone getting there Grandfathers tractor up and running!

 

[used red MN]

Another thought which will not apply if you are using a hand crank for starting. If you are using a starter to crank it did you just get this recently? The question is does the starter crank the engine the right direction? An incorrect starter can be set up to turn the wrong direction. Haven’t been around one of those but just about 98% of old US built tractors turn clockwise as you look at the crank from the front. The fan will tell you for certain, the blade angle should pull air back away from the radiator as it turns.

 

[Fritz Maurer]

Go through your sequence again and just make sure all of the valves have clearance... doesn't matter what it is at this point. If there is clearance the valve is closed.

If you have clearance on every valve, and you still have vacuum at the exhaust, then dirt or whatever has fallen into the ports and is holding one or more valves open. Having the head (s) "gone through " could mean anything to anyone; it's also possible that the job is screwed up and the top has to come back off.

But , if it is simply foreign material, continue to prepare the tractor for its first start, and then, if you are certain everything else is in order, carefully tow the tractor to start it. This will blow the dirt out and the compression will come back.

After the tractor has been started you have to set the valves at their proper lash, as when the dirt is gone you will lose some or all of your clearance.

 

[JOCCO]

If you have one valve sucking air it could be what Frits said. If all of them I would recheck timing.

 

[used red MN]

Looks like your off by a decimal point on both? But maybe just a typo? In my opinion the the sure fire way to set valves is simply- turn engine in normal direction of rotation until the exhaust valve starts to open or exhaust pushrod starts to come up on the particular cylinder you are adjusting, at this point set clearance on the intake. Then continue to turn engine until intake on same cylinder has fully opened and gets close to being fully closed again then set your exhaust valve. Takes a little more turning of engine, but this way you dont get mixed up. This method will ensure you are on the base part of the lobe on the cam. Great to see someone getting there Grandfathers tractor up and running!

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

 

[Tybowers87]

Go through your sequence again and just make sure all of the valves have clearance... doesn't matter what it is at this point. If there is clearance the valve is closed.

If you have clearance on every valve, and you still have vacuum at the exhaust, then dirt or whatever has fallen into the ports and is holding one or more valves open. Having the head (s) "gone through " could mean anything to anyone; it's also possible that the job is screwed up and the top has to come back off.

But , if it is simply foreign material, continue to prepare the tractor for its first start, and then, if you are certain everything else is in order, carefully tow the tractor to start it. This will blow the dirt out and the compression will come back.

After the tractor has been started you have to set the valves at their proper lash, as when the dirt is gone you will lose some or all of your clearance.

Professional Minneapolis moline restoration and machine shop in north Wisconsin. disassembled heads, hot tanked, cleaned, cylinders honed out, new piston rings installed, valve job done all reassembled for you to bolt back on. Highly doubt any dirt or debris

 

[Tybowers87]

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

 

[Tybowers87]

Lil fresh paint

 

[used red MN]

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

What about my suggestion in reply 13? Is it turning the right direction? Not trying to be funny or point fingers, things happen that even the most knowledgeable individuals miss. You’re new here we have no idea where your level of mechanical knowledge or skill is. Apparently you are able to follow instructions and reassemble the engine. Another thing about a forum, I asked a question about it turning the wrong way. If you know the answer but don’t confirm or deny it then myself and others can’t remove that from a mental list of possible causes and move on.