Rod in MN

Member
I'm working on a 1936 WC With a FM-J4 Mag on it. Having problems with it with No. 1 on TDC the Fire mark is at 10 clock. When the F mark is at the bottom of clutch housing the # 1 piston is at the bottom of the stroke. The flywheel will only fit one way the cam gear will only fit one way to

Thank You
Rod
 
The timing mark can be at that spot 2 times so you have if 180 out so yep piston is down instead of up. Spin it over til it shows up again and you should have the piston at TDC
 
You probably not at the "bottom" of the stroke, but not the top either. The mag is timed to 30 degrees BTDC (before top dead center) if you follow the instructions and time it with the "FIRE" mark.
 
I can relate to OLD , about being out 180. Take out no 1 plug , spin it over until you feel compression and then check the flywheel mark . If not sure remove the valve cover and make sure both no 1 cylinder valves are closed.
 
Ok with No. 1 On TDC were should the F on the flywheel be at. On the flywheel 30 degs. should not the F mark be at 4 o-clock not or I'm all screw up on my thinking?

Thank You
Rod
 
The fact that I had to turn it so far to line up the "F" after the compression stroke was complete is what made me realize that the flywheel was installed 180 degrees from the factory setting.


My whole problem was that the flywheel was installed 180 degrees off. Apparently the last time my Great Uncle ( he bought it new in 38 )had the engine apart he chose to install the flywheel so you set the timing looking through the hole ( small plate with two thumb screws )on "top" of the clutch housing instead of laying on your back under the tractor. These old farmer/mechanics were pretty smart-the factory could have learned something here.
Thanks for the input
Bud

I found this could this be my problem with mine?
Rod
 
Ten o clock would be correct to where number one should fire at TDC. Fire mark comes into play when running. The confusing part when not sure how everything works when the fire mark is called for when installing the magneto. If you try to set the magneto at TDC the impulse spring will not let you enter the drives in that position. If the magneto internal gears are meshed correctly and the rotor is pointing the correct way when the magneto is set at the fire mark when cranking by hand slowly the magneto will spark at TDC.

Another point is that when the timing mark is at TDC the piston is up every time because the crankshaft has made one complete revolution. If the piston was down it would only be a half revolution and the TDC line would be on top where it could not be seen. The camshaft and magneto/distributor runs at half the crankshaft speed so it take two complete revolutions of the crankshaft to make one revolution of the camshaft, magneto/distributor.
 
The flywheel can only be set in one position. The one bolt is off from the other three. It can only be bolted on correctly. The thing that can happen is the timing gears can be set to the wrong marks. The cam gear has a mark for the governor gear which some have confused with the engine timing mark on the cam gear. They don't line up correctly but still happens once in a while. (misunderstanding details) Might not be your problem but the flywheel is not you problem for the reasons stated.
 
The F line is 30° before/advance the TDC line. I would think it would be closer to 5 O'clock if TDC is at 6 O'clock.
 
360° is one revolution so if you look at your clock and count each hour 30° you have 30° X 12 = 360° Does this help?
 
There will never be a time when the piston can ever be at the bottom (if) the flywheel is at TDC.
That is what TDC means. The timing gears mixed up changes the when the valves open which could confuse where things are compared to others.

To check it out I would first check the valve settings making sure when number one was up both rocker arms were up. then go to number two rocker arms then number four and then back to two. This would prove the cam valve timing. that would take it to the magneto drive and on to the magneto. If you have a piston up on both revolutions and the valves are not closed on either one then the camshaft is not tined correctly. This would mean that the timing marks were mixed up. I must not have explained it well before. I have not figured out his problem because his finding do not compute in my mind yet.
 
I suppose that a flywheel from a different type engine with different markings might fit. That would not be a great problem to get it running by ignoring the marks and going by the rocker arms to find the compression stroke. If the cam is in time and you get number one cylinder on the compression stroke with both valves closed. You just turn the engine backwards until the magneto drives line up and install the magneto ready to fire on one. After it starts smooth it out by adjusting the magneto. Bill Long will tell you he never knew these engines had timing marks when he worked in his Dads dealership. All in how you learn to time engines. More than one way to skin a cat if you know the cat.
 
One of the cats from years back.

PicturedownloadJune12004007-vi.jpg
 
That will work for sure but read below. Finding TDC is not really necessary (if) valve timing is correct.
What I posted below..
I suppose that a flywheel from a different type engine with different markings might fit. That would not be a great problem to get it running by ignoring the marks and going by the rocker arms to find the compression stroke. If the cam is in time and you get number one cylinder on the compression stroke with both valves closed. You just turn the engine backwards until the magneto drives line up and install the magneto ready to fire on one. After it starts smooth it out by adjusting the magneto. Bill Long will tell you he never knew these engines had timing marks when he worked in his Dads dealership. All in how you learn to time engines. More than one way to skin a cat if you know the cat.
 
If you read the manual the "Fire" mark is 30degrees BTDC. That is the position right where the impulse should start to engage. The impulse retards the timing ~30 degrees so when it actually "snaps" it fires right after TDC. In addition the FMJ mag has a mark on the upper left of the rotor used for timing the mag at this point. If you rotate the mag backwards (so as not to engage the impluse), line up the rotor with the mark and you have the flywheel set to "FIRE", the mag should slip right into the drive. I time both my WC and B with this method and neither have kicked back at me when hand cranking.

To me this method is much more accurate for Allis engines, than trying to guess that you are at TDC and timing the mag just after the mag "clicks".

On a side note I did have to time my JD LUC with the impluse method b/c I believe the "Fire" mark on that engine is actually where the impulse trips so it is much easier to fine tune the timing (you can hear the impluse trip as the fire mark pass the inspection port.
 
Another thought on finding out when number one piston is actual up would be to thread a piece of rope thru the spark plug hole to stop the piston or feel when it is up. You can feed more rope in a necessary. The rope trick is one way to remove valve springs without dropping a valve. Not something I came up with.
I don't understand why Bob got upset as we were both telling you basically the same thing only at different angles. Looking at a problem from more than one angle gives a person a better understanding of how things work. I hope he fills back in his contributions. If Bob was at your tractor he would find and solve your problem within minutes.
 
Hi, Guy"s You ALL have been a great help. Now I come to put on the mag and the drive lugs will not reach in to the mag drive coupler. I had two mag"s apart at the same time must of got some parts switched. still working on it. Bob you have good ideas and now what your talking about I hope I did not say anything upsetting to you if I did I"m sorry.

Thank You
Rod
 
Will I clamped the mag on engine with the front cover off so I could see the marks. I just timed it with finger on #1 compression and watching the valves set mag in with rotor lined up just be for the mark in cap turned engine till # 1 plug had spark took cap off and rotor was on the mark. I checked it about 6 times and the "F" mark on flywheel is at 9:00 o-clock. I'm going to go with this need to put front cover on and oil pan and try it hopefully it works

Thanks for all your help
Rod in MN

It's 8:30 and -12. Wind chill has been Teens below 0 all day
 
Question?
You had the front cover off looking at the timing gears on the crankshaft and cam shaft?

When the timing marks were meshed you had the piston closest to the timing gears to the top and both rocker arms up meaning both valves on that cylinder (Number one cylinder) were closed?

When the engine was in this position the fire mark was at 9 "O"clock?

This is a picture of the B front but the crankshaft timing gears marks would be very similar.
TimeingGears-vi.jpg
 
With #1 on TDC both valves closed crank timing mark is in cam gear. Cam gear mark is 2teeth from lining with gov gear. "F" mark at 11:00 o-clock Rotor coming up on mark in cap on mag. Turn engine mag clicked rotor is on mark and "F" is at 9:00. There is only one mark on cam that I can see so I may lined up with the wrong cam mark.

I will have to find out to put pitchers on this sight have not done it. I will work on that to night

Rod
 
In Reply to: Re: WC Timing posted by Dick L on January 23, 2014 at 03:56:23:

With #1 on TDC both valves closed crank timing mark is in cam gear. Cam gear mark is 2teeth from lining with gov gear. "F" mark at 11:00 o-clock Rotor coming up on mark in cap on mag. Turn engine mag clicked rotor is on mark and "F" is at 9:00. There is only one mark on cam that I can see so I may lined up with the wrong cam mark.

I will have to find out to put pitchers on this sight have not done it. I will work on that to night

Rod
 
Forgetting the governor gear for now, when the mark on the camshaft gear and the mark on the crankshaft gear mesh, (meaning one will be on a tooth and the other will be between two teeth) the number one piston will be at top dead center and both valves for number one will be closed. That goes for (any) engine. Well (any) engines people on here will be working on. If you have the correct flywheel then TDC will be centered in the inspection hole. You will then want the governor drive to be horizontal even though it may not have marks.
 
Hi, Dick, Have not worked on the WC had to fix the oil leaks on my 425 with snow blower. Worked some last night got looking at the cam gear and only found only one mark removed cam gear and lined up cam and crank gears put on #1 compression
but both valves were not closed turn engine so both valves were closed and piston on TDC and the cam mark end up by the gov gear put magneto on checked the spark and it fired when #1 was to fire. It's got to be right going to put gov cover on and pan on and see if it will start

Thank You
Rod in MN
 

Rod in MN



01-27-2014 11:48:24
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Re: WC Timing in reply to Dick L, 01-23-2014 03:56:23



Hi, Dick, Have not worked on the WC had to fix the oil leaks on my 425 with snow blower. Worked some last night got looking at the cam gear and only found only one mark removed cam gear and lined up cam and crank gears put on #1 compression
but both valves were not closed turn engine so both valves were closed and piston on TDC and the cam mark end up by the gov gear put magneto on checked the spark and it fired when #1 was to fire. It's got to be right going to put gov cover on and pan on and see if it will start
Thank You
Rod in MN
 

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