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farmergene 
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 Topic: wd camshaft timing
Posted: 13 Mar 2010 at 1:41pm |
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I am overhauling my WD. I didn't pay attention when I was disassembling it and now that I am putting it back together, I don't know which mark on the camshaft to line up with the line on the crank gear. My camshaft gear has two marks opposite each other. The book says to use the mark opposite the keyway in the camshaft. My problem is, I cannot find a keyway in my camshaft. The cam gear bolts to the cam with three bolts. Is that a flange on the front of the camshaft that the gear bolts to? If so, do I need to pull the flange off with a puller to see where the keyway is?
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B26240
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Joined: 21 Nov 2009
Location: mn
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Posted: 13 Mar 2010 at 2:08pm |
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gene Yes there is a flange on cam, the three bolts are unevenly spaced, so you cant mess up there . Take bolts out and the gear should come right off so you can see key.Later WD45 the gear was pressed on. HTH Mark L
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powertech84
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Posted: 13 Mar 2010 at 2:25pm |
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You could look at the lobes and just judge which mark puts the cam in the right spot for tdc
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mlpankey
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Posted: 13 Mar 2010 at 4:05pm |
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I have looked at several bolt on cams and gears and the only one i have found that has a key in it is the one i machined for chevy degree keys.
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farmergene
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Posted: 13 Mar 2010 at 10:44pm |
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I have the cam gear off and still don't see a key. Do I have to pull the flange with the 3 bolt holes in it off the cam to see the key? I thought about just getting the #1 cylinder at TDC and matching up the intake valve cam lobe to about where the valve would open, but the lobe didn't seem to match up to where I thought it should in relation to TDC. I would really like to find this key the manual is talking about jus to make sure. Does anyone know how the flange that the gear is bolted to attaches to the cam? Is the flange just pressed on?
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powertech84
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Posted: 14 Mar 2010 at 10:14am |
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Like pankey said, there is no key on your cam.
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farmergene
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Posted: 14 Mar 2010 at 10:55am |
powertech84
So is the only way for me to time this thing is to look at the cam lobes when I am at TDC? According to the book, the intake valve opens at TDC (which seems odd to me), so will I just make sure the cam lobe for the intake is just starting to push the lifter up and figure this is the right location for the two marks on the cam and crank gear to line up? Why would the intake valve open when the piston is at TDC? Shouldn't gas already be in the cylinder at this point? If the book is right, it seems gas would be going into the cylinder when the piston is on it's way down.
Also, I don't see any mark at all on my magneto gear. Is there a trick to lining up the magneto to the other mark on the cam gear?
Thanks for all your help! I'm normally not this stupid, but this thing is kind of tricky.
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CTuckerNWIL
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Posted: 14 Mar 2010 at 11:03am |
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Gene, This is a 4 stroke engine. When the piston is at TDC the intake starts to open. The first stroke is down pulling in air and fuel mixture. The second stroke is compression as the piston comes back to the top( after valve has closed). When at or near the TDC for the second time spark is added to the compressed air fuel mixture and the 3rd stroke begins(combustion). At the bottom again the exhaust valve starts to open and the 4th(exhaust) stroke begins. After the exhaust stroke the whole thing starts over.
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CTuckerNWIL
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Posted: 14 Mar 2010 at 11:09am |
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I think somebody may have added a second mark to help line up the mag. The cam gear should only bolt on in one position, once you get the cam gear bolted on so the lobes are in sequence with the stroke of the engine, ignore the other mark on the gear. Set the engine to the TDC at compession stroke and line the mag up to fire on number one at this position.
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TomMN
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Posted: 14 Mar 2010 at 11:25am |
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To make the magneto gear correct the slot for mounting the mag needs to be horizontal when any of the pistons are at TDC. Since this turns at crankshaft speed you'll see by turning the engine with the hand crank that no matter which pistons 1&4 or 2&3 are at TDC the slot will always be horizontal when one set is up. The mags for these all impulse fire on the horizontal, then once up to speed the impulse coupler doesn't come into play and the spark is advanced to the proper fire mark. Make sure that you have the crankshaft on TDC though, look either at the mark on the flywheel or look at the set-screw on the front crankshaft pulley it will be pointing straight down when 1&4 are at TDC. Since the pistons dwell at TDC for quite a few degrees just looking at the pistons isn't good enough.
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farmergene
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Posted: 14 Mar 2010 at 2:23pm |
TomMN
Where is the slot for mounting the mag located that should be horizontal? I just want to make sure I have this right before I get the engine back in the tractor. The set screw for the crank pulley is straight down and the intake valve is just starting to open; so, I think I have the cam correct. I'm still a little foggy on the magneto. I have it so the little black plastic gear, that acts as the rotor under the distributor cap, is point to the number 1 plug wire as close as I can get. Is there a more certain way to make sure the magneto is in time? I feel like I am king of guessing by trying to point the rotor at the number 1 plug wire. Actually, I'm not even sure the black plastic, (rotor) is on in the right place. I have a small metal gear on the distributor cap side of the mageneto shaft and it doesn't seem to have any mark inidicating where the black plastic gear goes. The only unique thing I see about the small metal gear are two adjacent teeth that appear to be beveled. The black plastic hear has a yellow mark on one tooth. I'm just guessing at everything at this point. Am I a lost cause?
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ALinIL
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Posted: 14 Mar 2010 at 4:20pm |
Farmergene,
You need to 1st get the cam timed. Another way to confirm TDC of no. 1 is to watch the valve train. When the no. 4 ex. valve is just closing and the no. 4 in. valve is just opening you are at TDC on no. 1. As for the mag timing, you need to verify that noone has played with the metal and fiber gears inside. If so, you need to align the timing tooth on the metal with the CW mark on the fiber gear. With the cap removed, align the rotor with the timing lug on the mag cover. This will align the impulse to approx. position on the gov housing. Hope this helps. Just remember, It ain't that complicated.
AL
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TomMN
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Posted: 14 Mar 2010 at 5:07pm |
As was mentioned you first need the cam timed. The slot is right where the mag mounts, the impulse coupler on the mag fits into the slot. Here is a picture of it. 
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farmergene
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Posted: 14 Mar 2010 at 7:26pm |
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Thanks guys. I will look at tomorrow night and see if I can find the slot in the mag. I might need to take it apart some more. I haven't gotten any deeper than the points right now. It has been converted to 12 volt before I bought it. Does that make any difference. I spent all afternoon trying to get the motor back in the frame. I almost have it bolted in, but it won't go the last 1/2 inch. Damn the luck. I wrestled it for a couple of hours and gave up until tomorrow. All I can think of is that I didn't get the clutch plate lined up exactly center on the flywheel before I tightened the pressure plate down. I'll have to sleep on it. I've overhauled a lot of Ford and Chevy engines and never had one fight me like this WD.
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powertech84
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Posted: 14 Mar 2010 at 8:14pm |
As long as the marks are exactly 180 degrees off from each other, it wont make any difference which one is timed to the crank as long as the distributer is timed to the cam. The crank doesn't care what the rest of the engine is doing, its just gonna keep throwing that piston up and pulling it down.
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farmergene
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Posted: 17 Mar 2010 at 5:29pm |
ALinIL
Which tooth on the metal gear is the timing tooth and which tooth on the fiber gear is the CW tooth? Also where exactly is the timing lug in the magneto housing? Also, when I took the magneto apart far enough to see the horizontal slot in the shaft, I had to take two bolts out. These two bolts went through slotted holes in the magneto housing and into the section that has the points. This allows me to rotate the housing where the points are clockwise or counterclockwise a little bit. Why are these holes slotted? It's obvious they are to allow some kind of adjustment to the timing, but what does this adjustment do?
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TomMN
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Posted: 17 Mar 2010 at 6:10pm |
Here is a good link to help you get the cap on the Mag: http://dueyschutter.freeservers.com/photo6.htmlThe slots are so you can adjust the timing as you suspected. Getting the cap on the mag correct just points the rotor to the right plug wire, the spark happens when the points open and which teeth you have together on the fiber and metal gears have no affect on that. HTH Tom
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