wg750-e cam timing issues

[racerc2000]

ok so heres the story. 2 years ago i purchased a forestry truck. the pony motor never worked. it would try sputter and die.

i finally got into it. tore it down and started replacing what i found to be broken.

it had 3 bent exhaust valves and pushrods. a few freeze out plugs needed to be replaced.

rebuilt the head fixed the plugs and attempted a reassembly. on rotating engine by hand the valves would hit the pistons. so i took off the front cover aligned the idler and still same issue. loosened the adjustment on the valves and it has clearance now but valves are loose.

is there a trick to this any help would be much appreciated

 

[Daren Todd]

Here's a link to a free manual source for kubota engines. One of these pdf links for the workshop manuals, may contain your engine. I know, after some searching, I was able to find the work shop manual for my light tower engines.

http://www.kubotabooks.com/AutoInde...s/&AutoIndex=b41c5ea05df8b9778f174f8b5b1a2323

 

[racerc2000]

thanks for the link i will look there. i do have a service manual for the engine however it is pretty vague when it gets to the subject of the cam and ignition gears. it prettymuch states lineup the marks and thats it.

i wish i had more history on the engine. it looks to be very clean and a fresh rebuild. one that something was overlooked and the valves hit the pistons.

 

[100 td]

I'm guessing that the usual timing marks on the cam gear, the idle gear, distributor gear and crankshaft gear would be there ,and they all need to line up at exactly the same time when initially assembled.

If they are all lined up correctly, one thing I would check is that the key aligning each gear to it's respective shaft is in place and not worn. If it has been rebuilt before and is "new", so to speak, and has bent valves, perhaps when it was rebuilt one of the keys fell out during assembly?

 

[lugbolt]

Have seen one of those engines that didn't have timing marks on all of the gears, so the next monkey to monkey with it would either have to mark it himself, or do it the really hard way....trial and error. Could that be the case with this one?

All of the gears SHOULD have marks, and all of them should be timed all at the same time. One gear will have one dot. Another gear will have 2 dots. The third will have 3 dots. The idler gear will have 3 different marks on the same gear; on mark has one dot, another mark will have 2 marks, another mark will have 3 dots. They line up with their respective gears, and they all have to line up at the same time. Since the gears are helical cut, it takes a bit of fiddling to get them lined up properly. If that was done properly, check the keys or pins in the cam gears and the crank gear. If those are ok, you've got something out of the ordinary-perhaps the wrong cylinder head for that engine? Twisted crankshaft?

 

[North Idaho Wolfman]

Did you set the gears like this?

 

[racerc2000]

yes gears are all lined up as per illustrations. pins on all gears look to be intact. will have to pull them off to inspect them further

going by numbers head seems to match the block engine wise.

 

[lugbolt]

I wonder if the pistons are incorrect? I.E. incorrect valve reliefs for the gas engine? I remember an old man doing one of these a long time ago and he thought it was identical to the D722 with the exception of the head, ordered/installed the diesel's pistons and bent some valves. Probably not your case but worth mentioning.

 

[racerc2000]

will deff look into that. i know the engines are very similar gas to diesel which makes for a stout gas engine. but i would believe the pistons would be very diffrent even though they would fit and work with crank and rods.