I have just replaced a cracked head on a v1902 Kubota engine that is going back into a Bobcat skid steer. Got valves ground in and set etc. professionally. Cannot find any marks to show TDC for setting tappets. I used the minus 9 procedure to try and set them. i.e. when valve 8 is fully open set no.1 etc. Engine has started fine with a little heat but smokey(white smoke- unburnt diesel), even after it warms up and run for 10-15 minutes. I take it tappets are still out. Any help appreciated.
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OldMachinist
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Here is the procedure that is in the service manuals for Kubota 4 cylinder engines. The clearance may be different for your engine but the procedure is the same.
From memory the clearance is supposed to be .007 - .009".
To find TDC the front pulley should have markings. Along the lines if 14tc and 23tc (not sure exactly) there should be a pointer attached to 2 of the bolts holding the water pump in place that point to the pulley. When its pointing to the mark for each number, it means its TDC for one of those cylinders. Say its 14, either cylinder 1 or 4 is at TDC. you will see if the valves are closed. The order should be 1 4 3 2, so when you work the first one out, just go with that order while turning the crank clockwise.
Good luck.
Thanks for help guys. set tappets and engine running a lot more smoothly and starting fine, but still got the smoke problem. Guess injectors are next thing to look at. When head was removed injectors weren't covered, maybe some dirt got in, could this cause my smoke problem or is there anything else I should check first?
Its possible, if you haven't had them cleaned before, it isn't a bad idea to get them done.
You can clean them your self, but you can't set the cracking pressures. I have done it in the past with exdcellent results, but an injector shop will get them to factory settings for you.
How much smoke it is puffing out? could it just be burning old oil/fuel thats still in the bores?
Smoke could be from lower compression too, worn rings, worn bores. There are multiple things that could be causing it.
It is quite smokey when under load and not to much when just ticking over, white smoke. The amount of smoke doesn't appear to change even when engine is warm after 15 minutes running. The reason I think it is something like injectors is that I didn't have the white smoke before I did put in the new head. With old cracked head it was virtually smoke free until the engine got hot and then got black smoke. Did test on cylinders when stripped down i.e. filled them with diesel to test rings and they proved fine. There is a local diesel engineer that does iinjectors locally so will bring it in to him to have a look at. Will let you know how I get on.
Its a little odd, black smoke is excessive fuel thats not being burnt, white is un-burnt fuel or coolant. Its not using water is it? as you did just put a new head gasket on and head.
Ensure you re-torque the head too.
Water level is going down, not very quickly though, no water leaks visible elsewhere. The radiator cap is not great so am replacing it and checking again, but looks like my white smoke is mainly steam. It does dissapate very quickly. Looks like nicked gasket when replacing head. No oil in water though. Will try retorque head bolts but looks like head off again. What do fumes from water leaking in smell like. I havent added antifreeze/collant yet.
Without anti-freeze i don't think you will be able to smell anything.
It shouldn't be an issue, but if you run an engine that is detonating water, it will pit the cylinder head. I believe it will take time to do though.
The head gasket should be re-torqued after running the machine for a few minutes. After its warmed up for the first time since a new gasket was installed, you need to re-torque it as it will crush a little bit.
Update on my smoke problem. Re torqued head bolts and majority of smoke has disappeared and water is not going down any more. Took the bobcat for a good run and most ofthe rest of the smoke has cleared, will get injectors done at some stage which will problem leave it perfect. Thanks Tazza for your advice, saved me a headache
Douglas751
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This is confusing to me. If looking at the dia. B with the exhaust facing me as in picture, the the fly wheel is on the right. Correct. So then that would but cylinder 4 on the far right and cylinder 1 on the far Left?
yes the flywheel would be cylinder 4, the radiator or water pump is at the cylinder 1 position .
