so I posted over a year ago about this engine being low on compression, pulled it, had the block resleeved and the deck milled true, had brand new valves bedded they had to cut the seats slightly and the head milled flat all at a machine shop, checked the valves myself and they vacuum down to 30hg, put it all back together mind you this is like the third time and im having a heck of a time with it, its giving me 140psi on 1, 100 on 2 and 220 on 3, I did add a tiny amount of oil and it bumped it up some but not much, maybe 40 psi each. tried a leak down and it seems like it's leaking between cylinders which I don't understand, I used a brand new kubota gasket and followed the torque sequence and spec for the d950. I'm really just getting fed up with it if im being honest, not sure what to try next 🫤
rebuilt d950, not enough comp to run 🤦🏻♂️
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North Idaho Wolfman
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Well if it's truly bleeding compression between cylinders then you have a head, block, or head gasket issue, can't be anything else.
The only way you would know is to static test each cylinder.
You do this by loosening all the valves and pumping air into each cylinder and seeing if it leaks directly out one or more of the other cylinders.
The only way you would know is to static test each cylinder.
You do this by loosening all the valves and pumping air into each cylinder and seeing if it leaks directly out one or more of the other cylinders.
hmmm.... given..
head was decked
valves were done
new head gasket
by process of elimination, only thing I read is that the block isn't flat ??
really, what else could be the reason ??
head was decked
valves were done
new head gasket
by process of elimination, only thing I read is that the block isn't flat ??
really, what else could be the reason ??
Lil Foot
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North Idaho Wolfman
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Oh I thought of one other reason it would act like that, Timing being off.
Did you line up all the timing marks at the same time when you rebuilt it?
Did you line up all the timing marks at the same time when you rebuilt it?
the shop never mention anything about cracks, wasn't over heated or anything and the deck of the block was also milled flat. I was thinking maybe the cam could be off a tooth.
I did line everything up but the cam gear marks where kind of wonky and not exactly stamped exactly over a tooth, is it possible to check valve timing without removing the cover?
North Idaho Wolfman
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Sorry no, I don't know of a way to do that.
You'll need to pull the front gear case cover off of it.
Once you get it off you'll immediately notice that none of the marks are lined up.
That's because they only line up something like every 244 rotations, you will need to reset all of the marks.
Before you close it up again, post a picture and I can confirm if it's right or not.
I pulled the cover again and turned it until they lined back up, the keyway on the crank for the pulley is down the others are straight up, someone has had this apart before me, the cover had red rtv on it when I pulled it apart originally. to me the cam marks look weird but I dont think its out of time though so its gotta be a head or headgasket issue
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I tried retorquing the head using the sequence in 3 steps but now I'm getting 220 on all cylinders unless my gauge is off 🫤
I'll try a leak down again when I get a chance see if that tells me anything useful
I'll try a leak down again when I get a chance see if that tells me anything useful
Lil Foot
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I agree but I don't see any other marks on the gear, from other photos I've seen of one of these set in time, the keys on the cams go straight up and the key on the crank goes down. I didn't get a good photo of it but it looked that way to me, no issue pulling it again if I need to
anyone have one of these apart and can tell me how many teeth from the key the marks are supposed to be lined up to so I can be sure or have a cam or cam gear laying around?