2 cylinders leaking thru intake valves

[FLHELOPLT]

First post here. Please be kind.

I've owned this YM330 for about 20 years. For the past few years, it's gotten harder and harder to start.

I've been searching threads on this forum regarding hard starts and started troubleshooting. Going thru the steps, I got to the point of using compressed air thru the injector "holes". #3 cylinder held my 100 psi compressor tight. However, #2 and #1 was hissing distinctively thru the intake.

Pulling the heads shows much carbon deposits on 1 and 2, with 3 being clean. This I would expect.

Do you think if I get the head worked, this will solve my hard start problem? I don't want to start pulling pistons if I don't have to. I also don't want to put the thing back together just to take it apart again. If I can get away with only the head work needed, I'll be happy.

Thanks in advance,

Steve

 

[careyo63]

Without knowing how many hours are on the motor and with that amount of carbon build up on the valves if it were mine I would replace the piston rings and rod bearings.I sure would hate to put it back together and find out I had low compression and have to pull it back down.Since you stated a problem with cold starts in FL. and was using ether absolutly.

 

[FLHELOPLT]

I have 1250 hours on it. Are parts hard to come by? You're assuming I used ether? I did for a short time until I learned not to.

Thanks.

 

[careyo63]

Yes parts are available hoye has them.I just woudn't risk it.After you freshen it up you should be good for years.In the cost of parts not doing just not worth it.It not hard since you already have the head off hoye will gladly tell you the do's and don'ts they have excellent technical support.

 

[kenmac]

I would also build the bottom end. If not ,You may have to pull the head again... It's your call

 

[FLHELOPLT]

With these motors, are we generally talking about only rings and maybe rod-end bearings? If I pull pistons, and ring gap and rod-end oil clearances are within specs, do you still reccomend replacement? And we don't hone liners like when seating gas engine rings? The liners on all cylinders are smooth (I can't catch a fingernail edge anywhere).

I only need this tractor for a couple more years.

Thanks.

 

[Egon]

With the head off what do the cylinder bores look like. Can you see discernible wear or ridges?

Was the valve lash ever set or adjusted?

Questions from a non mechanic so take em for what they are worth..

 

[FLHELOPLT]

I adjusted the lash to .006. The cylinders are smooth where I cannot even catch a nail.

Thanks for the reply.

 

[careyo63]

What was the culprit to the carbon build up.Dirty injectors,fuel filter.Oil carbon black looking build up. Did you have blowby?

 

[FLHELOPLT]

I'm assuming the carbon build up was caused by incomplete combustion because of the leaking valves. Are you implying the carbon build up is the reason I was losing compression thru the intake valves? I haven't removed the valves yet to check their true.

So there might be an underlying problem which caused incomplete combustion, thus carbon buildup, leading to the leaking valves on 2 cylinders? Maybe low compression because of worn rings to begin with? But I get no more than a little vapor out of the block vent (blow by). Or possibly a blown head gasket? I say that because I had trouble with boil over when air temps are HOT. I went from the 13lb cap to a 20lb to stop that. But no transfer of coolant/oil.

I had the injectors checked and cleaned when the hard start problem surfaced. It seemed to help (some) for a while.

I'm a car guy. I've never worked on a diesel before.

Thanks for the replies.