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.

 

[kenmac]

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

Thanks for the replies.

Me either. Should be to hard as long as you've got the basics & the specs

 

[FLHELOPLT]

Yeah, everything's right there. Might as well pull the pan. A lot easier to get to stuff than most cars...just heavier!

 

[Willl]

Only 1200 hrs and already major rebuild ?

 

[FLHELOPLT]

Only 1200 hrs and already major rebuild ?

Right. That's what I've been wondering. Albeit, almost 30 years old.

How about the head gasket leaking because of mis-torqued head bolts? While troubleshooting I only found 1 bolt below specs, however. Would that be enough to cause incomplete combustion, leading to carbon buildup on the leaking valves on cylinders 1 and 2?

I'm curious what the rings spec out to.

 

[FLHELOPLT]

Here are some scary pics.

One piston is certainly history. What about the other? Can it be salvaged? Maybe clean up the skirt and those 2 spots on the oil ring land? (the third piston is perfect)

The 2 sleeves have some scoring. Not as bad as the pistons would make you think. At $150/liner and the difficulty removing them without the puller, I really don't want to re-sleeve. What about honing?

2 rod-ends spec'd good at .020. The good piston rod-end spec'd at .023 with copper showing. Makes sense since that one was pulling the load.

 

[Egon]

One piston is certainly history. What about the other? Can it be salvaged? Maybe clean up the skirt and those 2 spots on the oil ring land? (the third piston is perfect)

Now that you can see what is what do it properly.

 

[FLHELOPLT]

Now that you can see what is what do it properly.

What exactly is "properly". This is an old tractor. I don't want to spend money unnecessarily.

Can I reuse the better piston of the two, if I clean it up? What about the cylinder liners? They're expensive...but even more, how to remove them without a liner removal tool. I don't even know where to get one. Hone them?

Thanks,

Steve

 

[SailorBob]

What exactly is "properly". This is an old tractor. I don't want to spend money unnecessarily.

Can I reuse the better piston of the two, if I clean it up? What about the cylinder liners? They're expensive...but even more, how to remove them without a liner removal tool. I don't even know where to get one. Hone them?

Thanks,

Steve

I rebuilt the engine on my YM1700. I did replace the liners. (it is a 2 cylinder and they cost $340 each. Ouch!) Getting the old liners out was the hardest part of the rebuild to me. I could not find a tool either. So, I made one from a long threaded bolt and some angle iron. At first I kept bending the angles and the liners would not release. Someone suggested that I pack the liners with dry ice and then try it. It worked!

Having said all of that if the liners are useable I would probably try to use them too. I ran my tractor hot and there was lots of damage. I also replaced the pistons, rings, wrist pins, rod bearings, valves, stem seals, valve springs, and had the head re-worked by a machine shop. I also added a water pump kit. The 1700 does not come with a water pump.

Hopefully, mine should give me many years of good service now. Good luck with yours

Bob

 

[Egon]

[/What exactly is "properly".QUOTE]

Yes; a bit of ambiguous statement.

The amount you spend on the tractor should be based on future plans for the tractor.

 

[FLHELOPLT]

Bob,

Good idea on your homebuilt tool. I'll hone the liners and check the results. I'll also try to clean up that one piston. If I'm not satisfied then, I'll replace it too.

The valve guides are within limits, as well as 5 valve stems. However, with the abundant amount of carbon and pitting, I'm going to replace them all. Haven't checked the springs yet.

"Egon",

This tractor has served me well for almost 20 years. However, I only need it for another couple of years or so.