John Deere 330 - Low Compression #3 Cylinder - Help :-)

tractorbuds · Jul 29, 2014

Hi there, I just bought my first diesel JD garden tractor. It is a 330 model. She's a pretty nice looking tractor from 5 feet away and I am hoping that with your help, I might be able to get her back to her former glory. The machine has about 1600 hrs and started dying after about 20 mins of work time. It went to the JD dealer and they found 280 psi on cylinders 1 & 2, but 50 psi on #3 (front of tractor, furthest from rad). When it's cold, it can take 2 or 3 starting cycles to get it running and then the mechanic said that the oil/fuel creates a wet condition by then which boosts compression. 20 minutes into working when the cylinder condition dries up, it goes back down to 50 psi and stalls. The unit has a completely new fuel system and cylinders 1 & 2 have new/newer injectors.

I'm wondering if this is a typical motor failure for this model of tractor? I bought it as a flyer for the value of the usable parts, but think I might take a crack at re-ringing the faulty cylinder.

Your thoughts, experiences? Cheers.

Yellowfever440 · Jul 31, 2014

If you are going to tear it down I would make sure they backed the valves off on that cylinder just to make sure the valves were closing all the way. I would imagine they did. One cylinder can have a problem and has less compression but I would check the head gasket and head very well to rule out a faulty gasket or cracked head. If you pull one piston pull them all and if that cylinder is fixable hone it and all 3 until you get a good cross hatch then re ring all of them. I mean rings are probably 30 bucks a hole. Then hopefully all 3 cylinders will be good. I find it odd that one cylinder is that low and the other 2 are good. I have a feelings theirs an under lying problem. That 3rd injector may be bad and washing the cylinder walls down so the cylinder has been running dry.

I worked on a very small John deere skid steer(wouldnt start with out ether)when I was a dealer mechanic and it had the 3 cylinder yanmar in it and the guy only wanted rings so we pulled it and found broken motor mounts amongst other cracked or broken frame pieces. Disassembled enough to get pistons out and check the cylinders and they were worn odd for the hours and top of the cylinder had wore more then the rest so the rings had to expand and contract a lot as it moved up and down. I told him I didn't think it would fix his problem to ring it. I was 22 or 23 at the time which was only a 5 or 6 years ago, so I was young and dumb with no experience as he told me and sure as **** I got the thing all back together(new rings and honing the cylinders) and stuffed into this tiny skid steer and it still wouldn't start very very. It would it you let it crank for a good minute or so. It would fire right off on ether and ran better. So he went with my original advice and put a short block in it. I earned a little respect and he trusted me a little more from then on.

That was a completely different problem from yours though just wanted to share a story I guess. It had even compression on all 3. After the rebuild it had more compression but still not near spec.

I would just rule everything out that you can before you start buying parts. The motor should of run 3 or 4000 hours before anything even close to that happened.

tractorbuds · Jul 31, 2014

My son just cut 12" high grass for 45 mins and couldn't get it to stall as per previous owner?he said 20 minutes it should cut out.

beenthere · Jul 31, 2014

The dealer did something to it, or did not?

tractorbuds · Jul 31, 2014

The PO said it was hard to start and stalling out after 20 minutes. Dealer installed $600 fuel system repair and sent it back. Owner had the same issue and questioned if dealer had retested compression after it was warm/jot/cylinders dried out (which they had not). Then dealer suggested a rebuild, but then changed their minds and offered to repower it for $4000! Then I bought it. This things runs so nice. It just seems to take a bit to fire up, at least two preheat cycles. I have not been able to get it to run on two cylinders yet. And, I don't have a diesel compression tester to check it myself.

Yellowfever440 · Jul 31, 2014

It's cheaper to re power then rebuild for you. The dealers labor is high so the parts don't cost much but labor is high. Then they will get it machines they won't just re hone it unless that's what you ask for.

DrBill · Aug 3, 2014

If you want to take a crack at fixing the engine you can, but be ready for a whole lot more than rings..

A lot of these Yanmars who's whole life are cutting grass can be worn down a lot at 1600 hrs. I bought one myself that way at 1400 hours..

Your compression on the good cylinders are 100 pounds low, but if your son has been mowing with it for 45 minutes and the temperature light (hopefully working) has not come on, then at least the engine might not be cracked anywhere.

The head will be shot (valve wise), and the pistons and rings will be also.. The cylinders might be worn past limits, but the yanmar 66 your mower has can be bored twice..

So you can fix it, but be ready for an outlay in time and money (1500.00) if you are doing it yourself..

I bought a 755 worn out for 3000, and put 1500 and my own labor in it, and finally have a tractor that runs like new.

None of this matters unless you really need the thing.. If you got it just to play around with, I'd probably send it on down the road..

tractorbuds · Aug 11, 2014

sold it as-is, $1500

DrBill · Aug 12, 2014

Thanks for letting us know.. A lot of people post a topic,, people reply but you never hear back from them. As my first post mentioned,,, you did the right thing on this one...