D1105 failure to start - need ideas

[NorthwoodsLife]

Timing off does not explain low compression test results!

Actually, it could. Depending on the compression guage, they typically read and stay at the highest compression reading. If he's getting 150 on an upstroke, then it drops before TDC, because a valve opens, it's still going to read 150... but the reading wasn't at TDC.

I'm ignorant about the details of the particular engine the OP has, and for that I apologize. But I assume that the OP removed the crankshaft. And I assume that the end of the crankshaft is a shaft or timing gear with a keyway. What if it's off 360 degrees!??? Might not matter...
Just sayin'.

Teach me. I love learning.

 

[hagrid]

D1105 failure to start - need ideas

Have you tried profanity yet?

 

[North Idaho Wolfman]

Actually, it could. Depending on the compression guage, they typically read and stay at the highest compression reading. If he's getting 150 on an upstroke, then it drops before TDC, because a valve opens, it's still going to read 150... but the reading wasn't at TDC.

I'm ignorant about the details of the particular engine the OP has, and for that I apologize. But I assume that the OP removed the crankshaft. And I assume that the end of the crankshaft is a shaft or timing gear with a keyway. What if it's off 360 degrees!??? Might not matter...
Just sayin'.

Teach me. I love learning.

You would have to pull the front gear case apart to remove the crank and he said he did not remove the gear case.
He just did the rings not a full rebuild.

 

[North Idaho Wolfman]

Do you have the serial number for the mower?
Do you have the serial number for the engine?

 

[Kubota_Mac]

Do you have the serial number for the mower?
Do you have the serial number for the engine?

Let me fetch those numbers in the morning.

 

[lugbolt]

what was the ring gap on the new rings? What was the piston-to-cylinder clearance?

also I wouldn't have used oil in the cylinders to "check compression" no matter how small the quantity used was. Maybe, just maybe, no damage was done.

If I had it in front of me, I would turn a cylinder to TDC compression stroke and then apply air pressure to a glow plug hole. Where's the air come out? If out of an intake port or manifold, intake valve's leaking. If out of the exhaust, exhaust valve leaking. If out of the crankcase, leak in the cylinder somewhere. If out of the radiator? Oops...wrong head gasket or leaky head gasket, for whatever reason.

 

[sitric]

Sounds like maybe an inframe rebuild. (Just guessing) If so, how well did you clean the cylinder walls after deglazing with hone. If you don't get the cross hatch really clean, those rings won't seat.

 

[Henro]

If I was at then end of my rope, I would probably put the old head back on an see if it started…thinking that might help point me in the right direction.

After trying Lugbolt’s suggestion of course…

 

[Kubota_Mac]

what was the ring gap on the new rings? What was the piston-to-cylinder clearance?

also I wouldn't have used oil in the cylinders to "check compression" no matter how small the quantity used was. Maybe, just maybe, no damage was done.

If I had it in front of me, I would turn a cylinder to TDC compression stroke and then apply air pressure to a glow plug hole. Where's the air come out? If out of an intake port or manifold, intake valve's leaking. If out of the exhaust, exhaust valve leaking. If out of the crankcase, leak in the cylinder somewhere. If out of the radiator? Oops...wrong head gasket or leaky head gasket, for whatever reason.

I was thinking a leak down test might be useful until I read the following post.
Now I am not so sure.

Repeated from another forum (for comment):

In the automotive industry, a cylinder leakage test is referred to as a leak down test. In an automotive piston engine, if you pressurize the cylinder to 200 psi it will only take seconds for the pressure to escape. The best gauge to use is a dual gauge leakage tester. It will have two gauges (one with air pressure and one with leakage %) and an adj. regulator. You calibrate the % gauge to 0% by turning the regulator then you hook it up to the cylinder. The universal rule for cylinder leakage is no more than 30%. Make sure that the cylinder is at TDC. You should only perform this test on a warm engine. And NEVER try this on a newly rebuilt engine. You will wonder what you did wrong when you have 70% leakage into the crankcase. The rings don't seal until they are fully seated after break-in. It is also a good idea to pull the rad. cap and make sure there aren't any bubbles with the gauge hooked up just in case.

If you know you have excessive leakage, you can use your hose off your compression tester. Just hook air line pressure to it and start listening. The leakdown tester will limit the air going into the cylinder when its setup right and the hissing wont be as loud as "shop" pressure in the cylinder. Its likely leaking past the rings, as most diesels do after they get some good hard miles on them. It probably won't hinder the performance or longevity of the engine as long as its not burning a large amount of oil.

 

[Kubota_Mac]

If I was at then end of my rope, I would probably put the old head back on an see if it started…thinking that might help point me in the right direction.

After trying Lugbolt’s suggestion of course…

If I cannot get it started after warming the engine up, I will pull the head and mic the cylinders to confirm that things are in spec. Then as you suggest, I will put the old head back on and give that a go.

 

[Kubota_Mac]

Sounds like maybe an inframe rebuild. (Just guessing) If so, how well did you clean the cylinder walls after deglazing with hone. If you don't get the cross hatch really clean, those rings won't seat.

Those walls were clean enough to eat off of after honing and cleaning. I did put some clean lube on them before inserting the pistons. The rings seemed to scrape that oil away after a stroke or two... so some oil could be in the crosshatched parts. Will that cause a problem?

 

[sitric]

Those walls were clean enough to eat off of after honing and cleaning. I did put some clean lube on them before inserting the pistons. The rings seemed to scrape that oil away after a stroke or two... so some oil could be in the crosshatched parts. Will that cause a problem?

No, it is the residue from honing that would cause a problem. If it passed the white rag test, you should be good.

 

[Kubota_Mac]

Let me fetch those numbers in the morning.

D1105 Engine S/N: 3C4238 Mower: TBD

 

[North Idaho Wolfman]

You didn't answer or I missed it, on the compression test after the rebuild were all the cylinders the same numbers give or take?

 

[lugbolt]

in my experience unseated rings will still seal well enough to generate compression sufficient to start the engine. It might smoke a little or it might have some blowby (or both) but it still should start. Unless there is some other underlying issue. Hence the suggestion to see where the cylinders are leaking from. With compression that low it should be obvious.

 

[Kubota_Mac]

You didn't answer or I missed it, on the compression test after the rebuild were all the cylinders the same numbers give or take?

Yes, they were all close to the same.

 

[North Idaho Wolfman]

It's all pointing to a possible cylinder head issue more than a ring issue.

While the P/N is the right part number, I would do some serious (comparisons to the two heads) possibly the volume of the pre-chamber is different.

Have you checked for leaks at either the glow plugs or the injectors?
A little soapy water will do that, spray and crank, it will bubble if there is a leak.

 

[Kubota_Mac]

It's all pointing to a possible cylinder head issue more than a ring issue.

While the P/N is the right part number, I would do some serious (comparisons to the two heads) possibly the volume of the pre-chamber is different.

Have you checked for leaks at either the glow plugs or the injectors?
A little soapy water will do that, spray and crank, it will bubble if there is a leak.

Checking for leaks around the plugs/injectors is certainly worth a look. How would I go about comparing the volume of the pre-chambers?

 

[North Idaho Wolfman]

How would I go about comparing the volume of the pre-chambers?

You would pull the head and install a injector and glow plug in the head, then fill the pre chamber with liquid measuring what you put in.
Then compare that to the original.

If you post a really clear hi def picture on here or Pm me, of the old head and the crack, I can tell you if it's a worry or not and if there is a difference in the look of the cylinder space and pre chamber space.

 

[Kubota_Mac]

You would pull the head and install a injector and glow plug in the head, then fill the pre chamber with liquid measuring what you put in.
Then compare that to the original.

If you post a really clear hi def picture on here or Pm me, of the old head and the crack, I can tell you if it's a worry or not and if there is a difference in the look of the cylinder space and pre chamber space.