B8200HST Engine troubles.....

John in France

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Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Hi good people.

I am a newbie member but have been reading your forums for years - very informative and also strangely addictive...

I recently bought a second orange tractor - a B8200HST from 1988. 2 previous owners: a city council, where it was used for mowing a sports ground for 12 years, and then the lying ******* that I bought it from. (He is a very lucky man. He sold his tractor AND he lives a long way away AND my back is recovering from major surgery).
And then along came John.

Anyhow, enough of that. I got the tractor home, started it up again, black, and white smoke until all cylinders firing properly. Would move, hydraulics worked properly, seemed fine and ready for a little TLC. Then the engine bogged down and died, with dark grey smoke from exhaust and breather.
Tried to start it again, but it seemed reluctant to turn over, almost like it was seizing up, but it didn't overheat at all. A few minutes later and she fired up just as before, ran for a few minutes and then died, just as before. Dark grey smoke, bogging down, normally means fuel problem. Cleaned tank, lines, changed fuel filter (fair amount of crud and a small amount of water in there), also changed air filter, though it looked fairly new and was pretty clean. Fired her up: same.
Decided to take the muffler off to see what was happening on start-up. Found a coal mine in there! About 1/8" of carbon on all three ports and a small oil well -leakage onto No 2 inlet valve stem. Fired her up, and the same, but much better without the muffler. Turns out that was nearly blocked up, so ordered a new one. Also ordered a compression tester as my workshop only had one for gas engines.

Checked and adjusted valve clearances that were not quite correct. She ran better, and the horrible knock that she had had, disappeared.
Still bogged down and died though! I've 'listened' to different parts of the engine with the old long-screwdriver-in-the-ear trick, and didn't hear anything out of the ordinary.

Compression tester arrived so took off the injectors and discovered that No3 injector was not tightened up properly, with lots of crud around the threads and the port.
Dry test: 1: 200, 2: 300, 3: 100.
Wet test: slight improvement, but not more than about 10psi. Decided to rip its head off (previous owner wasnt around so couldn't do his!), and had a look inside. Plenty of carbon, but gasket looked good, and bores clean and with hardly any wear ridge at the tops. Encouraging...
Rockers and valves off. There were no oil seals in place. Lots of wear to valve stems and guides - they obviously needed replacing. At this point I decided to get a complete new head from Kumar Bros - by the time I'd got valves, guides, springs, etc and got it all back together, that's a fair bit of time and money, plus I'd have to have got the guides removed and replaced by a specialist - no press in the workshop yet....
So, head arrived, rang Kumar Bros to check if valves were honed-in and they said 'yes, just bolt on and go'. So, I bolted it on, and it didn't go.
New compression tests: Dry: all around 200psi. Wet: the same. That was encouraging in a way, as they were all similar pressures, just not enough. Valve clearances checked again, compression test the same. Decided that this MUST be the valve honing not up to scratch so had a look and it LOOKED OK.
I didn't try testing the valves for leakage with a bit of fuel before installing the head; forgot that one. I also feel that the starter isn't turning the engine over very fast, so that might be impacting on the compression figures too.

I have ordered a new starter motor, (battery is new by the way), and also a fresh set of injectors from Oregon Fuel Injection; I reckon the parts these will replace are 29 years old, so it's probably time...

My next step is head off again, check for leaks with fuel in the valve ports, and then hone in the valves anyway. Then Ill re-assemble and see what happens.

I'm not even thinking about the bottom end, partly because I don't want to;) and partly because there's no blue smoke or significant blow by, and all the bores are clean. I should have said that I've left some ATF in the cylinders for 24 hours, but no discernible difference. I had thought about stuck rings, but then surely I'd get plenty of blue smoke and blowby. Wouldn't I?? And if the rings were stuck 'expanded' surely I'd be seeing some scoring to the bores.....
Mmm. I hope this isn't boring to the scores. Scores of great people on OTT!
So Lovely Orange Tractor People, what are your thoughts please? I'd be really interested and grateful to hear.

Thank you for reading of my woes and thank you in advance for any thoughts you may have!
 

D2Cat

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John, hate to tell you, but I'd focus on replacing the rings and checking the rod bearings. You'll already have the head off. Just take the pan off and then when you have it back together you know what you have, and it'll last forever!
 

85Hokie

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Reading and looking at those compression numbers - I am surprised it once ran!!!!

YOU should be in the mid 400's for a diesel!

I am with D2Cat all the way.......you are this far along, go ahead and get 'er right!
 

North Idaho Wolfman

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I will put in my third for ring job.
Get the cylinders bore checked then new pistons and rings to match. ;)
 

85Hokie

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I understand that these are different engines but the D1305 and the V1505 engines have an allowable lower limit of 327psi.
That may be true, however - if this is a late B8200 - it needs to be up there a little higher :


Kubota Tractor Model Kubota Engine Model

B8200 (LATE)
D950-DT

Engine Model: D950-DT
Head Bolt Torque: 48

Tractor Model: B8200 (LATE)
Main Bearing Case Bolt 1 Torque: 18

# of Cylinders: 3
Main Bearing Case Bolt 2 Torque: 26

Displacement (CC): 927
Rod Bolt Torque: 23

Displacement (Cu In): 56.6
Flywheel Bolt Torque: 44

Bore (MM): 75
Rocker Arm Bolt Torque: 15

Bore (In): 2.9
Compression (PSI) Standard: 450


Stroke (MM): 70
Compression Lower Limit: 325

Stroke (In): 2.7

Engine HP (Net): 19

Valve Clearance (Cold): 0.008

Piston Ring End Gap (RV): 0.017

Piston Ring End Gap (AL): 0.035

Main Crank Journal (Front): 1.7297

Main Crank Journal (Center): 1.7297

Main Crank Journal (Rear): 1.7297

Rod Journals (Standard): 1.4553

Crankshaft End Play: 0.012

Front Pulley Nut Torque: 116

Cylinder Liner ID (RV): 2.953

Cylinder Liner ID (AL): 2.959

Piston Diameter: 2.95

Dimensions are inches. Torques are foot pounds.
 

lescarpentier

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B3350
Oct 12, 2016
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6
Washington
:)
That may be true, however - if this is a late B8200 - it needs to be up there a little higher :



Bore (In): 2.9
Compression (PSI) Standard: 450


Stroke (MM): 70
Compression Lower Limit: 325
Not sure what you mean but I got my info from my WSM which lists the D1305 as having a max as 541 to 597 psi with a lower allowable limit as 327 psi.From what i see it is very similar to what you just posted listing the D950 as having a lower allowable limit of 325 psi.
 

al m

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Forgive me ,some of you seem to be splitting hairs,numbers are way low,seems a bore job is in order. If it was a gas engine,would do a leak down test to confirm,not sure if that can be done on a diesel,if so it would most likely confirm what is being speculated,needs at least a ring job,and might as well do the bottom and be done
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Amazing! Thanks so much for such quick responses!
I’m aware that according to the numbers she shouldn’t have fired up at all. That’s the one thing that makes me question the starter motor. If, when the new motor is on and the valves re-honed, the numbers don’t improve dramatically, then no question, I WILL be going the whole hog and doing at the very least, a new set of rings. I just want to be certain that the top end is good before I go further. Over the next couple of days I hope to get the head off, check for valve leakage and early next week try another compression test with the new starter motor. That will tell me, I believe, whether to go further. As you say, having got this far....

Are these KBros heads reliable do you think? I read somewhere here about the valve recesses being deeper, thus lowering compression. I’ll look at that when it comes off again....

Thanks again! More as soon as... have to fit this excitement into normal life!
 

North Idaho Wolfman

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I've had issues with Kumar Bros heads, as several did not have even what I would consider close to a good seat seal, so it's very likely that having the heads worked on will help with raising the compression. ;)
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Thanks Wolfman, thats what I have read elsewhere. I'd really like to do a leak down test, then i would know for sure where the trouble lies. Just got to make up a tester. This weekend should bring more news...
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Well I got thinking about those compression figures. No change between wet and dry, no obvious blowby, no blue smoke. Doesn't sound like rings...
The new head evened out the readings from 200, 300, 100, to all at near 200.
This suggests that the problem lies with the head. The 100 has improved to 200 and the 300 has worsened to 200. New head, new valves, springs et al, that sounds to me like it must be leaking valves.

Took the head off this evening and did a leak test on the valves. Every one of those new valves on the brand new Kumar Bros head, that has been 'pressure-tested' and is 'bolt-on', was leaking. Tomorrow I'll be sorting the valves, and then doing another compression test. I'm waiting on the new starter motor, injectors and also a leak-down test kit, to find out what exactly is going on, but if anyone out there decides to get themselves one of these heads - hone the valves in yourself before you install it! (Or get a shop to do it, of course). They do not seal!

I'm coming round to the idea of changing the rings anyway. Can I do that by dropping the oil pan and taking the pistons out from the top? If I can avoid splitting the tractor I'd prefer it, and I've got a 2 post lift that would allow me easy access to the bottom... The thought of the alternative makes the screws in my spine torque up!!! :eek:
Anyone done it this way?

Thanks again,

John
 

Shelbygt660

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Feb 27, 2017
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echo bay
As long as you have access to remove the pan then I see no issue popping the pistons out with the engine still attached to the transmission.

Sent from my SM-G930W8 using Tapatalk
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Well, I've just done a leak-down test on all three cylinders. All three came in at 5 - 7% leakage; hardly enough to stop it running through loss of compression. Cylinder 2 was leaking just a little through the inlet valve, so a bit more honing there. All leaking a little to the crank case, but I didn't think excessively.
The last time I fired her up, cylinder 1 had stopped firing at all, so I decided then to bite the bullet and get the engine out, de-glaze the bores and change the rings. Now I am not so sure and am left wondering if this could be a combination of a faulty compression tester and a faulty injector. I have new injectors from Oregon Fuel Injection. Several people have expressed doubts about the engine starting on only 2 cylinders and at only around 210psi. Theoretically it shouldn't, so could my compression tester be lying to me? And where to go next? Is the 5% leakage a reasonable figure (as it seems to me), or could my valve clearances be out as well at .008"? (Something I am very used to doing on other engines). :confused:

Any ideas would be very welcome
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Re-set valves, another compression test: all cylinders 210psi. Bores are clean so new rings then. This afternoon I have split the tractor, engine out and now on stand ready for work. Really pleased I’ve done this. Everything else looks very clean - hydraulic oil, screen, clutch, flywheel etc, so hopefully it’s going to be a simple job to fix....:rolleyes:

I’ll keep you posted as to what’s inside when I see it!
 

100 td

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B21TLB (B21, TL421 & BT751) Toyota SDK4 T116 Bobcat
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The bit I don't get is, you had 300, now you have 200, sure your gauge isn't crapping out on you?
 

John in France

New member

Equipment
B7100HST, B8200HST
Oct 11, 2017
18
0
0
Tarbes, Midi Pyrenees, France
Hi 100_td, that's what I thought for a while. Now I have dug further, I have found the problem; cylinders 1 and 3 almost no big-end bearings! No 1 had one half-shell left and that was welded to the con rod. No 3 the two half-shells had welded themselves together to make a ring! Centre shells badly 'eaten' away, but intact. There was a huge amount of play in 1 and 3. Pistons and bores are fine. Not sure about the crankshaft..... Picked up a replacement engine today from a marine gen-set, with only about 500 hours. Now I have to swap over various parts to fit it. This started badly with six of the gear-case bolt heads shearing off. Obviously a bit of salt water ingress, as they are corroded into the gear-case. WD40 is at work while I sleep tonight....
I have to figure how to get some photos up here as they are impressive.
Had been hoping to get her running tomorrow, but that is unlikely now. I'm afraid a may have to cut the gear-case off and torch the bolts to get them out.
Any ideas for loosening them? They have all sheared at the head so theres 2" of bolt shank corroded into the alloy casing.

More tomorrow.....
 

100 td

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John, hate to tell you, but I'd focus on replacing the rings and checking the rod bearings. You'll already have the head off. Just take the pan off and then when you have it back together you know what you have, and it'll last forever!
Now I have dug further, I have found the problem; cylinders 1 and 3 almost no big-end bearings! No 1 had one half-shell left and that was welded to the con rod. No 3 the two half-shells had welded themselves together to make a ring! Centre shells badly 'eaten' away, but intact. There was a huge amount of play in 1 and 3. Pistons and bores are fine.
OUCH! Bad luck there.
Cutting the housing may be the go or cut the rest of the heads off and remove the housing.
 
Last edited:

D2Cat

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John, the WD40 isn't going to do much for you as far as loosening the seized bolts. Might do as 100 td suggested, cut off the remaining heads to get the cover off and then work on cleaning them up.

I keep this list in my Bookmarks. Kind of interesting.



Machinist's Workshop Magazine recently published some information on various penetrating oils. The magazine reports they tested penetrates for break out torque on rusted nuts.They are below. They arranged a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a "scientifically rusted" environment.

Penetrating oils ........... Average torque load to loosen

No Oil used ................... 516 pounds
WD-40 ..................... ... 238 pounds
PB Blaster .................... 214 pounds
Liquid Wrench ...............127 pounds
Kano Kroil .................... 106 pounds
ATF*-Acetone mix............53 pounds

The ATF-Acetone mix is a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note this "home brew" released bolts better than any commercial product in this one particular test.

ATF-Acetone mix is best, but you can also use ATF and lacquer thinner in a 50-50 mix.

*ATF=Automatic Transmission Fluid.
 

85Hokie

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Bedford - VA
John, the WD40 isn't going to do much for you as far as loosening the seized bolts. Might do as 100 td suggested, cut off the remaining heads to get the cover off and then work on cleaning them up.

I keep this list in my Bookmarks. Kind of interesting.



Machinist's Workshop Magazine recently published some information on various penetrating oils. The magazine reports they tested penetrates for break out torque on rusted nuts.They are below. They arranged a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a "scientifically rusted" environment.

Penetrating oils ........... Average torque load to loosen

No Oil used ................... 516 pounds
WD-40 ..................... ... 238 pounds
PB Blaster .................... 214 pounds
Liquid Wrench ...............127 pounds
Kano Kroil .................... 106 pounds
ATF*-Acetone mix............53 pounds

The ATF-Acetone mix is a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note this "home brew" released bolts better than any commercial product in this one particular test.

ATF-Acetone mix is best, but you can also use ATF and lacquer thinner in a 50-50 mix.

*ATF=Automatic Transmission Fluid.
That chart has been around a while, many dont believe the last one......but how true it is!!! Hard to store for a long time but damn good mix!;):)