1979 B7100DT Delivery Valve Torque & Low Oil Pressure

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BackYardWrench

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Equipment
B1700
Jul 17, 2015
25
1
0
Wisconsin Dells, WI
Total newbie here. Appreciate the resource and all that contribute. Used the search option and could not find answer.

This is a parts tractor I picked up with a history of "bad motor" and no other info.

Is there a torque spec for the delivery valve? They are leaky and the rear most cylinder does not fire. Is that cylinder 1 or 3? I ordered new O rings and "gaskets" but did not see a copper crush washer in the parts diagrams.

On a E300 diesel, I torqued to something like 35 pounds of torque and then another 5 or so, if I recall correctly and the thing was golden. Asking if the B7100 has a similar procedure.

The other problem with the tractor is low oil pressure (10-15 psi) so I can't run it much. Im trying to eliminate the non-firing cylinder as I "think" I hear a knock. Hoping this is a fuel knock caused by a missing crush washer, which is throwing off the timing/fuel delivery to that cylinder. Im not at the tractor, which is several hours away so I can't and didn't compare the delivery valve with the other two.

I've checked and swapped injectors and spray patterns. The non working cylinder is getting fuel. All of the cylinders have compression, not perfect but its there and it runs on the front two.

I know I need to pull the oil pan (bad rod bearing) and front cover (cam plug) to resolve oil pressure. Which should I do first? Oil pan or front cover?

Thanks
 
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coachgeo

coachgeo

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sitdwnandhngon

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B7100
Aug 25, 2015
45
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NY, USA
Do the cam plug first.

I just did one two weeks ago and bumped it up from 5psi at full throttle to about 50.

It was an easy fix, just a bit time consuming, I managed to go start to finish in about 5 hours.
 
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BackYardWrench

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B1700
Jul 17, 2015
25
1
0
Wisconsin Dells, WI
Thanks coachgeo and sitdwnandhngon

Off with the front cover. I'll update my findings.

There are two plugs 15261-96860 and 15261-96880. I ordered both(not expensive and wasn't sure which is right one) and plan I using permanent locktite. Any reason not to use JB Weld on top of locktite for double insurance?

Looked over the WSM and did not see any procedure for torquing delivery valves. Kubota diagrams are fuzzy and hard to discern as to crush washer vs gasket. O rings are easy to figure out.
 
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Jim L.

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Jun 18, 2014
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This is way above my pay grade, but there may be a Technical Service Bulletin on this.

It may be that the plug material was changed, and that the plug(s) are to be tack welded in. Good idea to check on that first.

Loctite requires a completely clean surface. It also does not do well with heat.

JB weld epoxy putty also requires a completely clean surface. It also does not do well with heat.

So I would be curious if you find a TSB and what it might have to repair this.
 
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BackYardWrench

New member

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B1700
Jul 17, 2015
25
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0
Wisconsin Dells, WI
Thanks Jim L.

I'll try to dig up the TSB.

In the meantime, I found the tightening torques in the WSM for the 70mm Stroke Series engines and attached a pdf of it.

It lists many of the torques but does not mention the delivery valve holder, 2nd pdf. May not have a tightening torque. Hmmm.... I guess this must be where experience comes in.

The reason Im pursuing this is the delivery valve holders come loose when I try to remove the hard fuel line at the injection pump. The middle holder cannot be backstopped with a wrench as there is no room. This is how the delivery valves got leaky.

Did some more digging and the closest torque I found was on a Yanmar 2GM, which is 15 ft/lbs. I'll call Bosch next week to see if they can give me the official answer for their Bosch K type injection pump.
 

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North Idaho Wolfman

North Idaho Wolfman

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BackYardWrench said:
Total newbie here. Appreciate the resource and all that contribute. Used the search option and could not find answer.

This is a parts tractor I picked up with a history of "bad motor" and no other info.

Is there a torque spec for the delivery valve? They are leaky and the rear most cylinder does not fire. Is that cylinder 1 or 3? I ordered new O rings and "gaskets" but did not see a copper crush washer in the parts diagrams.

On a E300 diesel, I torqued to something like 35 pounds of torque and then another 5 or so, if I recall correctly and the thing was golden. Asking if the B7100 has a similar procedure.

The other problem with the tractor is low oil pressure (10-15 psi) so I can't run it much. Im trying to eliminate the non-firing cylinder as I "think" I hear a knock. Hoping this is a fuel knock caused by a missing crush washer, which is throwing off the timing/fuel delivery to that cylinder. Im not at the tractor, which is several hours away so I can't and didn't compare the delivery valve with the other two.

I've checked and swapped injectors and spray patterns. The non working cylinder is getting fuel. All of the cylinders have compression, not perfect but its there and it runs on the front two.

I know I need to pull the oil pan (bad rod bearing) and front cover (cam plug) to resolve oil pressure. Which should I do first? Oil pan or front cover?

Thanks,

John
Click to expand...
John,
Most likely the reason it won't fire and the low oil pressure is the bad rod bearing! ;)
Very highly unlikely that it's a cam plug as this motor does not have an issue with that!
 
S

sitdwnandhngon

New member

Equipment
B7100
Aug 25, 2015
45
0
0
NY, USA
BackYardWrench said:
Thanks coachgeo and sitdwnandhngon

Off with the front cover. I'll update my findings.

There are two plugs 15261-96860 and 15261-96880. I ordered both(not expensive and wasn't sure which is right one) and plan I using permanent locktite. Any reason not to use JB Weld on top of locktite for double insurance?
Click to expand...
I just used a piece of rod (broken drill bit) that I had in the my pile of random stuff, and then put a tack weld over top of it.
 
B

BackYardWrench

New member

Equipment
B1700
Jul 17, 2015
25
1
0
Wisconsin Dells, WI
Planning on working on tractor over the weekend as it is 200 miles away in Wis.

In the meantime, I received my parts and what is listed in the parts diagrams as a gasket is actually a copper crush washer.

Called Bosch and a local fuel injection shop to get torque specs for delivery valve holders but both places are asking me for the injection pump number, which I wont have until next week.

Edit: Thought I had a Bosch K Type Mini Injection Pump but now have been told I may have a Zexel injection pump - . Unofficially, Im told the torque spec for the Zexel is around 30 ft/lbs. This would make sense since on the Mercedes E300 diesel, the torque spec was 30, loosen, 30, loosen and then 35 ft/lbs as the final torque. Some guys just went straight to 35 ft/lbs. Both methods seem to work.


TIA
 

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BackYardWrench

New member

Equipment
B1700
Jul 17, 2015
25
1
0
Wisconsin Dells, WI
Thanks Steve. Exactly my scenario as to low oil pressure.

Took front cover off - no plug, just a hole in the end of the cam.

Ended up pulling the head and cam. One head bolt head was broken and another snapped off. BTW, there is not a good way to remove the front cover without removing the magneto/water housing. They overlap each other. The front cover goes on first and then the magneto/water housing gets mounted to the head and then the head gets torqued down.

The plug on the back of the cam was wobbling around. It did not fall out since there is a wall back there that kept it in place. The aluminum plugs are flimsy and I see why they did not hold vs 60 psi.

Made plugs out of old drill bit (7/64 IIRC) and both plugs are welded in place.

Anyone know of a Kubota number for a gasket set, either for the head gasket or the front cover??
 

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