B7100D won’t run, puffs black exhaust, “backfire” thru intake…

[IdahoNative]

Long story short, I replaced my clutch. While apart, I pulled the motor and installed a few gaskets, removed carbon on valves & cylinder tops, replaced valve seals, and set valve clearance 0.008”. I also ended up dis-assembling the injection pump and running parts through my ultrasonic cleaner. All 3 delivery valves now fountain at about 5”. New air filter and clean new fuel. BUT….Now it won’t run. It cranks and tries to run. It puffs out a lot of black smoke and then “pops” out the intake before stalling out.

It ran before the clutch failed, but a lot of white smoke, lots of of black gooey unburnt fuel out the exhaust, and the injection pump barely pumped ( fountained about 1”). But it had no issues running and never “backfired” out the intake. I will add it didn’t have a head shim, but I put on with the new head gasket.

I re-adjusted the valves by bumping the starter, setting the intake at 0.008” when the corresponding exhaust valve spring was at the highest point. The exhaust valves were set when the intake spring was at the lowest. I think this is the EOIC method, correct?

Any suggestions, besides double checking my valve clearance?

 

[85Hokie]

when you took the pump apart.......... did you shim it exactly the way it was before?

 

[Russell King]

Timing is set by shims between engine and injection pump. Hopefully you kept up with them and replaced them and didn’t use any gasket sealant

The injection pump probably needs the fuel delivery valves properly adjusted on the top of the pump by a person that knows how to do that. I have no idea how but have read threads that describe something similar to your problem when people have accidentally turned them

 

[Dieseldonato]

Pumps should be worked on by pump shops. Your pump is likely out of calibration, and I'm also going to assume your timing is way off as well.

Timing is set by shims between engine and injection pump. Hopefully you kept up with them and replaced them and didn’t use any gasket sealant

The injection pump probably needs the fuel delivery valves properly adjusted on the top of the pump by a person that knows how to do that. I have no idea how but have read threads that describe something similar to your problem when people have accidentally turned them

The delivery valves arnt the issue it's the barrels that get out of sync by being turned.

 

[ACDII]

Classic case of timing. Sounds like the fuel is being injected too early, not burning cleanly and firing off when the intake is open. Can also be shooting in too much fuel. Check the oil for fuel dilution. Diesel fuel injection systems are very complex and intricate, I wouldn't mess with it unless I had someone who knew them inside and out helping me.

 

[IdahoNative]

when you took the pump apart.......... did you shim it exactly the way it was before?

Thank you for your reply.

Yes, each valve had a shim and I reinstalled them exactly as I found them. I originally did put a gasket on, but later removed it.

 

[IdahoNative]

Timing is set by shims between engine and injection pump. Hopefully you kept up with them and replaced them and didn’t use any gasket sealant

The injection pump probably needs the fuel delivery valves properly adjusted on the top of the pump by a person that knows how to do that. I have no idea how but have read threads that describe something similar to your problem when people have accidentally turned them

Thank you for your reply.

Yes, each valve had a shim and I reinstalled them exactly as I found them. I removed the new gasket. That appeared to help the fountain height. I also reinstalled them to the same torque as when I removed them. But it's certainly something I can adjust.

 

[IdahoNative]

Pumps should be worked on by pump shops. Your pump is likely out of calibration, and I'm also going to assume your timing is way off as well.

The delivery valves arnt the issue it's the barrels that get out of sync by being turned.

Thank you for your reply.

You're right about "should be worked on by pump shops". But when shops don't answer the phone or respond, it's not an option.

For what it's worth, I was very methodical when removing and replacing the injection pump assembly. I even torqued the barrels to the same as post-removal. Visually, they all fountain about the same height and, as far as I can see with a video camera on slow motion, they don't discharge at the same moment and there's a definite pattern. Perhaps the barrels need turned a little in/out...good thing this is only a three cylinder. I know that analysis sounds kinda silly. I would gladly send the pump body out to be tuned by a pro. I think I found a shop in Oregon that I can mail my pump to. But before that happens, can you help me eliminate the other two culprits?

Putting injection pump to the side for now (but not ignoring it), I would appreciate your input on how I adjusted the valves. Or, perhaps there was a reason why the head shim wasn't on. Should I remove the new one installed?

I truly hope I don't come across as a smart A$$. I appreciate your input, just trying to narrow it down by doing what I can do myself to improve the situation and understanding it could be a combination of all three.

 

[IdahoNative]

Classic case of timing. Sounds like the fuel is being injected too early, not burning cleanly and firing off when the intake is open. Can also be shooting in too much fuel. Check the oil for fuel dilution. Diesel fuel injection systems are very complex and intricate, I wouldn't mess with it unless I had someone who knew them inside and out helping me.

Thank you for the reply.

I'll check the oil for fuel. Hopefully, what little amount of times I cranked it, it will be obvious.

Aside from the injection pump, the valve train is the only assembly that I adjusted. Any comments on how I adjusted the valves? Or the missing head shim? I'm just trying to eliminate the potential causes before sending my pump to a shop, once I find one.

You're right about having someone to help....I am in a very remote location, but the few neighbors I have, they all have at least one Kubota. I see them tearing them apart and getting them working again. I will definelty ask them.

 

[kubotasam]

. I will add it didn’t have a head shim, but I put on with the new head gasket.

I re-adjusted the valves by bumping the starter, setting the intake at 0.008” when the corresponding exhaust valve spring was at the highest point. The exhaust valves were set when the intake spring was at the lowest. I think this is the EOIC method, correct?

Any suggestions, besides double checking my valve clearance?

A head shim is only used if the head or block needed to be machined to true them up. By installing one you have reduced the compression ratio.

I do not understand your explanation of how you set the valve clearance.

 

[torch]

I re-adjusted the valves by bumping the starter, setting the intake at 0.008” when the corresponding exhaust valve spring was at the highest point. The exhaust valves were set when the intake spring was at the lowest. I think this is the EOIC method, correct?

Any suggestions, besides double checking my valve clearance?

According to the factory service manual for the B7100, shimming the head is done based on clearance:

(1) Remove the nozzle holder.
(2) Lower the piston in the cylinder to be
measured.
(3) Insert a high -quality fuse from the nozzle holder hole. Be careful not to let the fuse touch the valve surface.
(4) Rotate the engine by hand.
(5) Take the fuse out carefully.
(6) Measure the place where the fuse was crushed with a set of vernier calipers.
(7) If the measurement is not within the reference value, adjust by inserting a shim between the cylinder head and the gasket .
• Reference value
0.6 to 0.8 mm (0.0237 to 0.0315 in.)

(by "fuse" they refer to a product like Plastigage. One could also use a suitable diameter solder -- something that will retain the dimension after being squished between piston and head)

Adjusting the valves is done at top dead centre for each cylinder in turn, by aligning the flywheel mark (TC) with flywheel housing timing window. From the FSM:

(1) Measure and adjust the clearance with a feeler gauge after al igning each cylinder with the top dead center of compression.
(2) Adjust them in their injection order. (1 --> 2 --> 3)
NOTE: Measure and adjust when cold. 0.145 t o 0.185 mm (0 .0057 to 0.0073 in.)
Valve clearances other than reference value may cause output fluctuation, excessive noise, or valve or piston breakaqe.

 

[IdahoNative]

A head shim is only used if the head or block needed to be machined to true them up. By installing one you have reduced the compression ratio.

I do not understand your explanation of how you set the valve clearance.

Thank you for the reply.

Sounds like I need to pull the head shim. Stupid mistake by me. I got in a hurry and looked at the WSM pictures and skipped the text.

I tried to follow the EOIC valve adjustment method. When the exhaust is starting to open, set the intake. I think this exhaust valve position would be with the valve stem at the highest point (the valve is completely closed and just about to open). Same idea for the intake, but the reverse.

 

[IdahoNative]

According to the factory service manual for the B7100, shimming the head is done based on clearance:

(1) Remove the nozzle holder.
(2) Lower the piston in the cylinder to be
measured.
(3) Insert a high -quality fuse from the nozzle holder hole. Be careful not to let the fuse touch the valve surface.
(4) Rotate the engine by hand.
(5) Take the fuse out carefully.
(6) Measure the place where the fuse was crushed with a set of vernier calipers.
(7) If the measurement is not within the reference value, adjust by inserting a shim between the cylinder head and the gasket .
• Reference value
0.6 to 0.8 mm (0.0237 to 0.0315 in.)

(by "fuse" they refer to a product like Plastigage. One could also use a suitable diameter solder -- something that will retain the dimension after being squished between piston and head)

Adjusting the valves is done at top dead centre for each cylinder in turn, by aligning the flywheel mark (TC) with flywheel housing timing window. From the FSM:

(1) Measure and adjust the clearance with a feeler gauge after al igning each cylinder with the top dead center of compression.
(2) Adjust them in their injection order. (1 --> 2 --> 3)
NOTE: Measure and adjust when cold. 0.145 t o 0.185 mm (0 .0057 to 0.0073 in.)
Valve clearances other than reference value may cause output fluctuation, excessive noise, or valve or piston breakaqe.

Thank you for the reply!

I need to slow down and read my WSM in detail!

 

[ACDII]

Either method works for adjusting valve clearance. When at TDC with both valves closed, both should be at the lowest part of the lobe. Likewise, when the exhaust is open, the intake should also be at the lowest part of the lobe and reverse for exhaust. Rotating to TDC for each cylinder is common practice, but the other method works as well.

If shimmed and not needed, that could be why it isn't running. Diesel needs as much compression as it can get to fire off, and if it doesn't have it, well, it doesn't run well, if at all.

 

[IdahoNative]

Either method works for adjusting valve clearance. When at TDC with both valves closed, both should be at the lowest part of the lobe. Likewise, when the exhaust is open, the intake should also be at the lowest part of the lobe and reverse for exhaust. Rotating to TDC for each cylinder is common practice, but the other method works as well.

If shimmed and not needed, that could be why it isn't running. Diesel needs as much compression as it can get to fire off, and if it doesn't have it, well, it doesn't run well, if at all.

THANKS!