B7000 - Z650 cylinder head job

tractor_beam

New member

Equipment
B7000, some unidentified attachments in the bracken
Jan 13, 2011
5
0
0
Wee Cumbrae, Scotland
Hello everyone!

I am helping out looking after a little island at the west coast of Scotland. In the shed we've got a B7000 all in parts. There are even two engines. One with a bad case of big end damage, the other one was left out in the rain and seized up. At least with lots of diesel oil I could convince it to turn over once more and it turns not too bad now. The plan is now to stick this one back together and get it to run somehow. If that can be done I'll try and reassemble the whole tractor to see what works and what doesn't to have an idea how much we'll need to spend to get it back into service.

First attempt to start the engine I had diesel fog coming out of the intake. So the head went down and the valves are ground in. Obviously they don't look new anymore but should do the job now. One of the cylinders inside looks ok, the other one is damaged by oxidation. Fortunately the damage is in the lower third of the liner so the pressure loss should not be too high (touching wood here). At least the piston operates smoothly.

Now I need to put it all back together and give it a try. I was wondering if anyone could help me out with the torque for the cylinder head bolts, fixing sequence and maybe the torque for the rocker bolts too.

Thanks for keeping up this forum by the way. All the information in here has been a huge help already!

Cheers,

Peter
 

stuart

Member
Lifetime Member

Equipment
B7001 with loader & tiller, 3 point hitch and 4' rear blade
Aug 9, 2009
280
0
16
Aldergrove, BC, Canada
Here is the spec for the d750

Tighten cylinder head securing cap
screws to 42-47 N-m (31-35 ft.-lbs.) torque.
Tighten rocker arm stands to
16.7-20.6 N-m (12-15 ft.-lbs.) torque.
Tighten injector nozzle nut to 29.4-49.0
N-m (22-36 ft.-lbs.) torque. Adjust valve
tappet gap as outlined in paragraph 20.
Adjust compression release as outlined
in paragraph 21.

I have other engine manuals here, but not the z650.
 
Last edited:

tractor_beam

New member

Equipment
B7000, some unidentified attachments in the bracken
Jan 13, 2011
5
0
0
Wee Cumbrae, Scotland
Vic, there are no markings on the bolts at all.

They are 10mm bolts so your torques seem to be right on target.

The sequence makes perfectly sense! Thank you so much for posting everything!

Stuart, you forced me to make some homework here :)
I found some pictures of the D750 and can see now why you posted these specs. Thank you!

Somewhere on this forum I've seen mentioned that there is no water pump on the D750. On first glance there seems to be one on the Z650 but that unit turned out to be an alternator. Is that right? Would be good to know if I'm working with convection cooling in case I need to improvise things on the coolant circuit (i.e. keep the hose diameters big and make extra sure there is no air lock).

Thanks guys, that was a great help! I'm still waiting for the torque wrench but once that's here I should have everything for the test run on the bench.

I got the outboard on my rib fixed today, so I might just nip over to the mainland and get it :D
 

stuart

Member
Lifetime Member

Equipment
B7001 with loader & tiller, 3 point hitch and 4' rear blade
Aug 9, 2009
280
0
16
Aldergrove, BC, Canada
Vic, there are no markings on the bolts at all.

They are 10mm bolts so your torques seem to be right on target.

The sequence makes perfectly sense! Thank you so much for posting everything!

Stuart, you forced me to make some homework here :)
I found some pictures of the D750 and can see now why you posted these specs. Thank you!

Somewhere on this forum I've seen mentioned that there is no water pump on the D750. On first glance there seems to be one on the Z650 but that unit turned out to be an alternator. Is that right? Would be good to know if I'm working with convection cooling in case I need to improvise things on the coolant circuit (i.e. keep the hose diameters big and make extra sure there is no air lock).
I couldn't get the 2 and 3 cyl sequence diagrams to scan in, but I am sure Vic's would be correct, i just didn't see why the torques woul dbe so different.

Yes my D750 is convention cooled. Keep it clean inside and make sure the coolant level is high enough so the heated coolant gets into the rad efficiently.
 

tractor_beam

New member

Equipment
B7000, some unidentified attachments in the bracken
Jan 13, 2011
5
0
0
Wee Cumbrae, Scotland
Jolly good. That's quite a bit away from what you posted before. You are quite happy these are right then?

I understand there is only a service and maintenance manual in Japanese for this engine? So I might as well get the caliper out and post all details for these bolts for a better cross reference to other engines. If nothing else it might allow someone else to move with more confidence:

Length over all: 93mm (from the bottom of the hex head)
Shank diameter: 10.0mm
Shank length: 59mm
Thread: M10x1.25 (metric fine)
Thread length: 32mm
The head is a hex 14mm

There is a quite pronounced runout between shaft and thread that tapers down to 9.2mm before the actual thread starts. That runout accounts for the difference between length overall, thread and shank.

This are the specs for the top down bolts. There are two bottom up bolts that are secured with nuts. These are probably there that way to ease installation of the cylinder head and to prevent damage to the oil line that protrudes a bit into the cylinder head. On the Z650 these bolts are on positions 9 and 10 if you refer to the torque sequence in Vics post above.
 

tractor_beam

New member

Equipment
B7000, some unidentified attachments in the bracken
Jan 13, 2011
5
0
0
Wee Cumbrae, Scotland
Back to life!

Got a torque wrench yesterday and had some good time this morning.

Both pots are pushing pistons once more! Incredible good performance considering the state this engine was in before. Even the weak cylinder does it's part. Can't say any more right now. I'll get the engine into the tractor now and another test with the cooling system hooked up.

Having said that. No black smoke and little white smoke from both cylinders :)

Honestly I can't believe it. I expected a far worse performance :rolleyes:

Big thanks to Vic and Stuart for all your help!