Valve Clearance for D750 engine

[nikos]

Could someone help me? I have a kubota B 7001 with the engine D750 and I want to set the valves. i dond now exactly what should be their distance, how many mm gap must be given to how much entrance and exit(valve clearance) .thanks .

 

[kubotasam]

The service manual for my B7100 with a D750A engine lists 0.15 - 0.19 mm for both intake and exhaust valves set with engine cold.

The adjustment for the decompression lever is listed as .8 - 1.1 mm

 

[en_teng]

.15 .19




Valve Tappet Gap (Cold)(mm)
0.15-0.20



wich is correct please advise thanks i know its OLD thread. ive used the search button.

 

[100 td]

Not sure what you are asking, the specs listed at the start are close enough to the 750B manual I have at .145 .185 ?
Remember this is a tolerance/range.
.145 = 5.7 thou
.15 = 5.9 thou
.185 = 7.3 thou
.19 = 7.5 thou
.2 = 7.9 thou
So set them between 6 and 7.5~8 thou from the above

 

[North Idaho Wolfman]

Valve clearance cold is .008 inch, or 0.2032 mm

 

[100 td]

HI NIW,
There's only a cats whisker in it but is that measure an update on the info in the workshop manuals at .15-19mm and .145-.185mm for the 750A and 750B? I understand over time they probably work out what works best, but seeing they closed the setting slightly with the B, it's interesting to see it widening again. Perhaps they had some issues with the tighter setting and adjusted to suit?

 

[100 td]

Hi NIW,
Got another one for you, generally speaking, do you see/or have you noted any differences in valve settings on kubota engines that run full time/full load constant 3600 rpm as genset prime movers, compared to the same engine in tractors? (or do you personally set them differently)
I'm currently looking for a ~15kW set, ideally with a kubota prime mover and are just interested generally.

 

[North Idaho Wolfman]

Some of the differences has to do with rounding errors when changing from inches to MM so the numbers vary.
I use the specs strait from the WSM's of the motors not necessarily the tractors that they came in.
I have set quite a few D750's, D850's, and D950's, and have found tighter is not good, too easy to float a valve.
Am I right, I don't know for sure, but all that I work on come out running smooth and good.
You sure its 3600 RPM Kubota engines don't rap up that high, most generator units run in the 1800 RPM range.
I just got done rebuilding an Onan that was Kubota D950 powered and it was 1800 RPM.

 

[Tooljunkie]

My experience is mostly with gas engines, too tight and as niw sais too easy to float a valve. As valve clearance increases valve timing changes. I recall a dog of an old long block 318 in a 66 powerwagon. Set valve to spec and that truck became a crazy bush monster. It made incredible torque.

Saying that, if vaves are set by guess and by golly you take your chances.
Manual by tractor or engine model will be the most accurate.

 

[100 td]

Thank for the info NIW

You sure its 3600 RPM Kubota engines don't rap up that high, most generator units run in the 1800 RPM range.

Yes the smaller Kubota "J series" and "GL series" gensets (up to ~20kW) run 2 pole gensets at 3600 @ 60Hz or 3000 @ 50Hz, engines are Z482, D722, D1005 & V1305. The 4 pole heavier duty ones run at 1800/1500 from ~14 kW and up. The engines are also bolted up to other branded gensets.

 

[en_teng]

Valve clearance cold is .008 inch, or 0.2032 mm

sir wolf .008 inch both intake and exhaust

 

[North Idaho Wolfman]

Thank for the info NIW

Yes the smaller Kubota "J series" and "GL series" gensets (up to ~20kW) run 2 pole gensets at 3600 @ 60Hz or 3000 @ 50Hz, engines are Z482, D722, D1005 & V1305. The 4 pole heavier duty ones run at 1800/1500 from ~14 kW and up. The engines are also bolted up to other branded gensets.

I too learn things all the time on here!
Your right the newer diesels do run at a higher RPM range.

sir wolf .008 inch both intake and exhaust

Yes sir they are both at .008.

 

[en_teng]

I too learn things all the time on here!
Your right the newer diesels do run at a higher RPM range.



Yes sir they are both at .008.

its ok to not follow the .006 in .008 ex on the wsm?

sorry for my ignorance.

:-D

 

[North Idaho Wolfman]

Yes the .008 is a better measurement.

 

[JosephGozo]

Hello.
I am interested in adjusting the valves on the D750. I have not done it in years!
I was reading here that adjustment should be carried out on each piston independently from others. (Bringing each piston at their TDC and adjusting to 0.008" ) this this correct? I have some downloaded documents advising to align the flywheel marks with the cover. Is this possible or I just rely on Valve movement ?

 

[lynnmor]

A sure method, on nearly all 4 cycle engines ever made, is to choose a valve, turn the engine till it fully opens, mark the flywheel or pulley and then give it one more turn. This will put the valve lifter opposite the cam lobes highest point and on the base circle. Adjust and repeat for all valves.