B7100 (D750-A) Low Oil Pressure and Camshaft Plug (some pictures)

Hello, OTT!

This site, along with a few others, was helpful in diagnosing my B7100's low oil condition, without tearing into the engine. Since it is an orange tractor, I think this belongs here. Hopefully it will help others in the future, as your threads have helped me a great deal. I'll be telling many of you things you already know.

I bought the tractor a few months ago and only used it a few times. As many people have experienced, the low oil pressure light came on at low RPM. Higher RPM would bump up oil pressure enough to turn the light off, but after fifteen minutes or so, near WOT was needed to keep the light off. I decided to throw a gauge on the oil pressure port. Sure enough, the engine was getting between 7-10 PSI at idle AND near WOT with cold oil. Those figures changed to 5-7 PSI with warm oil. 7 PSI is low enough to trigger the factory oil pressure sending unit.

At this point, I knew it was either a bad oil pump, badly work mains or (thanks to this site) a camshaft plug had fallen out. Unfortunately, Tinypic shut down so I lost the few pictures I took.

Front of cam (facing timing cover): This end was missing its plug. This is the end that likes to spit out the aluminum plug. Because aluminum's expansion and contraction characteristics are very different from the steel cam's, the aluminum plugs lose their interference-fit after enough heat cycles.

Rear of cam (facing driver): This end still had the aluminum plug in it, but it was loose and I was able to remove it with my fingers. The good thing about this end of the cam is that it sits very close to the rear of the block. On my engine, there isn't enough room for the plug to fall out.

I got everything from my diesel engine distributor. They couldn't get the cam plugs for me, so I got those from Kubota.

15261-96880 Plug, Blind
I ordered two plugs, at $3.42 each.
The updated cam plugs are steel. I shouldn't have to deal with this issue again.


In summary,
-Get a tractor that has 10 pounds of oil pressure
-Remove head
-Remove push-rods and lifters
-Remove crank pulley (29mm, deep socket)
-Remove timing cover (I had to lift the front of the tractor and drop the axle, along with the front frame section)
-Remove cam
-Replace plugs
-Install cam with assembly lube
-Install lifters with assembly lube
-Install timing cover
-Install crank pulley
-Install head with new head gasket
-Install push-rods
-Install rocker assembly
-Set valves
-Put the rest together, start it and see that it now makes between 45 and 55 PSI.


I invested about four hours in the job. As long as you have a jack, basic tools and a 29mm socket, you can do it in an evening. That said, you should always order parts AFTER tearing it down, because you might find something else.

Cheers!

JOKER

tradin1 said:

good job. makes me want to tear mine apart tonight!

Click to expand...

Do it! Tear it down, make a list, then order some parts.

Post up if you have pictures or questions.

Cheers!

I bought another B7100 and it looks like I'll be doing this job again. I'll snap some pictures and use a more reliable image hosting client this time. I didn't mean to leave anyone hanging en-teng.