D640 Compression
 

Does anyone have the compression specs for a D640?

The way i read the manual is the factory spec is 448 but allowable limit of 337psi!!

That sounds wrong. That would be around a 30 to 1 compression ratio

I have no idea what the spec for a D640 is but I can give you some numbers from larger diesels for comparison. the old Detroit 2 strokes you check while the engine is running at idle . naturally aspirated under 500 psi was worn out. they had around a 19-1 comp ratio. the turbo engines were always lower around 425 - 450 . they had around a 16.5 comp ratio. I just checked compression on a International VT365 which is turbo charged and the spec for that was 300-350 cranking. 2 holes were at 275 and those 2 cyl's showed poor on the inj cut out test. The VT365 is the engine Ford called a power stroke. allot of engine's these days they don't give specs for compression just because there's not decent way to check them such as the DT466 HUEI you should be able to make up an adaptor to go into the glow plug hole on the D640.

I got this off another diesel engine forum I check out on occasion

During work i got a call asking to do a comp. test for my uncle on a little 3 cylinder Kubota engine. I said i would....So i went down and pulled the 3 glow plugs out....Pulled the fuel line off the injection pump. This engine took the same glow plug tester as the duramax did. Added some never seize and went to town on the test... Number one was about 215....I thought to my self. Man thats alittle low for my liking when this thing is Naturally aspirated. I would think its gotta have more compression than that....Well i guested right... Cylinder number 2 was 520 And then Cylinder three was 120 I did the hole 5 minute test again Just to be sure. Needless to say i think the engine needs a rebuild....Smptoms were as told to me: It constantly makes like a....well i guess like a ....Fog coming out of the blow by tube all the time....Engine had about 2500 hours on it. And had little actual oil blow by but had alot of steam.....Uncle and cousin said it has most likely sucked a lot of dirt in its day...So im blameing the dirt on the cylinders being scored or worse.....Just thought you guys might like to hear about what i did today

I ordered a service manual for it but haven't gotten it yet. The only info I could find was that the pressure tester needed to be 600 psi minimum.
448 PSI sounds right.

I guess I was wrong. This is from a Bota forum.

http://www.orangetractortalks.com/20...tarting-fluid/

Wow that block looks like a softball came out of it.

allot of the newer diesels have grid heaters in the intake. seen a few trucks come in with rather large burn holes in the air filter from ether. that warning sticker on the hood don't seam to stop people.

This motor starts hard, idles rough and dogs out under load. I pulled the glow plugs and injectors out today and tested them. Cyl1 has a good plug but the injector drips when not under pressure. Cyl 2 has a good injector but a bad plug. Cyl 3 has a good plug but gets no fuel through the injector at all.