B7100 bypass tube smoke?

[JohnJohnson]

My recently acquired B7100 (mid 90s, 600 hours) has some steady white smoke coming from the valve cover vent tube and also the exhaust. I've done a compression test and all three cylinders are around 375 psi, so I don't think it's a compression issue, but not sure what else it could be?

I've previously had a diesel shop rebuild the injectors and the injector pump and I adjusted the timing back to factory spec, and that solved other smoking problems I was having, but I'm concerned about the smoke from the valve cover vent tube.

Ideas on what to look at? Can a cracked head gasket be the problem? I saw some coppery particles in the coolant that I just drained, did someone try a "stop-leak" product previously? Is there a test that can positively identify it's the head gasket before I sink a few hours into taking the head off? Could glazed cylinders be the problem?

Thanks!

 

[Dave_eng]

Please indicate which model of B7100 you have....... manual trans 4 x 4, HST

There are more knowledgeable B7100 owners on the forum so wait for their posts.

Your compression of 345 is just at the lowest acceptable level. which is 341. The wsm suggests adding a SMALL amount of oil and doing the test.

If the compression readings do not recover to higher values head problems are possible
.

The engine does not have a water pump. Instead it uses thermo syphon principles. Checking in the rad cap opening can show head gasket problems evidenced by small bubbles. The copper particles are concerning because they did not come from the engine itself.

Dave

 

[JohnJohnson]

It's a 4x4 HST, luckily I took videos of the compression test, and after I went back to look at it, one cylinder has a compression reading of 340psi, and the other two cylinders are at 375psi. So I guess that's the problem cylinder. I have not seen any bubbles in the radiator neck. I'll test again using a small amount of oil If the pressure recovers I guess it's mostly likely due to the rings in that cylinder, right?

 

[Dave_eng]

It's a 4x4 HST, luckily I took videos of the compression test, and after I went back to look at it, one cylinder has a compression reading of 340psi, and the other two cylinders are at 375psi. So I guess that's the problem cylinder. I have not seen any bubbles in the radiator neck. I'll test again using a small amount of oil If the pressure recovers I guess it's mostly likely due to the rings in that cylinder, right?

Without knowing the history of the tractor it is difficult to come up with a diagnosis. My inclination would be to use it under heavy load conditions for a number of hours and then check again. Sometimes tractors (diesels) are operated under light loads at high rpm's and the rings are not sealed to the cylinder walls which results in a lot of blow by.

Dave

 

[JohnJohnson]

Without knowing the history of the tractor it is difficult to come up with a diagnosis. My inclination would be to use it under heavy load conditions for a number of hours and then check again. Sometimes tractors (diesels) are operated under light loads at high rpm's and the rings are not sealed to the cylinder walls which results in a lot of blow by.

Dave

That's easy enough, I won't stress about it then until I run it hard for a few hours.