DSG gear question

[tom yuenkel]

A little history, my 91 suburban has 250000 miles on it and developed blow by and I choose a military engine (87 660 block) to replace it because of cost. To begin, the install of the gear set went well, I installed the small gears with the larger of the two on the left meaning the idler gear is on the right. When I rotate cthe engine cw the left gear is tight and the idle floats or is loose,I had .020" shaft end play between the block gears. All apeared to be correct and so I finished assembling the front timing cover.
Now after installing this gear set I removed the military oil pan and rotated the engine quite a bit to inspect the cylinder bores from the bottom just to get a feel for wear and my bores are all still crosshatched. I then installed the original 91 pan and rotated the engine by hand with a wrench and I'm hearing a metallic clink, visually you can see the cam shaft gear jump along with gear set pump exactly when the clink is heard. I disassembled back to the DSG gear set and this is what I see. WHEN i rotate the engine the left gear is tight I metallic clink is heard and the left gear pops looge and the idler gear is now tight. Rotate it a little more and the left gear is tight again. This pattern repeats it self and a ppears to be a product of the cam shaft kicking the gear out, the gears are clean with no debris. Is it possible I bleed the oil out of the lifters and now i see this behavoir? I'm no0t sure what to do next. Fill it up with oil and get my lifters re filled? need help

[tom yuenkel]

Sorry for the spelling I'll type slower. To be more specific, when you hear the metallic clink you can see the cam shaft move "CCW" a half degree, this unloads the left gear and pulls in the right gear producing the clink. Turn the shaft more and the left gear is pulled back under load again. So to me the relationship between the cam shaft and lifters is creating this problem, probably i have bled down somw of the lifters. What I'm after is if some one else has seen this and if I should do any thing.

[More Power]

Sounds like the valve train is producing what you're seeing/hearing. Each lifter creates a load on the cam on the uplift (resists rotation), then accelerates the cam on the way down. This is normal...

Jim

[tom yuenkel]

I'm assuming with the lifters filled solid with oil, the problem I see now would be gone and I'm safe to move ahead. you agree?

[More Power]

Due to the cam lobes and lifters pushing or resisting cam rotation, it'll always do this when you turn the engine by hand. It's perfectly normal, and you don't have a problem. smile.gif It's just that with the gear drive, it's more noticeable when rotating the engine by hand.

This won't happen while the engine is running, because of the inertia of the timing set and valve train.

As an aside, you'll also see this effect with the injection pump, as it rotates the head & rotor (pumping plungers).

Jim