C15 cam gear timing question

[Chrisso]

Just replaced a crankshaft in an LHX C15 from a Cat 740. Have gone through timing procedure, mounted front housing and this is where I’m at on the cam gear.



The book mentions if you set it to #6 TDC compression instead of #1 you will be half a tooth out on the cam gear (stops short in saying which direction - half a tooth advanced or retarded).

I don’t have rocker gear installed yet so I could potentially set it up on #6 comp stroke if needed.

Anyone come across this?

Only complicating factor is the cheap aftermarket crankshaft. Wouldn’t surprise me if the dowel that locates the crank gear is out a bit, or the one on the flywheel too for that matter.

Might pull an injector tomorrow and check if TDC is actually TDC, unless someone has a better idea?

 

[Mobiltech]

These cam gears are almost always half a tooth off with no problems.
The cam is what determines number 1 or number 6 tdc and the gear can only go on in one position due to dowel pin so it is irrelevant where the engine is at. If you pin the flywheel the installation of the cam gear in that position will determine that it is tdc number 1. What I’m trying to say is that there is no 1 vs 6 tdc until the cam gear is installed.

“The book mentions if you set it to #6 TDC compression instead of #1 you will be half a tooth out on the cam gear (stops short in saying which direction - half a tooth advanced or retarded).”

When they say this they mean half a turn not half a tooth meaning the divot would be at the bottom.

 

[ahart]

cheap aftermarket crankshaft

This is scary all in itself. I’ve contracted for companies that do things like this, always makes me nervous when they put cheap parts in critical places. But, to them, parts are parts and the only difference is price.

 

[Chrisso]

These cam gears are almost always half a tooth off with no problems.

I feel better knowing that, thanks.

TBH my brain was hurting trying to understand what they mean by this. After I posted I thought about the cam dowel, then thought how is that even possible .




Ahart it's a constant battle. Customer made an informed choice I'll say that much.