Oh No Need Help

[Mikeandwendy74]

Hi just took apart front of motor to swap in a new double roller timing chain, need your help on an issue. When installing the cam sprocket and crank sprocket where should the timing marks be? I read people put the timing marks at= crank 12 and cam 6 is this right? the keyway on my setup is telling me different. if I put the new gears on the keyways will be forcing me to have the crank at 12 and the cam at 12 also, unless the guy who had this truck before me installed the old chain incorrectly please help wanna finish project today thanks in advance.

[JeepSJ]

Since the cam spins at half the speed of the crank, it really does not matter if the cam is at 12 or 6. If you do install it with both at 12, spin the crank 1 revolution and the cam will then be at 6 and the crank will be back at 12.

[Mikeandwendy74]

AHHHH so your saying install the gearset, even though the marks will be cam at 12 and crank at 6 then turn align them then install the other gears?

[Robyn]

The cam and crank sprocket marks must align with crank at 12 and cam at 6 so they look at each other.
The pump drive gears also must look at each other.

Anything other than this is gonna produce serious frowns ;0(

[RoverIIa]

Before you take off the old chain, reconnect the IP gear, then turn the crank by hand until the CAM / CRANK gears line up. Then remove everything, install the new, and put it all back together just as it sits.

I just went through a 180 out situation on my 6.2 with a gear drive. I still haven't resolved it fully. Trust me... you do NOT want to deal with this.

good luck!

[GSE2SCHMIDT]

So basically everyone is saying just one crank revolution....either way from #1 cyl being top dead center....correct?

Are 6.5's non-interference engines?......oh my tummy hurts

[RoverIIa]

The valve rings in the top of my old pistons would suggest that 6.2 engines are interference engines. The cracks in same pistons would seem to indicate that the interference will work itself out in time... :D

The shop manual, and haynes diesel book, both say to set up the crank timing with the #6 piston at TDC compression. Line up the crank / cam marks, install chain or gears, then rotate crank 1 turn before installing IP drive gears.

I managed to not read that correctly the first time, spent a lot of time establishing #1TDC, and proceeded to get to take my engine back apart when it refused to run.

** Read it for yourself before taking any drastic action based on what I have typed here! **

[Mikeandwendy74]

Here's what i found, if you align the pump to camshaft timing marks, injection pump gear at 6 and cam at 12 then the other 2 marks for the crank and cam are both at the 12'oclock position, forced this way by the keyway on both shafts. After setting the injector pump line for line, I still have a white smoke condition, alot more when its cold it goes away as the motor warms up. Not completely gone when I hammer it I still see a good blast of smoke. I have new injector nozzles that I am in the process of setting pop pressure on, we'll see if that helps I know the first injector nozzle after a rebuild with the shim that was inside the injector it didn't want to pop any earlier than 2300 psi. I got that one down to 1900 but I was impatient and slapped em back in after the timing chain to hear it run. Pop pressure set too high must have a retarding effect on the timing. We'll see what happens tomorrow.