TDC timing pin?

[R.E. Miller]

Just a question to see if I'm going to have to build a TDC locator to time my truck or not

 

[Alan Reagan]

I thought the pin went away with the P700 to VP-44 change on the 24 V. On my 12 valve, the pin was too big a PITA so I found TDC with the #1 Valves, marked the balancer and went from there. I'll do the same on the 24V when it's time.

 

[Power Wagon]

For setting the valves, no need to have it all that close.



the TDC pin is not reliable for timing purposes, however, unless you set it... and then you'll notice the engine will still move some with the pin in place.

 

[Alan Reagan]

Power Wagon, Is the pin still there on the 24V? If so, where. The only time I tried to use it on a 12V, it was such a pain, I gave up. A mechanic at Cummins South showed me how to get it to TDC with the valves and a feeler gauge and after that, that, I had the marks so that I didn't have to do that again.

 

[Power Wagon]

It has to be... . That's the only way to find TDC for a backyard mechanic



it would be in the same place. Nobody said it's easy to see, though.



Honestly, I've never actually needed to find one on a 24V. Sorry.

 

[Alan Reagan]

On the 24V engine the timing pin has been eliminated. Now, to find TDC without using the valve lash method, you remove the fuel pump gear cover on the front of the engine. The gear has a mark that is straight up for TDC and doing the first set of valves and straight down for doing the second half of the adjustments.

 

[R.E. Miller]

Thanks for the input guys. I got the timing and valve adjustment things mixed together and see the point here about not needing to be super precise for valve adjustment, but for timing... yes.

 

[paccool]

Power Wagon is right about the pin timing. Wentland Diesel reset mine and it was off about 2. 5 degrees. made a difference in how the truck ran.



There was a post about finding TDC (or close enough) using the valve lash method. I can't remember who the post was from but it was a good one. Was easy to set the valves and didn't need the pin.

 

[Alan Reagan]

Paccool, I agree on finding the precise timing. What I'm saying is on the 24V, I don't think there is a pin anymore. I think we have to use the fuel pump gear mark now. On my 98 12V, the timing was off by 2. 5* based on a bulletin from Bosch and the pin was used to find TDC. On the 24V I have now, I think the pin was removed when the pump was changed to the VP44. I haven't crawled up under there to try to find it but I do not the mark is on the gear on the front of the engine. If I'm wrong, I just want to know where the pin is now.

 

[Joseph Donnelly]

The overvalved engines (24 valve) don't have a timing pin. No need to set timing with the VP44! You will get plenty close enough if you rotate the engine until either #1 or #6 is at overlap meaning one valve just closing and the other just opening the same amount. Then set 1/2 of the rockers per the manual; go to the other TDC where the other cylinder is doing that and do the other 6 rockers. I used yellow paint to mark my crank/tach sensor and the crank dampener to facilitate doing it in the future.

 

[Alan Reagan]

Thanks, Joseph. That's what I thought. I do the same as you. Once I find TDC, I mark with paint so it's easy to rotate 180 and easy to find next time.