TDC/timing

dennhop · **Posted:** Thu Mar 27, 2014 9:05 pm

Does anyone know the procedures for finding TDC or refining one of these motors if either you needed to start from scratch or had no confidence that the previous timing was correct? For the lifenofnme I can't find anything here or online...

mark2m · **Posted:** Thu Mar 27, 2014 11:09 pm

Here are a couple links to the timing belt replacement which has setting TDC.

http://colorado4wheel.com/content/KJ_TB.html

http://www.beesvillebeefarm.com/jeep.html

Hope that helps.

Hexus · **Posted:** Fri Mar 28, 2014 7:02 pm

To find TDC you can either remove the head and watch the pistons, or use the timing pins which are included in any timing set.

There is a timing pin which inserts on the intake side and the exhaust side, as well as one that installs through the flex plate on the transmission if both of the intake pins are installed correctly.

You need the VM.1052, VM.1053 and VM.1085 by Miller. Sealey also makes a set you can pick up from across the pond for about $100.

It's very intuitive and once both of the intake pins are installed you verify that you are 90 degrees past top dead center, even if you still need to rotate the crank another 180 degrees to get the 3rd pin in place.

dennhop · **Posted:** Sat Mar 29, 2014 4:05 pm

so you can rotate the crank even with the cam timing pins locked in place?

papaindigo · **Posted:** Sun Mar 30, 2014 6:52 am

If you want to visually find TDC you don't need to remove the head; you can remove #1 injector but reinstalling it requires a new "O" ring and copper crush washer.

Easier to "pin" it and you need to do so anyway. Remove serp belt, fan/radiator shroud (place cardboard or towel in front of fan during removal to prevent radiator damage and do fan shroud mod for future access viewtopic.php?f=98&t=64278&p=709322#p709322), remove plugs in "pin" holes on both sides of valve cover; rotate engine clockwise only (21mm socket on crank nut WITHOUT pins in place) until the pins can be inserted (you can watch one of the pin holes in a camshaft come by thru the oil filler hole); the bolt holes on the crank should be at 12/3/6/9 o'clock and the dimple next to one hole at 3 o'clock; insert 6mm/1/4" long allen key into hole in flywheel (see 05 FSM for how to - be sure to tap around hole in surface of flywheel to be sure allen key is going into small hole not large cut out); if flywheel pin/allen key won't go in rotate engine once more as it's 180 out. This sets the mechanical timing between the cams and the crank.

geordi · **Posted:** Sun Mar 30, 2014 1:32 pm

Papaindigo has it down for finding the crank pin... IF you are looking to use that.

The biggest thing to remember however is that the cam pins WILL NOT both go in if the crank is not at the correct part of the cycle. The intake cam is the one that I start with. If the intake cam is able to thread in, then the exhaust cam has to be in the correct location. If both pins are in, the crankshaft bolt holes should be 3/6/9/12.

All of this is predicated on the CRD driving itself to the timing job. If it runs, it has to be within 1 tooth of correct. Any more than that, and bad things happen and it will either not run... Or run really really badly.

In my experience, the crank hole is just not worth the effort. If the bolt holes are correct and both pins are in, then it is correct. If the crank holes are NOT vertical/horizontal but the pins ARE in, then loosen the belt and correct the crank - it is a tooth out.

The cams are not keyed, but there is a "keyway" that when the cams are properly pinned, these should be directly pointing at each other. DO NOT USE THE PINS TO HOLD THE CAMS when you are doing anything with the cam bolts! They CANNOT hold any torque. The VM 1085 is the "correct" tool for the job, but the "tooth" on that tool must match up with a valley on each gear in order to properly lock the gear. On each of the CRDs that I have used that tool with, I have yet to find that tooth match up with the tool on a used belt. As an alternative (since you want the cams to be perfectly timed) I have used the "universal cam holding tool" from Metalnerd (Sold at IDparts) to counter-hold against the big torque wrench. Don't use vice grips to hold the cam pulleys to each other... That may not end well. Yes, I have experience with that. That is why I suggest the 1085 and or the counter-hold tool.

Hexus · **Posted:** Sun Mar 30, 2014 8:01 pm

Um, didn't I just say all of that. ROFL.

dennhop · **Posted:** Sun Mar 30, 2014 10:13 pm

It makes me feel a lot better then, about my last timing job...I didn't lock the crank in, but I did use both the cam tools and locked both cams in place that way. Couldn't find the VM cam gear tool anywhere in stock, but I did find a generic one that worked to pin the cam gears together while torquing the bolts on and off. I did have a ton of marks on everything to make sure that it all went back together the same, but I was paranoid about it skipping a tooth...

After 28k miles since the timing belt change, I'm hoping that had I skipped a tooth on the belt change I would have found out by now.
I just ordered a blue tooth dongle and bought the torque pro app in order to check my MAF when it all comes in. I also discovered the Snap On VS Pro does work fairly well on the Jeep, as I was using my buddies today to look at the data....I did discover that I don't seem to be able to pull a MAF sensor reading in anything other than volts. But I mag have been doing it wrong.

TDC/timing

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