Engine/Transmission (1994 - 1998) Where the Hell is the Timing Pin?!?

[Sasquatch]

I've got all the tools to do a valve adjustment, but I guess not "the smarts". I've spent the past twenty minutes (okay, half an hour... ) crawling all over the engine spaces trying to find the "timing pin" and/or the hole in the "bellhousing" that the barring tool is supposed to fit in.



Somebody put me out of my misery, please.



I've looked around/under the injection pump on the back of the gear housing and don't see anything that looks like the picture in the manual depicting the timing pin (one showing hand with finger extended pushing pin). Ditto the plug-covered hole in the bellhousing: where the hell is that sucker. . ?



Also, as a final indication of my incompetence, I can see a white mark on the underside of the 'Crankshaft pulley' (same as "balancer?") but can't see a corresponding mark on the engine/gear cover, though there is a mark on the bottom of the fan hub. Am I supposed to bar the engine over until the white mark on the crankshaft pulley aligns with the white mark on the fan hub?



Can I trust the previous mechanic's marks, or do I need to insert the timing pin (that I can't find) and make my own, new marks?



Thanks for whatever advice you can offer.

 

[Joe G.]

Look low on the passenger side bell housing for a rubber plug about two inches in diameter. That's the barring tool hole.



The timing pin is beween the injection pump and power steering pump on the back of the gear case. It's such a PITA to deal with that I never use it for valve adjustments. Turn the engine until both valves on #1 are loose and both valves on #6 are tight. That is TDC on #1. The opposite situation is TDC on #6.

 

[Sasquatch]

Hey, Joe,



Thanks for the response.



I found the timing pin by laying underneath the truck and shining a light up; no possible way to see that thing from the topside.



I removed #1 valve cover and barred the engine around using a 7/8" socket and the alternator nut. I watched the intake and exhaust valve rocker arms and noticed that they both came identically horizontal as the white mark on the crankshaft damper came up to "12 O'clock" when viewed from above. There are a couple of problems, though, as I tried to follow the instructions on pg. 44, TDR issue #29. First, the instructions call for marking the "crankshaft dampener to the engine oil pan". I think the author meant the timing gear cover, as the engine oil pan is nowhere near where the top of the crankshaft damper is. Second, there is already a mark, from a previous valve job on the damper, but there is no corresponding mark on the gear cover.



When looking at the rocker arms over the valves on #1, they both look horizontal, but the exhaust valve looks to be very slightly higher, say 1/16" of an inch. The exhaust rocker arm has lots of play, but the intake is rocker is a little tighter.



Anyway, with the with the white mark on the damper at 12 O'clock, I located the timing pin and tried to push it in. It went in on the first try, but only about an eighth to 3/16" of an inch. I'm not sure how much of the pin is supposed to go into the hole, so it's tough to tell if I've located official, by the book, TDC or not.



Have you ever successfully gotten the pin pushed into its engagement hole, and, if so, how far does the pin travel when properly seated?



Thanks.

 

[Joe G.]

My timing pin was so stiff that I gave up trying to use it for valve adjusting. Later on I made a tool to replace the timing pin out of a copper bolt. It sticks out a couple of inches to I can get a good grip on it. Anyway, I only use it to locate TDC for pump timing, not valve adjusting. I didn't notice how far it went in. I was slowly turning the engine with a barring tool until I felt it click into place. That is using the tool I made. I don't think I could feel my plastic pin do anything because it's so stiff. Like I said above use #6 to locate TDC for valve adjusting on #1. Looking at the rocker arms is not a good way to do it. Better to test for slack with your fingers on #6 and find the small overlap point where both rocker arms have no slack.

 

[Cooker]

Wow if you got the timing pin to push in on the first try you are having some good luck today. It is a very tight fit and even after marking the dampener I still need to wiggle the barring to back and forth a bit to get the pin to push in. You are correct though that the nipple on the pin is only about 3/16 of an inch so it will not push in any more than that.



I agree the timing pin is pretty stiff and difficult to feel the engagement. To get it to work better I pull it out and remove the orings. It moves much easier then.

 

[rjones]

must be nice to have a pin... some yo yo who had my truck before me not only broke the pin off inside the engine he broke the part thats on the outside..... I tried for hours to get that darn thing out, so I can put a new one in... I gave up.....

 

[bighammer]

You don't need to use the timing pin for valve adjustment.

 

[Sasquatch]

Cooker:



I have no clue what I'm doing, so I'm not sure that the timing pin went in like it was supposed to.



I barred the engine around until the white mark on the damper (is it "damper" or "dampener"??) was at 12 O'clock, but that was just my best guesstimate, because there was no corresponding white mark on the gear cover, nor any other alignment mark. I stopped when I thought the white mark was straight up and down. Then I found the pin in the back of the gear case housing, and, after scraping most of the skin off my left arm, managed to reach up and push it. There was some resistance, then it popped forward about a 3/16", and I had no way of judging whether it had "gone home," because I'd never tried to push it in when I knew it wasn't in the TDC position.



It's possible that the mechanic who timed/adjusted the valves 60,000 miles ago simply didn't push the timing pin in far enough in its storage position, but it felt like I was pushing it into a snug hole, so I'm hoping I'm lucky. I'm going to take the #6 cover off tomorrow (got distracted, today) and see if, as Joe G says, the #6 rocker arms are tight.

 

[Joe G.]

Sasquatch,



Just so you know what is going on. The firing order for an inline six that turns in the normal way (some marine engines turn the other way) is 153624. So you have three sets of "companion" cylinders. 1 - 6, 5 - 2, and 3 - 4. When a cylinder is at TDC to fire both valves are closed (rockers loose). The companion cylinder has the exhaust valve closing and the intake valve starting to open. Depending on the cam shaft grind, both valves will be tight or loose. If it is not exactly on TDC one valve will be loose and the other tight. The "same" point is pretty small on our engines so TDC is really close. On most engines you can't do half of them at a time. In that case you do them in the firing order and use the companion method to find TDC.



The best way to find TDC exactly with the head on the engine is to use the drop valve method. I did that to check out my timing pin. It's right on for me. I marked the damper and the timing case so all I have to do now is roll it over until the marks are lined up and the valves are loose on #1.

 

[Sasquatch]

Joe G.



I toot all the covers off, and #6 rocker arms are super tight; they have no movement at all. #1 intake rocker has a very miniscule amount of play, and #1 exhaust has a lot of play. All the other valves in the diagram correspond to the amount of movement that you'd expect with #1 at TDC. The exhaust valves on #1, #3, and #5 are loose, as are the intakes on 1, 2, 4.



I'm pretty sure that I must be at TDC and ready to do the adjustment.



The next problem is that the Cummins "Performance Tools" Valve Adjustment tool set includes a set of feeler gauges that don't correspond to the tolerances called for. The kit includes a KD barring tool, two box-end wrenches, a stubby screwdriver (for getting to #6), and a basic ratchet set w/1/2" drive.



The included set of feeler gauges has 25 metal paddles which graduate in size from 0. 04 mm to 1 mm. The specs for valve lash are: exhaust . 508 mm and intake . 254 mm. The included metric set doesn't have those gauge sizes. The nearest it has is . 50 mm and . 25 mm.



Is it okay to use feeler gauges that are off by 4 and 8 ten-thousandths of an inch? Seems strange that Cummins would bundle a set of feeler gauges together with a set that includes a laminated instruction sheet, a KD barring tool, and metric feeler gauges that don't include the right size gauge for the adjustment.

 

[Sasquatch]

Joe,



Another question/observation. I just got back from Pep Boys, and tested the valves on 1, 3, 5. All the exhaust valves gap perfectly, or at least as far as this inexperienced mechanic-wanna-be can tell. I used the feeler gauge (. 020) to test the exhaust valves, and all of them feel "resistance" when inserting the feeler. With the feeler inserted, the rocker arms have no movement, and the gauge doesn't feel super tight or loose, either. Just right. All the intake valves, on the other hand, are tight; they won't admit even the point of the . 010 gauge, though I didn't try too hard to force it.



From what you've read so far, does this sound about what you'd think would be "normal" for a valve adjustment, with #1 at TDC?

 

[Joe G.]

The intake is . 010" and the exhaust is . 020" if you use standard feeler gauges instead of metric.

 

[Joe G.]

Oops, you were back before I finished my answer so you know about the . 010 and . 020. The feeler gage should rub but not be real hard to move. It's a matter of feel which can be kind of awkward on cylinders #5 and #6. The valves tend to tighten up on these engines as far as I can tell. They did that on mine. That may be caused by the valves seating in the seats in the cylinder heads. I don't really know. The last time I did mine I had a couple that were a little loose, but not too bad. That was about 50K miles ago. I really should check mine again before too much longer.

 

[Dull Pain]

Sasquatch - Appreciate your self-deprication, but I think you know / have more experience than you are willing to admit. Good advice from others. Keep plowing ahead.

 

[Sasquatch]

DullPain:



Finished the valve adjustment and took the truck for a spin. I couldn't tell any difference at all, which means I'm home free (knocking on wood), and glad for the experience. I was anxious, because I work out of this truck, and couldn't be without it if I screwed things up.



I found that the #6 exhaust was a little tight, and three of the intake valves were a little tight, too. Nothing was way out of spec, but I could tell that it'd been 60,000 miles since the last adjustment, and that's probably the outer limits of how long you'd want to wait. One of the things I found, that I hadn't realized, is that three of the six valve cover gaskets had become brittle and cracked around the bases. All of them were slowly seeping oil, which I hadn't realized. I replaced these old, gray gaskets with new, Cummins black gaskets.



I'm glad I made the effort to do this, and appreciate everyone's patient responses.

 

[Turbo Thom]

SQ... ... ..... Why all the frustration? Just a phone call is all it takes. You can be talked through it like a walk in the tulips. I guess you like typing. Garmon's Diesel or Turbo's Custom Truck. It's that easy.



. . Preston. .