jb_five

I was using the timing pin to locate TDC and once the pin engaged i couldn't get it to come back out. I put a socket on the alternator and tried to wiggle it hoping the pin was just bound up in the hole a bit. Well I ended snapping the pin. Tried pulling the pin housing off but I guess the previous owner stripped the heck out of one of the Torx screws.

If I pull the front of the gear housing off will I be able to pop it the pin out from the front?

Montana2x2

The plastic pin is held into the housing with a star washer sort of thing that is held in with tension. If you pull on the pin hard you can pull out the washer thingy. I do not know if you can get the broken piece of the pin out by just removing the big part of the pin or not. To replace the pin use a deep socket to push the star washer back into the housing. If I remember right there is a groove that it sets in. Whenever I need to use the timing pin I pull it out and clean it so that it moves easily.

jb_five

Thanks... I'm pretty sure that star washer is already gone because I could pull the pin completely out before I located TDC and it got stuck there. I cant get vice grips on the broken pin, I'm going to try to run a screw into the pin and see if that will work, I just can't really get my drill into that tight location. The only other thought I have is to take the front of the gear housing off, but I'm not sure if I can access the pin from that side.

torquefan

Maybe try heating up the end of a paper clip red hot and pressing it into the broken piece of plastic. Once it cools, it may be attached to the plastic well enough that you can use it to pull it out.

dan123dbl

I had trouble getting my pin out a few times too. I have a small set of vise grips that I clamped on there, and used a big screw driver to pry against it using the timing cover for leverage.

However, that'll only work if you still have a bit of meat left on the pin to get a hold of it.

j_martin

The timing pin is a dirt magnet. Any time I use one, I first pull it and clean it, and wipe out the bore as well. Then it's finger operation from there.

You need to get the pin out, then maybe a clean new one will push the vestigial "tit" out of the pump gear. It'll fall to the bottom of the gear case harmlessly. If not, you may have to reach in with a long pin punch and tap it through.

After the coupla fights I've had, and seeing this thread, I think I'm going to find a CaPlug to seal the bore, and put the pin in the tool box.

Jim Lane

I just serviced my timing pin when I had the side open, the only thing inside mine was an o-ring, also not sure but there might be small ledge inside the bore so the pin does not back out.



I had to take it out as an assembly to get it apart, I did not want to break it by prying on it.



I cleaned and lubed it and installed a new Cummins square ring to seal it.

Jim

BC847

Since it's only me messing with the engine, I just pull the thing out and using a dentist's mirror, visually center the little hole in the big hole.

bigragu

I am surprised no one ever discusses the "companion" method of obtaining TDC when adjusting valves. It works, it bypasses the use of the timing pin, and is a one man show. Back in the day when our trucks were new, I remember my neighbor and I would help each other do our valves and you needed one guy to do the barring while the other contorted himself and ended up with cramped and bruised finger tips applying constant pressure on that pin. I've found out that the dealer mechanics that specialized in the cummins used the companion method to adjust valves

Jim Lane

Not bad idea as long as you can remember where you left it.
There has got to be something you can use the hole for, a photodetector for a tach signal?

Will a transom plug fit?

jb_five

Thanks for all the replies. The timing pin would not budge out of the bore. I drilled a screw into it, heated up a pick nothing worked. I ended up having to pull the injection pump and power steering/ vacuum pump to get a clear shot at the timing pin housing. Both torx screws were completely stripped so I cut a slot with a Dremmel and used a screwdriver and punch to get them backed out. I think j_martin is right you need to clean that pin up real good! After I got the housing off that pin is absolutely stuck there is no way it's ever coming out. I have a new one ordered.

MARF75

Yup, companion method is what I did 3.5 yrs and 32,000 miles ago after the timing pin wouldn't budge.

BigIron70

I broke my fair share of timing pins when I first started wrenching on Cummins diesels back in the day. I always used a air blow gun to get broken piece out, worked every time. Air would get behind pin and would blow the broken piece out. I always mark the harmonic balancer once TDC is found, I also have used the opening of the exhaust valve on #2 cylinder. Once the valve has fully opened rocker is completely down you are at TDC #1 cylinder.

12 Valve engine

Setting valve lash using the companion cylinder method.

There are many ways to adjust valve lash on a 12 engine. The following method I believe is an easy an accurate method and only requires you to remember one thing to be able to set valve lash. If you can memorize which cylinders are companion cylinders, then you will be able to use this method without charts or illustrations.

Each cylinder in the inline 6 Cummins has a companion cylinder. This means that at any time two pistons will be at the same position within the cylinder. The companion cylinders are:

1 and 6
2 and 5
3 and 4

So when # 1 is at TDC so is # 6 and so on.
One of the cylinders will be in valve overlap, and the other will be at TDC on the compression stroke.
Valve overlap is when the piston moves up and forces exhaust out, at the top of the stroke the intake valve will open and allow fresh air to enter the cylinder for a brief period before the exhaust valve closes. This helps scavenge exhaust from the cylinder and cools the back side of the exhaust valve to keep it from overheating and being damaged.
When any cylinder is in valve overlap, both intake and exhaust valves can be adjusted on its companion cylinder.
This is how to do it:

Once you have the valve covers off rotate the engine to the right as viewed from the front. (Have your ratchet in tighten, make sure truck is in neutral)

I use the 30mm nut on the front of the fuel pump to rotate the engine. (P-Pump 12 valve) This nut can be exposed by removing the oil filler tube assembly from the gear case. It is easy to unscrew no tools necessary.

You can start with any cylinder but lets start with # 6
Watch # 6 exhaust rocker arm (the exhaust rockers are the longer rocker arms toward the back of the engine) as the exhaust valve starts to close watch the intake valve carefully. As soon as it moves you are now in valve overlap on # 6. Set both the intake and exhaust on # 1. Perform the same procedure now watching # 1 cylinder. When it is in valve overlap, set both intake and exhaust on # 6.
Repeat the procedure for the rest of the cylinders.

2 and 5
3 and 4

I am sure most of you guys already knew this, but just in case someone was unsure, I hope this helps.

j_martin

Companion cylinder valve overlap is the easy way to be sure that both valves on the other companion are on the flat side of the cam, but I don't think it's accurate enough to determine TDC within a degree for injection timing purposes.

The visual concentric alignment (Lookin' in the hole) would be, however.

jb_five

I think even though the new timing pin housing I bought comes with two new torx screws. I'm going to go to the hardware store and see if I can match up a hex head bolt for the housing instead. The back bolt near the block is just to hard to get to, and too easy to strip with the very little room you have to work.

J_martin, the visual method seems like a good idea, but how the heck are you able to see in that hole??