Engine/Transmission (1994 - 1998) For trucks that don't hold timing.

[Jeff H]

This is something I was thinking about.

This is related to the timing gear that tends to slip. For some it seams to happen often.

Set the timing to your desire. You will have to pull the gear case cove off. Pull the gear off the pump. Clean all the oil off good. Clean pump shaft too. This where my idea comes in. Stick the gear in the oven. I suppose 300 degrees not to much hotter. Don't want to ruin the heat treat. I'm thinking this will open the hole in the gear a little. To allow it to seat farther on the pump shaft. Once it cools it will clamp on to the shaft a little harder. May want to torque it twice also. Especially after it has cooled down.

I'm just guessing when it comes to the temperature you can heat the gear up. Probably could be hotter?

One thing a may be a little harder to pull the gear off if you do so in the future.

This maybe a little extreme. But it may work?

Would like some thoughts on this or if you have done this.

 

[Jim Fulmer]

I ran into this Friday night for the very first time, put the pump back on once again after working on the push rod cover again (another story) set TDC snugged it up, unpinned the pump ect, then out for a drive. After the first time I got on it it sure felt like a dog and really smoked bad... . gray puke out the pipe, then while I was at the car wash I wondered what the deal was then ding the light came on, never had this problem before, started the truck to leave and WOW were is my 20 degree cackle, got back home and checked the timing and it was off 7/8th's on an inch on the balancer... . 6 degrees or so, reset it noticing that I had the lock washer on back wards (pressing against the gear and not the nut) so I went back over the steps and usual anal fashion re cleaning the gear and shaft then back together it went and it fine now, guess I got complacent in yo-yoing the pump so many times lately..... food for thought!



Jim

 

[JGK]

A friend of mine and I have set timing on trucks 6 or 8 times in the last 6 months and so far none have slipped. The method we use is to liberally squirt brake cleaner between the shaft and the gear once its popped lose using the little tube on the brake cleaner can and then blowing it out with compressed air. We do this 3 times before setting the timing and torquing the gear on.



The most difficult pump to time is the 215 pump on the '98s (mine). Using the traditional method of the dial indicator on plunger 1 of the pump, we discovered (after many frustating and useless hours over 3 days) that when you pop the gear to rotate the engine back to TDC after getting the pump up to the desired lift setting, the pump will rotate backward the equivalent of a couple of degrees in the blink of an eye, which we didn't notice at first. This is due the steepness of the slope on the pump cam and the pressure exerted by the plunger on that cam. Since we weren't catching that, we were actually setting the timing retarded (in more ways than one!). There's a long thread in here about that event where I get to eat crow once we discovered our oversight. Anyway, we learned to compensate and set the timing off TDC.



If you clean the gear and shaft of all oil and torque the nut to spec, slipping is extremely rare.



As for heating the gear, keep this in mind: While it is true, a ring, or torroid, when heated will increase the circumference and theoretically make the hole larger, the metal also expands radially. If the radial expansion is large enough relative to the arc expansion, you may actually shrink the hole. Think of donut dough dropped into the hot oil. As the dough swells does the hole in the center become smaller or larger during cooking than it was as before cooking? Heating will work for rings, not sure for this gear. Maybe.



FWIW,

-Jay

 

[Howard Durand]

Possibly packing the shaft with dry ice prior to placing the gear would be effective.

 

[Scot]

Jay,

Back in my aircooled VW days we heated the steel cam gear and brass distributor gears before dropping them on or off of the crank. It was a press fit but not a taper. I do not see any reason why it would be any different.



I would definitely re-torque the gear.

 

[98rammer]

joe donelly told me how to do it right...



i installed my injection pump, rather than timing from the front but anyways. spray some Mopar *Non Chlorinated* brake cleaner gently onto the pump shaft, and then gently blow dry until it's fully dry. not one problem. remember, if it doesn't hold at 150, then it's probably not going to hold at 170 either.



Tom

 

[CumminsPower98]

I have done 4 trucks and my own twice and have not had one slip that I know of. I did as many have mentioned and hosed the shaft and gear down good with brake cleaner and then blow dry with compressed air. I also torque them to 160 ft/lbs. As far as heating the gear I have no idea if that would work or not. I heat bearings such as rear differential carrier bearings so they just drop on all the time. I think JGK has a good point about the hole possibly getting smaller. - Mark -

 

[fest3er]

Considering the heat method works for attaching train wheels to axles, I suspect it should work for gears as well.

Fest3er

 

[Jeff H]

deep subject

I guess measuring the hole before and after heating it up would probably answer that. Hope someone can try it and see if in deed it does increase or decrece or stay the same?

One thing I worry about chilling the shaft is the formation of dew. But maybe doing both maybe the ticket too? I'm just being extreme here.

 

[JGK]

If you've removed the cover and taken the gear complete off, another approach is to put 3 or 4 tiny marks (about 1/8 inch long) of chaulk on the shaft to add a bit of grit for better grip. This has been discussed here with both pro and con opinions. My only experience with this was when I had my pump removed for bench tuning by a popular Bosch shop. They chaulked the tapered shaft. When I later re-timed my truck, the gear was on really tight. It made quite a bang compared to others when it finally popped off.



FWIW,

-Jay



Scot: Thanks for the reply on the gear heating. Like Jeff H. said, it would be an interesting experiment to check the diameter of the hole before and after heating. Heating obviously works in many cases, just not sure it would in all cases.