Engine/Transmission (1994 - 1998) Setting timing, but the gear keeps slipping - Help!

[Jim Fulmer]

His final solution was, after snugging the nut to 20 or 30 lbs, to put the socket on the nut up against the gear and smack it with a 3 or 4 lb hammer.



Piers is a freakin cowboy, you either love him or hate him... ... as Rodney Carrington said... God Bless that Man!..... LMAO.



Jay, Joe and Chris are the type of people that make the TDR, just help or input, no *****ing. I hope all can learn from this thread as I have.



Jim

 

[Sled Puller]

Do this, do that, ah hell, just whack it with a hammer a few times!! Now that is my kind of science!!

 

[JGK]

LMAO!

Piers is a freakin cowboy...

Yep! A crack-up to talk to. And I'm glad as he!! he's there.

Do this, do that, ah hell, just whack it with a hammer a few times!! Now that is my kind of science!!

Exactly. And, hey, isn't that what working on trucks is all about?



Scrubbing up for surgery...

-Jay

 

[JGK]

Quick update

We checked the timing first thing this morning and yes, it had slipped from Thursday's efforts. So we pulled the gear, sprayed, blew, and cleaned 3 times, reset, and banged the gear with a hammer as Piers suggested. Buttoned it up and started it. Let it idle for 4 or 5 minutes and shut it down. Then checked the torque on the nut. No change. Started it up and rolled in to the throttle slowly. It was good to about 1400 revs, then blubber/stumble and all kinds of white smoke. Nuts



So we pulled the gear cover and checked things out. On the good side, everything looked very nice. Our cleaning process seems to be quite successful. Also, no apparent gauling or other contamination. On the down side, there doesn't seem to be any thing there that would give it reason to slip.



We discovered to our surprise there is a key way cut in the shaft. The inside if the gear had a very slight imperfection we could just barely feel with a finger that matched the location of the key way. The shaft had no imperfections.



We dressed the shaft and the inner surface of the gear lightly with 1500 grit sand paper, with special attention to whatever we could feel in the gear due to the key way. I placed 5 or 6 little chalk marks on the shaft for grip, put the gear on lightly, and replaced the cover. We are all ready to set timing and try it again, but since it was after 10 PM and we are both bushed (my friend and his wife went partying until the wee hours this morning, so he's not 100%), we decided to wait until tomorrow morning.



One thing: A VERY big THANK YOU to Joe Donnelly regarding checking the seating of the dial indicator on the plunger. We were amazed at the change in reading we got by lifting plunger shaft up and setting back down. We learned quickly that after every change in the dial, to tap the knob on the top of the shaft lightly to re-seat it. We will be re-checking the timing on my friends truck when we finally get mine done just due to this one point.



Time for bed.



-Jay

 

[Reb.B]

Hey Jay, did u try the lock tight? i didn't think so. It only takes a sec and u won't have anymore problems. I have used it and have never had a problem since. Use the red, install and torque immediatly, and let it sit for a hour, then drive it. that thing ain't gonna slip. Take it for what its worth... one other thing, tapping the gear on when u are torque the nut down, is a very good idea and should be done any time u change the timing. If u find that the timing wants to move alot while torqueing the nut down, do two things, . . have somebody put even pressure on the barring tool and lock the pump in place by loosening the two nuts on the side of the pump and putting the plastic piece in the right spot, then tighten the nut down. This will help with the little movement. Also make sure u're at TDC 1, i pull the first injector, but if u have no injector washers available then don't do this. One other thing, ... u didn't loosen the two nuts on the deliver valve holder did u? if u did, and they moved at all, u could be SOL. By loosening the holder and turning the barrel, u could get a blubbering too. Oh one more thing, make sure all the slop is taken out of the gears before u torque the nut. Need to finish with the engine going clock wise, the torque the nut.

 

[JGK]

Reb. B



We didn't try the Loctite. First, at least yesterday, we couldn't get back to TDC with the gear cover off since the damper is off, so we didn't torque the gear down. Just put it in place and put the nut on finger tight. We started the tear-down at TDC, but the pump wasn't set to where we want it since we knew we'd be messing with it. So using Loctite would have to wait until we were ready to set timing with the case back together. I guess we'd just squirt some between the shaft and the gear with the nut off, eh?



Second, I think it was Al and one of the Bosch shops that recommended against it. The didn't feel it would help. However, if this thing slips again, I'm ready to try just about anything! I do have a tube of "red" in the drawer.



No, we didn't loosen the nuts on the pump. I know about those from watching the Bosch tech test/tune the pump.



The timing moves very little when torqueing the nut. So other than holding the barring tool, nothing else seems to be needed.



Yes, all slop is taken up between the gears before we torque it down.



Thanks for the input. We're going to give it another try in a few hours after things warm up.



-Jay

 

[Reb.B]

Well i'm not going to argue with what AL has to say, he's a great guy, and very helpful with anybody who calls, ... but all i can say is, it has worked well with me several times. The best way to do it is to pull the hear cover off and do it, but in a pinch, u can do it by putting between the gear and shaft, just pull the gaer back as far as u can to get more clearance and try to get it clean as can be before putting it in. Curious to see what happens with the chalk.

 

[Joseph Donnelly]

I recommend not using Loctite.

Here is an example: many of you have a drill press, and realize that the chuck is held into the spindle solely by a Morse taper fit(and a large bit is directly held that way in many presses). We usually keep the chuck in by tapping on it with a block of wood to jam it into the tapered hole in the spindle. With no more "press fit" than that, how many remember slipping the taper vs. stalling the press if you bear down too hard while drilling something. Right, the press stalls, the taper fit doesn't slip.

It's hard enough to crack loose the gear from the P7100 without adding Loctite.

I talked with JGK today and it appears that the pump was jumping back 2mm on cracking off the gear and he just didn't notice the change on the small dial before. This points out how easy it is to have a problem, and how hard it is to find it over the internet because the key observation was not made/reported. Best wishes to JGK for solving his problem today.

 

[TurboSandman]

I'm way out of my sphere of knowledge here, but your air pressure line doesn't happen to have a lubricator like for an impact wrench, does it? That might introduce some oil when you blow the degreaser out and make it more likely for the gear to slip.



Just a thought; probably not the answer. Hope it all works out.

 

[JGK]

Success, but not without it's cost!

First, let me thank all of you who provided input into this situation. The TDR (i. e. you members) are a priceless resource.



Second, let me sheepishly declare WE SCREWED UP! Yes, a programmer and an aviation mechanic are not infallible. We both should have known better. As Joe D. said above, much to our astonishment, when we popped the gear off after getting the pump up to our desired setting (about 5. 58mm of lift on the dial), the needle wasn't moving back just . 1 or . 2 mm, but a full 2 millimeters plus . 1 or . 2. 2 mm is a full revolution of the dial, but it happens so fast our eyes didn't see it. Only today, after 6 or 7 attempts since last Wednesday to set the timing, did we notice this. One of us just happened to look after it jumped at the smaller, inner dial that marks off full millimeters and noticed the big change. Da#@ that little dial It took a couple more attempts and a conversation with Joe by phone before it began to dawn us that this extreme change was occurring every time we popped the gear.



It even happened when we torqued the nut to only 2 ft-lbs, which was adequate to move the pump to get our desired setting, then popped the gear. Apparently, the ramp of the cam is so steep at that setting that simply breaking the gear loose from the shaft allowed the pump to rotate backward that much in the blink of an eye (4 eyes, actually).



What we finally realized was that in each case the pump timing was retarding itself roughly 2. 1 mm from our desired setting, only we thought it was simply . 1 mm +/-. We would then compensate for the . 1 or . 2 mm change, reset TDC, and torque it down. We found that when it "slipped", it was slipping by about the same amount each time, down to about 3. 5 or 3. 6 degrees. Note that this is roughly our desired setting minus the actual jump of the pump. So when the truck didn't run right off idle, it wasn't due to slipping, but just retarded timing (and 2 *mumble* "mechanics").



Anyhow, since we couldn't get the pump to stay put at 5. 58mm, we finally set it to 3. 5mm at TDC, a setting that would hold when we popped the gear. We then rotated forward to our desired lift of ~5. 58mm and measured the distance from TDC the damper moved to get there. Back at TDC and 3. 5mm of lift, we popped the gear, rotated backward (retarded) by the distance measured on the damper, snugged the gear on, then rotated up to TDC. After about 3 attempts, we had it. Torqued it down, buttoned it up and started it (after a brief prayer). It ran just like it was meant to



Our costs: 2 evenings and 2 full days in the garage, 1 gasket and seal kit, a trip into the gear case (KDP was jigged last summer and in its place as expected), and a lot of frustration.



Our gain: well, beside my timing up where I want it, a whole lot of experience on timing these things and what it takes to pull the case cover. We also found our process of cleaning the gear and shaft to be quite adequate - 3 or 4 rounds of brake cleaner and compressed air. I will be quite prepared for the next one.



BTW: 150 ft-lbs of torque is all that is needed to hold this gear on (in most cases anyway), just as Joe said. Listen to the voice of experience (his).



TurboSandman,



I don't have a lubricator on my compressor, just plain ol' air. That seems to work just great. Thanks for thinking of it though.



OK, what's next... maybe a ported head! Hmmmm... .



Calling it a night,

-Jay