6.7 cummins timing gear housing removal

View Full Version : Removing Camshaft timing gear vs pulling cam

Chris H.

01-09-2013, 04:11 PM

Anyone just remove the camshaft gear instead of removing the camshaft and all that is associated with that?

rdsutton

01-09-2013, 07:55 PM

What are you doing?

MAXTORQ

01-09-2013, 08:36 PM

The answer to that is no. There is no way to reinstall the gear once off. If you try and beat it back on you will just knock the cam plug out of the back side of the block.

Chris H.

01-09-2013, 08:52 PM

I guess cummins mechanics have been doing it for a long time using an oven at approximately 300 degrees and it slides right on no problem. No hammer needed, two sets of hands are thou for a moment or two.

We do this at work all the time with bearings and gearsets with ovens and or Eddie current machines.

Interesting.

MAXTORQ

01-09-2013, 08:56 PM

Been there done that.

Oh and the puller cost about 700 bucks.

And I'm not a mechanic either.

Chris H.

01-09-2013, 09:01 PM

So someone would save 400.00 and a lot of time right?

MAXTORQ

01-09-2013, 09:02 PM

Huh not sure I'm following you.

Chris H.

01-09-2013, 09:07 PM

You charge 1100.00 for the repair of a leaking timing case right?

MAXTORQ

01-09-2013, 09:12 PM

Yes I do. Reason for this as its done properly. Not half assed. And I will continue to use the method that has work for years for me.

Chris H.

01-09-2013, 09:21 PM

Cool, just seeing if someone has used it on this site. Sounds like you did and went a different direction.

MAXTORQ

01-09-2013, 09:31 PM

I did. And I'll tell you why.

I used the very tool even still have it. Use to heat the gear and what I've found after three times using it and that technique two jobs where done successfully and one the the plug came out of the back costing me what I paid for the tool.

So cost analysis says to me if I use the tool and the plug comes out it cost me double. So 1400 bucks. 1100 sounds pretty good huh.

So lets say I use the technique on your truck or mine in your driveway and we knock the plug out of the back. Sorry but I'm not yanking a 700 pound tranny on my back.

Chris H.

01-09-2013, 09:38 PM

Yep, that would suck. I'm discussing this with someone. Doing this is a risk analysis that has to be calculated in. Some people are willing to take the risk I guess.

I'll send him your way if he knocks out the plug...lol

MAXTORQ

01-09-2013, 09:39 PM

That's good I like people to take that risk.

Wanna know why?

HerkyBird2001

01-09-2013, 09:41 PM

Because they are going to knock the plug out and you will get the money.

MAXTORQ

01-09-2013, 09:43 PM

Because they are going to knock the plug out and you will get the money.

And who says us Airforce guys have no common sense.

Chris H.

01-09-2013, 09:50 PM

Will do, maybe you should rent the tool out to him as well to help it along.

MAXTORQ

01-09-2013, 09:56 PM

People reading this understand one thing I would much rather you be informed about a project than to make the same mistakes as I did. In this day and age money is at a premium and while I very much enjoy making money, I would much rather you try and save some as well. Trust me I work damn hard for mine and I'm sure you do too.

While knowledge is power, experiance is priceless.

I know a Cummins tech that did that 1 time out on a road job. Says it was a major PIA, had to make a tool to hold the cam in place...but got it done.

He would not reccommend doing that either uless there's absolutely no other way. I agree.

Clunk

01-10-2013, 06:46 PM

Replace a busted gear with camshaft left in place???

Chris H.

01-10-2013, 08:33 PM

Yes Clunk, this is what was posted:

Most Cummins shops no longer remove the cam when replacing the case, cuts about $600 off the bill. By not removing the cam you don't have to take the front end all apart, remove valve covers or fool around with wooden dowels.

After the timing case cover is off turn the engine till the line up marks on the gears are lined up. A high quality three prong puller (Snap On is best) is used to remove the gear off the cam but there is also a special Cummins puller made just for it that works way better. The gear goes back on by heating it and sliding it on to the cam.

The gear can be heated in two ways, 1) Toaster oven, next to the truck so the gear does not cool down: 2) Propane space heater, one that can have the elements turn up like a grill. Set the temp around 300 F. The oven is the easiest way, depending on the oven it could take 30-45 minutes to heat up, in the meantime you can clean some parts. The propane heater is faster about 10-15 minutes.

You need an extra hand for a few minutes to hold the cam from moving back and pushing out the rear cam plug. The cam is held by removing the fuel lift/transfer pump (don't drop the pump actuator arm into the crankcase!) and using a pry bar on the cam lobe, apply a little force to move the cam toward the front of the engine. The cam can move slightly but all you want is the cam not to move back when the gear is going back on. Once the gear is up to the temp, the crank and cam timing position has been set, someone is holding the cam from sliding back, you then grab the gear with high temp welding gloves and slide the gear back on, sometimes might have to tap it back with a plastic mallet or dead blow hammer but never with a steel hammer. I've done this three times and never had to use a hammer, the gear slid right on.

I would only recommend this to someone with mechanical experience. Sounds a little complicated but is way easier. There are three draw backs: 1) gear cooling down half way, then you have to wait 10 minutes to cool and remove it again to start all over; 2) Not aligning the crank and cam; 3) Allowing the cam to move back and pushing out the rear cam plug, then you will have to pull the engine.

Some people think this method causes a weaker fit for the gear but Cummins has been using this method exclusively for several years, I've never heard of a problem

CaptainCummins

01-10-2013, 09:24 PM

I would rather pull the engine apart than try to heat the gear, Heating gears is a pain in the ass, and you really only get one shot to get it right, or you have to pull the gear back off, and if it gets cocked sideways, its even worse. I like the rear gear train ISB's, three bolts and the gear falls off. I did a crank gear on an ISX, that was a total Pain in the ass. Had to cut the old gear off then heat and it on right the first time, or you were cutting a new gear off and ordering another one :O

If ya ask me, messing around with the dowels is pretty easy compared to messing with a puller.

MAXTORQ

01-10-2013, 09:29 PM

Dowels are really only used in the 3rd gens. No side cover.

The earlier trucks the cam followers can be held up with 3/8th hose line clamps.

Another reason I don't like heating the gear is it aneals it. Makes the gear brittle.

You still have to heat the gear to get it on the cam. I've had a few in my day that were heated, then only went about 2/3 - 3/4 on. Block of wood & a BFH to get it to seat.

carom

01-11-2013, 01:33 PM

how would all this discution apply to a 3rd gen ?

ScottRacing

01-11-2013, 07:17 PM

From what I'm gathering, the third gens use a bolt on cam gear, and the reason they're replacing the cam gear is bc of a dowel pin that falls out and into the cam gear on 12valves and I believe some early 24 valves, as far as I know. I've owned two 12 valves and it fell out on both of them, one before I owned it, and another while I was driving it.

MAXTORQ

01-11-2013, 08:08 PM

There all press on gears. No retainers other than the thrust plate.

The dowel pin is the KDP and can fall out on any of these trucks.

The discussion started out as how to replace the rear gear case gasket. Some choose to remove the camshaft. Other choose to remove the gear only. The gear or the cam assembly must be remove to facilitate the gasket replacement.

Now before some of you nuck nucks ask why. Re read the entire thread.

Clunk

01-11-2013, 09:15 PM

Yes Clunk, this is what was posted:

Most Cummins shops no longer remove the cam when replacing the case, cuts about $600 off the bill. By not removing the cam you don't have to take the front end all apart, remove valve covers or fool around with wooden dowels.

After the timing case cover is off turn the engine till the line up marks on the gears are lined up. A high quality three prong puller (Snap On is best) is used to remove the gear off the cam but there is also a special Cummins puller made just for it that works way better. The gear goes back on by heating it and sliding it on to the cam.

The gear can be heated in two ways, 1) Toaster oven, next to the truck so the gear does not cool down: 2) Propane space heater, one that can have the elements turn up like a grill. Set the temp around 300 F. The oven is the easiest way, depending on the oven it could take 30-45 minutes to heat up, in the meantime you can clean some parts. The propane heater is faster about 10-15 minutes.

You need an extra hand for a few minutes to hold the cam from moving back and pushing out the rear cam plug. The cam is held by removing the fuel lift/transfer pump (don't drop the pump actuator arm into the crankcase!) and using a pry bar on the cam lobe, apply a little force to move the cam toward the front of the engine. The cam can move slightly but all you want is the cam not to move back when the gear is going back on. Once the gear is up to the temp, the crank and cam timing position has been set, someone is holding the cam from sliding back, you then grab the gear with high temp welding gloves and slide the gear back on, sometimes might have to tap it back with a plastic mallet or dead blow hammer but never with a steel hammer. I've done this three times and never had to use a hammer, the gear slid right on.

I would only recommend this to someone with mechanical experience. Sounds a little complicated but is way easier. There are three draw backs: 1) gear cooling down half way, then you have to wait 10 minutes to cool and remove it again to start all over; 2) Not aligning the crank and cam; 3) Allowing the cam to move back and pushing out the rear cam plug, then you will have to pull the engine.

Some people think this method causes a weaker fit for the gear but Cummins has been using this method exclusively for several years, I've never heard of a problem

Thanks Chris!

ScottRacing

01-11-2013, 10:29 PM

9 beers in and nuck buck is cracking me up!

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