w250_93

Ok so my engines had a lope to it for like 40,000 miles an i thought it was just because i had big injectors but it got a lot worse last spring an i just kinda gave up on it an drove it an put up with it. Well i recently started trying to figure out whats wrong with it, i did every test you can think of to start ruling stuff out like leak down, compression test, switching injectors around an so on an everything was alright so i started leaning towards a cam. While the engine was running i pulled the front 2 valve covers, the exhaust push rods were spinning just fine but the intake push rod on cyl#1 was turning really slow an the push rod on cyl#2 wasn't turning at all so i decided i needed a cam an set of lifters.

Yesterday me an a buddy started taking it apart. When we got the front cover off i immediately noticed that the cam gear had walked forward on the cam an had started rubbing on the timing case cover but the key wasn't sheared the gear just came forward off the cam, well we both scratched are heads wondering how that could even happen an then moved on to pulling the cam. After the cam was out we couldn't find anything wrong with the cam other than some pitting on the lobes so its getting replaced, next we pulled the intake lifter on cyl#2 an it looked brand new. So we figured since the gears are helical cut an the gear moved forward it threw the timing off causing the lope but it didn't explain the push rods not turning but im going to replace the cam, gear an lifters, i would like to replace the cam bearing too but i dont know if it can be replaced from the front or not.

Do any of you guys have any info you can share about replacing the cam bearing?

Thanks in advance an sorry for the long thread

jimbo486

Sort of a common issue with Cummins cams. Thus, the reason for Hamilton Cams offering a bolt-on cam gear with their cams.

Which cam bearing are you referring to? The thrust bearing just behind the gear?

93flatbed

So the gear came off of the cam or the whole assembly walked forward? I've read that high rpm p pumps will walk the gear forward and take out the thrust plate. I do believe they make an updated thrust plate out of billit to help with the problem.
As to why the tubes weren't moving; were the valve adusted right? Measure all the push tubes and make sure they are all the same length.

w250_93

I was talking about the cam bearing in the cam bore not the retainer. No the retainer was fine, the cam gear came off the cam not completly it moved forward enough to rub the case cover, the cam was where it was supposed to be it didn't come out of the motor. I know the valve lash was fine, I've ran the lash probably a dozen times trying to make sure I had it right over the last year so I know it wasn't that. As far as the push rods I couldn't see anything wrong with them as far as visual inspection, I'll check the length on them before I order any new parts. I did do a p-pump swap so it could be what caused it to walk off the cam but I only have 3000rpm gov springs so it's not a high rpm engine.

w250_93

I've read a couple post that they make a cam bearing tool that you can remove the bearing from the front of the engine unlike traditional cam bearing tools that you have to pull the motor so you can go through the back of the motor too push the bearing out I was just wondering if anyone has used it or knows where to get it

j_martin

I would think you'd be able to get it with an inside bushing puller on a small slide hammer.

w250_93

Yeah something kinda like a rubber plug the kind that you can tightnen a bolt on the back side of an it expands an then rig a slide hammer to it. Then use a seal driver to put it back in.

93flatbed

If you could knock it back wouldn't you be able to pull it out threw the tappet cover?

w250_93

Yeah probably could, i never thought about that.

You guys know of any cams other than Hamilton that I should look into

93flatbed

You should confirm that before you go off knocking it inside of the engine.
There are others who make camshafts, but he is the guy everyone uses. And I don't think its just the name, but I have no personal experience....yet, that's next on my long long list.

w250_93

Yeah I know what you mean, Id have to pull the pump to get at it through the tappet cover so I doubt I'm going to go that route anyways but it was a good ideal. I'll probably just find one of those rubber plugs I was talking about an remove the rubber an weld a long bolt to the back of it an make a slide hammer an put the rubber back on. I'm just worried about putting it back in cause it has to be perfectly square in the bore.

Yeah Hamilton cams seems to be the ticket at the moment, I'd like to put factory stuff back in it but the last quote I got on a factory cam was $135 more than a 181/210 so why not buy the 181/210 lol. Also do u think I can reuse my gear or is it ruined since it slipped.

j_martin

http://www.toolsource.com/pilot-bear...upcdhph73i8rj1

This is a cheapie, which I sense is the direction you want to go. There are quite elaborate positive (cammed) inside hook slide hammer setups that will neatly pull that bushing. You could also probably get away with peeling it out with a cape chisel.

Where there's a will, there's a way.

w250_93

Yeah I don't see any reason to spend a bunch of money on something I'm only going to use once. I'm more worried about putting the bearing back in though, heck I don't even know if it can be done for sure or not lol