12/2 Center Cam Bushing

[als]

  The center cam bearing is loose in my block. Retaining pin in place. A .008 feeler guage fits betwixt the bushing and the block. I believe the original Lister had a tapered retaining pin. Does anyone know if  it also had a tapered bushing?   

[cujet]

Interesting.

My center cam bushing is tightly held in place with a bolt. The alignment seems good, as the cam turns free.

Chris

[als]

  Yes

  And thanks for the reply,.
 
  This Power Solutions 12/2 has a modified bolt whereas the last 1 1/4 inch has been turned undersize (apparently with a stone arrowhead) past the thread roots, creating a device;   bottom half  being a straight pin and the top half being left as a bolt. It is rope sealed under the bolt head, to the deck. The pin protrudes down into a corresponding hole in the cam bushing. When snugged down to effect the rope seal , it prevents the bushing from spinning in the block, but does not bottom out. I assume a bottom out would be the cam but need to check that. It is a LOOSE fit staking pin contraption. It does work, probably just fine,  but it just seems a bit loosey/sloppy to me. And the original Lister sectional drawing describes it as TAPER PIN size 6.

Is yours similar?

I either,

a:  don't understand the brilliance of this simple effective time tested tough flintstonian design.


b:  might be able to fix this by cheating. Smear the bushing outer with whatever space age polymer has the best pitch on the package at the auto parts store. As long as the stuff is not some kind of amazing insulator, it seems like good idea to me. But that could be me. I know people who swear by this kind of stuff. I also know others who swear at it.
   
Any other PS 12/2's out there on final?

Issues I've been dealing with:

New oil pump check valves.
Sump cartridge immersion heater.
pressure lubing rear cam bushing, and ?? else
head porting (really just radiussing the backside of the intake valve seat)
drilled dippers (ths was easy to do and seems almost too obvious)
Lexan sump cover
thermosiphon cooling w/  3 way diverting valve.
liner protrusion
tappet face regrinding (CHEAP! toolpost grinder that worked GREAT!.)
etc etc

Many questions.

A few answers, but learning, and having a blast

I've been read only for awhile. Thanks to ALL of you for the wealth of info already, AND the entertainment. Some of you should be writing professionally. Maybe you are. 

Thanks again

[hotater]

als---

It *sounds* to me like, since I've never cast my eye on a twin, yet, that the center 'bearing' is actually a loose carrier.  It keeps the cam from deflecting 'too' much, but doesn't actually KEEP it in position.

 UNless the camshaft is not running true at that point, I think the bushing should be a bearing and not just a 'bushing'.

  LocTite has a goop that's specifically made to take up the slack in bearing recesses.  I'd use it, but put an indicator on the cam near that place to see how much force will be on the bushing, first.  Ten thousandths total indicator reading is no problem.  Straightning to < .010 shouldn't be either.

It wouldn't surprise me that some Indian mechanic thought it was a good idea to put a sloppy bushing in place rather than straighten the cam shaft.   

[als]

Thank you sir for the advice. I really appreciate it.
 
 My center cam bearing is definitely "orbiting". I slip in a .007, get the "feel". Remove it, rotate the cam 180 degrees, the same feel comes from a .002 guage. I think that would be  .005 runout  ??

  I also have .010 runout at the  back end of the shaft (Not the gear end) where I can more easily measure it. It is in phase with the feeler guage results to be;  one long bent shaft, but I don't understand the big number.  If I end up pulling the cam (I probably will) would a channel  in the top outside of the bushing parallel to the camshaft axis, wick some oil in there? Would that be good?  I think any magic goo that sets up hard would do more harm than good.

Also. The rear end cam bushing in the FI pump cover was hand shaped in and seems too loose fitting to do anything at all OR the cam deflects a lot more than I would have thought.

  I have piped pressurized oil out of the crankcase to a distribution block. I plan on running it through a homemade pill (of unknown size at this point) through eighth inch pipe to the rear cam bushing. And possibly some other areas?  Am I being silly? 

Thanks for any responses.
   

[oliver90owner]

Your figures might not indicate a bent shaft perse.  It may just be bending/flexing/moving as each cam is operated.  Slightly different but not good either way!

Regards, RAB

[hotater]

als---

The engines have run a LONG time on the way they're set up at the (English) factory.  I'd use the standard splasher to oil the innards and only use an oil pump if you have bushed mains. 

I agnonized over the off-side cam bearing a lot.  With the first engine I made a 'reed' that caught and directed oil into that bushing.  It seemed to work ok.  The bushing has 7250 hours on it and still not worn out.

If you have access to a lathe, you could do a 'Tesla pump'.   Just grind a 1/32 radius tool and 'thread' the cam shaft under the bushing about .010 deep.  You want the 'threads' leading into the bushing and dead-ending there.  Have about an inch of these 'threads' exposed to the splashing oil.   As the camshaft rotates it 'pumps' oil into the bushing.

A radiused cut doesn't cause stress risers like Vee form 'thread' would.

I did this on MT-II and can readily prove it works by removing the cover and watching the oil coming through the bushing to drain back into the case at the bottom of the cover.

[als]

Thanks and thanks again.

It's definitely runout as there are no tappets or FI pumps installed.

As far as the outer cam oiling, I saw this section drawing of a Lister 10-2:



When I saw that little knurled thingie I shouted eureka and figured I'd run oil through an orifice and tube up there and "fix" that manual oiler for the dry bushing. Oh what fun this is. I have since realized that the mystery thingie is on the gear end of the cam. Might you know what that thing is/for?

[als]

  BIG dent in  lobe collar. half inch from pin. Looks worse in person. really mushroomed. Either really REALLY bad aim or a straightening effort??



  Next I tried this:

I loosened the center bushing pin, rotated bushing 90 degrees. snugged down to "pinch" center bushing against block. Camshaft is well supported by rear  and center bushing.   .027 runout at the front.

  Needs straightening? Never done THAT.  I do have a  press. I can even sort of visualize how I'd attempt it. Push, release, measure, Push a little more, release measure, etc. If its anything other than a single radius bend - - -  I think I will need a new cam.

Or RUN IT ! 
 
  Again and again - - - thanks for any advice

[hotater]

als--

Please do this--- Take a picture of what you're talking about.

I take it there's a 'crank-side' bushing for the cam....same end the cam gear and governor or on.
There's an 'off-side' bushing on the other side of the block, and then theres' a bushing somewhere in the middle?

Support the cam with the two outer bushings and then put a dial indicator on the shaft where the center bushing supports it.  How much TIR is there at that spot when the cam is rotated WITHOUT load?

You have to bend the shaft by half that amount to straighten it.   It doesn't take MUCH at all to bend a shaft that limber.

The ding in the collar is nothing but a miss-hit hammer mark and makes no difference to anything.

[listerdiesel]

The Lister 10/2, 12/2 and 16/2 all share the same camshaft support arrangement.

A large cast-iron bush is placed on the camshaft before the cams are fitted. The bush has a centre diameter which is a close fit in the block, and is held in position by a round-nosed bolt through the casting.

Two oil catching holes are machined in either side, both heavily chamfered, the location of the locating bolt hole ensures that oil catching is maximised.

The Centre Bush was P/No 7-157, the Locating Screw P/No 27-519.

Just had a quick peek at the camshaft off my own 10/2 to make sure it was the same, and it is.

Peter

[hotater]

AH HA!!   THanks Peter--

als--  Put the engine together and RUN it.   THat's just a carrier-locator that keeps the cam shaft from bowing TOO much.

[als]

  THanks, thats GOOD news     and bad

  This is a "hobby" engine. I read quite extensively about the Indian Lister before I bought one. I expected a mess. I pulled the sump cover, to get started on the sand. No sand. Nowhere. Crankshaft end play? None and turns smooth as silk. Big end bearing crush? fine. Clearance? .003. Rod side clearance? fine. piston pin, ring end gap, cylinder wall finish, blah blah, etc, all fine. So far all I have done is drill the dippers, ground the tappet faces and made a suction side check valve. THe only other things I plan on working on are idler backlash, cleaning the cylinder/liner  shoulders/head gasket shimming, lapping in surfaces, and tappet/valve stem geometry. Most of which may already be fine. Haven't gotten that far.

  I'm doin the cam  anyway, even if it doesn't REALLY need it. If I mess it up I'll never speak of it again. If I get it right, anytime someone mentions a bent shaft I get to say "I straightened the cam in my diesel engine myself" I have no idea why I act so.

  Here we go.

  Thanks so much for the help.

[hotater]

IF your going to straighten, here's how---

support both ends of the cam with wooden beams with a notch like a vee block.  Set up an indicator of some kind to 'see' the runout better.   Set it high side up and just tap it with a 'dead blow' mallet and remeasure.  You'll be AMAZED at how little it takes.

[als]

THANKS,

Its in vee blocks and bushings I made out of conduit.  Runout is .015 in the center. fades away in both directions. all in the same plane. I think this could work.

I don't have a dead blow hammer. I do have a maple mallet. I was going to hit it right on the bushing. I coulld make a jig to straddle the part of the center bushing that contacts the block and get a dead blow if need be.

Thanks again,