Cam bearings

[Morris]

My 1500's cam bearings are scary groovy. And I don't mean they're wearing bell bottoms and peace medallion.

Moss does not list replacement cam bearings. Is this something the machine shop will be able to order?

 

[Bugeye58]

Morris, use the cam bearings from a 1300. 1500's didn't originally have bearings. The cam ran directly in the block. If yours has bearings in it, someone has changed it, and you are running the smaller journal camshaft.
Jeff

 

[DrEntropy]

Actually a "very good thing" too! The only BAD part is once replaced they need to be reamed to size, and it's a machine shop job.

 

[Bugeye58]

Doc, the new bearings don't have to be reamed anymore. They come "Pre-sized". I've done a bunch, and have never had to dress any of them. I check the clearances with my bore gauges and the micrometers, and all have been within spec "as installed."
Jeff

 

[DrEntropy]

Wow. A "do it to yerself" cam bearing install! I want those for the jackshafts in the twincams!

 

[Bugeye58]

I just want a Twink!
Jeff

 

[DrEntropy]

NEENER-NEENER!

I have in me hot li'l mits a set of 125E conn rods, fresh outta th' box. Not done with Herself's B yet and I'm already plotting the ressurection of the S-3!!!

 

[Bugeye58]

I also want a 23B wrapped around the aforementioned Twink.
Oh, crap! Off topic, again! /ubbthreads/images/graemlins/grin.gif
Jeff

 

[DrEntropy]

[ QUOTE ]
...Oh, crap! Off topic, again! /ubbthreads/images/graemlins/grin.gif
Jeff

[/ QUOTE ]

Yeah, you'll have that now and again. Just 'happens.' /ubbthreads/images/graemlins/yesnod.gif

 

[Morris]

The Maggothadid stikes again!

[SHAKINGAK47INAIRWHILESCREETCHING] YA-LE-LE-LE-LE-LE-LE!
[/SHAKINGAK47INAIRWHILESCREETCHING]

Ps. Jeff, I can't tell for sure if I have pressed in or "bored in" bearings. If my engine is as stock, is it possible to turn my cam to fit the bearings? I don't have any Triumph literature, can you tell me diameter and clearance specs for the journals/bearings?

morris

 

[DrEntropy]

NO cam journal cuttin' if you pleaase! The bearings Jeff referred to are a nifty 'trick', ie: a cam from the 1300cc engine and a set of pre-sized bearings from same into the block. A VERY nifty improvement. Sounds as if you have only to replace bearings, if tolerances check correct. I've no 'rumphy data to hand, so will have to wait for that.

 

[Morris]

So even though my cam journals are, well, not smooth, I can put it in with new bearings?

If you are going to tell me I have to buy a new cam, you may need to hold my hand while I cry.

 

[DrEntropy]

Depends on how "not smooth" it is. A clean-up with FINE (Frog-fur fine) emery cloth? Best done by machine shop, and then mic. it to check O.D. New bearings in the block, mic. those and do some math. Running tolerances will tell you if it's go/no-go. I'll hope for the best.

 

[Bugeye58]

Morris. If you have the cam that runs directly in the block, the cam journals should measure 1.8402" to 1.8407"
The bore in the block should be 1.8433" to 1.8448". I don't have the small journal cam dimensions handy, as all that information went with my 1500 stuff when I sold the racecar.
I'll see if I can dig it out, but I seem to recall that the small journals were in the 1.750" range.
But, to answer your other question, it is possible to have the cam jounals ground down to fit the bearing inserts. About .0016" to .002" clearance should be right.
Jeff

 

[DrEntropy]

Taking the cam journals down to fit the inserts sounds like a nice, neat "fix".

 

[Bugeye58]

Well, Doc, there are some pitfalls there. If you grind down the journals, you lose the scroll that feeds the oil to the rockers. I solved that problem by milling a small flat on each journal to act as a dipper, and then running an external oil feed hose to the back of the head. I can't really advocate this approach, but it worked for me. On a race engine, with regular teardowns.
The 1300 cam swap makes a lot more sense.
Or just have a machine shop look at the existing cam and see if it is salvageable. If the journals are scarred, it doesn't bode well for the lobes, does it?
Jeff

 

[DrEntropy]

True. Evidence of a less-than attentive DPO. "Don' need no steenkin' oil changes!"

 

[jcatnite]

My cam journals are 1.9688 on the two outside journals and 1.9655 on the two inside journals. Haven't dove inside the block to see what the measurements are there yet. Wonder how I ended up with a cam that was larger than spec? The journals are pretty smooth, seems to be in good shape.
JC

 

[DrEntropy]

Your micrometers are calibrated? The cam journals were "sprayed" to build 'em up?

T'is odd. But I've not the 1500 experience or info to offer an educated answer.

JEFF?!?!

 

[Bugeye58]

Well, if the two center journals are 1.9655, and the outer ones are 1.9688, how are you fitting the rear journal through the center bores? /ubbthreads/images/graemlins/confused.gif
I'm sure I miked a big journal cam, but I'll go check a bare block tomorrow. I don't think I have a small journal cam lying around. The diameters I gave were right out of the book, and I miked a new cam to verify.
Jeff