Interesting camshaft binding problem

[1950Panhead]

I am rebuilding a very late 53 engine (8th from end).
This engine has the 54 style gear cover.
The camshaft and bushings had very significant wear and I bought new parts.
When I install the gear cover the pinion and cam bind in the bushings and the crank will not spin.
If I install the original cam the crank will spin.
Original cam od=.807, new cam od=.811
My theory is the cam bushing hole (or pinion) was mislocated by factory causing the cam (and bushings) to rapidly wear .004
Has anyone seen this before?
I can buy another gear cover or relieve the cam bushing .001 to .004 where it is binding.
Ideas? Advice? All advice greatly appreciated past and present.
Jerry

[steinauge]

I have indeed seen this problem before but never from the factory.Did you replace the inner cam bushing as well as the one in the gearcase cover? If so did you ream the inner bushing and then align ream the cam bushing in the gearcase to it?If you didnt it likely will do what you describe. Has the crankcase or gearcase been welded around the bushing bores? If so you may well have a misalignment problem.I have had some success using a machinists scraper to fit bushings when this occurs but dont think I would have done it on a customers engine.Be sure you have .001-.0015" cam\pinion to bushing clearance all the way to the bottom of the bushings.I have seen many cases where the last 1\4" or so of the bushing didnt get sized for whatever reason.Best of luck.

[1950Panhead]

steinauge,
I replaced both bushings, both bushings have .001 - .0015 clearance.
Cam spins free in either bushings (one at a time)..
No case or gear cover damage/welding.
If I align ream from case bushing to cover bushing, cover bushing will become oblong, similar to idea in first note.
Your note prompted an idea. I could remove .004 from half of outside case bushing, use piece of .004 feeler gauge when pressing bushing in gear cover, effectively changing the center of the cam bushing in the gear cover to correct what I think was a factory mistake.
Please keep comments and ideas coming.
Jerry

[Cotten]

Jerry!

The solution is indeed to relieve the bushings only where they need it.

That eliminates the proper application of a self-centering reamer or hone.

Instead,... some ink or Prussian Blue, a triangular machinist's scraper, and honest patience is all you need.

Seriously,

....Cotten

[steinauge]

I am not quite clear on this point,did you align ream the bushings and get an out of round hole? If you did it is an indication that you do in fact have a misalignment problem.If you havent done it that way that is likely the source of your problem

[1950Panhead]

steinauge,
Cotten,

The situation is getting clearer.
If you stack the pinion gear and the new Sifton cam together and measure with a micrometer the result is .010" larger then the original cam.
This means the Sifton gear tooth profile differs from the original cam, causing the misalignment and binding.
Are all Sifton cams junk or did I just get a bad one?
I sent a detailed explanation to Zoom.
Andrews does not have a stock cam but they do have a mild cam, .013 more lift.
Thanks for you replies yesterday. If you have opinions on Sifton and Andrews cams tell me.

Jerry

[Cotten]

Jerry!

There was a time when Sifton cams were the finest. Now Tedd owns the name and will box anything up.

And there was a time when Andrews cams were short-lived. I sincerely hope a decade or two has allowed them to be better, or they wouldn't still be in business.

Back in the good old days, we would just swap the bumpy part of cams and re-use the original cam gear to assure perfect mesh. You will probably find, however, that aftermarket billets will not accept an OEM gear on purpose. Or key in differently for a different base circle.

I wouldn't give up on the bushings just yet.

.....Cotten

[kitabel]

the result is .010" larger then the original cam

This may be the problem, but measuring the OD across both gears isn't definitive.
The pitch diameter can only be measured by placing the correct pin in each of 2 spots between a pair of teeth, and opposite each other.
H-D specifies that the correct pin size is .105". If you can't find one, that's between a #37 drill (.1040") and a #36 drill (.1065"). Using 1 of each will be you pretty close.

[socalpig]

all replacement cams are for cam bearings gaged rollers meaning 58 and later 57 and earlier ran in a bushing 57 and earlier cams have a bushing end (end with gear on it) that is .8105-.8110 58 and up have a bearing side that is .8120-.8125 there is your .010 diff you must ream your 54 bushing to accept the larger end or bore you case to use the roller bearings if you ream the bushings it must be done with the cam cover installed and then you align bore from inside the case out at the same time they CAN NOT be done individually that is most likly why yours are off

[kitabel]

there is your .010 diff you must ream your 54 bushing to accept the larger end

Read his post again, it has nothing to do with the journal diameter.

[Cotten]

Jerry!

I would suggest first inking up the cam bushing,
and then another trial installation with the fat cam. Hopefully the pattern revealed by the ink will tell you if there is a real alignment problem, or at least its direction.

Frankly, with modern 'pre-sized bushings, it is most often just a pucker from the dowel pin that needs to be scraped away.
And honestly, even piloted reamers and hones like to 'walk away' from that spot.

Ink the face of the bushing as well. Are the cams exactly the same length, shoulder to shoulder?

Then I am afraid you will need a fresh bushing, and to start all over.
If the ink reading shows little skew, I would return to inking and scraping.

If there is a true alignment problem, however,.. (such as after weld repairs, etc.)...
I have encountered circumstances where bushings had to be cut with undersized bores, and then indexed and bored on a mill.

(For instance, its about the only way to do an ideal Chief!)

....Cotten

[kitabel]

Is no one reading this?

The cam gear is too big.

[1950Panhead]

Thanks for everyone's input on my camshaft problem.
I have returned the Sifton cam to Zoom and am waiting for the Andrews cam to arrive.
Hopefully it will fit perfectly and I can move on to my next crisis.
I learned yesterday that if you use a Duoglide tree in a Hydraglide frame the headlight trim holes do not align (it came with my pan basket)
I will report on the Andrews cam when I receive it.

Jerry

[1950Panhead]

I received the Andrews cam and it has the same problem as the Sifton cam.
I insert two .110" pins across from each other the original cam is 2.777" and the Andrews cam is 2.790".
The gear tooth profile differs from original (again) causing the binding.
My pinion gear OD=1.424 to 1.4245, you have to swing the micrometer because the pinion is 21 tooth. Original cam OD=2.748

If anyone has panhead cams or pinion they can measure I would like the numbers.
It is beginning to look like no one makes the same cam gear profile as Harley.

Jerry

[Robert Luland]

If your going to put tin on you got to have the 57 and down bearing cups and bearings and they will fit right on.