Engine: Cam/Crank Timing gear fit issues 1955 V8 259

[Craig]

I went to fit the cam with new fiber gear into the V8 259 engine with new crankshaft timing gear...
and the cam with new fiber gear will not go into the crank gear then into the cam bearing/block.
The gears seemed to be the issue.
I pulled the crank and the cam fits just fine.

the cam /crank gear engage about 1/8" to 3/16" and you can rotate this partial cam/crank fit but he cam will not go into the bearing. Seems to be an interference fit with no clearance between gears.

The block was not line bored, the cam not rebuilt/profiled.
New cam bearings, new engine bearing, new timing gear, new fiber cam gear.




what is the common fix for this issue?
What did you do the last time this happened to your rebuild?
thank you
Craig

[Mike Van Veghten]

Others will come in, but...
A few weeks back there was a post put up about ill fitting "aluminum" cam gears. Never heard of the fiber gears giving any problem(s).

Is it possibly because the cam want's to "rotate" as it goes back into the block ? This is normal because of the angled teeth, it's normal, let it rotate.
If it's an actual tooth mesh interference, that's another problem. Have you tried to measure the tooth to tooth (cam to crank) clearance when they start to mesh ?

Mike

[Craig]

zero clearance between my new gears.
How did the alum fit get resolved?

[DEEPNHOCK]

Was the block 'line bored'?

[Craig]

not line bored, views as original

[64studeavanti]

Just to be sure, you are trying to put the cam in the block with the gear already installed?

[Craig]

Please be sure, new fiber gear is installed on the cam as an assembly.
New crank shaft timing gear installed as well.

[64studeavanti]

Still confused. Is the timing gear installed on the cam before you are trying to fit it in the block? The crank should be installed and end play set. The crank gear holds the end play. The camshaft should be installed without gear attached. The cam end play is set with a spacer and is held with a retainer. With the crank and cam properly installed, the cam gear is installed.

If you are doing this as per shop manual, and the cam gear will not go on, it is likely you are using one of the repop crank gears. I have had issues with them and will not use them. I prefer to use original, used, crank gears in good condition.

[Craig]

From the manual for 1955 259 V8

[64studeavanti]

Try following the procedure as outlined in the section camshaft gear installation. I have always done it that way without issues.

[Craig]

Pulled the new gear off the V8 crank.
Set it on top of new V8 fiber cam gear.

Doesn't appear to be be a good mesh

[64Avanti]

What do you mean by the mesh doesn't look good?

[Craig]

The tooth profiles don't look to be fitting as well as I would expect. close but wrong shapes.

[64Avanti]

You can't tell from the picture if they have correct form or mesh. They of course should not have full contact into the root.

[Ron Dame]

Lets start with what engine you have. V8's and Commanders are one thing, but Champion ( 170 CI and 185 CI) are another, as the deck height changed in.... 1956(?). A mis match of gears between earlier and later Champion engines could cause this.

[Craig]

Thank you, this is a 55 259 V8

[StudeRich]

I see that you loose fit checked them, but what is IMPORTANT is the Fit of both gears fully installed IN the Block.

There ARE several ways to do this Crank/Cam install.

After checking and setting/Shimming the Crank end play with a Long Crank Bolt, Large Flat Washer and a piece of 2 Inch exhaust Pipe, I remove the Crank.

Then, after measuring the difference between the Cam thrust Plate and the Spacer Ring, I install the Camshaft WITH the Gear, Spacer Ring and Thrust Plate installed, bolt it in, then simply drop the Crank with it's, Shims, Thrust Washer, and Timing Gear, upper Main Bearings and Flywheel Bolts installed, onto the Cam Gear.

Then if there is No clearance, replace the NEW Crank Gear with a NOS or Used Crank Gear,
Failing THAT; Replace the New Cam Gear with an NOS or Old Stock replacement one.

After TWO Large well known non-involved Gear Grinders checked samples of all Repro Gears, Fiber, Aluminum and Crank, all were deemed Good per Drawing and modern Tech. So the Blocks MAY be the variable.

I am Not saying I believe either, make your own decision.

[JoeHall]

Remove the repro crank gear and reinstall the OEM one, and see how it meshes with the cam fiber gear. If it meshes OK, the problem is in the repro crank gear.

[Dan Timberlake]

I see that you loose fit checked them, but what is IMPORTANT is the Fit of both gears fully installed IN the Block.
............
After TWO Large well known non-involved Gear Grinders checked samples of all Repro Gears, Fiber, Aluminum and Crank, all were deemed Good per Drawing and modern Tech. So the Blocks MAY be the variable.

I am Not saying I believe either, make your own decision.

============

Hi StudeRich,

This post is not related to cam shaft installation.

Please send me the link to 3rd party gear reports that said some tested aluminum cam gears were deemed Good.

Are you referring to Al Kurz's thread starting 11/28/2021 ? Cam Gear Broken Teeth, aluminum gear 289

The latest I could find was Post 109 towards the of the thread (page 8). 64 avanti said about his 3rd party gear inspection of a problematic aluminum cam gear - "The angle on the cam gear is a little worse than my measurement of about .3 degrees and turned out to be about .36 degrees which is a huge error. "

thanks,

Dan T

[Craig]

Maxey video installing SI aluminum cam gear.
Aluminum gear installed on cam, cam slid into block and crank gear with no issues.
Nothing about cam end play, gear mesh measurements, but discussion on reduced head bolts/splitlocks for cam plate.

[Craig]

I see a set of Studebaker V8 timing gears on eBay.
Are these a good fit?


Description - THIS IS A NEW STUDEBAKER V-8 TIMING SET, PART # 1685777 & 527084. FITS 1951-64 V-8 232, 224, 259, 289, 304 INCLUDING 1963-64 AVANTI. FITS ALL JET THRUST & R SERIES ENGINES. USED ON ALL V-8 TRUCKS WITH HEAVY DUTY ENGINE. THIS SET INCLUDES THE ALUMINUM TIMING GEAR AND STEEL CRANK GEAR. THIS IS AN UPGRADE FOR THE FACTORY FIBER TIMING GEAR. THE CAM GEAR IS MADE OF 7075 BILLET ALUMINUM I DON'T THINK YOU WILL FIND A BETTER OR STRONGER TIMING GEAR FOR A V-8 STUDEBAKER. THESE ARE A LOT STRONGER THAN THE ORIGINAL CAST ALUMINUM GEARS. MADE IN USA.

I see an aluminum cam gear listed by SI.
Is this from a different fabricator than the eBay gear?
Do SI gear sets work as intended?


The Maxey video seems to show an SI alum cam gear duplicating the eBay listed.

Would not an aluminum cam gear of this diameter grow substantially as it came up to temperature?
And if it were made from some high strength alloy, it might not "wear-in", simply fatigue and fail.
Where as a lesser alloy might wear in?

[StudeRich]

The S.I. on-line Catalog does not have correct Photos, only "Representative Photos" of their Parts, this is a Photo of the Fiber Gear. The Reproduction Aluminum AND Fiber Gears are ALL the same, wherever you buy them.

There should not be ANY "Growing" issue with 7075 Aluminum it is the same alloy that Alcoa used on the "REAL" 1685777 Factory Cam Gears, same Material, different Gear and Mfg.

Did you check the installed clearance yet on your earlier production Silver Crank Gear and Repro. Fiber Cam Gear?

As you See, the New Crank Gears are BLACK.

[Craig]

Who supplies "the new black" crank gears? Who supplies a fiber or alum cam gear to match?

Are all suppliers returning their current inventory of suspect crank gears and resupplying with "new black gears"?