Allis CA

Friend Matt whittled out the offset key to my specs tonight. Assembly fit back together nicely. 

John came over today and helped put the centers in the CA wheels:

Small moves at snail pace. Weather has been cold. May get a slight break to start preparing to make maple syrup next week.

We get some results on the cam movement results soon.

Regards,

 Chris and Cheryl

A cam with more duration will appear less pointy, kind of counter-intuitive but less "hump" = longer duration

I'm impressed by your dedication to get this thing running to it's fullest potential Chris. Interesting to note the "offset" on Les' camshaft. I wonder, if firing order is in fact an issue Allis had to work around why did they stick with 1243? And do any companies make a more "standard" 1342 cam for the 125 engine?

Nice! I do believe you are on the right track.

Just looking at the picture the cam lobes do not appear to be as pointy as the cam in my B-125 Power Unit engine.

I made a new thread about that cam in case you missed it.

 I am going to get the offset key made in the next day or two. Decide to use a .25 wide key and trim it down to fit the keyways. That should be about .036 inch offset in the key moving the cam CCW from the cam gear. 

I will have to check the exhaust angles after I get the cam back in.

Regards,

 Chris and Cheryl

I have some of this backwards too.

The crank stayed at TDC and the cam lobe center-line moved CW or CCW one tooth.

 i will work on finding the duration (197) More trials to do to find this and be repeatable.

I am using the plus and minus .050 inch from the top of the intake cam lobe to capture the degrees and then average them to get the lobe center-line. Seems to give good numbers.

Regards,

 Chris and Cheryl

 I escaped to the shop. Rolled the cam gear one tooth each direction.

First rotated the cam gear one tooth clockwise the final degree number of the center-line of the intake lobe = 126

Next rotated the cam gear back past crank TDC mark one tooth counter clockwize. and the Lobe centerline final number was =96.

interesting that the math 126 + 96 = 222 divided by 2 = 111 humm!

So will need to cut a new keyway in the cam at the correct location I believe. More thinking on that location and dimension.

Regards,

 Chris and Cheryl

steve(ill) wrote: i was wondering about that Les... the cam has "about" 50 teeth so divide that into 360 degrees and each tooth is "about " 7 degrees ??  ........... i would guess thats how it works..

Yup.

360 degrees/46 teeth = 7.826

That 'might' get it close enough. It is the easiest thing to change anyway, and given my inherent laziness I would try it before doing any fancy machining work. Plus, it would get it closer so an offset key wouldn't need to be quite as big.

If it were mine I would focus on finding that Intake Valve Closing Event @ 0.050" lifter rise before (and after) moving it one tooth because that is what controls the trapping of your compression.

So I was able to spend some additional time playing with the cam and its location. My systems and tools are rather crude but continue to improve and learn on this degreeing thing. Will have some questions. Some of these things no one will ever use!

Note I added a stiff angle bracket out the front to do two things. First I can mount the dial indicator base in a place. I can see the dial while I use a bar to turn the crank at the back of the block. Second I can use this bracket to stop the piston before TDC in both directions.

A small short socket provided the stop, about 3/4 inch below TDC. Checked the degree wheel numbers both ways and averaged those to get the wheel set on the snout of the crank.

The magnets worked very well to hold the degree wheel in place:

On the back of the stiff paper wheel I added a circle to see if the paper was moving. The magnets held the wheel fine. Saved building a tool I would not use again. Good suggestion by Les.

Shot of the cam in current location.

Ok some numbers. 

The cam lift is .260 About .004 shy of the spec. But after about 10 checks that's what it is.

The intake cam lobe center-line spec was 105.4 degrees ATDC. I watched some additional videos and began using the .050 inch before and after the top of the cam lobe inspection method.(as mentioned above)  And then checking the degree wheel numbers and averaging them to get the actual cam lobe center-line number.   After another 6 checks of the center-line I have determined it is approx 111 degrees ATDC therefore 5.6 degrees more than the spec. Checked about 6 times and I feel this is correct. 

So next will be to plan the cam and gear work required to get this back near the correct location.

Regards,

 Chris and Cheryl

Not expecting much improvement in CA horsepower, if we get the new 175 grind cam issue resolved.

Made a run at the checking of the cam specs today, more to learn and do. Just some random pictures.

May pick up a couple sets of plugs for that first pull.

The original goal of this cam change was to replace the original cam because of worn lobes. Did it run? Yes it did.

Regards,

 Chris and Cheryl

  Although in all seriousness when we first conversed as he started this project, he informed me his local pull are the Grampa Gear restricted type and with the slow ratio low gears a CA has, As long as the engine runs balance is more important than power. He's going to have a beautiful tractor when he's done.