Timing Gear Drive

[POS Dakota]

well guess you can't see the cat logo, glare. The keyway that lined up was the second counterclockwise from the logo.

what else can i screw up here?

Same here. That was 106 degrees ICL for me. Two keyways counterclockwise from the cat logo. That is correct.


Guys, yes, if the gear does not sit flush on the step of the crank snout, when the balancer is torqued the sharp chamfer of the hardened gear (seemingly much harder than the crank) will press into the radius of the crank scoring a small circle into it. That is what is known as a stress riser.

Kind of how a piece of glass snaps right along a line you score with a diamond cutter....same principle. The chamfer should not under any circumstance rest on the radiused edge. the radius should not be touched by anything. The gear should rest on the step. This will eliminate any possibility of scoring a line into the radius and snapping the crank.

http://www.scatcrankshafts.com/scattechpdfs/Break_the_Nose.pdf

Read that. It will tell you all you need to know. They dont post it for nothing. They're posting it to save people grief.

 

[POS Dakota]

Thanks for all of your input, POS.

ne57, I think that he meant he was looking at the "Scat" faq, the crank manufacturer.

But I don't understand how it could score the crank snout. The crank turns, the gear is pressed on and turns with the crank, not on the crank. How would it score a line on the crank snout?

I must be missing something.

And thanks for figuring out the keyway puzzle, POS.

Now to get back to building my engine.

You're welcome, but I'm only expanding on what I learned from reading what Mad Dart did with his. So I cant take all the credit. And even after reading how he did his I was about to throw the thing against the wall. haha I got really frustrated with it at one time.

I think at this point the info is refined enough where someone can read this thread and install this thing with no surprises. Everyone's cam phasing will be a little different. But other than that the rest ought to apply to everyone except for NE57 who is building a hemi. Seems here are a few very minor differences for him. But he seems to have it under control.

Kind of cool that it works on that too!

 

[ne57]

>Kind of cool that it works on that too! <

I'll tell ya what's cool. This site and the attitude here are cool. Pretty much everybody is trying to help and there's not much if any condemnation of neophytes. Its not often like that on the web.

So many thanks to everyone especially the moderators.


Oh, one more thing. I had a hell of time trying to find sturdy cam plate bolts locally ( the napa guy said 'we don't have bolts, nope, not cotter pins either'...bad day?). I did an online search for the size needed and came up with Chevy cam retainer bolts. Imagine that. Well, since they're ARP bolts, technically, I don't have to have the embarassment of chevy parts in my hemi.

Still may paint the engine bay black though *ducks*

 

[pishta]

4. looking through my drill bits...I have a 1/4 inch cobalt bit that looks perfect. 9/32 looks too small. I see the "proper" bit to tap a hole for 5/16 bolt is listed as a "type f" (bastards) no width listed.

17/64 is acceptable per Milodon for the 5/16 bolts so in theory 3/64 short of the bolt size may be enough for the thread height but that would be worth a looksey on a thread rolling chart.

Oh yeah, about the stretched chains (actually more of a wearing set of cogs) not introducing timing variations, they do whip and they do look like eggs when they are running. I have seen it too, you rev the motor and the crank sure does pull the cam along, but when you let off, watch the chain deflect in the other direction and at a steady fast idle, you can see a bowed chain on both sides. This was on a B with an electric fuel pump, no tensioner available yet. We saw it on a Pete Jackson too, but the idler would rock back and forth on power and deceleration. Im sure we could have logged the minute timing variation on a dyno chart but you could see it when you were on the timing light. Belt would be pretty slick on a B/RB if you run a remote water pump. Run what you want, "in spec" is better than "out of spec" in almost everything.

 

[fvmopar360]

We are running one in our 422 small block that spins up to 7000 with no problem. Another racing buddy had one in his 408 and has been running it for over two years which made us a believer that CAT stepped up its quality. just remember to always check everything for fit before installing. These are good but they do come with torrington bearings and the cam can move about 15-16 thousands.

Is there anything you have about setting up the gear clearance?
Or is this something that is what it is?

I ask because I believe the milodon for example is clearanced with a sheet of paper.

Thanks for posting this I am definitely interested now. I always was interested, but the trash talk on these is knee-deep.
110 bucks is a steal for it and I now see the auctions on ebay for them have better pictures of the parts too. They definitely look up to the task.

This may just be going on my 408.

P.S. Make sure you divert some of that bottomless budget of yours on a camcorder! I would love to hear the mad dart and this new one whining away! Just bought all the stuff I need from brian yesterday, so I need inspiration.8)

 

[64DodgeThis]

Is there a reason these do not come with dual idle gears instead of a plate mount? I mean bot the CAT set and the Milodon set are both plate mount instead of dual idle gear like the BBs.