Were you measuring the thickness across the hub or just the teeth?
Can you measure the diameter of the rollers on the chain?
The next step would be to measure the width and depth of the keyway.
The other question is how much clearance is there between the chain and
cover.
My Martin and Browing books do not list a 40 tooth so one possiblity is a
42/21
combinationn if there was clearance for added diameter of chain over
sprocket.
The od of the 20t is listed as 2.59" and the od of a 21t is 2.70 so the 21t
will need
approx. 1/16" additional clearance.
The max recommened bore for a 20t is 1 5/16"
By going with a less than standard key depth, the bore could be pushed to
1.375"
A 21t would have not problems with a 1.375 bore and standard kw
What is the means of holding the crank sprocket in place on the shaft? Are
there
set screws anywhere in the sprocket or are spacers used to maintain
alignment or does
it float on the shaft?
Martin minimum bore sprockets can be ordered bored to size for a very
reasonable price.
How big is the hole in the middle of the cam sprocket? The standard Martin
24t sprockets come with a 1/2" hole.
Any other mechanical engs or machine designers care to check into this and
comment?
Using off the shelf #35 chain and sprockets is getting to look very good.
daveS
----- Original Message -----
From: Brian Hollands <Brian_Hollands@adp.com>
To: Dave Stoll <dgstoll@gwi.net>
Sent: Thursday, May 16, 2002 10:15 PM
Subject: RE: Timing gears..get the calibers
> Dave,
> I just measured the ID of my old timing gears with vernier calipers - I
> don't have an inside mic and my shafts are in the engine.
> Crank gear ID is 1.375 inches,
> Jackshaft gear ID is 1.105 inches.
> I'm not sure what you're looking for with the 0.561 inch measurement. If
> you mean the thickness of the gear I got 0.612-0.614 depending on which
gear
> I measured.
> Let me know if you need more. If I get a chance next weekend - won't
happen
> this weekend - I can mic the nose of Woody's shafts. Wow, that doesn't
> sound good does it? Anyway, his engine is apart and I've got a set of
mic's
> if no one else has come up with the measurements by then.
> By the way, this came to me without the list being cc'd.
> Hope that helps,
>
>
> Brian '69 2000
> Tampa, FL
> http://web.tampabay.rr.com/oilleak/
>
> -----Original Message-----
> From: Dave Stoll [mailto:dgstoll@gwi.net]
> Sent: Thursday, May 16, 2002 9:09 PM
> To: Brian_Hollands@adp.com
> Subject: Re: Timing gears..get the calibers
>
> Bingo!!! thats just what you need to search the available hardware in the
> industrial world.
>
> Can someone tell me the shaft diameter of the jackshaft which the 2
> jack sprockets go on and the diameter of the crankshaft where the
> crank sprocket goes on?
>
> A 3/8 pitch chain is a #35 chain
>
> Both my Martin and Browing catalogs list the sprockets with a minimun
> bore. (Like a sprocket blank with a minimal hole in the center.)
>
> The catalogs area listing these sprockets as 0.561" wide from outside of
> tooth to outside of tooth. Can someone verifiy this?
>
> Can someone communicate with me who has a used set of sprockets
> and calibers to read dimensions?
>
> If the crankshaft diameter is less than 1.3125", all but the cam sprocket
> may be relatively easy to machine from stock sprockets.
>
> Thanks,
> daveS
> ----- Original Message -----
> From: Brian Hollands <Brian_Hollands@adp.com>
> To: Dave Stoll <dgstoll@gwi.net>
> Sent: Thursday, May 16, 2002 3:37 PM
> Subject: RE: Timing gears...again.
>
>
> > Dave,
> > The comp prep manual states "A good replacement (for the stock chain)
> would
> > be a Reynold 3/8th inch pitch duplex chain part number 114038"
> > Hope that helps,
> > Brian '69 2000
> > Tampa, FL
> >
> >
> > -----Original Message-----
> >
> > Thats what I've asked for in an earlier email but no one has
responded....
> > I've been paid to design gearboxes and this simple information would be
> very
> > helpful.
> >
> > The pitch of the chain is the key information
> > daveS
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