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Author Topic: Inline-four crankshaft  (Read 210546 times)

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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #210 on: May 19, 2015, 11:16:44 PM »
... I used http://www.bbman.com/ as a source for my cam pulleys...
Thanks for the link to B&B Manufacturing. Very good site; looks like I can get my GT-2 sprockets from them.
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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #211 on: May 30, 2015, 12:34:53 AM »
... B&B Manufacturing... looks like I can get my GT-2 sprockets from them...
Well, sort of. The two larger ones (50 tooth) are only stocked in steel, which weigh over five pounds each! Their website says "available in aluminum alloy"; however, the aluminum versions show on the quote as "special order"- at up to $300 each! And a minimum 7-week lead time. :x
« Last Edit: May 30, 2015, 12:37:34 AM by Jack Gifford »
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Offline generatorshovel

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    • http://www.dlra.org.au/forum/viewtopic.php?t=556
Re: Inline-four crankshaft
« Reply #212 on: May 30, 2015, 02:40:14 AM »
Try these guys Jack, the had everything I needed, at a good price too,
http://www.naismith.com.au/nnews/article/4_3.htm
Tiny
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I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE

Offline tauruck

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Re: Inline-four crankshaft
« Reply #213 on: May 30, 2015, 02:48:40 AM »
... B&B Manufacturing... looks like I can get my GT-2 sprockets from them...
Well, sort of. The two larger ones (50 tooth) are only stocked in steel, which weigh over five pounds each! Their website says "available in aluminum alloy"; however, the aluminum versions show on the quote as "special order"- at up to $300 each! And a minimum 7-week lead time. :x

Jack, I don't know what a GT-2 sprocket is. Can you please enlighten me?. Thanks. :cheers:

Offline generatorshovel

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Re: Inline-four crankshaft
« Reply #214 on: May 30, 2015, 03:37:11 AM »
The GT2 or 2GT Tooth Profile timing pulley is prevailing in the 3d printing hobby cause the Round tooth profile brings high precision and anti-backlash, were known as today's Reprap Pulley.
Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE

Offline jacksoni

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Re: Inline-four crankshaft
« Reply #215 on: May 30, 2015, 07:22:59 AM »
As I understand the toothed belt (synchronous drive) design has changed with time as a lot of things. The classic "Gilmer" or trapezoidal tooth, which works fine for moderate loads, evolved to a "curvilinear" tooth design which was called "high torque drive" or HTD belts. A rounded tooth. That then had minor design changes to become the Modified curvilinear tooth design with smoothness and excellent torque delivery and belts designed for it are, ( according to Gates anyway), the best high strength belts (Polychain GT Carbon) belts available . So far of course. These are the GT2 belts and pulleys. . They are pretty stiff, at least when new. Best I can tell, just looking at the teeth there is not much difference but you are not supposed to mix up GT2 and regular HTD belts and pulleys though they may physically fit. All three of these belt types- Trapezoidal, Curvilinear, and Modified Curvilinear have been used for cam drives by the OEM's.

Jesel cam drives use a custom width/length HTD belt, for instance.
« Last Edit: May 30, 2015, 07:29:36 AM by jacksoni »
Jack Iliff
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Offline jacksoni

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Re: Inline-four crankshaft
« Reply #216 on: May 30, 2015, 07:29:06 AM »
... B&B Manufacturing... looks like I can get my GT-2 sprockets from them...
Well, sort of. The two larger ones (50 tooth) are only stocked in steel, which weigh over five pounds each! Their website says "available in aluminum alloy"; however, the aluminum versions show on the quote as "special order"- at up to $300 each! And a minimum 7-week lead time. :x
Ouch!. I spent a lot of time looking at stock and aftermarket pulleys (light aluminum) for my application. I couldn't go any bigger than a 34 tooth because of the cam spacing. Because of how I was going to adapt pulleys to a cam drive system that originally used lubricated chains, hubs to cam and then pulley on that became an issue. I ended with steel pulleys and yes they are heavy. Also on mine the crank drive pulley would have needed to be totally custom hub etc and only 17 teeth with the above 34 and I thought that would be too small with the belt routing for adequate tooth engagement. Soooo..... Am driving the cams from the existing Jesel drive system with another 34 tooth belt and a Polychain GT carbon belt with the GT2 pulleys. Will see...... :roll:
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 176.245  2018
 G/GMS-182.144 2019

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #217 on: May 30, 2015, 11:30:24 PM »
Yes, it appears that tooth design of synchronous belts/pulleys is continuing to evolve. When I began looking, GT-2 profile was the latest/greatest. But now Gates has developed their new GT-3 belt tooth profile, so little different from GT-2 that it employs GT-2 pulleys!

Thanks for the help. I'll take a look at Naismith.com.au
« Last Edit: May 30, 2015, 11:32:14 PM by Jack Gifford »
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Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #218 on: June 15, 2015, 12:11:26 AM »
Jack, machining tough metals was a subject of an earlier post on this thread.  My brother, the machinist, is helping me with a problem of the bit chattering while machining tough stuff.  It is a boring problem.  He recommended a carbide shank boring bar.  It works.  This website shows them [url]www.globalcnc.com/Carbide Boring Bars.htm[url] 


Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #219 on: June 15, 2015, 12:15:11 AM »

Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #220 on: June 15, 2015, 12:20:54 AM »

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #221 on: June 15, 2015, 12:39:35 AM »
Interesting. I never used a carbide boring bar. I'm sure the vibration characteristics are quite different from steel bars.
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Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #222 on: June 16, 2015, 01:23:36 AM »
The carbide shank does not vibrate as much as a steel one.  They do cost a lot.  That is their drawback. 

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #223 on: July 27, 2015, 12:49:06 AM »
Christmas in July- received the two camshafts that Crane "built from scratch" for me! All measurements are spot-on (I have yet to measure lobe profiles, but don't doubt them). Photos to follow soon of complete DOHC top-end trial-assembled.
« Last Edit: July 27, 2015, 12:51:04 AM by Jack Gifford »
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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #224 on: July 28, 2015, 01:00:09 AM »
Photos of DOHC top-end mostly all assembled- the only valves in-place are #1 cylinder, springs are light 'test' springs, and camshaft rear thrust bushings are yet to be surface ground to set endplay. And an "enclosed" view- my insistence on fitting it all under a M/T rocker cover caused many headaches!
« Last Edit: July 28, 2015, 01:02:22 AM by Jack Gifford »
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