 Pulled apart 1st core transmission today, What gears do I have |
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| vintage914racer |
 Oct 13 2010, 09:53 PM
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#1
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Member  Group: Members Posts: 429 Joined: 28-December 03 From: Minneapolis, MN Member No.: 1,473  |
In anticipation of my first tranny rebuilt, I tore apart a core transmission over the last couple days. The stamps on the gears are not decipherable, so I'm hoping you can help me determine what the gears are based on the number of teeth.
3rd-5th have 31, 29, and 27 teeth respectively. What gears am I working with? I looked at the charts but they don't make sense to me. |
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Replies(1 - 9)
| echocanyons |
Oct 13 2010, 10:05 PM
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#2
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Advanced Member Group: Benefactors Posts: 2,094 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California 
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you just have to read this page it is very comprehensive.
The spreadsheet has a list of all of the gears ID'd by teeth. |
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| echocanyons |
Oct 13 2010, 10:12 PM
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#3
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Advanced Member Group: Benefactors Posts: 2,094 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California
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The numbers you refer to don't add up but the stock and most common are N, V, ZD for 3rd, 4th and 5th.
here is the list cut from Race914's page with the numbers you listed Third HB 19 : >31 1.63 I 20 : > 31 1.55 J 21 : >31 1.48 KA 22 : >31 1.41 Fourth/Fifth M 22 : >29 1.32 N 23 : >29 1.26 P 23 : >27 1.17 Q 24 : >27 1.13 R 25 : >27 1.08 V >27 : 25 0.93 W >27 : 24 0.89 XA >27 : 23 0.85 |
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| vintage914racer |
Oct 13 2010, 10:16 PM
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#4
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Member Group: Members Posts: 429 Joined: 28-December 03 From: Minneapolis, MN Member No.: 1,473 |
Which number corresponds to the teeth on gear among the pair of numbers separated by the colon (29:22 for example)?
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| 914itis |
Oct 13 2010, 10:19 PM
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#5
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Advanced Member Group: Members Posts: 2,892 Joined: 9-October 10 From: New York City Member No.: 12,256 Region Association: North East States |
QUOTE(vintage914racer @ Oct 14 2010, 12:16 AM)  Which number corresponds to the teeth on gear among the pair of numbers separated by the colon (29:22 for example)? wish i could help! good luck buddy |
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| echocanyons |
Oct 13 2010, 10:21 PM
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#6
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Advanced Member Group: Benefactors Posts: 2,094 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California
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You need to count each gear in the paired gear set.
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| Richard Casto |
Oct 13 2010, 10:46 PM
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#7
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Blue Sky Motorsports, LLC Group: Members Posts: 1,465 Joined: 2-August 05 From: Durham, NC Member No.: 4,523 Region Association: South East States |
QUOTE(echocanyons @ Oct 14 2010, 12:05 AM) That page is a great resource. BUT... If you are having a hard time understanding the spreadsheet you might want to look at this as it might be a little more simpler and easier to understand as it doesn't try to cover as much material... http://www.roadglue.com/wiki/index.php?tit...14_transmission QUOTE(vintage914racer @ Oct 14 2010, 12:16 AM) Which number corresponds to the teeth on gear among the pair of numbers separated by the colon (29:22 for example)? As mentioned above, each gear, is a set. One is on the input shaft and one on the output (pinion) shaft. So for example a stock first gear on a 914 uses an "A" gear set which as a ratio of 11:34 (3.091). If you looked at the input shaft, you would see a small diameter gear with 11 teeth, while on the output shaft, you would see a large diameter gear with 34 teeth. So if you look at the chart on the 914 Wiki, the number on the left of the colon would be the teeth count for the gear on the input shaft and the number on the right is the teeth count for the gear on the output shaft. Assuming you kept everything organized and know what gears are which, you should be able to count the teeth and match them to the chart. When I rebuild a transmission, I document the what gear sets are used and in what locations they are installed in prior to pulling them off the shafts. |
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| vintage914racer |
Oct 14 2010, 10:01 PM
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#8
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Member Group: Members Posts: 429 Joined: 28-December 03 From: Minneapolis, MN Member No.: 1,473 |
After further investigation I've determined the core tranny I tore apart has stock gearing.
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| Joe Ricard |
Oct 15 2010, 08:24 AM
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#9
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
Now go find a box out of a 912 and steal 4th and 5th. This will make a nice short gear set with ZD 3rd. short 4th and short 5th. Of course you will be running 4000 RPM @ 75 MPH.
Which isn't bad if your motor can spin to 7500. |
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| vintage914racer |
Oct 15 2010, 02:55 PM
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#10
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Member Group: Members Posts: 429 Joined: 28-December 03 From: Minneapolis, MN Member No.: 1,473 |
QUOTE(Joe Ricard @ Oct 15 2010, 06:24 AM) Now go find a box out of a 912 and steal 4th and 5th. This will make a nice short gear set with ZD 3rd. short 4th and short 5th. Of course you will be running 4000 RPM @ 75 MPH. Which isn't bad if your motor can spin to 7500. My primary transmision for the car, which I plan to tear into within the next week, has short gears into it and once I tear that one apart I'll know what I'm working with. I'm hoping for MSX, but we'll have to see. The problem I have with short gears, though, is that Road America is my primary track so I need gears for the ~mile long straights too. |
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