Use of Porsche synchros - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 38 (permalink) Old 05-31-2013, 07:01 PM
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Guys:
This is a very good, informative thread and I'd like to help it evolve a bit further, if you please; so thank you all in advance.

I have a small box of old "moly" transmission rings stashed away from earlier rebuilds -years gone buy. As you may have read on one of the racing post, the current production of moly rings seem to be too stiff for street transmission rebuilds. Has anyone investigated or have knowledge about the process and application of moly coatings. I've found a few places on the web of companies that apparently apply moly coating to metals. Is it possible to get old rings blasted and recoated? Maybe some friction disk out of the differential limited slip unit could be milled out and coated too.

......... Bud Feigel ........<Oo \*/ oO>....... Lexington, Kentucky ........
'82 RED GTV6 / 2.5 - '86 WHITE Spider Veloce 2000 - '71 GREEN GTV 1750
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post #17 of 38 (permalink) Old 05-31-2013, 09:36 PM
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Bud,
You asked an excellent question about resurfacing old moly synchros.
You don't drive with the kerosene/diesel mix. You put it in the tranny and let it roll aroun din there with the car at idle. There isn't sufficient lubrication from the two fluids to protect your bearing. How long do you let it go around? I can't remember, but someone said watch what comes out. It takes the sludge, slime and everything else that is gunked in there out. Refill with the correct fluid and your good to go. YOu might have to flush a couple of times to get all the improper finish off the synchros.

Christopher

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post #18 of 38 (permalink) Old 06-01-2013, 12:35 AM
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Quote:
Originally Posted by Little Italian View Post
As you may have read on one of the racing post, the current production of moly rings seem to be too stiff for street transmission rebuilds.
Here in Europe the main reason for getting into troubles with last time available new synchros was not only the stiffness - mainly it was the wrong shape of the synchros which caused dog teeth failure, too.

From late 2012 on you can get synchros from a new production batch - have a look. As their latest product Alfaholics also offers now a new production of sleeves.
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post #19 of 38 (permalink) Old 06-01-2013, 09:15 PM
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Richard can/would you explain the machine work that has to be done to the later slider so it works with the early syncro? Are the early quandrants used with this modification? The needle bearing 5th gear upgrade seems worth looking into to me,as the original bronze? bushings are hard to find,so what's it take to do this? Pictures are of a NOS early syncroPN#101.00.13.216.20,taken out of a sealed package for the pictures.
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post #20 of 38 (permalink) Old 06-02-2013, 06:32 AM Thread Starter
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Yes, I would also like to know.
I ruined some of the individual gear bushings with the failure of the rubber boot that covers the sliding washers at the shifter. Over a 6 hr trip cruising at 4-4500, 20 minutes from home the rear wheels locked up with all the oil gone from the box. Had to disconnect the d shaft and tow it home. After replacing the bushings had to be cut to the proper runnig clearance, that happened about 35 ago! I was a kid coming home from college.
George

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post #21 of 38 (permalink) Old 06-15-2013, 07:37 PM
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Synmcronizer failures

The later slider ring has to have a machined groove cut into the exact center of a later slider to use with a 101/106/102 type balk ring. I use a radirsed cut rather than the squared off groove as in the original sliders.

Below are pics of what occurs with excessively slipery lubricants and "speed shifting" Alfa transmissions.
The dog teeth are broken away and the syncro internals scattered in the gears.
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post #22 of 38 (permalink) Old 06-15-2013, 08:01 PM
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This question may be slightly off topic but .... If I get my '83 Spider box rebuilt and am a "good shifter" how well will that box hold up? ..and how easy is it to beat the synchro?...not sure if I am asking that correctly, may be the wrong question, it is just that I usually shift smoothly but sometimes you do need to rush a shift or don't double clutch.
I am asking because my trans isn't that bad, but it is the only thing I dislike about the car and when it comes time to finally do the trans I am leaning towards a T5 swap, (I've heard that can be done.... yes, I know heresy).
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post #23 of 38 (permalink) Old 06-15-2013, 08:33 PM Thread Starter
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Originally Posted by Alfar7 View Post
The later slider ring has to have a machined groove cut into the exact center of a later slider to use with a 101/106/102 type balk ring. I use a radirsed cut rather than the squared off groove as in the original sliders.

Below are pics of what occurs with excessively slipery lubricants and "speed shifting" Alfa transmissions.
The dog teeth are broken away and the syncro internals scattered in the gears.
I thought those pictures were typical of exploded 911 syncros, in their 915 box. The big snap ring pops off..... Never seen it in a street Alfa box.
Could you elaborate on the slider mods so it can be used with early syncro rings, I couldn`t follow very well.

George
64 TI (the violin), 87 911 Carrera coupe, 89 Peugeot 505 Turbo Wagon sleeper
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post #24 of 38 (permalink) Old 06-15-2013, 08:44 PM Thread Starter
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Quote:
Originally Posted by maseratiguy View Post
This question may be slightly off topic but .... If I get my '83 Spider box rebuilt and am a "good shifter" how well will that box hold up? ..and how easy is it to beat the synchro?...not sure if I am asking that correctly, may be the wrong question, it is just that I usually shift smoothly but sometimes you do need to rush a shift or don't double clutch.
I am asking because my trans isn't that bad, but it is the only thing I dislike about the car and when it comes time to finally do the trans I am leaning towards a T5 swap, (I've heard that can be done.... yes, I know heresy).
I`ve had my Alfa since 74, got it as a college kid and believe me I did some hard driving with it, (still do)having a Duetto engine in a light TI with 5.12 rear its like a race everywhere you go and never had a syncro explode. I think the box is well matched to the engine power. Say less than 140 in a street car. 911s OTOH lost reliability with the increased power as they started to get to 200hp. I`ve had to replace exploded syncros in those boxes. My theory, I think, others will correct me if I am wrong.

George
64 TI (the violin), 87 911 Carrera coupe, 89 Peugeot 505 Turbo Wagon sleeper
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post #25 of 38 (permalink) Old 06-16-2013, 07:25 AM
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Failures

Quote:
I thought those pictures were typical of exploded 911 syncros, in their 915 box. The big snap ring pops off..... Never seen it in a street Alfa box.
Could you elaborate on the slider mods so it can be used with early syncro rings, I couldn`t follow very well.
__________________
The snap ring isn`t the issue at all, The teeth are broken away alowing the band to escape and dump the internals.

Richard Jemison
RJR Racing

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post #26 of 38 (permalink) Old 06-16-2013, 04:30 PM
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I've seen this type of failure in all Alfa gearboxes: 105/115, transaxle and Sud. Common feature being the design of the synchro.

Usually in cars driven by people who are not mechanically sympathetic (read: don't realise/care that a big graunch when changing gears means that the car is not happy...)

These are also the people that sell their Alfa after several big repair bills and tell all and sundry what a unreliable heaps of ****e Alfas are.

Luke Clayton - 1986 GTV 3.2 24V // Past: 8 x 105, 8 x 116, 4 x 900, 4 x 160
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post #27 of 38 (permalink) Old 07-03-2013, 08:18 PM
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Quote:
Originally Posted by Clayton105 View Post
Usually in cars driven by people who are not mechanically sympathetic (read: don't realise/care that a big graunch when changing gears means that the car is not happy...)
Quote:
Originally Posted by giulia_veloce View Post
Many are NOT contributing to this discussion,in fear of upsetting their mechanics,parts suppliers etc..and because they read the first post about only reputable people to add to this discussion.
I've been looking at a couple threads containing the quotes above and thought I would help with a solution I'm experimenting with.
What I've discovered is what Porsche did in a redesign of the anchor block. Instead of "rocking" in it's slot the new design also pushes out on the band/ring and the block is longer spreading-out the apply effort on the ring.
I've been using this Porsche design for 2K miles now without clashing 1st to 2nd at all! Could be other factors involved in the improvement; but maybe it alone made the 100% improvement. I'm still evaluating it and will be doing more modifications to see how they perform.
Initially the shift to the modified syncro (2nd gear) was 20% harder getting into gear than the others but now after a bit of break-in, it takes maybe 5% more pressure (actually I can't tell the difference somtimes) to get in 2nd gear than the other non-modified syncros.
I'm VERY pleased with 1st to 2nd apply as it's clean with no clashing. In testing, I have been brutal with shifts (1 out of 10 shifts), so far it's a wonderful thing getting every shift into 2nd without that awful clash
I've been building Italian boxes for customers and my own cars since 1978 (still learning) and I'm always looking for other ways to do something better than just installing new expensive parts or lightening gears (expensive too!) with average results.
I'm hoping this concept will help this thread show us new ways to get the Best Shifts Ever! Feedback Welcome.

Below is a late 911 style anchor block modified to work with a 65mm ring.

In some cases when larger rings are used; an actual 911 anchor block might be a direct fit for just $16-$25. Porsche calls this part "Anchor Block" in part descriptions, other makes call them "Servo-Lock", "Stop Block", "Synchronizer Pad" and some other names. They come in different sizes to fit gear/rings from about 70mm to 86mm.
As far as I know Porsche might be the only manufacture who has continued development of this synchro design from it's inception on the 1952 356 transaxle to I believe the late 80's 911/930/928.

Last edited by superfast; 07-07-2013 at 10:08 AM.
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post #28 of 38 (permalink) Old 07-04-2013, 06:23 AM Thread Starter
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Superfast, could please you show the 2 side by side to better see what the differences are. Is the anchor block the lower one on the pic?
It would be helpful too if you remind me which is the direction of rotation, it seems the syncronizer is biased to work in one direction more effectively than the other, ie downshift vs upshift vs long band vs short band.
Thanks for your input!

George
64 TI (the violin), 87 911 Carrera coupe, 89 Peugeot 505 Turbo Wagon sleeper
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post #29 of 38 (permalink) Old 07-04-2013, 07:28 PM
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So, to clarrify what you have done...

Is the experiment in a 105/115 box or a 116/transaxle?

The image you have uploaded: is this showing the full Porsche setup?

Did you modify a Porsche anchor block to use in an Alfa box or make one from scratch?

Could you define your description of "tighter" and "not as smooth" a bit better... Are we talking that the box has more active "balk"... As in, modern gearboxes (like my Subaru box) will pretty much not allow the syncho sleeve to engage the dogs unless there is no torque on the syncro ring.

How different does the box feel when you change with simpathy as opposed to brutally slamming it throught the gears?

I can see how this would assist in creating a more active balk mechanism in the box by forcing the syncro out (with greater force) over a longer portion of the ring for a given rotational torque. The issue gets down to is that the friction materials (sleeve/ring inferface) can only cope with X amount of use (or abuse).

Don't get me wrong with the bucketload of questions, I would be willing to give this a go and think it anything that can improve these boxes for a few bucks would be great....

Love to hear more.

Luke Clayton - 1986 GTV 3.2 24V // Past: 8 x 105, 8 x 116, 4 x 900, 4 x 160
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post #30 of 38 (permalink) Old 07-05-2013, 11:44 AM
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Quote:
Originally Posted by Clayton105 View Post
So, to clarrify what you have done...

Is the experiment in a 105/115 box or a 116/transaxle?

The image you have uploaded: is this showing the full Porsche setup?

Did you modify a Porsche anchor block to use in an Alfa box or make one from scratch?

Could you define your description of "tighter" and "not as smooth" a bit better... Are we talking that the box has more active "balk"... As in, modern gearboxes (like my Subaru box) will pretty much not allow the syncho sleeve to engage the dogs unless there is no torque on the syncro ring.

How different does the box feel when you change with simpathy as opposed to brutally slamming it throught the gears?

I can see how this would assist in creating a more active balk mechanism in the box by forcing the syncro out (with greater force) over a longer portion of the ring for a given rotational torque. The issue gets down to is that the friction materials (sleeve/ring inferface) can only cope with X amount of use (or abuse).

Don't get me wrong with the bucketload of questions, I would be willing to give this a go and think it anything that can improve these boxes for a few bucks would be great....

Love to hear more.
Don't mind providing more details and I'm glad you can see what this idea is all about;
"Improving the outward pressure on the band".

Here is a link to the Porsche forum post where this idea came from.
Pelican Parts Technical BBS - View Single Post - 1970 (911/01) transmission refurb issues

Here is a link to the entire thread; Of Course you could look all over this forum and maybe get other ideas; I Did.
1970 (911/01) transmission refurb issues - Page 5 - Pelican Parts Technical BBS

I have used actual Porsche anchor blocks and changed the radius on them by heating them in a special jig or clamping them to old gear to bend them. I have also machined them out steel from scratch and oil hardened them.
This particular 2nd gear is out of a modified Fiat 850 which is driven on the street. I think in the photo I'm showing an actual 911 anchor block (pn. 91130231701) used in 2nd-5th gear on some 911's and 1st-5th 914's. Some 911's and 928's use different diameter synchro rings depending on the gear. Larger for 1st and 2nd and smaller for 3rd-5th. The width and height of the block seems identical to what it replaced; it's just in my case the application uses smaller diameter rings like in all 850's, X1/9's, Yugos and others.
Also need to mention the 2 brake bands, or what I call "banana springs". They need to be shortened or new ones fabricated. My calculation for how much to shorten them is buried in my notes someplace; I'll dig it up if somebody needs it.

Last edited by superfast; 07-05-2013 at 09:32 PM.
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