Use of Porsche synchros - Page 3 - Alfa Romeo Bulletin Board & Forums
Reply
 
LinkBack Thread Tools Display Modes
post #31 of 38 (permalink) Old 07-05-2013, 03:28 PM
Registered User
 
superfast's Avatar
 
Join Date: Jul 2013
Posts: 5
Quote:
Originally Posted by ganunez View Post
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!
Yes, the anchor block is the the lower one. Direction is both ways on everything but 1st gear in every gearbox I know of.
Something interesting posted elsewhere in this forum and Porsche forums is something that seems engineers overlooked; the shift from neutral to 1st. There's a mod discussed to make 1st have the same parts as 2nd-5th. Great idea to avoid gear "crunch"; But I'm not going to do it unless I have a customer complain about it. I probably won't do it on my cars, unless a 1st gear is disassembled in front of me on the work bench. I'm reluctant because I see one more problem which syncro's don't solve in a 1st gear shift from neurtal and that is something called "indexing". When the teeth are not allowed to index correctly you get something called a "block-out" condition. This is when the synchro teeth and gear dog teeth are resting "point-to-point" and won't mesh.
What I do in this case is shift into neutral to reposition the gear cluster. I've had this happen repeatedly where I'll have to spin the cluster more than once.
An example of synchro tooth indexing is shown at the 4 min mark in this video.
I'm working on a modified syncro collar with larger spyder hub slots to allow the collar to reposition itself by almost 1 synchro tooth. Hopefully I can post the results soon.

Here is some interesting pages about how Porsche engineers describe the Servo Synchro:
Pelican Parts Technical BBS - View Single Post - 1970 (911/01) transmission refurb issues
Hope this helps bring out more discussion...

Last edited by superfast; 07-11-2013 at 06:12 PM.
superfast is offline  
Sponsored Links
Advertisement
 
post #32 of 38 (permalink) Old 07-06-2013, 09:00 AM Thread Starter
Registered User
 
ganunez's Avatar
 
Join Date: Nov 2007
Location: Miami
Posts: 507
Garage
Quote:
Originally Posted by superfast View Post
Yes, the anchor block is the the lower one. Direction is both ways on everything but 1st gear in every........
Here is a link to how Porsche engineers describe all this better than I can:
Pelican Parts Technical BBS - View Single Post - 1970 (911/01) transmission refurb issues
Hope this helps...
Fantastic, tech article ....many thanks, baulk ring synchronizer theory finally explained in detail without math!
I would really like to buy that Porsche literature. There are two pictures of it with different covers in one of the pages of your previous posts links.
btw if I remember Fiat 124 boxes they used a mix of Porsche baulk ring and cone types for different gears, I.e. 1st and 2nd were cone types and the upper gears baulk ring, ...I think Fiat knew what they were doing.
Alsothe links have tons of detail on inspection and rebuild of the baulk ring synchro, .....I guess I,ve been lucky just changing the ring and sleeves when rebuilding my tyranny.

George
64 TI (the violin), 87 911 Carrera coupe, 89 Peugeot 505 Turbo Wagon sleeper
ganunez is offline  
post #33 of 38 (permalink) Old 07-06-2013, 06:59 PM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 6,986
Porsche Syncros

I hope you read the part about allowing time for the syncros to work, and the internal friction that is necessary for then to work properly!

The tapered anchor block has been used by Alfa on the transaxle cars only. Not on the smaller diameter syncros as used in earlier cars.

In the pics below you can see the differences in the smaller fitment syncros as used in the transmission cars, and the larger syncros as in the transaxles.

As well there are numerous versions of the anchors, and internal straps (3 different lengths badsed on internal measurements and parts.)

Later syncro rings were machined with microscopic grooves radially (You might be able to see in the pictures) while the early OE moly ones were smooth inside.

When rebuilding them it is necessart to media blast the surface area of the straps and inside of the nands to increase friction. I use fly ash as the media.

All iderations of the syncros work when used with proper lube (Redline 75-90NS, not other GT%s or 50 year old stuff), and undamaged parts.

There is more to rebuilding syncros than changing the bands and slide rings.

1st pic worn/polished strap (center) and refinished ones to each side
2nd & 3rd pic inside early and late bands before and after refinish
4th pic The many versions of internals used by Alfa.
5th the 3 different strap lengths, The anchor in the small straps is a late version.
Attached Images
     

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
Sponsored Links
Advertisement
 
post #34 of 38 (permalink) Old 07-07-2013, 03:22 AM
Registered User
 
superfast's Avatar
 
Join Date: Jul 2013
Posts: 5
Richard,
Very interesting information about the transaxle and Fly Ash (had to look that up). I think I've heard it called "Black Diamond" which I think is derived from the same coal slag. Preparation of syncro parts is definitely an area to look at in getting better shifts.
Is using blasting media to increase friction on the mechanical movements inside the synchro ring supposed to promote a better application of outward pressure on the band? Could it eventually cause binding on parts used to expand the ring?
Here are anchor/stop blocks (red arrow) scored from friction. Same with both of the curved springs (green arrow) but to a lesser extent.

Seems engineers thought there is a need to reduce friction inside the syncro ring given the grooves inside; presumably to hold oil & reduce friction while spinning and allow a path for oil to exit during apply.

Don't know for sure what is best; I'm still learning.

I'm thinking as the thrust block pushes on one of the brake bands during a shift and then into the anchor block everything is sliding inside the Ring expanding it. The activity taking place inside the Ring/Band during a shift seems more like a process of mechanical leverage with a some sliding to accommodate growth of the band.
Wouldn't more slipping be needed inside the band rather than friction? Doesn't the anchor block and the brake band need to slide on the inside surface of the ring as it expands.
I thought the friction aspect of these syncros was designed to occur on the outside of the ring; that's why they have a course surface. The inside working surfaces are all machined or cast smooth from the factory.
What would polishing the surfaces on the inside of the sychro ring and blocks/springs do? Increase gear clashing or help the sychro ring expand faster when the dog-collar tries to grab the ring from the rough side? I don't know for sure; has anyone tried this.

John T
Fiat 600 60HP, Fiat 850 60HP, 70 Plymouth GTX 500HP

Last edited by superfast; 07-11-2013 at 05:35 PM.
superfast is offline  
post #35 of 38 (permalink) Old 07-07-2013, 07:25 AM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 6,986
Learning

Quote:
Don't know for sure what is best. I'm still learning.
That`s a good thing. There are several closed minds out there.

What`s best?? I can only say my customers are not the ones complaining of syncro problems.

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
post #36 of 38 (permalink) Old 07-09-2013, 01:52 PM
Registered User
 
superfast's Avatar
 
Join Date: Jul 2013
Posts: 5
Syncro Stop Block Video

I've reviewed this video a few times to catch what this guy was trying to show on camera.
My evaluation is:
This style of "stop block" can exert an outward pressure on the ring on the outer 10mm sections where it's split. I've always thought it put pressure on the brake band then down to anchor block to expand the ring from the bottom. Looks like it's been engineered to do more work than I thought. Could it be trying to expand the ring at the top?
The block looks low in height to allow it to rock. The top portion has a pyramid shape to allow it to slide and lock in an angled position.



Here is another view where I think he's showing how the block "rocks" and/or "fits" into position to push out from under on the leading 10mm of the ring.

It's such an odd video; It must have meaning Maybe it's there just to play with my mind.

Now where can we find an Alfa/Porsche Syncro movie like this

John T
Fiat 600 60HP, Fiat 850 60HP, 70 Plymouth GTX 500HP

Last edited by superfast; 07-13-2013 at 12:34 AM.
superfast is offline  
post #37 of 38 (permalink) Old 07-09-2013, 08:10 PM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 6,986
Video

That is not the area that needs expanding at all. The early "porsche" anchor works in the middle of the band. The ends are overly expanded as is...

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
post #38 of 38 (permalink) Old 07-12-2013, 08:52 PM Thread Starter
Registered User
 
ganunez's Avatar
 
Join Date: Nov 2007
Location: Miami
Posts: 507
Garage
Right superfast, I`m not sure what the short video is showing except for the small "click" at the end of the rotation. Don`t have a clue why it`s there. Also, was there an explanation for the lengthening of the stop block in a previous post?
I did see how early short ones would get chipped at the edge. Perhaps that was the reason.
Also, I just reviewed the top video where the rather roughly handled parts of the cone type syncros were actually explained quite clearly. Good video, thanks for posting.....I was in awe at the size of those shafts, geez!
Alfar7 I saw this post from a german ebay link ....what do you think? A replacement for the early non moly ring? No mention of the material, what do you think it is? Quite pricey though. Pic below.
Of course you would need the sleeve to go with the ring if overhauling a tranny. Don`t know if those are available.
Attached Images
 

George
64 TI (the violin), 87 911 Carrera coupe, 89 Peugeot 505 Turbo Wagon sleeper
ganunez is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome