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So this tranny bill just put my "Project 928" over the $15,000 mark - yay But the sunny side is its a first year ROW car. Yes it isn't original (M28.22, MSD ignition, Cayman S Brembo brakes, 1984.5 headers and crossover pipe) but damn! she is going to be fun and fast I'll take the hit on any retail value
So this tranny bill just put my "Project 928" over the $15,000 mark - yay But the sunny side is its a first year ROW car. Yes it isn't original (M28.22, MSD ignition, Cayman S Brembo brakes, 1984.5 headers and crossover pipe) but damn! she is going to be fun and fast I'll take the hit on any retail value
Fronkenstein
Let's quit getting all excited...well, at least until we see that trans moving the car...lol
"Project 928" started this week - Woo-hoo here we go!
Oh yeah I also collect guitars. Here is a recent addition from the 60's. One of my favorite brand marks - Hagstrom. Also an early Ibanez from the 60's and a Fender strat customized by Chandler.
"Project 928" started this week - Woo-hoo here we go!
Well we didn't get 2nd and 3rd synchros today so couldn't assemble However we did staged everything and replaced all gaskets and seals. Cleaned all the hardware and installed the synchros I did get. Here is where we're at:
"Project 928" started this week - Woo-hoo here we go!
Brian,
I had to source then from three different vendors to keep the cost down. the 2nd & 3rd synchros are coming from Einmalig who uses slower-than-molasses-during-an-Alaska-winter UPS GROUND!!! From California no less!
Anyway no one had all of the parts in stock except Porsche at 2X the price.
All in all I saved about $400 off my $600 sourcing the parts via multiple vendors and using specialty alternative shops like MSP Seal.
At least the transaxle is laid out like the manual shows in the breakout diagram and should go together very quickly :-)
Fronkenstein
Last edited by Fronkenstein; 05-08-2015 at 06:27 PM.
Reason: spelling
"Project 928" started this week - Woo-hoo here we go!
So I got bored waiting for my parts to arrive and decided to do some home decorating :-) I am a junkie. It doesn't matter what it is that attracts my attention (cars, cars, cars, more cars, motorcycles, guns, guitars, oil paintings...) I can't just have one or two, I gotta have 5 or 10 or...:-)
"Project 928" started this week - Woo-hoo here we go!
Ok soooo. Went to the garage today and had the gear set finished by noon and full assembly of the transaxle by 3:00 PM. Went through the gears and 2nd gear would not engage. Looked at the synchro and it seemed oversize. Then I realized I had forgotten to measure the circumference of the 2nd and 3rd gear synchros.
Checked the dogs real close for the nth time and voila! a fractured slider ring gear on 2nd drive great:' This totally SUX but it is my fault for forgetting to measure the O.D. of 2nd and 3rd gear synchros as I did for 1st, 4th & 5th gears.
If I had then I would have caught the oversize diameter and investigated further. This explains why the tranny wouldn't stay in 2nd gear.
There are ring gears (that had the "dogs") interference fit onto all the drive gears (1st thru 5th). The thin side of the synchro is inserted into the ring gear which squeezes the synchro making it smaller in diameter and putting a preload on it (it acts as a spring as well as a synchro). This means that the synchro is trying to expand and pushes against the inside of the ring gear.
The thick side of the synchro butts up against the slider hub and should be at the same height as the splines on the slider hub. In this position the synchro is ready for mating the gear with the slider. However when the ring gear is cracked or the synchro is worn the diameter of the synchro increases.
This increase in O.D. causes the synchro's thick side to rise above the slider hub splines thereby preventing the slider from slipping over the synchro and engaging the gear.
The synchro should measure a constant O.D. (82mm if memory serves me).
As usual esoteric over engineering for the sake of engineering with too many moving parts (12 vs 8 on Muncie) for each slider set which are too delicate for most US drivers to handle properly.
The Muncie and Borg Warner is a simpler design able to withstand a lot of abuse.
Oh well, tear down commences in a day or so.
Fronkenstein
Last edited by Fronkenstein; 05-13-2015 at 02:05 AM.
Did you have another synchro? And did the breakage happen during installation? If I'm reading it correctly, you installed synchro 2 in the wrong spot or used 3 instead...I'm loosing you somewhere. Granted, it is broken...and needs attention.
According to PET 2nd and 3rd use the same synchro part # 928 302 302 31. The issue is not the synchro, it is the dog band or synchro gear ring the that is fitted to the "Loose gear 2nd gear". This was broken all along from the original transaxle. Here is a picture of the ring gear:
The synchro gear ring that is interference fitted to 2nd gear is on the left. On the right is the slider, slider hub and barely visible are the slider dogs. The synchro is in between the hub and dogs. In my case the left gear ring is fractured allowing the synchro to expand above the slider hub.
According to PET 2nd and 3rd use the same synchro part # 928 302 302 31.
That's what I would have thought and had a reply typed out earlier this morning mentioning that...they should be the same...but chicken out saying so...since I've never actually had this trans apart, physically. Only in my mind through your pictures and others schematics I've found.
The issue is not the synchro, it is the dog band or synchro gear ring the that is fitted to the "Loose gear 2nd gear". This was broken all along from the original transaxle. Here is a picture of the ring gear:
You're fired for not finding this earlier...lol
The synchro gear ring that is interference fitted to 2nd gear is on the left. On the right is the slider, slider hub and barely visible are the slider dogs. The synchro is in between the hub and dogs. In my case the left gear ring is fractured allowing the synchro to expand above the slider hub.
Making tons more sense in my old noggin now...thank you. And, it's definitely cool that you found something physically broken.
05-04-2015, 02:24 PM
But the sunny side is its a first year ROW car. Yes it isn't original (M28.22, MSD ignition, Cayman S Brembo brakes, 1984.5 headers and crossover pipe) but damn! she is going to be fun and fast
I'll take the hit on any retail value
However we did staged everything and replaced all gaskets and seals. Cleaned all the hardware and installed the synchros I did get. Here is where we're at:
