Modified engine with which rear end?

[Daniel]

If you ever get copies made ill be one of the first to place an order!

You sure could have a special item here with some good mark up that and if you can get the Spax Shocks from
Germany place me at the top for a set of those too...

[Tobi]

Gb Motorentechnik in Germany offers a long fifth that lowers the rpm by 800.
They don't say how many Euros they want for it and I assume they would want to install it so one would have to send the transmission to Germany.

[Daniel]

Gb Motorentechnik in Germany offers a long fifth that lowers the rpm by 800.
They don't say how many Euros they want for it and I assume they would want to install it so one would have to send the transmission to Germany.

everyone has a price lol sending a tranny to germany would cost more then the price of rebuilding it

[djape1977]

FSO Polonez after 1990 had 0.82 fifth gear ratio. maybe diesel had 0.8. if it was from petrol powered car, it can be converted to use remote shifter from 124 spider/coupe. it's a simple bolt on job. whole rear half of the gearbox housing plus lots of fiddly bits inside need to be swapped out, as well as the bellhousing. maybe you could swap just the fifth gear, i haven't tried that so far.

there's also a lada 5sp gearbox with 0.82 fifth gear ratio, but i haven't tried to convert it to remote shifter and i think it couldn't be done as simply as with one from polonez. other than that, it's still a colloti type gearbox, so bellhousing, bearings etc are the same but fifth gear and shifter are diferent than fiat/fso. ruskies have made a excellent shifter, completely diferent than fiat's, much more complex but far more precise and softer. fifth gear is bolt-on to a 4sp main and secondary shaft which is in itself a neat solution. however, shifter position makes it suitable only for use in 124 AC, sedan and familiare.

[vandor]

Djape,

>FSO Polonez after 1990 had 0.82 fifth gear ratio. maybe diesel had 0.8.

I was told this 0.80 came in the pickup and the 1.5 liter Polonez. Mind you it does not make sense that a pickup would need a longer fifth gear...

> maybe you could swap just the fifth gear, i haven't tried that so far.

That's what I did. It was a bit of work.

> i think it couldn't be done as simply as with one from polonez.

Agreed.

[djape1977]

it would be great if i could (or someone out there) figure out a way to convert a lada gearbox to use in 124/125. they were made up to 2012 in large quantities and parts and new gearboxes will be available for years to come. so far i've figured out that it would require serious machining and/or making a cast extension diferent to one on 124 gearbox.

polonez - only logical thing would be that diesel or late EFI models would have had longer fifth gear ratio, but they were made in 90's in time of post comunnist transition in poland in small numbers so i don't get to see many of those. there are some that were made in '96-2004. around but they're still being driven and aren't available for pennies so i could buy one just for gearbox.

[81SPIDERMATT]

By the way, How can you tell by looking at one to know what type it is?

pardon the interruption .... but how does one tell what rear end they have

[djape1977]

you can only tell the diff ratio if you open it and count the teeth on croiwn and pinion gears

[81SPIDERMATT]

you can only tell the diff ratio if you open it and count the teeth on croiwn and pinion gears

thanks... for now i will live in ignorance

[divace73]

you can only tell the diff ratio if you open it and count the teeth on croiwn and pinion gears

there should be markings on the crown wheel to indicate what ratio. (I found a pic the other day but cannot find one now??)
As you may know there are two types of housing

Odds are if an early style (pre 78ish-2L) it would be 4.3, after 3.9 (if manual), however it could have been changed over the years. For example I have put an earlier style diff in my 1980 2L with a 3.9 ratio so by 'looking at my diff you really can't determine it is a 3.9, but I did mention odds are...
If you note your 4th gear rpm at a given fixed speed (which I believe is 1:1 in all the fiat gearboxes) compared to others it should give you an indication. (tyre sizes may vary this a bit)
I do believe for the later style of diff there weren't that many options other than 3.9 and what ever the auto diff ratio was (3.5 I think??)
The later style is easier to check bye removing the panhard rod and opening the plate on the back (after draining the oil??) and spinning the crown pinion till you see the marking....however the centre's are harder to change over on the diffs..

[Tobi]

Couldn't you just lift the car of the ground, mark the drive shaft and a wheel, than turn it by hand and count the revolutions?

[djape1977]

i've seen more diff's without markings than with...

guess you could lift a wheel, but it's a big if you could tell the diference between 3.9, 4.1 and 4.3

yes, 4th gear is 1:1 so driving in 4th gear at 100kph at 3900prm would mean that you have 3.9 rear end, but that's only if you use stock tyre size for that particular model/year and if speedo drive pinion is original one, properly coupled to diff ratio. than again, that would mean you have a stock car, without any mods, and than you could tell the diff ratio by looking at the manual.

[divace73]

i've seen more diff's without markings than with....

Even on the ring gear?? All the ones I've seen here in oz (and even recently purchase LADA items) had some form of identification on the ring gear, nothing on the outside (apart from the Argenta diff I had that had a white stamped writing)

Couldn't you just lift the car of the ground, mark the drive shaft and a wheel, than turn it by hand and count the revolutions?

I believe you can do this but the revolutions isn't quite what you may expect when counting...
When doing my 3.9 it was something like 4. something turns of the pinion to one crown wheel revolution (if I remember correctly)...has anybody tried this method with the different ratios?

[djape1977]

i believe most if not all ring gears had markings pronted with paint but over the years marks wear out. strangely enough, even new ones have the same problem, being NOS and having spent decades in less than perfect conditions.

[FiatMac]

Couldn't you just lift the car of the ground, mark the drive shaft and a wheel, than turn it by hand and count the revolutions?

I believe you can do this but the revolutions isn't quite what you may expect when counting...
When doing my 3.9 it was something like 4. something turns of the pinion to one crown wheel revolution (if I remember correctly)...has anybody tried this method with the different ratios?

You can jack one wheel off of the ground with the transmission in neutral and either turn the input shaft and count wheel rotations or turn the wheel and count the input shaft rotations as described in my posts linked below:


http://www.fiatspider.com/f08/viewtopic ... al#p137365 8th post down on second page.

This thread references the above post and contains further information about using wheel turns and counting differential input turns.
http://www.fiatspider.com/f08/viewtopic ... al#p149404