Technical Marea LSD

[mick_131]

Don't get the chance to post here as often as I'd like due to work commitments and the 131 project, but I thought that I would post this as it may be of interest to someone !!.

It's a little long winded but explains how it all came about

Ages ago I bought a Coupe Turbo 5 speed box with Visco drive, with a view to fitting it to the Marea 20v, but was put off by gearing issues.

My brother and I are going back to the Ring this year, so I decided to start fettling the Marea for the trip. One of the things I wanted to do was change the clutch, so I thought I would have a look at the Visco drive to see what condition it was in.

So I took said part, along with final drive, out of the Coupe gearbox. As my brother has an Alfa 155 V6 ( with Quaife LSD and 156 six speed box ) he wanted to look at my setup and compare parts.

He brought his standard diff and final drive. We checked the teeth on both final drives and they where the same, as was the cast number 7783659. So where the cast numbers on the diffs - 7783660.

So, apparently, a standard Alfa 156 V6 Q2 LSD diff could well fit into the Marea box with a rough cost of £200 :devil:

So I now need to remove the Marea diff to have a look !!.

 

[Venters]

Thats interesting.
Be sure to update us when you have looked inside the marea box.

 

[bulldog5046]

is that on the older 147 gearbox or the newer 155 box?

did you look at bolting the differential from the 20vT onto the 20v N/A gearbox?

and, as above, please keep us informed

Ry

 

[mick_131]

is that on the older 147 gearbox or the newer 155 box?

did you look at bolting the differential from the 20vT onto the 20v N/A gearbox?

and, as above, please keep us informed

Ry

As mines an R reg, I presume that it's the 147 version. I've got hols coming up in early March, so my brother and I will have a look at the Marea box then.

Didn't think about bolting the turbo diff to the Marea box, any major differences between the two that you know about ?.

Once my brother told me about the 156 Q2 diff, I just thought about using that and retaining the Marea final drive and gears. Once the Marea box is taken apart I can compare cast numbers to the turbo and V6 items.

Bear with us and I'll let you know as soon as.

Mick.

 

[bulldog5046]

i just have a feeling it might be possible to bolt the 20vT diff on to allow the Visco-drive, gotta be a worthy upgrade for 20v N/A users

i never compared them myself when i dropped my 20v our to swap for the 20vT

Ry

 

[mick_131]

i just have a feeling it might be possible to bolt the 20vT diff on to allow the Visco-drive

Can't see why not, do you have the old N/A box lying around ?. If so it doesn't take long to remove the casing to get to the diff / final drive to get some measurements of width / teeth numbers / cast numbers etc

Apologies for quality but here are two pics of the Visco unit..

Cheers
Mick.

 

[bulldog5046]

Thanks for the photos Mick, unfortuantely i junked the 20v N/A engine & box as soon as it was out of the car.

i dunno if anyone else has one lying around they can strip down?

 

[mick_131]

No worries Ry.

Had a look today at the Coupe centre driveshaft that I got with the box and there may be a problem.

The shaft has two areas on it which have splines. The one at the end and the centre one, which will drive the Visco unit. See pic below..

So there's no use in using the Marea one and from memory the Coupe centre shaft has a bigger flange on the end..I think

I guess that would mean using Coupe outer shafts and possibly the hubs ??.

Did you use Coupe hubs Ry or just the Marea ones ??.

Mick.

 

[bulldog5046]

No worries Ry.

Had a look today at the Coupe centre driveshaft that I got with the box and there may be a problem.

The shaft has two areas on it which have splines. The one at the end and the centre one, which will drive the Visco unit. See pic below..

So there's no use in using the Marea one and from memory the Coupe centre shaft has a bigger flange on the end..I think

I guess that would mean using Coupe outer shafts and possibly the hubs ??.

Did you use Coupe hubs Ry or just the Marea ones ??.

Mick.

now you get me thinking about it....

the visco drive pushes all the way onto the shaft and should sit on the centre spline.

the flange is differ as you have said, i remeber noticing it when i did my conversion.

because of this you will need to use the turbo driveshaft and hubs, because of fitting the hubs you will need to fit the Brembo brakes and you will also need the steering rack as it is a slightly different length.

its quite a bit to change but i'm sure thats where it ends, i know i used my old powersteering pump and pipes so it will fit the rack fine.

it would actually be a nice upgrade package as the coupe has a faster steering rack (2.2turns lock-to-lock), 305mm Brembo 4 pot calipers and the LSD/Visco.

just need to get someone to fit it and see how they find it

in answer to your other question, i have everything i've described above but with a 20vT gearbox & engine (deffinately a worthy upgrade )

Ry

 

[mick_131]

...just need to get someone to fit it and see how they find it
Ry

Uh Oh......I feel another project coming on .

For the mean time I think I'll remove the Marea box and compare diffs. If they are the same, and the Coupe diff is for sure the same as the 156 V6, then I think I'll take the plunge and get the Q2 torsion slip diff.

All being well, I should be able to find out in a month or so

cheers
Mick.

 

[mick_131]

Got the Marea box of today , all bolts came undone with no major drama so I was a happy bunny .

But, and it's a big but, the Visco drive will NOT fit my Marea box.

The ( very poor ) pic below, of the Turbo box, shows mainly it's diff/final drive housing...

This is the Marea box...spot the problem

The difference in the diff housings is huge

So it can't be done . The only way to fit Visco drive to the Marea ( if my box is the same as all Marea's ?? ) is to use the Turbo box.

All is not lost though, as the Turbo 23 mm ARB was fitted ( with droplinks ) to the Marea crossmember ( to replace the p*ss poor 18 mm ) and later this week will be fitting a Whiteline 22 mm ARB ( off an Alfa 155 ) to the rear .

Cheers
Mick.

 

[MAREA MAD]

the20vt box should fit mate as both cars are built on the same platform!the box from your marea is the same as a 1.6 or 1.8 family b model by the way and they are all interchangeable

 

[bulldog5046]

bum

as above, the next move would be to fit the turbo box, maybe getting a little extreme though.

well done for putting the in effort for everyone considering

Thanks,
Ry

 

[mick_131]

the20vt box should fit mate as both cars are built on the same platform!the box from your marea is the same as a 1.6 or 1.8 family b model by the way and they are all interchangeable

Yeah, I know the turbo box will fit, but again it's the gearing issue with the N/A 20v. Plus the fact if I fit the box then I'll have to get the hubs, brakes, rack and wheels etc. I was hoping I could get away with just a diff swap

Can't justify the expense at the mo ( have to concentrate on the 131 ). If the Marea was my only car then I'd go down the same route as Ry.

However, if there was a box out there that could house the larger turbo diff etc but allowed me to use gears similar to mine, my driveshafts, rack etc. then I'd just bolt in the visco unit. Is the 155 box exactly the same as the 20vt one ?.

At least 20vt owners now know they can fit the Q2 diff, which is a lot cheaper than a Quaife unit.

PS - thanks for your comments Ry

 

[Venters]