Murena high fifth gear

[Oetker]

I think it is best to go and see for the gears, and not buy a compleet gearbox.
See the pics of differences I found in some 2500 turbo gearboxes.
Both have 31 tooth, but diameter is different.

[Oetker]

Today we started with the gearswitch.


Last week I had lots of trouble to get the right wheelarm off, (had to saw it out) and of course it wasn't any better with the left one


After strugling for a few hours we had the bloody thing out and could get started with the gears.


Then grinding of almost 2mm off the fork to make it fit.



This was a piece of cake to do.
Everyrhing looks good and running free.



We didn't manage to get the Job ready today, because we couldnt get the bolt out of the arm, and besided that I didn't have a replacemant bush.
Puted the arm in the car and drove over to Car-joy to get a new bush fitted.
They were so kind to help me out.
It took 3 man to get the bush out, but it is fixed.


Tomorow I hope to complete the task.

[Oetker]

Puted the things back together an made a testdrive.
Grinded a little of the housing.




RPM before modification
http://www.youtube.com/watch?v=Huez4YZ7Zgo

120kmh = 3500 RPM
160kmh = 4700 RPM

After modification.
Driving 120kmh 3200RPM
http://www.youtube.com/watch?v=1N_I1Wd0-ek

Driving 160kmh 4400 RPM
http://www.youtube.com/watch?v=qZOTFz3bjoY

About 8-9% better.

I have to do the job again, because after modification a little noise is coming from the gearbox.
Have to find out what the problem is.

Edit:
After driving 2 seasons with the car the noise is almost gone.
I think the gears had to set.

Herman

[Anders Dinsen]

Grinded a little of the housing.

Nice work. Why did you have to grind off the housing? To accomodate the larger gears? Nice videos too Maybe you should find a friend to hold the camera next time...?

I have to do the job again, because after modification a little noise is coming from the gearbox.
Have to find out what the problem is.

Ouch. Well now at least you know how to do the operation and won't have to spend hours taking the trailing arm off! I hope you will be able to spot the problem. Is it gear of bearing noise?

By the way: Your videos lead me to this one (Murena leading 1984 rally cross championship at Brands Hatch):
http://www.youtube.com/watch?v=Ng7i5eHx0VU

/Anders

[Oetker]

The housing was very close to the gears, and I was not sure if it would hit it or not.
So to be sure I grinded a bit of.
The noise in the box sounds like defect clutch bearing but a bit louder.
Also I hear all the synchros work in all shifts.
When I puted in the last gear with the synchro, it falled appart.
I puted it back toghetter and have the feeling something is not right at that point.
Next week I will take a look if I can find a solution.

[roy4matra]

Today we started with the gearswitch.

Last week I had lots of trouble to get the right wheelarm off, (had to saw it out) and of course it wasn't any better with the left one

If anyone downloads my instructions, and reads them fully, you will note that there is no need to remove the trailing arm at all.  The job can be done with the arm in situ.  This can save a lot of additional work.

Roy

[Oetker]

Yes I saw the instructions about the wheelarm, but they both needed servicework and oilfilling.
The holes on the top need to be welded to fill with oil.
The right one I replaced last week, and this was a combined job doing gearbox and arm.





Bolts with copper so next time no problem.


The place where water can give problems closed with kit.


Filled with oil.
This will stay rustfree forever.


Job wel done.


Herman

[Oetker]

There seems to be differences in gearboxes on the Murena to.
Another Murena that is in the work for a modification is clearly different.
Other bushing
Other gears and smaller.

Also the fork is smaller and doesn't fit around the gearsurround.
Probably a older type gearbox??
They are preparing a set of spacers and another synchoring to make it work.
It is not in all cases a straight forward job, so be warned.

Herman

[JV]

Thanks Herman, for the nice pictures.
I presume this is my gearbox.
It turns out to be the early type of the gearbox (from 1981) for which Roy already warned.
There has to be changed more than with the newer ones.

Jan

[roy4matra]

There seems to be differences in gearboxes on the Murena to.
Another Murena that is in the work for a modification is clearly different.
Other bushing

Different  synchroring.

Other gears and smaller.

Also the fork is smaller and doesn't fit around the gearsurround.
Probably a older type gearbox??

Yes, this is the earlier box, which I did say has differences so that the kit I listed does not fit.  The problem is that I have seen this type even on a late Murena so you can't tell from the cars age, and as I've never found a gearbox serial number, the only way to tell is when you remove the end casing and can see the fifth gear synchro.

Roy

[Oetker]

I did look for a serialnumber on the box, and you are right.
Nowhere to find.
Ordering parts for this gearboxes is a shot in the dark

[michaltalbot]

Oetker: nice job 

Only one question - I heard, that using of used engine oil for anticorro protection is a big mistake, because used engine oil includes particles of sulfur which causes the corrosion paradoxically  Do You know about this?

[Oetker]

Quote Michael.
-----------------
Do You know about this?
=================

No, it is that you mention it, but never tought about that.
On the other hand it needs oxygene to corode.
The oil is out the arm now.
There was to much leaking and you don't want that with the brakes near by.
Maybe fill it with something thicker, but I think I just put waxoil in it.

The other car has the gears also fitted with some spacers, and is on a testdrive to Corsica.
Also this car has secundair noises from the gearbox.
@ Michael.
Is there extra noise coming from youre gearbox after modification?

[michaltalbot]

There was a little noise for first cca 100m, it was something like when You drive back on Reverse. But after short time it disappeared, so I think that it needed to be oiled properly. But some small problems came, like when Murena was saying: "So You want to try my patience with Your experiments?" for ex. middle axle-shaft boot broke a little and vaseline went out right to the exhaust right in that moment, when Skoda SuperB 2,5 TDi was behind me in cca 217km/h. You can imagine that smoke and well-oiled front part of SuperB - it will never be corroded   Next time I came to my garage and wanted to start it, but not even a "click" - the earth cabel leaved its place on starter... And I'm not speaking about 3 times repairing the clutch slave cylinder which fell of its place because of weak C ring  
But I still love her  

[Anders Dinsen]

for ex. middle axle-shaft boot broke a little and vaseline went out right to the exhaust right in that moment, when Skoda SuperB 2,5 TDi was behind me in cca 217km/h. You can imagine that smoke and well-oiled front part of SuperB - it will never be corroded 

Hahaha poor guy!

/Anders