Race Engine Forum UK

Can any one help me with this?
I¢ž¢m going to swap the gearbox out that is currently fitted to my 131, due to a noise from the input shaft bearing (no noise when the clutch is engaged, lots of noise driving or even standing in neutral). It has a Fiat Strada Abarth engine fitted and mated to a standard 131 box.
I have been told that the input shaft on the gearbox I¢ž¢m intending to put in (another standard box) will be too long and will need modifying (cutting back).
Does anyone know how much to take off the end? And is this really necessary?
I do have a theory that the current input shaft bearing is failing due to this modification having been carried out, not so sure if it is failing because too much has been removed or not enough, if the shaft has to be shortened I suspect the later, due to the shaft putting pressure on the input bearing.
Help please.

Steve

From search 'gearbox input shaft' enter all terms..

http://guy-croft.com/viewtopic.php?t=66 ... nput+shaft

I don't know how much by, Cos might. Hope that is a start.

GC

sorry, it'll be a few months before i get to that point.

1. The bottom of the counterbore (actually a drilling) on the 131 crank is not flat - measured from fw mounting flange on the crank to where the 15mm dia 131 gearbox input shaft would hit (ignore the point depth of the hole) it is 27mm, 16mm on the FWD Integrale and 130TC cranks.

2. To be sure of your crank measure the depth of the small bore from fw flange to a point on radius 7.5mm from centre - in the bottom of the counterbore and confirm 16mm deep. It looks at first if you have to shorten the 131 input shaft 11mm. But you don't because on the 131 that shaft is well away from the bottom of the hole. Not sure how much but a fair bit.

3. If your 131 box has an unmodified input shaft take a look inside the end of the 130TC crank and see if it's been rubbing. If it has - you better strip the block and check the thrust washers, it can burn them out, destroying the whole bottom end.

4. The std distance from the end of the input shaft to the spline? Not exactly sure if the one I have here is standard but it is 26mm. Someone measure theirs please for comparison.

5. The 130TC crank must have a bearing fitted in the end, if a also 130 fw usually this requires a sleeved bearing to support the input shaft; the bearing fits in the crank which is smaller ID than the fw bore.

6. Maybe you'd better just grind the input shaft progressively 1mm at a time and put some, say Plasticine in the 130TC crank counterbore and keep grinding till the shaft clears by say 1-2mm. To be honest I don't think it needs much at all taking off.

7. Check also that the smallest diameter in the crank end is 15mm + clearance on the input shaft (mine here measure 15.5mm which is perfectly OK, the shaft is 15mm and won't ever touch the bore if the support bearing is 15mm ID)

(revised after finding a 130TC crank in stores)

GC

Thanks Guy, excellent information.
Strange as it sounds (to none petrol heads) i cannot wait to get the two seperated and see what has been going on, photos and measurements are really usefull and will save me poking about with a torch and rod (although ill still have to have some way of measuring depth) ill take some photos and let you know how i get on. Lets hope the shaft was cut too short and not left too long! otherwise as you say ill have to be replacing the thrust washers at the very least.
Ill be back home Thursday and probably greasy on Friday!
Thank's again
Steve

4. The std distance from the end of the input shaft to the spline? Not exactly sure if the one I have here is standard but it is 26mm. Someone measure theirs please for comparison.

Measured at 2 different 131 boxes: 25.6mm and 26.1mm, so it seems to be standard.

Thomas

I have much the same set up, Strada 130 engine mated to a 131 sport gearbox in my spider. It's been four years since the fitment but I can remember grinding 5mm off the input shaft and chamfering. Went to Bearing Services for a bearing, fitment went fine and there has been no noise.
Hope this helps.

Its taken a while - but the box is now out and as you can see from the photos approx 15mm has been ground from the end of the original length input shaft, also there is some rubbing and general wear and tear (a groove before the splines!).
I¢ž¢ve attached a photo of the replacement gearbox input shaft for comparison before I modify it.
Incidentally the input shaft bearing is noisy - as I thought, so I¢ž¢m pleased I¢ž¢m not wasting my time.
The engine will have to come out so I can check if there is any damage to the bearing (I suspect so) that will probably be next week.

I¢ž¢ll keep you informed.
Steve.

OK engines out clutch removed and measurements have been taken, if you can follow this reasoning you may come to the same conclusion as me, if ive missed something please let me know.
a) Measurement from face of gearbox (mounting face) to front of shaft on old modified gearbox = 24mm.
b) Same measurement on un-modified box = 6mm
c) Measurement from face of flywheel to bottom of hole in crank shaft = 50mm.
d) Measurement from face of fly wheel to engine block (gearbox /engine face) 45mm.
So with those figures i can deduce that i have a minimum of 1mm to remove from the shaft of the new gearbox.

Conclusion: The reason why the input bearing on the shaft of the old box was noisy is because with the removal of 15mm the shaft was not sitting in the bearing/sleeve. The groove before the splines that can be seen in the previous photo's has been cut by the edge on the back of the flywheel, basically the end of the input shaft has been flapping around!
As for the fear of the old shaft rubbing the end of the crank shaft and the possibility of new thrust washers needing to be fitted! not needed.


I am yet to confirm all this with a trial fit of the new box with approx 1.5mm removed, and i have yet to measure diameters and clearences, ill confirm all my findings some time in March when im next home and can progress the work.


regards
Steve

Just an update to let you know that i have'nt forgoten.
Ive laid my hands on some internal calipers, and a micrometer and after some more carfull measurements ive come to another conclusion!
The latest measurements show the input shaft will be 1.5mm too long for the 130TC crank, however its not just a matter of removing the 1.5mm as the end of the crank is concave and has a small flat on it (see the pictures earlier in this thread).
Carefull drawing has identified the final length and shape of the input shaft, ill take photos before and after, some time later when ive double double checked my figures and start grinding.
I found it helps to draw it all out on some graph paper.
ill possibly be a week before i get round to the job.
Steve

Its done!
1.75mm removed and the end shapped to suit the back of the crank.
as suggested i used some blue tack on the input shaft and had a trial fit, after separating i found 0.25mm clearance (i hope the crank & shaft dont expand too much).
The input shaft is a nice fit through the flywheel and into the back of the crank, there is no where to fit a bearing! the rear of the flywheel centre locates into the recese in the back of the crank (see photo), leaving no space to fit any bearing. Only time will tell if ive done the right thing.
Im unsure why so many people told me that if im to fit a strada 130TC engine in an line set up that i would have to remove 11.0mm from the input shaft! This is absolutely wrong. In my case it was a little under 2mm.
Removing 11.0mm (in the case of the box fitted to the car previously 15.0mm) places the end of the shaft in the centre of the flywheel.
I intend not to post any more on this thread unless someone has a question.
And thank you to all who have helped me.
As a postscript i thought i would let you know how i had a good and a bad day.
The Good Day: Engine and box back together and back in the car.
The Bad Day: Engine fell over and i managed to smash my inlet manifold (see picture) does anyone have one they could sell me?
Steve

Im back!
Seems i may have made an error!
Apparently the previous photo, shows a bush (in the flywheel) that should be removed and replaced with a sleeved bearing!
Looks like the G/Box will have to come out again!
Watch this space.
Steve

Just wanted to log on and let you know that this subject is still active.
I simply havent had time to get around to removing the engine again!
Too much else going on at the moment.
Just bought a new Ford Fiesta Ghia 1.4, I dont know what Ford have done to their engines but I'm sure that somewhere along the line Torque is suffering at the expense of better mileage, the car doesn't have much 'get-up-and-go', but that's another story.
The Fiat is standing in my garage in Spain and won't see any attention until September time.

Steve

Its done, engine and box back out, seperated and bush removed from the fly wheel centre (see photo), all i need to do now is go find a sleeved bearing 32mm O/D - 15mm I/D, ill try 'Bearing Services' as suggested previously.
May be another month or so before i get to fitting the bearing and putting the lot back together again.
Regards
Steve

parrish wrote:Its done, engine and box back out, seperated and bush removed from the fly wheel centre (see photo), all I need to do now is go find a sleeved bearing 32mm O/D - 15mm I/D, ill try 'Bearing Services' as suggested previously.
May be another month or so before I get to fitting the bearing and putting the lot back together again.
Regards
Steve

I've used SKF 63002-2RS1 on my Fiat 131 with an Abart 130 TC engine