Fiat 600 engine replacement

[Paul vander Heyden]

ChrisD

I have never worked with the 127 flywheel, but I suspect that the offset of the flywheel is somewhat like the A112.  If so, then the starter would come in from the engine side, not from the gearbox side (as in the 600).  It may work, it is simply a matter of fitting it all up.  One thing for sure is that you will need to put the 600 starter ring gear on the 127 flywheel.  Compare the two flywheels and you will see how the ring gear is positioned differently. 

If you use the A112 clutch/pressure plate you MAY have a clearance problem unless you are using a SEAT bell housing.  I tried to mount a standard 600 flywheel drilled for an A112 pressure plate (170mm) as an emergency replacement at SPA in 2004, but it hit the inside of the bellhousing.  I KNOW that the Valeo 850 clutch with the 'raised fingers' works well (160mm).

Even though the Fiat 850 clutch was 'manufactured' for a counter-clockwise rotation motor, I prefer to use it as-is on clockwise 600 installations.  Let me explain.  The tensioning straps are there to keep the pressure disc parallel to the flywheel.  Now if we had 500 HP monsters, then I would want to have the straps under TENSION on upshifts.  As we do not have such engines, our engines are likely to create much larger torque moments on DOWNSHIFTS.  Hence, I would want the straps to be under tension on DOWNSHIFTS.

Secondly, there is a small (0.020 inch/.5mm) step up from the pressure plate mounting surface to the friction surface.  It is mandatory that this step be there, as this is what controls the amount of preload on the the pressure plate when it is bolted in place. 

I have NEVER lost a clutch.  None of my customers that have followed the above advice have ever lost a clutch that I am aware of.  What can I say, it works.

Hope this helps.

[ChrisD]

Thank for all info Paul.

Seems that I will use the 850 cluch adapted in the 600 flywheel. Finding a 850 flywheel in my coutry(Greece) even in junkyards is dificult. Only the VALEO brand works good without problems? Becides of drilling new holes in the 600 flywhel to much the cluch is there any other thing need to be done?

ChrisD

[Paul vander Heyden]

Chris,

Since you have the assembly apart, I would suggest that you lighten the flywheel 'some'.  The same machine shop that drills the flywheel for the new bolt pattern should be able to do this.  Only take weight out of the periphery of the flywheel, try to leave the area around the center hub alone, as that is where the strength is needed.  Likewise, the A112 (or 903) used 8 x 1.25mm flywheel bolts and a 10mm 'dowel'.  You will have to make sure that the 600 flywheel you are using is set up for both.  Do not leave out the dowel, as you do not want to rely on the bolts alone for location of the flywheel once it is balanced.

Again, check to make sure that there is a step up of .5mm from the outer ring, where the pressure plate mounts, to the friction surface area.  Make sure the friction surface area is clean and flat. 

If the ring gear is some what worn, and you want to replace it, now is the time.  I have this in stock if you cannot find locally (29 Euro).

Finally, after all of this has been done, you should get it balanced with the crankshaft from the new motor.  Have them balance the crankshaft first, then with the flywheel, and finally with the pressure plate attached.  In this way you can change the pressure plate later without having to rebalance the other assemblies.  The better the balance job, the smoother the motor.

Hope this helps and good luck.

Regards,

Paul
Scuderia Topolino
USA

[ChrisD]

The ring gear is ok. But since you mentioned it I have noticed that some times when the engine is hot the starter motor has trouble turnig the enigne. I thought it was because my battery is old and didn't had the power, but wondering in the internet I read of other people having the same problem only when the  engine is hot. Is it really common on the 600s when using bigger engines?

[Paul vander Heyden]

Chris,

The Fiat 600 Starter motor is notorious for not working well when hot.  Certainly if the starter is old, and you have a engine with higher compression and perhaps more ignition advance, this may push the starter beyond what it is capable of handling.  Certainly those of us who race the Fiat 600 have had this experience.

Along with a friend we developed an alternative.  This is to use a starter from a 1980, Subaru along with a special adapter that I manufacture.  These starters are 'reduction drive' starters and will even start a large V8 motor.  Many of my customers around the world are using them successfully.  I can supply just the adapter, or a complete starter with adapter.  I have also recently developed a complete new starter for the Fiat 850 (same problem when hot).  If you look on the "SPECIALS" page on my website you will find more information.

Regards,

Paul
www.scuderiatopolino.com
USA

[ChrisD]

I still have the starter motor of the A112 engine. Could I use this one somehow?
The Subaru starter motor you mention come from witch Subaru model?I can find it here, I just need a parn number or the car it was used to.

Thanks,
Chris

[alapimba]

Paul what is simpler for a machine shop?
drill a fiat 600 flywheel to hold a fiat 850 pressure plate or give them a fiat 850 flywheel and ask to put the king gear from a fiat 600 flywheel?
The result for the car will be the same, right?

[Paul vander Heyden]

Alapimba,

If you have both flywheels, remove the dowels and lay them both down on a flat surface, with the friction surface laying down.  Now do the following

1.  Measure the height of the center hub where the flywheel mounts on the crankshaft.  This will give you the distance that the friction surface is from the mounting surface of the crankshaft.  If this is the same Hoorah.   If it is not, you know what you have to compensate for.
2.  Note the relative positions of the starter ring gears.  If it looks like you can put the ring gear on the 850 flywheel and have it come out in the right location (even if you have to spot weld it in place because it is not up against a retaining lip.  Put a spot weld in 6 locations, even spaced and you will not have a balance probem)  Hoorah.  Note:  You may have to machine off the retaining lip on the 850 flywheel as the ring gear presses on from the opposite direction as the 600.

If you are able to use the 850 flywheel, then you do not have to drill a hole for the dowel. 

That is really all there is to it to compare them.

Regards,

Paul Vanderheijden

[alapimba]

Hi

At the moment i only have a 600 flywheel (in the stock engine in my car and i didn't wanted to remove it or do any modifications on it, once i place another engine in the car i want to remove this with with his flywheel and clutch and just store it).
I have the 903cc flywheel from the engine i bought (fiat 127) but it seems it wont be of any use, right?
What should i look for? an extra fiat 600 flywheel or a 850flywheel and a fiat 600 flywheel to remove the king gear?

Btw..this is the flywheel i have at home from the 903cc fiat 127 engine:


Best Regards.

[alapimba]

in spain they seems to have this clutchs for the later seat 600. isn't this enought for our engines?
The pressure plate seems similar to the ones from the 850

[Paul vander Heyden]

Alapimba,

I cannot answer your question, as I have never worked with the Seat clutch.  I am afraid you are on your own on this one.

Regards,

Paul Vanderheijden

[guy moerenhout]

I have use this already and works well.You have also a easy shifting(softer pedal)

[grant gauld]

Chilli con carne also works !!   

[grant gauld]

Another nice advantage in using the high profile finger pressure plate (seat and Scuderia Topolino) is that it will mate up to the the throw out bearing of a 600D.When swapping Renault/Fiat/Lancia/127/A112/850/600 etc clutch kits people notice the direction of operation most times but occasionally over look the bearing shape and depth on adapter.

[Paul vander Heyden]

Alapimba,

While I have not personally used the Seat type clutch, I can make some observations.

1.  The curved finger arrangement is very similar to the Valeo brand Fiat 850 clutch, so it should work the same.
2.  The raised curved fingers work well with the standard Fiat release bearing.
3.  The "pressure ring" retaining mechanism is different to the 850 type and MAY cause some interference problems when used with a FIAT bellhousing.  The Seat bell housing is slightly larger internally.  So if you have a Seat transmission, then there should be no problem at all.  Note:  The larger bellhousing is not the only thing that is different about the Seat transaxle.  Seat also use much finer teeth on their gears, so they are not interchangeable with those from a Fiat transaxle.
4.  I cannot see how the pressure ring is "strapped" on the photograph.  These are small metal straps that are designed to keep the pressure ring flat when it engages against the friction disc/flywheel, ensuring full contact.  WIth the Fiat 850 the straps are installed in the opposite direction to most other pressure plates, because the engine rotates in the opposite direction.  Most people recommend to reverse the straps on the Fiat 850 type, but I DO NOT.  As small Fiat motors do not make large horsepower, the need to have the straps in tension under "up-shifts" is not a major requirement.  However, for "down-shifts" exactly the opposite is true.  On a down-shift you are going from a low torque situation to a much higher torque situation in a lower gear, PARTICULARLY if you are using the engine to slow down the car.  Therefore the clutch would last MUCH longer if the straps provide good pressure ring control on down-shifts. 

If this were a high horsepower application, where there is a high-torque environment in both up-shift and down-shift directions, then I would strap the pressure plate so that the straps are under tension in both directions.  After all, if you look at the arrangement in a Tilton multi-plate competition clutch, this is exactly what has been done.

In a perfect world, you would use the brakes to slow a car down, then put the gearbox in the desired gear and accelerate.  In this way each of the parts of a car are performing the job they were designed to do.  After all brakes can slow a car MUCH faster than downshifting through a gearbox.  Not only that, they are much more efficient at absorbing the heat generated by the braking action.  At a recent racing event I observed another by-product of incorrect downshifting, when a competitor down shifter from 5th to 4th gear when approaching a chicane.  The engine RPMs went up and suddenly there were large pieces of metal coming from the rear of the car.  Can anyone guess what happened?  Give us your answer !!

Best regards,

Paul Vanderheijden
www.scuderiatopolino.com