Tuning Stilo 2.4 rebulid

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Tuning Stilo 2.4 rebulid

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Having owned my wonderfully interesting and highly entertaining stilo Schumacher (christened Enzo :)) for two years now I've found myself pondering a few things. As a petrol head I've never been able to not fiddle with any of my cars so it wasn't long after buying Enzo that my thoughts turned to how I could get more performance from the 2.4 20v motor. In standard tune it pushes out 170 bhp which I've always thought was pretty weak (when you put it against the Clio 190 or the Mondeo ST 220) now there's probably a very good reason why this is so but that's a different subject altogether.

In the two years I've been pondering and researching possible engine upgrades Enzos "to do list" has been increasing - the gearbox has a whine in second and third, there's a tapping noise coming from the top end, an oil leak, the air con pipe has snapped off at the compressor end and just recently the clutch concentric bearing has announced it's retirement and is currently working its notice (I don't think it'll survive another winter) so I've been faced with a decision ....... Do I cut my losses and sell it for something else (the easy option) or spend some pennies and fix the problems and possibly upgrade a few things to satisfy my urge to create a stilo abarth more befitting of its Schumacher status (the more complicated and stressful option) ........ Well I like a challenge and I do love my stilo so I've decided to rebuild the engine and gearbox with a view of fitting some upgrades along the way :)

So I've started this thread to show everyone my progress from start to end and hopefully it will be useful to others and also sort a few myths out along the way. I'm not certain on the upgrades I plan to do yet as its all down to price and my own personal confidence so ill explain along the way :). What I can say is that I plan to give it a full comprehensive rebuild (new belts gaskets seals etc etc) and to take plenty of pictures to show my progress and to give a better understanding of the 2.4 engine.

So where do I start? Removing an engine/gearbox assembly stripping it and rebuilding it won't be done in a weekend especially as I need to use the car daily so I plan to do some of the work off the car so I've acquired a cylinder head to modify and rebuild and another gearbox. This will shave a lot of time off when the rebuild happens as I won't be messing around rebuilding the parts on that are currently on the engine. I realise this is more costly but it means I can do the work at my own pace and time.



So to answer my question I've started on the gearbox, acquired for sum of £95 .I had been previously quoted £250 and £300 before this one so I see this as a bit of a billy bargain ........ Providing that all the innards don't just pour out as soon as I open the case up, in which case ill have just wasted £95! :eek: so wish me luck not sure when this will all be finished but it'll keep me out of trouble :D
 
if you want to dissaseble your engine to the last bolt and nut, I strongly recommend to modify pistons - additionaly drilled holes under the oil control ring wil prevent from enormous oil consumption when the cylinder tolerances will be on the upper side

like on this link...
http://www.alfa147club.nl/forum/viewtopic.php?t=6957&start=0

its a commont topic for all AR TS/JTS/ Fiat 1.6-2.4 engines....

you can also slightly increase the compression ratio with bespoke pistons (even slightly increase the volume of the engine by overboring to 84mm..) with flat head (standart has 2mm deep bowl..) and remap from FC performance...
 
Thanks guys all links and advice are most welcome, I have looked into lightened internals and given the price I may not go down that road but that's not the final say as it depends on my budget and a rebore is a deffinate no no as I don't have the time to take the block to an engine specialist. I was thinking perhaps fast road cams, gas flowed head and perhaps bigger injectors? But it's early days so I won't commit to anything until I get stuck in :)

Honza that's quite interesting what you say about the pistons? I hav'nt heard of that modification before? How does is help? :)
 
I think what honza was getting at with the pistons was to remove the bowl with new pistons to increase the compression ration - squeezing the air and fuel into a tighter space to make more power :)

No I meant about the drilling of extra holes to help with the oil compsumption :) mine drinks it! I figured it might be the piston rings worn
 
Good luck with the build Gadge. Are you sure that's an Abarth gearbox? It's just that I can't see the characteristic dipstick on top...

Yeah it's deffinatley the the right one, the dipstick is present and correct on top of the differential :) just had it all apart and it looks pretty good! (y)

 
Ok I kick started the rebuild today by stripping the gearbox down and inspecting whether I had bought a box of serviceable gears and bearings or a box of lemons...... And to my surprise and joy I found nothing to be alarmed about - the gears all looked fine and I was able to select all of them by hand what's more the bearings looked in excellent order in fact I'ld go so far to say that this box doesn't look like its done a lot of work at all so happy days indeed. It must be said that unlike some fiat gearboxes this one seems very well built as the gears are moooohassive! It has to be one of the heaviest car gearboxes I've ever handled :D




So with the gear shaft assembly's and selecting rods all to one side I was able to clean the casings down ready for a lick of satin high temp paint


And then all un painted areas were then masked off and the compressor pressed into acton.......... Just hope I can do what all the kings men couldn't do and put it all back together again without any drama
 
I know mate I must be! Lol :D but it i can't ignore the faults for much longer so I might as well fit some goodies along the way whilst I have the opportunity - plus it sounds like fun! (In my head anyway :D) ......... And I'm still plodding along with luigi but Its problem after problem and I keep turning my attention to the stilo! ...... I need therapy lol
 
It must be said that unlike some fiat gearboxes this one seems very well built as the gears are moooohassive! It has to be one of the heaviest car gearboxes I've ever handled :D

I think the gearbox is a C530 and directly related to the one fitted to the Alfa 164 where it copes with the torque of a 3L V6. I've had several 164s including one just before my first Stilo (in 2006) and I remember spotting the identical dipstick on the diff housing.

I've never had a problem with a 164 gearbox - even one with 320,000km on the clock - the gear change would get a little notchy/tearing/metal-against-metal feeling but the synchromesh still worked (would never grind a gear). I think the Selespeed version for the Stilo has even stronger synchromesh.

One of the characteristics of the C530 design is that some of the synchronisers are placed on the input shaft, and some on the middle shaft. This reduces the rattle noise when the engine is idling (I remember that often with early FWD FIAT gearboxes - 128/127) and also the synchronisers can be made wider.

One thing though, I think the whine in third gear is characteristic, as my first Stilo did that when I got it, under three years old with only 15,000km on the clock. I suspect in a 164 it is not audible due to extra soundproofing, but I bet it's there. (When I removed bulkhead soundproofing from my Uno Turbo, the most noticeable new sound was whining from the gearbox in several gears; therefore I believe soundproofing is effective at blocking gear whine).

Anyway - just to say I agree, this is probably FIAT's best gearbox (the six-speed in my Spider would run it close, but those have a habit of blowing diffs). I was told it started off as the Lancia Beta gearbox, but I know there were a few modifications made for the 164 application (such as, offset selector forks) - and I reckon the early 164 was quite possibly THE best quality car FIAT/Alfa/Lancia have ever made, considering the engineering, performance, and reliability on offer (solving the problems of earlier models while avoiding the weaknesses of models made since) :eek:

-Alex
 
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That's outstanding knowledge you have there on fiat/alfa gearboxes Alex :D that would explain its quality and robustness design and I must admit I am quite impressed with how well built it is (I also heard on the grape vine that this box is also shared on the alfa 147 gta aswel so I suspect you may well be right in saying its an alfa gearbox). Unfortunately I never really drove another manual 2.4 so I ave no basis for comparison however just like you mentioned my gearbox slips in and out very nicely and doesn't rattle in neutral either but I can't help thing that its gonna let go soon as the whining just doesn't seem normal? It kind of sounds like a mini supercharger winding up?
 
Ok I finished work early yesterday so I grabbed the chance to reassemble the gearbox. Looking at the freshly painted case and all the gears and other asocitated parts it was clear that it wasn't going to go back together as easy as it came apart. So the kettle was boiled, and a coffee was made as I pondered how I was going to squeeze it all back in. And I was right, it wasn't easy and after several attempts I still had a table full of gears and an empty gear case. The kettle was boiled once again. The problem I had was space and I didn't have much of it! In the end I had to insert both gear shafts, the linkage and the reverse idler all as one piece as it was impossible to do it piece by piece, and being covered in box oil didn't help matters either but in the end I was victorious! :)


Once the gears were all in place everything else was pretty straight forward and before long I had a nearly fully resasembled gearbox on my bench - I say nearly as I haven't fitted the diff yet just the cover.
 
and finally all back together (minus the diff) :). and just for the eagle eyed...... you can now see the dip stick on top of the diff case (y)


oh and just an unrelated quirey but how do I upload my photos so they are nice and big as opposed to the tiny ones I have at the moment?

You legend (y)

Fab work there bud, If I was near by I would have loved to get my hands dirty and give you hand, plus also learn some new skills at the same time..... and I can make a mean brew too ;)
 
I am also deeply respectful, as getting gearboxes back together is a fiddly puzzle :eek: There's always some part of the selector mechanism that 'hangs up' - and there's those bullet-shaped interlock plungers that are so tricky to get in place. When I was 9, I 'helped' my Dad put a 128 gearbox back together... it wasn't until it was back in the car when we realised it was stuck in two gears at once... I had wondered about those leftover bits, but had kicked them under the workbench.

I've hardly ever taken gearboxes apart since! :rolleyes:

I think the last time I pulled a gearbox apart was to replace an input shaft bearing on a Croma gearbox (similar again I think), when I worked out that leaving the input shaft in the freezer made it easier to get the new bearing on.

I wonder if your other half can still smell the gear oil around you...

I'll be watching this thread with interest to see how you go with getting more power from the 2.4. It's a good idea, as you've had the standard engine for some time, so you'll notice the difference. I know it's often thought that 170bhp is on the low side, but it's a better specific output than even the 80bhp 1.2 16v. Unlike the 1.2, the 2.4 delivers its torque over a much wider rev range, has lots of torque down low. I wonder if tuning for an extra 20bhp at the top end might compromise the torque below 4000rpm. With variable valve timing and variable inlet manifold, maybe not? Just a compression boost (98 octane petrol), improvements to the port smoothness, and a remap might get an improvement over the whole rev range and inspire us to do the same? I am genuinely interested :)

About the oil ring issue. While I had my Twinspark apart (late CF3 version from 2003 156, Singapore-only, other markets had the JTS) with the narrow 2mm oil rings, I machined out the piston grooves and fitted 3mm oil rings intended for the earlier engine. No need to drill holes in the piston - the earlier rings have long slots that work properly. Oil consumption was greatly reduced from 1L/800km to 1L/6000km. I also gave the head some work smoothing out the ports, and was rewarded with amazing fuel economy (not necessarily more power, but it certainly ran sweetly after the fettling).

-Alex
 
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