My rebuild!

Please post a pic of yourself or your car tell us about yourself and let us know where you are from.
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75evo
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Re: My rebuild!

Post by 75evo » Sat Feb 23, 2019 11:01 am

the OliverMobil

https://youtu.be/l3J-cXazB2Q

This car got black flagged for sound at Zandvoort when an F1 car didn’t , LMAO :lol:
Epic sound!
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75evo
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Re: My rebuild!

Post by 75evo » Sat Feb 23, 2019 11:06 am

Just one thing Jules, another perspective, we’re not getting any younger. If you keep on having very high goals for a project, you’ll eventually give up or move on to something else. Seen that happen, as I’m sure you have too.

Keep it real mate. Not saying it can’t happen with the Vette box, but what about driving an 8000 rpm 3.2? It will eat bearings, but you’ll be driving it next month. Remember when you used to do Donuts in your 2.5 v6 10-15 years ago? Life was much simpler and realistic. Brace the clutch housing, the Kevin to build you a donut cage, and send the driveshaft to Beninca’s . Sorted. :mrgreen:
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SydneyJules
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Re: My rebuild!

Post by SydneyJules » Sat Feb 23, 2019 9:53 pm

105 GTA, you’re in Melbourne, I believe? Please PM me. I would love to have a look at your car. I saw the post in question last night after typing my other post. It looks awesome. Would love to see how you got it onto the pedal box.

Apparently the 75 TS booster is a better fit than the 116 and 119 booster, but like everything else, these are getting harder to find!

I completely see both points, Z and 105GTA-

In terms of pushing things and the timeframe?
A TS box is a nice thing, but i don’t want to worry about breaking it all the time.The tailshaft was a Beninca tailshaft! It was done years ago and only gave trouble at the end.

These parts are getting old too.
My front yoke had started to splay out at the ends from the revs when we pulled the 2.5 (8,000 is a lot of revs when factory limit is 6500 and the parts are 30 years old).

I don’t think that a 3.7 and a TS box can be comfortably pushed to any sort of limit. Kevin’s experience racing the 3.7 was that he started to break things. The AHM built 3.8 has a straight cut gear set in the Green GTV6.
I don’t want a straight cut box and the cost is ridiculous.

As for ratios, have you seen how much is available for these boxes?! Carbon fibre synchros... ratios till the cows come home!
The main thing for me is, it’s finally a driveline that maintains the character of the car (transaxle, still with de Dion), fixes what Alfa probably should have done initially (clutch up front, torque tube), the parts are more modern, tougher (700hp blown LS engines with stock boxes) and there are more options available to the end user (gear sets and rebuild parts etc).
Complexity?
Cutting sheet metal out and refabricsting for a tunnel is nothing new. Guys have been doing that in australia since the 80s.
Bellhousg adaptor plates are the same.

Time will tell.
The process should hopefully start soon.
I will post photos 😊
Fixing it bit by bit....
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MD
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Re: My rebuild!

Post by MD » Mon Feb 25, 2019 2:49 pm

Instead of a large diameter clutch plate requiring even more customisation, why not consider multi plate clutches like they have on high power motorcycles?
https://www.youtube.com/watch?v=AnySycF6aTM
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75evo
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Re: My rebuild!

Post by 75evo » Tue Feb 26, 2019 8:42 am

Oh look MD is still around :mrgreen:
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MD
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Re: My rebuild!

Post by MD » Tue Feb 26, 2019 2:03 pm

Unfortunately I am getting more round as time goes on.. :D
I have never been away. Just keeping a low profile to stay away from that pesky Greekster. Anytime soon they will be removing the white jacket he's been wearing for years and my fear is that he's going to hit that keyboard to get square after I reported him to the authorities for suspect behaviour.

...and Jules, with all these mods you are proposing, please measure the thickness of your wallet and let us know in metres. We all need a dream.
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75evo
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Re: My rebuild!

Post by 75evo » Tue Feb 26, 2019 8:34 pm

He has given up on this forum and is now extremely active on Farcebook. People there worship him, some confuse him for Zeus’ long lost son. I suggest you step up your efforts, Get a Farcebook account and put him in his place.

Don’t worry Jules, measuring the thickness of your wallet using a feeler gauge is quite normal....

:D
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Re: My rebuild!

Post by MD » Tue Feb 26, 2019 11:47 pm

I told you he was a low life. :mrgreen:
No chance getting me on Facebook. It doesn't have any centrefolds.

BTW Jules, how long does that piece of string have to be for you to get the kite back home?
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Re: My rebuild!

Post by KevinR » Thu Feb 28, 2019 1:06 pm

Hi Jules
I have just seen your post and so sorry hear about your nightmares .
Just some observations from my last year of racing with my 3.7 with gearbox in the place it came with and correct place - at the back . I think I did twelve races and no failures and the two years before that I had about four gearbox failures mostly crown and pinion and two clutch housing failures . So what changed to have zero failures ..
1) I changed the oil to redline 75w90NS
2) I moved the brakes to outboard
3) installed oil cooler
4) used MD design on clutch housing
5) kept all rubber in the prop with cages on front coupling only and aligned and braced engine
6) most import I had brilliant Gripper LS made with awesome ramp angles with a design that gripper uses that puts less shock into the box
7) definitely NO first gear pull offs and barely used second in anger . Even drove like this on one of our tight tracks and sacrificed 0.5 of a second for a whole season of no failures . Noted that only possible with huge 3.7 torque on my 10:41 box .
8) stayed off slicks and used 205:50:15

So in the above points the redline oil was critical even though my previous oils are EP and Gli4 or 5 with LS and and Synchro additives . Moving brakes outboard with cooler and side exit exhaust removes a lot of heat out the box this also reducing expansion and tolerances of the gear sets / pinion tolerances .
Most breakages I had was under hard second gear to third changes. But having the 3.7 I was so far ahead of the other guys I never worried about backing off a bit there .

When I sold car I put a mild 3.0 12v and the owner has raced it for past five years and box is still holding out other than replacing the Gripper clutches which comes in a pack of seven . My mates here in SA who race 3.7s with boxes in the back still break and bend shafts but they really do push them hard and that you can’t do .
That 3.7 which Glenwood built back then is in my front mount box car which I can totally abuse and drive like do*#% and not break anything so other words suits me fine !!
Now Jules one thing I did learn on the front mount box set up was the small 184mm Ap clutch twin plate definitely only like track use but I did not know then what my other options were . I have now a bigger 240mm M5 clutch with another flywheel and that whole set up is still under 10kg which is 5kg lighter than the standard GTV flywheel !
The shock waves on the ap clutch also created more wear on the sinntered plates rivets and affected gearbox bearings . All this is solved with my m5 spring organic clutch .

So where does is leave you ... go 3.7 with box in the back and keep it smooth and you will probably find you will be faster ..
If you do break a few boxes then go the route i have which is not massively expensive ...
oh my cams in my 3.7 are GTa 1 and Gta 2 ... you reckon yours are mild .. I think they are bit to wild ( maybe my imagination) and thinking of going less wild ...
Cheers
Kevin
Last edited by KevinR on Mon Mar 04, 2019 10:00 pm, edited 1 time in total.
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Re: My rebuild!

Post by 105gta. » Fri Mar 01, 2019 2:01 am

SydneyJules, pm sent
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Re: My rebuild!

Post by SydneyJules » Sat Apr 13, 2019 6:14 pm

Thanks so much for the write up there, Kevin.

I’ll check that out in detail and digest it, because it’s going to be a bit more relevant than I originally thought.

Having just sold my TS box to a friend, an engineer in my new home town of Melbourne has told me that he probably wouldn’t be able to engineer a corvette transaxle conversion because of the physical size of the gearbox - it sits a lot higher than an Alfetta box and I would need to remove a fair amount of floor to fit it.

I revisited the Maserati conversion and it looks like it will be much more achievable.
The problem is, the parts to manualise the box that are available total ALOT of money. ALOT! As in, I could buy a whole car for the same amount...

This means that in the interest of expediency, I’m going to fit a stock transaxle to the car to get it registered so that I can enjoy it, and work on my conversion on the side.
There could be a twist that I’ll let out of the bag soon enough.

Kevin, perhaps you can point me in the right direction, but I was probably going to try and get hold of a 75 3.0 transaxle. The rare (and very desirable) 75 potentziata box (3.7:1 diff ratio) is impossible to find.
I was going to settle on a 3.0 transaxle with the 3.53:1 diff ratio, then swap in a GTV6 2nd and 3rd gear, to bring the ratios a bit closer together-
Long 1st, shorter 2nd, slightly shorter 3rd, stock 4th and moonshot stock ratio (when combined with the long diff) 5th for the highway.
Hoping that the extra torque of a 3.7 will work with the long gears...

On the shopping list next, are some Pauter rods and a flywheel and pulley combination From AHM.
Fixing it bit by bit....
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Re: My rebuild!

Post by Giuliettaevo2 » Sun Apr 14, 2019 2:02 am

Another gearbox in the right shape for the gtv would be from the porsche 928. Strong gearbox but also quite rare in manual.
Drive it like you stole it...
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75evo
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Re: My rebuild!

Post by 75evo » Sun Apr 14, 2019 5:39 pm

What's wrong with a 4.10? The 3.53 really blunts the acceleration. Afterall this will be a fun car, not a highway cruiser.

Just prep the gears properly, and use all the parts we've documented on this site, cooling, bracing, new billet bearing center piece, and you should be good until you get an Albins in there.
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Re: My rebuild!

Post by SydneyJules » Tue Apr 16, 2019 3:58 pm

Albins lol now you’re talking, Z!

Z, I have done a few ratio comparisons and a 90 box, with shorter (same as Alfetta) 1st and 2nd, but with longer diff gearing, has very similar shift speeds to a 75, and then third is 20km/h faster and 4th is about 35km/h faster and tops out at 240.

The idea is to be able to chew up big distances by having a long fifth, but still have the car useable through 1-4 for track days and twisty roads.

I feel like it would be all over very quickly with a 3.7 and 4.11- and Kev, please weigh in on this at any time!

I really wish there was an aftermarket 3.73:1 or 3.9:1 option for diff gears!

GiuliettaEvo2, I went down that rabbit hole as well and it was actually the 928 T56 conversion that got me thinking about changing the box to a corvette T56.

The Maserati M138 box is by far the most compact and is very close in size to the Alfetta box from the clutch back (Maser has clutch at the engine). Pity about the linkage points and brackets off the side. A slick shifting, 6 speed transaxle in a GTV6 is still a dream...

I’m going to have to do some bracing and fit a transmission cooler for sure.

I’ll try to get a shot of the two boxes next to each other.
Fixing it bit by bit....
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Re: My rebuild!

Post by KevinR » Thu May 09, 2019 1:01 pm

Jules , that crown and pinion you sold me ages ago is still successfully been used on a 3.7 . I think you sold it then as it was so ridiculously tall. So yes I would go down this route sourcing the super long final drive from the " as I call the American 3.0 75)
With the 3.7 it will still pull like a train with all that torque. Nearly all the 3.5 GTV track day toys here use that box and due to those been less stress full ( taller ratios) we have not had any failures .... But those are not race cars !
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