Gearbox mix and match

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Dr Goggles
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Gearbox mix and match

Post by Dr Goggles »

The Belly-tank Lakester that we're building needs a REAL short drive train and so we're running a V6 and shortening an Aussie gearbox (6 cyl HX).Initially it was going to be 3speed , I mentioned to Rod Hafield at one point that we were using a 3 speed synchro and he said "that's the one you want"...I'm not sure why .Now we have a 4 speed .The reason for using the 4 speed is because with the reverse gear removed there is no need to cut a new spline when you shorten the output shaft , cheap!. So now its a 4 speed with no reverse .The only difference between the 3 and 4 speed is a small step on one of the gear splines and the method of locating the input bearing apart from of course the outboard reverse idler., I think .I'm wondering whether Rod meant that the shaft was stronger in the 3speed or is it something else ..

What I'm hoping someone can tell me is .What items are interchangeble between boxes , shafts? , , how do the 3/4speed cases vary?and in the case of road cars what are the points most likely to fail in the old Holden gearbox , does the four speed have an intrinsic weakness? I'm about to spend a bit of dough shortening the extension housing and they vary between the two so I'm interested in feed back on that one.

Meanwhile I just got the shortest tailshaft ever made up and balanced...this week Graham Robinson is finishing our straight tube front axle , 30 degrees castor no less!....fast things are slow to build though....................
Norm
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Post by Norm »

The first question I have for you is how long is your tail shaft?

At Gnome Racing we still use a stock aussie 4 speed behind a Chev 292 and havent had any problems to date. (touch wood). From our view its the way you put the power to the ground. You have to remember its not the drags or street racing where you load everything up in one go. We just take it easy. Some people will say you have to have ues bal bal bal.

Hope it helps.

Norman
Gnome Racing
SIX IN A ROW THE ONLY WAY TO GO
Dr Goggles
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Post by Dr Goggles »

Hi Norm
I made a mistake there , the "method of locating the input bearing " should have read " output"...and what I was wondering iiiiiiiiis..in the 4speed the bearing is held in by the transfer case whereas in the 3speed it has a ring I thinks...we most likely aren't going to be torturing it too badly but I'd like to know what to expect . Likewise I don't want to spend money going one way only to have someone who's seen thousands of them say ,,"oh , what you should have done .." after I've spent the "silly money"... In answer to the tailshaft question , it's got about an inch of tube between the ends .

I'd noticed you were running a "big block" six...we'll be in a similar power range . We've got a set of dished pistons for our Buick that should be around 252ci ,they were found NOS along with a bunch of hot cams..Eaton blower.and an assortment of manifolds .so the Buick will be a keeper rather than a dummy for a late model ecotec or such .It's something kind of unusual , and it's turned out cheap(kind , sorta) so we love him.

I'm hoping to avoid the real hard yards of just sitting down and trying to swap all the parts between the boxes to see what works...I want the four speed shaft , I'd like the 3speed box(more metal) reverse would be handy and in our speed range (150+) I don't think the in-between ratios are going to be an issue so really I'd like to get the 3 speed guts around the four speed shaft...I suspect that I am trying to do something that few have bothered to try and less would think a worthwhile pursuit , which kind of sums up more than a few things here I guess .
Dr Goggles
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Post by Dr Goggles »

Hi Norm , just another thing , I noticed you suggested the use of bal, bal, bal..........I can only assume that means Balancing , Ballast and Balls!!....BTW you're part of the "six in a row , way to go " push .I've always had 'em but this time I think we're gonna have to go with something like " two lots of three is fine by me".....
Dr Goggles
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Post by Dr Goggles »

We've just gone ahead with it , no-one stuck their head up and said hell no! so we just did it....The only problem that I can forsee at the moment is that the mainshaft now has no stress relieving narrow waist anymore.....meaning that the spline could well be the weakest part of the shaft .....added difficulty in the shortening process included making a mount because the old one was part of the ex'housing and is now gone ( ye cannae weld to nodular iron )and getting the shortened housing tig welded ( it became a Chinese gymnast contorting itself beyond recognition)...We now have a box and tailshaft that is shorter than the box used to be .This is money that all you production guys get to spend on engines so you can laugh, yep , you'd have to be mental to build a belly tank .
gazza414
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Post by gazza414 »

Hope you do well Googles. Maybe as a safety / confidence factor would be to have the spline checked for micro cracks before installing. If there isnt any stress relieving in the design it will be prone to failure especially if alignment is an issue.

See you guys in March :D
1 FAST HAYABUSA 217.443mph so far
9 Official Timeslips over 200mph
Very much the apprentice
Dr Goggles
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Post by Dr Goggles »

Thanks Gooza
The idea was to make the parts unique to what we need ( der ) to use an M20 Aussie 4 speed ...we can get shafts for bugger all , there may be a way of leaving a gear out in order to machine the shaft down but I haven't done the homework on that yet so as far as full stress analysis it's er, more like cut the f...er off there! ...we'll be going with a lot of spares me thinks....break lots of parts , maybe break a record...more like broken dreams...we'll see......oh yeah BTW you mentioned "see you in March " ...how come , what's on then? 8)
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Reverend Hedgash
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March?

Post by Reverend Hedgash »

The Commonwealth Games dummy... everybody will be in Melbourne.
DLRA Member#412
Dr Goggles
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Post by Dr Goggles »

The gearbox is done .It needed a new first gear and the shaft was goosed as well , apparently you need to put oil in the things....news to the previous owner by the look of it . I took it to a mechanic I've known for years ..he donated the shaft we needed..so he was well worth the three hours I paid him for..My shed ain't "clean" so those type of builds are best done elsewhere.

Our seat , dubbed the "Vaughn seat" after a local fitter who suggested it is made out of the inside edges of two HQ inner guards welded up the middle , we ran a piece of 1/4 rod around the outside of it and a piece of sq. tube across the back to stiffen it with a bit of heavy strap under the coight bit ...we got our harness ( 7 point) and so with a "driver " in it we worked out the best loc' for the mounts and have marked the seat where the belts will go through it....everybody had a sit in it , even Ben's girlfriend Christine who reckoned there was "heaps of room"(she's like ,3 stone)....even Graeme our engine man sat in it .

With the harness came our new suit , boots and full underwear sets..let me just say they'd be great in a blizzard but no-one in their right minds would think of wearing an outfit like that in the middle of a friggin' desert......

Commonwealth Games ?......aren't you in the potato race Gashie?

Dr Goggles
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
momec
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Post by momec »

Forty four in the shade in 2003 and I did the start line with no cover for several days.
Still better in a race suit than these bloody mad bikers in black leathers sitting on a polished aluminum bike in the sun.
Just degrees of madness I spose

Serious question Doc. Who'ed ya buy the suit and undies from and can you recomend them. I have to bite the bullet and spend the money and as we all know the clocks still ticking.
Thanks Chris
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Reverend Hedgash
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Post by Reverend Hedgash »

Hey Chris,

Reverend H here, co-conspirator of the belly tank project.

We purchased our suit from Revolution Racegear and I recommend them thus far thoroughly.

We were very lucky in that the suit was on special. It is a 2 layer suit and has the appropriate SFI credentials. It cost only $199. There are a few other suits there on special but they were of a smaller size. (Both the good doctor and myself are over 6'1.

They have the full cams approved long johns at $199.

This was the Mitchum store (Whitehorse Road Melbourne), they make the suits upstairs.

They make boots too (in China though) and have a range of gloves.

We also bought our seven point harness there.

Hope this helps.

Bless you.

Reverend Hedgash+
DLRA Member#412
momec
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Post by momec »

Bless your nomex sox to Rev and thanks for the good oil.
Chris
Dr Goggles
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the rev

Post by Dr Goggles »

....I can just see it now, the Rev' in a black flame suit , white dog collar with one of those smoking incense wand things blessing the car on the start line...here endeth the lesson.... :twisted:
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
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