Alfa V6 into 73 Spider

[adelspyder]

All the parts for the diff and deDion have arrived, and with the measurements that Remco provided, the install now begins!

The following photos show the trial install (tack welding only) of the deDion, including the front mounting beam and the spring/shock absorbers.

More trial fitting to follow in the coming days (hopefully it all fits cleanly),

Dino

[giuliettaevo]

Here are some pictures off a Sei bellhousing. The gearbox is somewhere in the shed, didn't have time to dig it out...






The holes where the bolts go through are about 80 millimeters in length, or 3".

greetings Remco.

[adelspyder]

deDion Suspension Install

Progress has been painstakingly slow the past two months due to my brother’s travels overseas & interstate, and the shop’s other work commitments. As a result, the fabrication still continues, but unfortunately without much to show for it (hence the lack of photos).

Planning the sequence to install everything was the first part of the challenge. Mounting the shortened deDion and the 75/Milano deDion front mounting beam was first (as simple measurements like the track can’t change), then the diff was positioned, aligning it to the driveshafts, tailshaft, setting pinion angle, whilst leaving space up top to change brake pads, run the handbrake cable, etc. Then you measure up & make the top mounting beam and the bolt on brackets to properly locate the diff, etc.

The top diff mounting arm is nearly ready, and it took several trial fittings to get to this point!

Meanwhile, the Sei diff has been stripped down, the cast iron nose has been removed, and the 50cm shaft within the diff nose has been cut down, shortened and tack welded true. The shaft (now less than half the length) is awaiting final machine welding and machining along the entire circumference for proper strength. The shorter aluminium diff nose is almost ready for trial fitting, and once this is finalised, there still needs to be a mount made up to bolt to the front of the diff nose to the body (this will limit the diff’s twisting motion in a vertical plane).

So while the critical mounting and location of the deDion, diff, springs & shocks have been set, there’s still the watts link, driveshafts, discs and calipers to be fitted.

Gearbox purchase

In earlier posts, you would recall that Stage II of the build had a Getrag gearbox slated to replace the Alfa ‘box. Well, with the recent strength of the $A (and the weakness of the $USD) he’s brought forward the plan to buy the Getrag. Right now, he’s just taken delivery of a rebuilt one from the US, and he’s in two minds as to whether to get the car on the road as-is with the Alfa box, or to just bite the bullet and start making a new bellhousing pattern to fit the Getrag.

That’s why Remco posted the photos of the original Alfa Sei (ZF) removable bellhousing earlier on the page – my brother’s just doing a little bit of R&D!

We will try to get some photos this weekend to post onto the BB – believe me, the pictures of the two gearboxes side by side will surprise!

More to come soon everyone,

Dino

[adelspyder]

The photos pretty much show the amazing similarities in dimensions between the two ‘boxes, but the larger size of the Getrag’s input shaft and bearings should be evident. And the more he is looking at the Getrag, the more he is leaning towards trying to fit it earlier into the car.

With the V6 planned to have between 230~250Nm, my brother really wonders whether to pour another AUD$2.5~$3k into the Alfa ‘box it for better / stronger gears (and still have a slow-shifting box with the infamous Alfa synchros), or upgrade to a stronger, more refined gearbox.

The early version of the Getrag 265 (a five speeed) was chosen for the following reasons:
. would take 350Nm of torque in standard form (no mod’s required)
. close in weight to the Alfa ‘box
. close in overall dimensions to the Alfa ‘box (little or no change to the tunnel)
. has a removable bellhousing (easier to adapt the ‘box to the engine)
. the shifter location is within 3/4” of the Alfa box (no change to centre console)
. fairly plentiful (used in BMW’s, V12 Jaguars, etc.)
. a BMW-sourced Getrag has an output shaft setup for a stronger Guibo
. a better shifting ‘box, with improved synchros (late 70’s / early 80’s boxes even have a synchro-type setup on reverse gear – and yup, that’s the one he found!)

The only major items to be built would be a different 1st gear ratio to better suit the Spider, and of course a new bellhousing to mate it to the V6!

Thanks for looking everyone, and have a Merry Christmas!


Dino

[adelspyder]

With the car still having the deDion and Sei diff installed at the engineer’s workshop, (yeah guys, progress is slow here, so no photos – apologies) there’s little more that could be done by my brother at home, so he’s decided to start the pattern for the Alfa-Getrag bellhousing.

The photos show the beginning of the pattern process required for the sandcasting. The two bellhousings have been cut and glued together with metal exoxy, the Getrag bosses that were used to mount the bellhousing to the engine have been removed and ground smooth (as they didn’t align with the Alfa V6 bolt pattern), and the starter motor cutout removed from the Getrag bellhousing (this needs to be kept and repositioned in the pattern).

A lesson learnt when the first bellhousing was cast was to make the front bellhousing a full circle design, allowing the finished bellhousing to be thinner, lighter and suffer less distortion than the first one.

The inner diameter measurement of the Getrag bellhousing revealed that clearances would be tight (especially when some shrinkage would occur in the casting process). Therefore, the diameter of the inner bellhousing was opened up 1.5mm to allow for pattern shrinkage and giving acceptable clearance for the starter ring gear.

So far, the bellhousing pattern fits the confines of the Spider trans tunnel, and maybe the rest of the Getrag will too (it’s too early to tell, but once the bellhousing is made and can take the weight, the final fitment will show if there is enough clearance).

All of the metalwork has now been done on the bellhousing, with the next stage being to build up the pattern with fibreglass to the required thickness (need to slightly oversize it as well, as it will slightly shrink in the sandcasting process), add new mounting bosses, and finally paint and sand smooth so it will form a neat pattern that will cleanly release from the sand mould.

The plan is to have the bellhousing made and the Getrag installed in the car in the next few months. If all goes well, the deDion and Sei diff should be installed by then and the prop shaft can be made to mate the two together.

[Tifosi]

LOL

That's entirely too cool!

[adelspyder]

Work on the bellhousing continues, with the next stage being the building up of the pattern around 1.2% both in width, height and thickness to allow for shrinkage in the casting process (e.g. a 350mm measurement becomes 354.2mm, so 4.2mm has to be added to the pattern).

If you look carefully at the photos, you’ll see that 2mm plastic has been added to the top and bottom of the bellhousing, resin has been added around the circumference near where the bellhousing bolts onto the engine, and the inside has had some fiberglass and resin added to the thickness in the area behind the starter ring gear.

Mounting bosses have been made using plastic conduit cut to size, and will be filled with resin. To retain access to the original holes mounting it to the Getrag ‘box, these will be filled with wax allowing the mould to be made, with gentle heat allowing the wax to be removed at a later stage (if required).

Next is the modification to fit the lightweight permanent magnet 164 starter motor, adding reinforcement ribs to the mould, then 1~2 coats of paint and a fine sanding to allow for its smooth release from the pattern prior to the casting of the mould.

Now, while we have a lead on a company that might sand cast this in Magnesium, would any other Aussies on the list know of any other places in Australia (preferably in Adelaide or Perth) that may also do Magnesium sand casting (just in case the first lead falls through)?

Many thanks guys,

Dino

[giuliettaevo]

That is really impressive! i have made a metal adapter plate to use the BMW-getrag gearbox with the alfa v6 engine. lot easier to do but sure as hell not as good looking!

Keep the pictures coming...

Greetings Remco

[bianchi1]

in the back of your shop space.....a shimano bike with campagnolo rims/wheels.. how could you??? to redeam your self.. get the rest of the bike full of campagnolo, you will feel better , and the car will know it( remembe she is also italian ) and your project will finish much sooner..( the alfa gods can see that bike)

[adelspyder]

Bianchi1,

Two out of three ain't bad - Campy wheels, Shimano gears, but Trek Carbon Fibre frame.....

Cheeky bugger

Thanks for the encouragement Tifosi & Remco - my typing is a little slow right now, as I have worn skin off from 4 fingers off my right hand (adding and sanding back bondo from the inside of the bellhousing). Making progress though, I just need to rest for another day or so (note to self - use plenty of band aids next time).

Dino

[adelspyder]

Well, the bellhousing has been modified to fit the lightweight 164 starter, and the inside of the bellhousing is now finished!

Because 3mm was removed from the outer radius in order to fit the V6 bolt pattern, 3mm had to be added to the inside.

The photos show a scraping tool that runs on the centre hole – the correct profile was made, the thickness set to 3.25mm, then the body filler was added and scraped back when wet to get the near-correct thickness. Once the filler is dry, you spin the tool around and the aluminium blade leaves a grey mark where the filler is too high and needs to be sanded back further (using a tennis ball as a sanding block!).

After several fill / sand iterations, the good news is that around 180~200g of filler was used, so this shouldn’t have added too much weight to the overall pattern

Plastic has been added to the base for the correct mounting height of the clutch slave, along with 6 reinforcing ribs for extra strength.

Sorry ‘bout the camera phone images – promise clearer photos when the bellhousing is actually finished!

Dino

[Craig_m67]

There has to be more than one person who'd love to use that.. what ever you do don't lose the mold.. are you making up more than one, any idea of cost?


love your work BTW

[Dan Walker]

Amazing- great work! Keep up the posts- it'll be fantastic to see the finished product!

[Hamish]

As ever, I'm very impressed at how thorough & well thought out this conversion is, and seeing the process of how you developed the sand casting pattern for the new belhousing is both fascinating and informative. Keep up the good work.

[adelspyder]

Hi everyone,

Thanks for the words of encouragement guys - with my brother working in Perth, finishing the bellhousing has been my responsibility for the last 6weeks or so, and I think that I'm just about there!

Craig, there is NO WAY that we're losing this pattern, with all the hours that have been poured into it! In order to test the pattern (and the new place who will be casting it), only the one will be made at first. As for price??? I'll let you know in 4~6 weeks!

The most recent photos show the outside of the bellhousing with the plastic reinforcement ribs (one for the starter and the other two going from the lower gearbox bolt holes to the lower engine block holes to resist flex). Another 6mm was added to the overall length (some of this for shrinkage, and some to add for machining).

Some extra plastic was added to remove undercuts, and to also smoothen the transition from the original pattern to the machined outer edge. Then prime, more rubbing, filling, rubbing, etc.

Don't get excited about the silver photos - it hasn't ben cast yet (the final silver paint is for the sand casting process to help it release from the sand mould).

More to come (I can strat to grow back my fingernails now - and that's no joke!).

Dino