24v V6 to Alfa 75 conversion.

[simmi1983]

Hey guys,

Wasn't sure where to post this and I'm sure it's been duscussed plenty of times before but here it goes.

Looking at helping a mate build a 75 track car.
Aftet builing one myself it should be alot easier the 2nd time round.

He wants to put a V6 in it. A 12v would be easier but I suspect they'd be hard to find these days. So may be easier to put a 24v V6 in it.
We figure it would be easier to buy a 166 or a gtv and pull the engine, wiring and ecu out.

Just unsure of whats involved with rotating it to north south. What do you do for the inlet manilfold , eng mounts, exhaust manifolds, rear flex plate/ ring gear and rear engine housing?

He has a twin spark box in it too.

If these anything else that needs doing I'd love to hear your advice.

Thanks in advance,

Luke

[julianB]

Oil pump pick up modified,
Lower oil pan section of sump modified
Water outlet on rocker cover modified
Inlet manifold modified (standard 12v V6 ones can be made to work but end up with short runners that only work well at high rpm)
Extractors needed
Space flywheel - I think it's 2 or 3mm with a 166 engine

[Craig_m67]

There's something else about a chain driven oil pump from memory being different between the 12/24v.. perhaps

Might be easier to chose a donor car based on ECU integration (or lack off) is, basic cable throttle GTV, 156 is flyby wire but not can bus, 147/GT are canbus. No idea about the 166

Check all this ^. I'm just thinking out loud.

Personally, I'd b inclined to get a 3.2 from a GT then figure out the ECU, catalysts etc. 
It is the pinnacle of the Busso after all (although some say the 2.5 revs harder and sounds nicer)

[rowan_bris]

Luke, you are welcome to have a look at my car sometime and i can talk you through what was done.  It is a 3.2 into a GTV6

[105gta]

Hi Luke, there is so many ways it can be done it gets confusing for many and most follow a similar path. It's far easier to start with a V6 chassis simply because of the parts needed but it's still not that hard to convert a 2.0 chassis. If you have the bits lying around.
Considering you're building a track car and not a road car that does make things a little easier
The main thing to consider is unless you're starting with a rwd engine and flywheel you'll need to balance the crank to be right, and that means sending your Pistons for the crank to be matched up balance wise. Which means engine apart.
If you'd like to discuss it further and see options send me a pm.

[LaStregaNera]

Modifying the shell from 4 to 6 is the easy part - one of the bolt holes is common on each side between 4cyl and 6 cyl, so you can weld on the back half of a mount from a v6 shell and have a set of shell mounts that will take a 4cyl or a 6cyl.

OK, so fwd GTV6, GT, 156, 147 GTA and 166 all have the chain driven oil pump. This requires fitment of a 1" thick spacer between the main part of the RWD GTV6/75/90 sump and the  bottom plate of it, makes for abysmal ground clearance - modifying the pickup *may* be posisble to do, but it's integral with one end of the oil pump, so not an easy job.
All need swapping to a rwd flywheel - problem here is you'll need a 3l flywheel because of the larger counterbalance weight in the flywheel (the Busso v6 is externally counterbalanced. You *could* get tungsten ("mallory metal") inserted into the crank to make it internally balanced and run zero balance flywheel and front pulley). This raises the problem of the crank angle sensor on the fwd cars counting teeth off of the flywheel and being mounted on the back of the sump - relatively easily fixed though.
Cooling system - the motors with the chain driven oil pumps also run the coolant out of the back of the heads. Fixed by either an ugly coolant hose run back out to the front, or removing the spigots on the back of the head and inserting plugs, removing the plugs at the front of the head and installing spigots. The water pump is then modified to take a rwd thermostat housing by welding and redrilling holes - clearance to the timing belt idler is very tight.
The fwd intake manifold is commonly modified by either cutting the flange off and adding a 180* elbow to point the throttle body forward, or blanking the back end of the plenum off and welding a flange on the opposite end of the throttle body. Neither of these approaches address the fact that the plenum is too small in terms of volume (Which is why bigger and bigger throttle bodies show improvements), so some guys blank the end of the FWD throttle body, cut the side out and build an box onto the side to increase volume and allow convenient fitment of the throttle body. Others modify the RWD v6 plenum - while the runners are short, they are also much smaller diameter than the fwd runners, and theres the same issue of being short on plenum volume.
Some have modified the FWD tubular extractors to work in the rwd config.

Converting using the FWD ECU is a massive pain in the arse - they need the key transponder to work, and while there is a guy in holland (?) who can disable that for you, unless you know the vin of the donor car, he won't do it for you (This is where my GTV24valve into 164 project fell over).

The easiest way to put a 24 valve motor in is to use the 164 motor - most of the above issues go away, but they're *much* harder to find.
There's probably something I've forgotten or missed, but all this has been done over and over and over by some of the guys at the GTV6.com forum
http://alfagtv6.com/phpBB3/

[simmi1983]

Thanks for all the helpful info guys.
Will see what we can find but I think he may be inclined to go with a 12v v6.

Rowan, I may have to take you up on that offer one day, even just to have a look at the beast.

If anyone has a 3L they want to sell PM me.

Thanks again guys,

Luke

[105gta]

The 3.0 12v is an easier route but harder to find at reasonable price. Best bang for buck if you're into a bit fab work is to find a broken 2.5 75 as it will have all the bits you need for a conversion. All same parts as 3.0. Bell housing, sump, prop shaft etc... spare twin spark box just minus the lsd. You'll need all these parts to convert to v6 anyway but I'd reccomend going 24v. Makes more power than a really hot 12v standard and then you can think about modifying it later. And seeing as you're building a track car 75. You'll have a load of spare parts! Suspension bits panels etc... you just need to convince the missus its saving money to buy another one 😉

As for the conversion, the big issues everyone seems to have is the sump and the cooling system. The sump is easy. No spacers needed! And the cooling system. Again I'd recommend using the rear mount thermostat (as I did)  for a few reasons.
Better coolant flow. Cold water in the front and hot water out the back flowing the length of the engine promotes better cooling for the rear cylinders,
Every wear(corrosion prone) part is off the shelf items if replacement needed, no modifying every time a water pump or thermostat is needed.
As for the ugly hoses... well that's subjective and up to the builder

[LaStregaNera]

The sump is easy.

Do tell?

[105gta]

LaStegaNera.
The upper section is pretty straight forward just try to fit it and cut out the sections of baffles  that interfe with the pump, there is one casting lump that needs to be ground down on the pump. The issue with the lower section is the bowl section is in the wrong location.
It's not hard to cut a neat rectangle and rotate it 180 and have the bowl at the rear where it's needed. You can set the height of he floor easily. From memory I think I have mine at approx 7mm at the lowest point of the strainer/screen, but seeing as the pick up is on an angle the oil available to the pickup is more than the combined flow of the tiny holes in the strainer.

[105gta]

More pics

[LaStregaNera]

Easy as.
I never quite got that far with mine to see the sump issue first hand.

[GTVeloce]

More importantly, how did you manage to get the booster on the pedal box? Are you using a mixture of parts like I have heard used elsewhere to accomplish this?

[deano]

Going to ask a straight up coin question...

I've always actually wondered what it realistically costs to do all this work converting to a 24? And Yes I get that we all do stuff in the shed over extended (sometimes very) periods of time and yes we all have mates that can do things for free and owe favours but by the time you actually start to driving the car around as a 24 valve what's it all worth in peoples experience??

Surely you wouldn't go to the trouble to do all this without putting something aftermarket ECU wise in the car for the bang for buck in future. Then the cost of a decent engine, conversion work, exhaust, ancillaries then getting it all in the car. Surely you'd be north of 10K by the time you actually keep all receipts? Then what about all the little things to get it all to work as a car afterwards. Obviously its a how long is it sort of question and how much "I'll do in the shed" vs the project actually getting completed before death.

Then what do you actually end up with at the end of the day? What does it put out at the wheels? What would the car be worth to sell? How fast in a straight line is it realistically?

Trying to get my head around whether its worth it overall.

[Citroënbender]

I can't answer the core question per the car and work at hand but want to salute your very fair and pertinent raising of these details.

Based on noodling around with other cars, my expectation is unless you have real favours to call in, an awesome workshop, good skills and a head for planning, it will cost a big fat wad of moolah.

I'd expect to pay upwards of $600 for sectioning and welding a sump like that, at Sydney prices. Similar coolant tubes to those pictured, cost me $450 from memory in brushed 316 with welded "beads" on the spigots (chappy didn't have a Parker beading tool and I wasn't confident to borrow one in case the steel broke it).

Harnesses, I am more a fan of starting with a blindsided OEM loom and chopping that in, depending on the level of "hotrodding" it means you can opt in or out for things like one-touch windows, power mirrors, the inertia fuel stop is there, fuse and relay panels, everything talks to everything and will run with half its sensors and nodes unplugged.  But there are hours and hours even in the most cut-down OEM harness, and unless you're a clued-in tinkerer with electrics this could easily be another bunch of cash. 

And at the far end, you want to enjoy the car.  If it all it does is remind you of the people who overcharged, the people who screwed up, the hassles, the disappointments - you won't get a buzz out of the finished project for a long time.

It probably doesn't show in the above remarks but I am actually quite a cheerful and pragmatic person, I'd just rather that people were fully aware of how much vexation and dosh can pass between the start of a project and where one calls it done.