Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

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Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 3:01 am

Hi Guys !

As I have introduced myselfe and my Race Alfa Romeo 75 some time ago I want to post here now the complete conversion from a 3,0 V6 12V LIMOS engine to a much more powerful 3,0 V6 24V serious race engine.

Engine came out of an Alfa 166 and was model 2001.

Before I want to start I want to say a very big THANK YOU to KEVIN and JIM. I´ve got that many ideas pictures and data to start and make that conversion. 8) 8) 8) :wink: :wink: :wink:


It´s so good to have such good friends here in the Forum !!!

Here now first pictures when I´ve got the engine, ... it was running but as almost all daily running cars, dirty.
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Cheers
Wolfgang
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 3:08 am

Some more Pictures !
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Some more pics will follow !

Ciao Wolfgang
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 3:27 am

As I´ve promised, ... more pics !
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First new parts have arrived, ... forged Pistons from CPS Italy and forged rods from PPM in Australia.
Save approx. 1.800g for all 6 piston-rods assys in comparison to OEM parts.
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After disassembling block, now cleaning of block has to be done.
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Block looks like new.

More Infos and pics will follow.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 3:41 am

More pics !
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Also I want to do some optical things, ... because a race engine also must look good, ... !
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Thread for oil filter / oil cooler Adapter has to be made into the block because on the 166 block there is an oil filter bracket which also includes the engine mount.
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Oil channel has to be opend and cleaned after threading the block.
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Ready for oil filter adapter, ... just have to make a bracket to secure the adapter against moving when I tighten or remove the oil filter.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 3:58 am

There are now two possibilities to go with oil sump, ... first option is to modify / weld 166 sump to fit and second option (my way to go) with a 75 V6 sump which had to be modified to fit the chain driven oil pump. Also it is required to use a sump spacer (Thank´s to Kevin :wink: ) to get enough clearance for the pump snorchel.
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Took an old 75 V6 sump, ... Looks terrible before cleaning !
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Sump looks beautiful after cleaning and glas perl blasting !
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Modification of 75 oil sump to fit chain driven oil pump.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 4:14 am

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Clearly visable is the sump spacer.
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Wholes have to be modified and new drilled, I closed old threads with M7 cutted screws. Also you have to grind away with a Dremel some material on the block to fit Hex screws on the front pully side.
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Next thing to do and to think about is an oil splash guard which I´ve hand made of a 1,5mm steel plate.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 4:28 am

Work is going to be continued, ... and Guys I can tell you, ... that conversion is not a work doing between breakfast and lunch ! :lol: :lol: :lol:
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As I have an old 75 3,0 V6 QV engine at home I´ve decided to use that front pully instead of the 166 pully. Anyhow I wanted to go with a V-belt and not with the new belt type.
I´ve modyfied the front pully on the latch to fit on the 166 cam belt small pully and on the block.
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4 mm thickness of the Bosch 60-2 wheel should be enough to get a correct Signal.
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Enough clearance to the front side.
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Just for sure so the shim woun´t tighten on the crank as it should tighten on the pully.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 4:44 am

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Next thing to do is to make a adjustable bracket for the crank sensor, ... OEM Position on the 166 engine is completely different (flywheel).
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Next problem, ... how to fit the alternator on the 166 block, main bracket will be on the 75 V6 sump as OEM.
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I took the OEM bracket of the 75 as a starting Point, ... but then I´ve seen that the cam belt bearing woun´t fit correctly.
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So I´ve to make my own bracket.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 5:09 am

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Enough clearance to bearing.
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Waterpump pully has to be made on the latch to fit on the 166 24V waterpump.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 5:39 am

Next step is to lighten the OEM Alfa 75 V6 flywheel.
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OEM weight 11,4 kg, and now 8,2 kg.
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Thermostat housing also has to be modified because flansh of waterpump from 75 V6 is different to the 166 24V waterpump flansh. Also a problem is the clearance of the middle Timing belt bearing, ... so what can I do ?
First step was just to modify Thermostat flansh to fit on the 24V waterpump but the clearance to the middle timing belt bearing was to small si I decided to take another thermostat housing, ... cut off the flansh, modify the whole housing so it will sit a few milimeter more away from the block / cylinder heads. I´ve made a new flansh by hand out of a 8mm thick aluminium plate.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 5:44 am

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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 5:52 am

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Here you can see that with this modification I have found a few Milimeters more clearance.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 6:16 am

Last week I´ve got the vernier pullies, race cams and hard valve springs from CatCams.
Heads have to be modified with a Dremel to get enough clearance for cams.
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by Alfa 75 Racer » Mon Mar 24, 2014 6:21 am

Next step what I´ve done is to make the correct bobweights for fine balancing crank-assy.
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First pics after working on the latch.

More infos and pics will follow, ...
Enjoy looking at my work, ... hope you like that tread !

Greetings from Austria
Wolfgang
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Re: Alfa Romeo 75 3,0 V6 Gr. A Conversion from 12V to 24V

Post by 75evo » Mon Mar 24, 2014 7:45 am

Lovely!

Who made the cam pulleys ? For my cam pulleys I'll most likely go with Jim K's cheap ass idea, which still requires custom work :(

BTW, for the water pump, do you think it would be a good idea to cut off the pulley and impeller of the water pump, seal it off, and use an electric water pump instead? For a race car, the pump needs to just run at 1/2 speed (to make sure the engine can warm up quickly) or full speed (during the race). Once the car warms up, it can run at full speed all the time.

The thing is the water pumps are low quality on these cars. Sometimes if you get a defective one they don't even last 10K miles. Just like the rubber guibos, some brand new ones explode in your hands after you paid the money (I'm exaggerating here :) ). And if the car is not driven for a long time, I wonder if the waterpump bearings will go back even before 10K miles. Such a hassle to do 24V timing belt. My 164 Super 24V has a water pump which went bad before 10K miles, what a painful job on a 24V FWD car.
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