Where do I begin?

Everything you need to know if you are thinking about racing in 750 Formula

Re: Where do I begin?

Postby Conway » Sun May 13, 2018 9:23 am

Rich

Interesting that at least 3 of the current 750F drivers used to race in Locost. I would be surprised if anyone ever goes to Locost from 750F!

My car has Herald front uprights, Merlin hubs and now GT6 discs. Also a narrowed rear Morris axle as Tony describes. If you're not too busy talking / looking / being pressed into service by everyone else at Mallory, feel free to come and see. Car number 12.

Happy planning!

Conway
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Re: Where do I begin?

Postby ninja » Sun May 13, 2018 1:32 pm

hi,
i went 750 - locost - 750
only went locost as no 750s for sale and i shared my workshop with a locost team.
locost does have some advantages, such as easy to rebuild after a crash, better for the larger, taller driver
downside is engines are fragile
overall i think 750 may be cheaper over a few seasons
but 750 cars are proper race cars and locost feel like road cars.
nige
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Re: Where do I begin?

Postby classictinker » Sun May 13, 2018 6:56 pm

Jimbob wrote:
pbove wrote:You do still see some Revolutions on eBay from time to time, so that might be worth exploring or Dynamic and Compomotive make wheels that fit -


I've a set of 4+1 revolutions surplus to requirements in good nick - can bring one to Mallory if you want to measure one up for suitability. Happy to let them go to a 750'er for a sensible price rather than ebay them.
I'll be up there collecting an exhaust off Sue / supporting some of the cars so will have plenty of time to talk car construction - i'm currently in the middle of converting an ADR1000 to 750 spec, having raced a different ADR last year.


Thanks yes I'd be interested in having a look at them. What do you mean by 4 + 1?

Cheers

Rich
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Re: Where do I begin?

Postby classictinker » Sun May 13, 2018 6:58 pm

Conway wrote:Rich

Interesting that at least 3 of the current 750F drivers used to race in Locost. I would be surprised if anyone ever goes to Locost from 750F!

My car has Herald front uprights, Merlin hubs and now GT6 discs. Also a narrowed rear Morris axle as Tony describes. If you're not too busy talking / looking / being pressed into service by everyone else at Mallory, feel free to come and see. Car number 12.

Happy planning!

Conway


Thanks, I will certainly come and say hi and also check out you front end if that's ok?

Cheers

Rich
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Re: Where do I begin?

Postby classictinker » Sun May 13, 2018 7:00 pm

Thanks again for the replies and offers of letting me check out your cars I'm sure it's going to be a big help. Would it be ok to take a few pics of your set-ups and maybe take some measurements so I have a place to start from when I begin the design stage?

Many thanks

Rich
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Re: Where do I begin?

Postby Jimbob » Mon May 14, 2018 11:39 am

classictinker wrote:Thanks yes I'd be interested in having a look at them. What do you mean by 4 + 1?

Cheers

Rich


4 in good condition, no tyres, one a different colour, not as good condition and fitted with an old tyre - basically 4 good wheels and one OK as a spare (not the tyre). I'll pop one in for you to measure then.
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Re: Where do I begin?

Postby classictinker » Mon May 14, 2018 12:58 pm

Jimbob wrote:
classictinker wrote:Thanks yes I'd be interested in having a look at them. What do you mean by 4 + 1?

Cheers

Rich


4 in good condition, no tyres, one a different colour, not as good condition and fitted with an old tyre - basically 4 good wheels and one OK as a spare (not the tyre). I'll pop one in for you to measure then.


Nice one, thanks :)

Rich
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Re: Where do I begin?

Postby classictinker » Tue May 15, 2018 7:56 pm

OK next question :) I've been reading around the forum and I think the gearbox I need is from a 1200 grande punto but I'm a little loss on the engine. I know it needs to be the 1108 8V fire engine but I read that you can use any of the carb, single point and multi point versions but I also read that you can't use the MPi version and that the right engine is the one with the sensor um can't remember now but it was with the sensor NOT in the cam cover. To make things ever murkier I've also read that I need a certain head...anybody able to clear this up for me a bit please?
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Re: Where do I begin?

Postby Baggers » Tue May 15, 2018 8:51 pm

Hi Rich,

This is how I understand it at the moment - I'm sure someone who knows better will clarify for us:

Engine
Yes you need to use the 1108 Fiat FIRE engine. This has been used for a long time now. The engine first came into use when the original fiat UNO/Panda was available as a donor. These engines were carbureted and used distributors for the spark. This 1108cc engine has been used in various forms over the years, including the fuel injected MPi engine. So that no-one can get an advantage by finding a cylinder head that was particularly good, the regulations state that a certain casting of cylinder head (casting number 46400108) must be used. For example. You may find cheaper by having a scrap yard hunt!

You also must use a control cam shaft. Other engine mods are restricted to engine balancing and flywheel lightening. In short - you can use the MPi engine but
-Change the head and add a carburetor (free choice of carb as long as it's single point - The Tillotson as used by formula Vee seems popular
-Add the control cam shaft
-Lighten the flywheel
-You will also need an ignition system and assuming you don't want a distributor you will need a MegaJolt kit. I'm afraid it's a bit expensive, and seems to hold it's value on the secondhand market.

Gearbox
This is the big design decision between live axle and transaxle.
If you are using a live axle car you can use any gearbox you like with any ratio of 4 forward gears. Engine can be rear/mid/front/central mounted.
If you are making a transaxle car then engine must be behind driver and you MUST use the Fiat gearbox without changing ratios, of which the Grande Punto 1.4 seems best out of the box (thanks Martin and Tony). I'll be using the Seicento one as I got a few boxes cheap. You get 5 gears but you can swap the 5th gear for an overdrive.

Thanks,

Alex
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Re: Where do I begin?

Postby pbove » Tue May 15, 2018 11:01 pm

The MPI engines use a different timing belt - so if you are planning to use one then you will need to make sure you’re using the right belt. There are also two different cranks with different flywheel bolt pcd - so it’s worth making sure you have the right flywheel before machining lots of weight off it!!

You are allowed a vernier cam timing pulley if you want to use one and you can use a steel flywheel subject to a minimum weight of 3.5 kg - and you can skim the head and face the block and modify the oil system including the sump and cam cover. External fasteners can be changed, internal ones (including the stretch bolts) have to be standard.

Everything else should be standard FIAT or pattern part to the Fiat design. However, make sure you read the regs as there are some subtleties that need to be adhered to.
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