Board logo

anyone know the biggest engine you can fit in a +4 chassis?
aerosam - 16/10/08 at 10:11 PM

Basically as per the title.

My BMW M60 V8 is 28" wide across the top and the sump is also quite wide, about 20" i think. It's 32" long too.

I have started building a much wider chassis but i'm having so much trouble working out the suspension geometry i think it would probably be much easier to build from plans.

[Edited on 16/10/08 by aerosam]

omega0684 - 16/10/08 at 10:21 PM

just a thought - what about fitting a dry sump kit for extra ground clearence and space saving?

Simon - 17/10/08 at 12:48 AM

Have a look at pics in my archive and blog (link below), and that should give you an idea of space of +4" chassis with Rover V8.

I had quite a lot of room before the turbos went in

ATB

Simon

[Edited on 17/10/08 by Simon]

speedyxjs - 17/10/08 at 06:52 AM

Mine is about the same size but i have made the chassis 6" longer (not such a tight fit that way).
I thing at a real push a Jag V12 would fit but its pretty heavy and not really worth it. You could have a supercharged AJ16 and have more power with less space.

aerosam - 17/10/08 at 08:29 AM

Hmmm.... food for thought there - thanks guys.

Triton - 17/10/08 at 09:55 AM

You lot get free petrol then....

James - 17/10/08 at 12:26 PM

quote:
Originally posted by aerosam


I have started building a much wider chassis but i'm having so much trouble working out the suspension geometry i think it would probably be much easier to build from plans.

[Edited on 16/10/08 by aerosam]


If you're just adding a few inches into the centre of the chassis (4" is the standard) then the front suspension geometry shouldn't change. Just stick with standard Locost wishbones at the front and fit longer extensions to the steering arms.

For the rear... are you going Locost (ie. fixed axle) or IRS?
If it's Locost at the rear then fit a Cortina axle as it's 4" wider than the Locost... so little will need to change.
If you are planning a Sierra based IRS system then either you are designing your own or copying someone like MK. In which case, just move your wishbone mounts 2" further outwards on each side.

I did mine by adding 10% to each of the chassis rails... this make the chassis 4" wider and a fair bit longer and 1" taller but the proportions of it are the same as a standard Locost. It's not very pretty looking (mostly because of the 1" extra height) but it's effective.
I was then able to keep the standard front wishbone pivots as the front of a +10% chassis is only 1.5" or so wider! So I just set the wishbone pivots inboard by 0.75" or so.

It sounds complicated.... it was all in the aim of keeping the wishbone pivots points (and therefore suspension geometry) standard (ie. as per the book) as I knew the book design works and I didn't know enough about suspension design to come up with my own!


Hope that helps!
James


EDIT: I wanted to add, is your Beemer engine much bigger than a Rover v8? Because I'm pretty sure that with suitable mods to the engine brace chassis rails it's possible to fit a Rover v8 in a standard Locost chassis.... just!

[Edited on 17/10/08 by James]

bartonp - 17/10/08 at 01:35 PM

May be a bit of a squeeze...
http://www.trainnet.org/Libraries/Lib006/DELTIC.GIF

tomprescott - 17/10/08 at 05:05 PM

Or you could take out a loan and talk to the boys that made the bike v8, basically two bike engines on a comon crankshaft to give around 300bhp, take up less room than a conventional v8 be lighter and still rev over 10,000!? If I had loads of money thats what I would do!

aerosam - 17/10/08 at 09:43 PM

thanks for all the replies guys, to answer a few questions:

I haven't the first clue about dry sump kits - sorry!

Petrol is now under £1 a litre round here (ASDA's) woo hoo!

The BMW V8 is considerably wider than a rover due to it having DOHC heads - I don't know the dims of a rover so I cant say exactly how much wider.

At the rear I'm hoping to use the BMW rear axle carrier, I know it's heavier but it comes with a free LSD and disc brakes. It's really solidly built and welded into the rear would make a very strong back end.

Well I've just come back from an evening in the garage, i cut up the old chassis, recut the bottom tubes and laid them out on the build table, and just by looking at it i can see the engine should (hopefully) fit ok.

I'll keep everyone posted! Thanks!

Jesus-Ninja - 18/10/08 at 06:53 AM

Not really answering your question, but I widened the track on y prohject by 100mm on each side (so 200mm in total). Couldn't tell you what the effects are on handling though....

http://www.locostbuilders.co.uk/viewthread.php?tid=98909&page=1#pid822844