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Engine compartment dimensions
davefried - 15/2/03 at 03:21 AM

I have been thinking of a transverse MEC since I started hearing about the Sylva Mojo. There are so many more potential donors and the seven types are getting enough attention.

It is too cold here in Ontario to visit the recyclers this time of year. Perhaps one of the readers on this list can help with a question.

In laying out the chassis, I am planning on a cabin of 60 inches from the bulkhead at the footwell to the bulkhead behind the pilots back. Setting the front bulkhead 12 inches back front the front axle, gives me 20 inches from the rear bulkhead to the rear axle on a 92 inch wheelbase. Is this enough for a transverse 4 cylinder?

I am considering a 2.0L Zetec or 2.0L Neon sized engine. If anyone has dimensions or can suggest a suitable envelope that would contain the engine/transaxle it would help me to get started.

Thanks

theconrodkid - 15/2/03 at 08:40 AM

when i did mine i just measured the engine and box i was using and added a few inches all round

TheGecko - 16/2/03 at 02:22 PM

quote:
Originally posted by davefried
In laying out the chassis, I am planning on a cabin of 60 inches from the bulkhead at the footwell to the bulkhead behind the pilots back. Setting the front bulkhead 12 inches back front the front axle, gives me 20 inches from the rear bulkhead to the rear axle on a 92 inch wheelbase. Is this enough for a transverse 4 cylinder?


Dave,

500mm (20") would be about the minmum for most transverse fours. I'm allowing about 650mm at wheel center height although I do intend to have the fuel tank nestled down at floor level against the bulkhead (close to CofG and well protected from impacts).

Have a look at Steve G's Bala website - he has some nice profile photos of his frame with drivetrain mounted. You can scale from the wheel diameter (600mm) to get the drivetrain dimensions.

Alternatively, have a look at your proposed donor in a car park or car yard somewhere and measure from the wheel centre forward to the nose, minus a bit for radiator etc. Motor shows and car yards are good because the bonnet (hood) is often open and you can measure where the front of the engine really is. No need to crawl around in the mud and snow in a wrecking yard. Snow is not a big problem here in my part of Australia

For bonus points, put a six inch high block in front of the car and sit on it, with the grille as your seat back. That's where you'll be relative to the powerplant in a middy. Now, wipe the goofy grin off your face and get to work building it

Hope this helps,
Dominic
Brisbane, Australia
http://www.DIYSportsCar.org

cymtriks - 17/2/03 at 10:20 PM

I have actually measured a ford 1300 as fitted to a KA. From the axle line to the front of the block is about 14 inches while to allow for all the other bits and pieces takes 18 inches.

From the back, very roughly, that makes 18 to cover the engine, 3 for space to work, 2 for the seat back chassis frame, 2 for the seat back, 9 to the base of the seat, 19 to the front edge of the seat, 7 to the dashboard, 24 to the footwell ends. That's a total of 84. I don't think that 12 inches is needed to go from there to the front axle, some mid engined cars actually have the footwell ends on or infront of the axle line.

The Lancia Stratos had a wheelbase around 85 inches and came with a V6 engine which was probably a bit bigger than the ford 1300 I measured.

The Lotus elise, Toyota MR2 and MG F seem to have wheelbases very close to 92 inches and do not seem to have 12 inches from the footwells to the front axle line. More like 8 to 4 inches.

The Stratos chassis is worth a look for ideas. Don't worry about it not being a proper spaceframe as most space frames would love to have the stiffness of a Stratos chassis. I make my living from structural analysis and I know that many spaceframe chassis are actually no better than ladder frames of the same weight. With a welded in roll cage some replica chassis can be up to over 6000ftlbs per degree of twist. Without it more like 3000. These are decent values for a small sports car (The lowcost has about 1200 in "book" form). The Stratos chassis consists of a small spaceframe around the front suspension that connects to a sheet footwell structure. This connects to substantial fabricated sills that connect to the rear frame around the engine bay. The rear frame includes a substantial square frame around the top of the engine bay. If you can locate a picture of a Stratos chassis you could try making a version of the chassis from 18 gauge steel, 1.5 inch square tube and 100 x 50 x 2mm wall RHS for the engine bay top frame. Just a suggestion.

garethpowys - 18/2/03 at 08:52 PM

quote:

The Lancia Stratos had a wheelbase around 85 inches and came with a V6 engine which was probably a bit bigger than the ford 1300 I measured.


Careful with the assumptions. The Stratos had the Ferrari V6 which had the transmission in unit (a la Mini), which *could* make a difference.

Also with V engines there is another consideration: There are many FWD cars out there that were designed to take a straight four and been converted by the manufacturer to take a V6 with no changes to the shell in white. This seems to be because the rear block leans over the diff so the front block isn't any further forward than the normal 4 cylinder block. Rover and Alfa Romeo spring to mind as examples. Hell, a friend of mine has even managed to get a V8 into his Mini! See http://www.v8mini.co.uk

He's given me an idea for my middy now. The question is do I use the same tranny as his for a tranverse installation or a Renault tranny for a longitudinal install?



Gareth

Alan B - 2/3/03 at 03:03 AM

Dave I have about 92" wheelbase and about 20" from rear bulkhead to axle line.
Here a partially complete picture (some brackets, gussets and diagonals not yet attached)