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Longer Chassis
speedyxjs - 11/3/07 at 08:49 PM

Im thinking about starting my chassis in a few weeks and im a bit concerned my jag aj6 might not fit .
I was thinking about extening the engine bay (chassis rails F1, F2 and G1, G2 in the old book and BR1, 2, 8 and 9 in the new book) but keeping the front the same width.
Will i run into problems with strength or anything if i do this or has anyone else got any suggestions/advice. (using a different engine is NOT an option )

Cheers


907 - 11/3/07 at 09:00 PM

Hi

Draw out the book chassis on the build board.

Sit your engine/gearbox on the board.

Change to suit. That's what I did.


Paul G


Ivan - 11/3/07 at 09:09 PM

That's going to be a difficult one to answer - firstly a lot depends on how far back you can set the engine (normally limited by bell housing width) so the wider the car the better. Also using a 6 weight distribution becomes a factor so you want the motor far back.

If you can get the motor far enough back then you shouldn't need to lengthen the engine bay - with my 4AGe motor theres more than enough room for 2 more cylinders in front of the motor.

I think if you lengthen the bay G1 & G2 are the weak links and will need strengthening/supporting to carry the motor - also you should duplicate member R on the other side

Have a look at papers published by Cymtrix on here at simple mods that significantly strengthen the chassis.


James - 12/3/07 at 09:05 AM

If you just lengthen those tubes then your suspension mounts will change position... not necessarily a good idea!

If you don't know what you're doing with suspension design I'd be careful with this... you don't want to trash the handling after all!

HTH,
James


Volvorsport - 12/3/07 at 12:47 PM

have you got any measurements for the engine and box ?

the volvo 6 cylinder fits in my chassis - it does come quite far foward tho , so i can measure it and see what we come up with .


speedyxjs - 12/3/07 at 02:24 PM

quote:
Originally posted by Volvorsport
have you got any measurements for the engine and box ?

the volvo 6 cylinder fits in my chassis - it does come quite far foward tho , so i can measure it and see what we come up with .


Have you got any pics?


907 - 12/3/07 at 05:54 PM

Is the g/box a Getrag?

Paul G


speedyxjs - 12/3/07 at 08:25 PM

quote:
Originally posted by 907
Is the g/box a Getrag?

Paul G


Yes it is .

The measurements of the engine are 34 Inch by 23 inch roughly


907 - 12/3/07 at 09:13 PM

Mmmm, That's a big lump.

I have a Getrag on a lotus engine.

My chassis is +4 wide. My foot wells are book so the extra 4" is in the g/box space.
By doing this the front end of the bell housing is level with the end of the foot well.
This leaves 35 1/2" ish to the front of the engine bay.
I can see now why you would want to make yours bigger.

If you don't follow this I'll take a photo.

Paul G


speedyxjs - 12/3/07 at 09:16 PM

I do follow but any pics would be great. Nothing beats visual aids .


Mark Allanson - 12/3/07 at 09:26 PM

I would make the upper and lower rails of 50x25mm 16g ERW and make the H tubes 50mm shorter. A small weight increase, but a massive sag resistance added to the chassis - needed with a big tubby engine


907 - 12/3/07 at 09:46 PM

I like Mark's idea.

Perhaps bolt in triangulation after fitting the engine???

Pic below shows added 4" although I did it just to move the engine back for weight reasons.

Paul G Rescued attachment lotus-pics-046-s.jpg
Rescued attachment lotus-pics-046-s.jpg


Volvorsport - 12/3/07 at 11:05 PM

sundays trip to santa pod .

should be some pics of use

http://forums.turbobricks.com/showthread.php?t=94099


andyps - 12/3/07 at 11:44 PM

quote:
Originally posted by speedyxjs
(using a different engine is NOT an option )

Cheers


Course it is an option - you should make it wider too and fit the Jag V12 in


britishtrident - 13/3/07 at 11:02 AM

My main concern would be weight, much as I love Jag 6s the AJ6 engine was a heavy bit of kit.

For starters I would think 4inch wider 4inch longer + 1 (or 2) inch deeper + Cymitrics mods.


britishtrident - 13/3/07 at 11:05 AM

quote:
Originally posted by Mark Allanson
I would make the upper and lower rails of 50x25mm 16g ERW and make the H tubes 50mm shorter. A small weight increase, but a massive sag resistance added to the chassis - needed with a big tubby engine


Might be better to keep the H tubes book length, the extra depth will make the chassis stiffer in beam bending and give more room in the footwells.


britishtrident - 13/3/07 at 11:09 AM

quote:
Originally posted by andyps
quote:
Originally posted by speedyxjs
(using a different engine is NOT an option )

Cheers


Course it is an option - you should make it wider too and fit the Jag V12 in


But real Jags have XK engines :-)


speedyxjs - 13/3/07 at 12:45 PM

quote:
Originally posted by britishtrident
quote:
Originally posted by andyps
quote:
Originally posted by speedyxjs
(using a different engine is NOT an option )

Cheers


Course it is an option - you should make it wider too and fit the Jag V12 in


But real Jags have XK engines :-)


2.9 aj6 is only for SVA. She will then be upgraded to 4.0 aj16 and SUPERCHARGED