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Mods to chassis design for straight 6 engine?
mr henderson - 5/9/08 at 10:44 AM

I'd be interested to hear what modifications people have carried out to provide space for a straight 6 (and which engine they fitted/are fitting/intend to fit?

I guess it would be possible to squeeze some 6's into the standard chassis, maybe, but a longer engine compartment has got to make the job easier?

John


novacaine - 5/9/08 at 10:59 AM

which straight 6 are you thinking of ?


mr henderson - 5/9/08 at 11:07 AM

quote:
Originally posted by novacaine
which straight 6 are you thinking of ?


It's not a question that applies to a specific engine, I'm just interested in the geometry problems of extending the chassis in the engine compartment. Obviously it's easy to make a Locost or Haynes roadster by lengthening the cockpit where the rails are parallel, but the tapered sections are more 'interesting'

John


Mr Whippy - 5/9/08 at 11:17 AM

If you were going that route, I’d personally use one of the chassis cad drawings on the net and just use the stretch function to extend the front, then alter the wishbone dimensions to suit, half hour job on cad. Car might look a bit odd though, hope its not on of those 2ltr triumph straight 6’s is it, they suck so much.


mr henderson - 5/9/08 at 11:24 AM

quote:
Originally posted by Mr Whippy
If you were going that route, I’d personally use one of the chassis cad drawings on the net and just use the stretch function to extend the front, then alter the wishbone dimensions to suit, half hour job on cad.


Easy if you know how to do it, and have the appropriate software. I don't. If and when I needed to do it I would build the chassis around the engine. I don't think it would be necessary to alter the wishbones though.

I've owned a triumph 6 (Vitesse Mk2) and I'm not doing that again!

Still interested to hear from anyone who has done it.

John

[Edited on 5/9/08 by mr henderson]


Hammerhead - 5/9/08 at 11:53 AM

benzine


82 Locost - 5/9/08 at 12:12 PM

With the gearbok fully rearwards (which 'box) I'd be surprised if a straight 6 didn't fit the standard chassis, although it may stretch the nosecone.

What's the length of the planned engine compared to a pinto/x-flow and are there any ancillaries at the front?


mr henderson - 5/9/08 at 12:18 PM

quote:
Originally posted by 82 Locost


What's the length of the planned engine compared to a pinto/x-flow and are there any ancillaries at the front?


It's not a question that applies to a specific engine, I'm just interested in the geometry problems of extending the chassis in the engine compartment. Obviously it's easy to make a Locost or Haynes roadster by lengthening the cockpit where the rails are parallel, but the tapered sections are more 'interesting'

John


Benzine - 5/9/08 at 12:22 PM

My gearbox (volvo M90) is pretty wide so I had to widen the firewall/transmission tunnel area.

This means I've lost about an inch on the drivers side (pedals are still fine to use) and a few inches on the passenger side (clutch is on that side)

If I were using a slimmer gearbox like matt claydon with his T5 volvo engine (getrag?) then it'd probably fit okay without any mods. Other than the gearbox I haven't really come across any major obstacles that I can think of. The straight six gives plenty of clearance for the steering components. The oil filter sits beneath the sump so it doesn't stick out sideways (that's obviously engine specific and not relevant to all straight sixes)




[Edited on 5/9/08 by Benzine]


James - 5/9/08 at 12:30 PM

There's room for a straight 8 in mine!

Almost literally, I could fit another Pinto in front of my current one.

1st (and minor mod) was to widen the tunnel entrance such that the bellhousing is entirely buried in the tunnel. This brings the engine back about 10".

2nd (and slightly less minor mod) was I increased the length of all the chassis tubes by 10%.
Consequently, I got a car of the same proportions as a Locost... but with 4" more cockpit width and about 6" more length. That also gives 6" or so more engine bay length.

It's actually more complex than the above sounds... but it did work.... kinda!

HTH,
James


Mr G - 5/9/08 at 01:53 PM

If it's gonna be a straight six then the only option would be a RB26DETT


Volvorsport - 5/9/08 at 02:49 PM

problem with a straight six is too much forward bias in std chassis.

the 442 offers this , and a 6 would fit mine luvverly, in fact i think im going to do that so im not outdone by benzine for noise , but only after ive got the 4 pot turbo up and running and beaten the 10 sec quarter .

for my money now , i wouldnt want a std type chassis at the front its too much hassle fitting brackets etc , it all wants to be straight , until it needs widening at the engine bay .


nstrug - 6/9/08 at 06:59 PM

Are there any suitable I6s? I love BMW engines but they've all been iron blocks up until the latest generation of engines and weigh a ton. Were the Toyota I6s alloy?

Just a thought, if you can fit an I6 in there, you could probably fit a V12...

Nick


Volvorsport - 6/9/08 at 10:41 PM

Are there any suitable I6s?

volvo


Peteff - 7/9/08 at 09:13 AM

If you extend the tapered section forward the nose will get narrower and if you extend it back the cockpit will be wider.


jamie1107 - 8/9/08 at 01:57 PM

the agm wlr uses basically a locost chassis and they fit sraight six s also there was a guy on here building a bmw m50 powered locost


wilkingj - 22/9/08 at 12:46 PM

Just buy a Viento. It takes almost any engine.

I have seen:
4 pot Fords
6 pot BMW
4 pot Pinto
V6 Cosworth Ford (an non cosworth)
V8 (Rover, and a Chevy 5.7)
V10 Dodge Viper - http://www.v10viento.co.uk

Its a BIG chassis, and gives you loads of room to play with. Why modify when a std chassis exists off the shelf?



EDIT:
A note on the Triumph Vitesse / 2000 engine.
They had only a single Half moon thrust washer on the crank. These wear quickly, then the crank grinds into the block scrapping both.
A school pal developed a mod (counterboring the block and cap to fit two thrust washers) with greatly reduced the problem. He was a Line Borer at an engineering company.

Tell tale is longditudinal play on the crank, and / or nasty sounds when depressing the clutch (crank grinding on the block)

Just my 2 reils worth.

[Edited on 22/9/2008 by wilkingj]


mr henderson - 22/9/08 at 12:52 PM

quote:
Originally posted by wilkingj
Why modify when a std chassis exists off the shelf?



I should have said modification to chassis design, I didn't mean modifying an existing chassis.

Sorry for the confusion

John


novacaine - 23/9/08 at 04:46 PM

quote:
Originally posted by Mr G
If it's gonna be a straight six then the only option would be a RB26DETT


i agree, BR26DETT all the way

tune it to 1000 bhp and put a dog box in


miles and miles of smiles (and wheelspin )