Low Capacity Straight 6's

[24seven 104]

Can anyone thing of any smaller straight 6 engines? I'm thinking 2000cc or less, OHC ideally. Nothing's going to happen for a while yet - I'm just brainstorming, but I want to build my own Locost type car from scratch and like the idea of a high revving small capacity straight 6 in there, but I couldn't think of any other than the 2.0 Triumph engine in the Vitesse, which isn't quite what I had in mind.

[Anthony 1,003]

BMW did 2.0 i6's on SOHC and DOHC format (M20 and M50/52 series engines)

[dcc 855]

Isn't the lexus LS220 a 2.0 striaght 6, 20v?

[24seven 104]

I didn't realise the bimmer straight six's were built in capacities smaller than 2500cc. Thanks for that. I had wondered about a de-stroked non turbo Nissan RB engine but it seems they were built in 2.0 form as well, although I don't suppose getting hold of one will be easy, or cheap.

 

Isn't the lexus LS220 a 2.0 striaght 6, 20v?

 

Yeah it seems so. Didn't realise they were as small either. All the Toyota/Lexus 1G engines are 2.0L apparently.

 

 

[edit] I can't find any info on the Toyota/Lexus engines but the BMW and Nissan lumps are all cast iron block. Does anyone know of any alloy block lumps out there?

Edited August 30, 2012 by 24seven

[S@m 156]

Mazda MX-3's have a small capacity(1.8) 6 - but i think its a V6. As is the 2.0 in the FT-slow. The lexus IS200 is 2.0 straight6 though.

[Anthony 1,003]

Does anyone know of any alloy block lumps out there?

BMW M52 series I mentioned earlier are alloy block, and they're common as muck.

[24seven 104]

BMW M52 series I mentioned earlier are alloy block, and they're common as muck.

 

Oh yeah. Sorry. I only looked at the M50 and saw it was Iron. Thanks.

[Tom Fenton 1,541]

A straight 6 for the noise I get, totally, but putting a 2.0 6 in when for the same amount of effort you could put a 2.5 or 3.0 in, I do not get.

[24seven 104]

In a tiny Locost I wouldn't need the extra capacity, nor want the extra weight. Building it from scratch it would be no more effort to put a 5L V8 in there, so you have to draw a line somewhere.

[dcc 855]

personally, I would just put a V8 in. If it were from scratch. We priced up some competition spec engines for my dads chevvy when he had to rebuild his 5.7. Theyre very cheap, circa £6500 delivered to our door! ONly issue is they Chevvy has 15 year old drive train, and a monster V8 would have ruined it!

[24seven 104]

I want it to be able to go round corners properly too! When they're small enough for people to put bike engines into them, it seems to defeat the object to slap a massive, overweight V8 into what is more or less (probably less) just a Caterham. £6500 isn't very cheap either, especially when 2L M52's are going on eBay for a couple of hundred quid.

[Anthony 1,003]

I would hazard a guess that the weight is broadly similar between different capacities of the same series engine - I don't have the specifics to hand, but I would be surprised if there was much in it between the 2.0, 2.5, and 2.8 variants of the M52 engine for example.

 

Edit: I checked and looks like I'm right. M52's with single VANOS are 167-170kg depending on capacity and later units with double VANOS are 177-180kg, so there's next to no weight penalty for a fairly significant increase in power and torque.

 

BMW M52 engine specifications

Edited August 30, 2012 by Anthony

[welshpug 1,657]

V8's are shorter

 

Toyota's 1g series - https://en.wikipedia.org/wiki/Toyota_G_engine#1G-FE

 

75mm square bore+stroke, no idea of material though.

[MiniGibbo 142]

There's no weight difference between the m52's.

 

 

[TT205 42]

Triumph 2000  

[24seven 104]

I would hazard a guess that the weight is broadly similar between different capacities of the same series engine - I don't have the specifics to hand, but I would be surprised if there was much in it between the 2.0, 2.5, and 2.8 variants of the M52 engine for example.

 

Edit: I checked and looks like I'm right. M52's with single VANOS are 167-170kg depending on capacity and later units with double VANOS are 177-180kg, so there's next to no weight penalty for a fairly significant increase in power and torque.

 

BMW M52 engine specifications

 

Thanks for that. Bookmarked the link.

 

V8's are shorter

 

Toyota's 1g series - https://en.wikipedia..._G_engine#1G-FE

 

75mm square bore+stroke, no idea of material though.

 

But they're wider and still heavier.

[MiniGibbo 142]

No m52's are double vanos, that will be the m54 in the e46.

[James504 12]

Nissan Rb20, 2L straight 6. May be hard to find over in the uk. Not much torque but rev like there is no tommrow. Best sounding RB engine imo (youtube).

Edited August 30, 2012 by James504

[Ryan 99]

Nissan Rb20, 2L straight 6. May be hard to find over in the uk. Not much torque but rev like there is no tommrow. Best sounding RB engine imo (youtube).

 

Also incredibly heavy, and physically enormous, even for a 6.

[Anthony 1,003]

No m52's are double vanos, that will be the m54 in the e46.

Late M52's are listed with dual VANOS on them everywhere that I can find?

 

Early E46's and E39's for example use M52 with dual VANOS, prior to the M54 engines replacing them.

[MiniGibbo 142]

No '36's have dual vanos that's for sure..

 

Early early '46's may carry an m52 but I'd be Suprised if they where dual.. Possibly but I've never heard of one.

[welshpug 1,657]

Yes, rb is bloody heavy, quite similar to xu in the way its put together but half as long again.

[James504 12]

Yes, rb is bloody heavy, quite similar to xu in the way its put together but half as long again.

 

You dont get something for nothing, but agreed it is on the heavy side. How is the rb similar to the xu in the way its put together? The rb uses a crank girdle for one.

Edited August 30, 2012 by James504

[24seven 104]

The M52 is probably about as good as I'll get to what I'm after I think. I wonder how much you can take off the top of the block of one - use the 2.5L pistons & rods with a 2.0L crank and shorten the block by half the difference in stroke (4.5mm) since they're the same bore anyway. That would be a nice short & low engine if it can be done. I'll get onto some 3 series forums nearer the time and see what they have to say.

[Cameron 16]

2.0 Duratec is the obvious choice, you don't need 6 cylinders.