Bike engines???

[300bhp/ton]

Ok then, school me please. What are the bike engines to look at and which ones to avoid?


To clarify why, well I'm always dabbling and doing different car related stuff. And I'd dearly love a vehicle to use for autosolo's and some other tarmac "rally" type events. These usually won't allow more than 4 cylinders or turbochargers (so my current rides don't qualify).

So I've been thinking about getting a small lightweight car on the cheap. Been thinking either a Morris Minor or a Metro/Rover 100. 1.8 K-Series seemed the obvious swap, but I'm intrigued as to whether a bike engine would make a good conversion instead?

Stripped I think each car could weigh in around the 700kg mark +-. So a revvy bike engine should be enough for a spot of fun.

So over to you guys, is it a good idea and what engines should I be looking at?

Thanks in advance.

Matt

[Chris71]

My gut instinct is that 700+ kg is getting quite heavy for a bike engined car. If you're after something for sprint/hillclimb purposes you also need to bear in mind that those sort of mods will probably put you up against full on racing cars!

For sprinting I'd be tempted to go for something that's widely supported in its standard form, like one of the more common Seven-type cars or an Elise, simply because they're still fun, but there'll be a field of 20 other people to compete against.

[300bhp/ton]

Chris71 said:

My gut instinct is that 700+ kg is getting quite heavy for a bike engined car. If you're after something for sprint/hillclimb purposes you also need to bear in mind that those sort of mods will probably put you up against full on racing cars!

Ok, point taken. I know 700kg is a lot heavier than many 7 a-likes.

But people seem to do similar swaps in smart city coupes/roadsters and classic Mini's which must weigh in at a similar amount. Although with a bike engine it must help shave some weight off.

Just thought it'd be "different" to a more common modern DOHC 4 pot swap.

Probably won't be climbs or sprints, more car rallies and Gymkhana's and auto solo's.

Chris71 said:

For sprinting I'd be tempted to go for something that's widely supported in its standard form, like one of the more common Seven-type cars or an Elise, simply because they're still fun, but there'll be a field of 20 other people to compete against.

I agree, but it's a cost thing. You can get a half decent Metro/Rover 100 or Morris for £500. Then build it up as you go. A home built K-Series conversion wouldn't break the bank, engines can be had for £400 if you catch my drift.

And Elise or 7 are going to be more like £7-10k straight off, which is far more than I'll ever have for this sort of thing.

[yazza54]

Get the metro and put a 143 or 160 VVC in it.

[mr_fibuli]

You might have trouble with reverse if you do autotest or gymkhana type events in a BEC. Reverse boxes for bike engines are fairly primitive and won't go into gear unless the cogs are lined up right - so you'd probably lose a lot of time faffing with it.

[Stubby Pete]

mr_fibuli said:

You might have trouble with reverse if you do autotest or gymkhana type events in a BEC. Reverse boxes for bike engines are fairly primitive and won't go into gear unless the cogs are lined up right - so you'd probably lose a lot of time faffing with it.

+1

To use a reverse boxed diff the cost spirals, see Elite Racing for details.
Electric reverses just won't change quick enough for autotests.

[300bhp/ton]

Stubby Pete said:

mr_fibuli said:

You might have trouble with reverse if you do autotest or gymkhana type events in a BEC. Reverse boxes for bike engines are fairly primitive and won't go into gear unless the cogs are lined up right - so you'd probably lose a lot of time faffing with it.

+1

To use a reverse boxed diff the cost spirals, see Elite Racing for details.
Electric reverses just won't change quick enough for autotests.

Not a problem, it's auto solo, not auto test. All forward no reversing.

[yazza54]

VVC engined Metro would destroy a bike engined metro in my opinion. 700kg is too heavy for bike power.

[Toilet Duck]

yazza54 said:

700kg is too heavy for bike power.

Out of curiosity, what is the general concensus on the maximum weight for a bike engined car?

[300bhp/ton]

Toilet Duck said:

yazza54 said:

700kg is too heavy for bike power.

Out of curiosity, what is the general concensus on the maximum weight for a bike engined car?

I'd be interested too. As said you see Mini's (Z car Mini also) and Smart coupes with bike engines in. Can't believe they are much less than 650-700kg.

[yazza54]

Well the Furys and Pheonixs are about 450Kgs. An extra 250-300 on top of that is a hell of a lot when you think about how a bike engine makes it's power and the extra weight the little clutch is having to cope with, plus the added traction of car tyres.

I think you could build a fast, reliable and cheap car with the k series in the metro. The engine would already fit, just have a bit of wiring to do depending on which engine you go for. Plenty of torque and power, engines are cheap and plentiful and pretty unbustable with the right head gasket and thermostat on.

Don't get me wrong, if the car was lighter OR you were allowed to go turbo, bike engine would be worth more of a look. But staying NA at that weight, car engine is your best bet in my opinion, but remember that's all it is - an opinion!

Edited by yazza54 on Wednesday 19th May 21:51

[mervyns]

I think a bike engine would be o.k. I was at a race meeting at Snetterton about 10 years ago and a Mini with a bike engine absolutely trounced the field!

[Stubby Pete]

mervyns said:

I think a bike engine would be o.k. I was at a race meeting at Snetterton about 10 years ago and a Mini with a bike engine absolutely trounced the field!

Was that a real Mini or a spaceframe chassis to look like a Mini?
Big difference in weight.

[Huff]

I think the real point is that much beyond (say 6-700Kgs) there's no benefit to having a BEC because the weight saving - maybe 30-40Kg - and lower inertia simply isn't going to be noticed the way it is in something nearly a quarter of a tonne less.

With appropriate gearing the BEC will have no problem getting it moving though.

Edited by Huff on Thursday 20th May 09:58

[300bhp/ton]

ok then, well assume this is only theory then.

What are some good (budget) bike engines too look for. I know the Hyabusa (sp?) is a monster motor, but I suspect it also carries a monster price tag. So what's good but cheaper?

Also how difficult is it to fit one to a FWD instead of RWD?

Thanks.

[mr_fibuli]

Lots of 1000cc bike engines these days are putting out 170+ hp. The R1 is popular as you can get away without dry sumping. Also heard of the big Kawasakis (1200cc?) being used as a cheap alternative to the Hayabusa.

Never seen a FWD BEC. I suppose it might be possible using a chain driven diff like a mid engined BEC?

There was a very nice Hayabusa engined Mk1 Golf for sale here a while ago, but I think that was converted to RWD.

[rhinochopig]

It is possible to not use the reverse box to reverse. I did a days worth of tests in my Westy Blackbird a few years back and it was quicker to flick the car 180 degrees on the handbrake and let momentum roll the car back into the box. It's just very very hard to do consistently. The chap who won did so in his wife's micra - the only mod being a knob on his steering wheel

[Toilet Duck]

mr_fibuli said:

The R1 is popular as you can get away without dry sumping.

Will the R1 engine not suffer oil starvation in heavy track use? I was under the impression that ANY bike engine fitted to a car was likely to suffer from this problem as the engine no longer tilts over when you go into corners as it would in its original application?

[rhinochopig]

Toilet Duck said:

mr_fibuli said:

The R1 is popular as you can get away without dry sumping.

Will the R1 engine not suffer oil starvation in heavy track use? I was under the impression that ANY bike engine fitted to a car was likely to suffer from this problem as the engine no longer tilts over when you go into corners as it would in its original application?

Some engines suffer more than others. Birds and Busas are a must. Blades and R1s are less susceptible. Personally I'd still dry sump them just to be safe, but many RGB racers just run a baffled sump and, I think, a few have just run standard without destroying the bearings.

[mikeveal]

The concencus for the R1 is that a baffled sump is mandatory for track use, and advisable for road use. It's all to od with where the oil pickup happens to be.

Sump baffles can be bought for about £60.

I'd steer clear of R1 engines from 2004 onwards. The 2004 was the first to make 170hp, previous engines were around the 150hp mark. The 2004 engine does develop more hp, but only above 7000rpm. Below this the engine has less oomph than the older R1's IIRC. Since youre planning to move a lot of weight about, I think the newer engines will be less driveable.

Also good are the GSXR's, there are a range of engine sizes. I know little about them other than people with them are happy.

Finally, I'm not sure a metro would be the best choice. Lighter is the Fiat Sciencento (sp?) and about the same weight is the ford ka. The Ka has the distinct advantage that the local scrap yard will be full of spares.
HTH