35 replies to this topic

[twign]

Hi all.

I've got a mayfair, 1380, 12G940 Stage 4 head, 286 cam.

I've recently had it on the rolling road at Nobles in Chesterfied. I got 90bhp at the flywheel. I must admit I'm pretty disappointed with this as I was expecting more.

My questions are as follows:

a) does this sound about right? I don't know really what to expect, but I know the guy who did the work & sold it to me expected much more than this.
b) what does a Cooper S have that makes it 90bhp? The way I see it I've got a pretty tuned up mini that's only putting out the same as a standard Cooper S?

Not happy!

Cheers

Twign

[Guess-Works.com]

Grunt is dependant on a lot of things other than the basic mechanics of the engine and head...

Does not matter if you have super fandangled crank pistons, mega compression, and a cam which closes the valves less often than a "women of ill reputes" legs on payday...

Manliy things like carburation, ignition, advance angles, exhaust... it's these things which make an engine go !

[lolipop]

What sort of torque figure are you getting and how does it compare to the 'S'?

[Wil_h]

Don't read too much into RR figures, but 90 isn't way out for a 1380 with a 286 I don't think. Also, predictions on engine power made by people who sell engines should be taken with a pinch of salt.

I may be wong but I'm sure I heard bad things about the RR you used, but that was turbo related.

As GW pointed out power is more than just head and cam (although they're an important part) what is the full spec?

[twign]

Lollipop: I haven't got the paperwork yet, I collect my car tomorrow, but I think he said about 80lbs/ft torque. Will post exact figures tomorrow.

Wil_H: 1380 offset bored A+ block, 11 stud 12G940 Stage 4 head J max 73.5 mm pistons running a 10.8:1 compression ratio, Kent 286 cam, 1:5:1 roller tip rockers, Ultra light Flywheel, Pre verto clutch, X-pin differential, Hiff 44 Carburettor, Pipercross foam induction kit, Big bore exhaust manifold, Rc40 Millenium stainless steel single box centre exit exhaust.

If 90bhp is about right, then fair enough. I just expected a little more. 100bhp would of been nice!

[Pauly]

I would of thought cam timing would be a big contender in power loses aswell. If the cams not timed right then it wont be working to its maximum performance.

Paul.

[Paul Wiginton]

You say stage 4 head, but what one man calls stage 4 and another man calls it can be completely different. Who modified it? Who timed in the cam? Who machined and assembled the bottom end? Are your front wheels pointed in the right direction? Are your tyres inflated correctly? What air filter? Rampipes?

Paul

[1380rich]

who built the engine?? i had almost the same spec but on twin 1 1/2 su's an got 98 @ wheels. surely somethings not right there??

rich

[mars red mike]

Always take BHP figures with a pinch of salt. How the car drives is what its all about.

[1380rich]

he was referring to his bhp figure. how the car drives depends on weight, suspension, tyre choice, power and torque!

rich

[Asphalt]

I think Paul Wiginton hit the nail on 'the head' - so to say

What head do you have exactely?
'Stage 4' doesn't mean a lot realy.

Eventhough marketeers make you believe it does...

[Sherlock]

I'm inclined to agree with Pauly, a friend had a 1440 which was very disappointing performance-wise, we stripped the engine & found it actually to be nicely built, but it had a 649 cam & it seemed that someone had timed it with the tappets set at their running clearance of 15 thou. The setting clearance is 21 thou, having put that right, it was awesome! With 45 DCOE carburetter, it was only 1 second slower at Santa Pod than the V-tec engine he eventually replaced it with.

[twign]

1380rich: That's exactly what i thought, and 98bhp @ wheels compared to 90bhp at the flywheel is a big difference if the only difference is twin 1 1/2 su's!!!

I didn't build the car, I purchased it all built and it's only got 2000miles on the engine, so Paul unforunately I can't answer most of your questions. I've recently had it all stripped though and the guy who looked over it said everything seemed in good working order (once I'd had a crown wheel and pinion replaced).

If I'm honest, after speaking with you lot and friends, I still think I'm shy of some bhp for what I should be achieving with my spec. I suppose if you don't do things yourself though, you never know how well they've been done do you. point taken.

cheers

twign

[Paul Wiginton]

Id suggest you check the cam timing and wheel alignment. As you bought it with the engine already in there - is it really a stage 4 head? could have been *cow poo* just to get a sale

Paul

[twign]

I'm aware that the tracking's out slightly - but that wouldn't make that big a difference would it?

I've had a garage take the head of recently so I assume they would have mentioned if it weren't stage 4. I can always double check though, but I do have a receipt for a 12G940 Stage 4 head.

So following all your comments (thanks) I to take it that it's suprisingly low on power?

Twign