12 replies to this topic

[Oldskoolbaby]

After a long think, Im stilll not sure on what cam to use. As long as it doesn't conk out on its own, Im not too bothered if it idles roughly. I was considering the SW5 but I reckon this is far too soft for an engine that will rev to 8000rpm. I need something that will pull from about 2000 to 8000rpm.

Has anybody used a cam that they think highly of and fits my needs????

The closest Ive found, is the Kent 286 but it falls 500 rpm short of my rev limit.

[deaks46]

A STR 940 (649 equivelent) would allow 8000 rpm on a developed engine.

[Cloverleaf]

I think you're asking a lot for a cam to cover that range, I had a 286 and it would pull from 2000 but it was done before 7000.

I've got a Piper 300 now, it's got nothing below 3000 but its much stronger high up.

[Dog]

SW10 with highlift rockers!
Is this going to be MOT'able?

If not, I'd say a Kent 296

[Oldskoolbaby]

Well it will be intended for the road so it will have to be MOT'd. I did think I was asking a bit too much If Im honest. I thought the 286 started to loose power at about 7500rpm. This is why Id rather ask people from experiance rather than what a piece of paper tells me .
Ill be fitting a 3.6 diff so itll be a pretty revvy engine. I spose this will mean Ill only experiance rough running in first gear when I pull off slowly.
As for the emissions, Ive never really thought about it If its a problem, Ill probably order a high flow cat from Jetex or the like.

[Dan]

Running carbs with this cam?
Lots of unburnt fuel in exhaust + hot cat = big hole in floorpan between the seats.

[Oldskoolbaby]

Yeah, twin 40 Dellorto's mate. It will be be properly set up though so it shouldn't be over fueled. Quite the opposite actually while wearing it in. Why would there be a big hole in between the seats? Backfiring?

[Dan]

It's not a question of overfuelling, long duration cams have a huge valve overlap and so spit lots of fuel down the exhaust especially with fixed choke, variable venturi carbs where the jets are never fully accurate. Cats run very very hot, they explode if fuel gets into them (its a small steel can with a white hot platinum coil inside, when you pump in a potent mix of fuel and air you have a pretty good bomb) which is why the air to fuel ratio needs to be so tightly controlled in a catalysed system. To use a cat with a carb car you have to use an open loop type catalyst which are very innefficient by nature (they run colder in order to cope with a higher amount of unburnt fuel in the exhaust and so they need to have more surface area to be effective menaing they offer more of an obstruction). And the carb still has to be very tightly controlled to avoid problems, carbs and cats are not a good mix. This is how I understand it anyway, maybe I'm wrong.

Edited by Dan, 02 May 2006 - 11:26 PM.

[Oldskoolbaby]

Thanx for that info Dan. I never realised that as Ive never fitted a cat before. Ive had no need to really, pure oldskool

[Willybum]

Any ideas what a '948' cam is like? I was given this and told it is a torquey fast road cam that would go nicely in my '77 1275GT...

p.s. this is my first post. HELLO EVERYBODY!

[Alburglar]

sw10

what crank are you using to get 8k???

[Guess-Works.com]

to get anywhere near 8k you're going to need a 290+ degree cam, in a bigbore motor... I use an old Kent 290 (predates the 296 but similar profile) and that's about out at 7.5k (or rather the engine is), not alot below 3k though...

If I get round to building the short stroke (which I'm aiming to get to 9k red line) I've been advise to go for a 310 scatter.

[Purple Tom]

Possibly look at the Morspeed phase 3?

Had this in my 1293, was still pulling strongly up to valve bounce at about 7600 rpm....

might be worth an email to Simon to ask about the cam.