6 replies to this topic

[mini-majic]

Ok, so ive been doin research on this a trawling throught the search results i get when i search for it but i just cannot find i definative answer, it always leaves me thinking different things when i do a bit more research.

down to business.

im going to be running a 1380 on a stage 3 head, 3into1 mani 1.5:1 roller tip rockers and supercharged. the problem is that im having trouble choosing my cam. originally it was going to be a kent 286 and from what i gather they are abit undriveable on smaller engines but on a 1380 they seem to be ok with decentish low down torque but they die out around 6500 on a 1380 and i really want mine to rev to at least 7000 aiming at 7500.

with my rev range in mind i set about researching on what cams are good up to that and i found the scatter cams, but on searching i cant find anybody that has got any info on a scatter in a 1380 and whether it would be anygood for driveablity such as in traffic etc. i would really like it to pull from around 3000ish to 7500 if possible so was thinking a kent 286 scatter???

any thoughts would be greatly recieved with all the wisdom that is in this forum!

cheers in advance guys n girls!

James.

oh, and im staying with a standard flywheel

Edited by mini-majic, 12 May 2007 - 08:27 PM.

[Sprocket]

The 286 or 286 SP will rev well beyond the 6500 mark. Im saying that in relation to my 1399 with a 274i cam, a fairly mild profile for injection engines, that has a rev band of 1500 - 6000 yet produces 100bhp right on the red line 6800. The 286 should be good for 7500rpm

The scatter profile gives more torque in the lower part of the rev band.

Im not convinced on the 3 into 1 manifold though, you would be better with a big bore LCB and 2" exhaust sytem. The 3 into 1 is more of a race manifold where the engine is at high revs for most of its running life, torque will tend to drop off at the lower rpm which is where you really want it on a road driver.

Come to think of it if you are supercharging it the 286 cam is deffo not the one to go for, i would recomend the 274SP which is actualy the scatter profile of the injection cam. This is far more suited to forced induction with short inlet duration but extended exhaust duration. You dont need megga cams with forced induction systems, they produce baggs of torque anyway. Not only that but you wont need to rev it as high either as the torque will be massive low down on a supercharged 1380.

Your strategy is a little mixed up. You want it to pull from 3k to 7.5k but you also want it to be driveble in traffic as well as supercharge it on a fairly wild cam. Step back a bit and dont go to extremes. pick a mild cam, this will give you the drivebility, 1380cc and the supercharger will give you the torque and you wont need to spend a fortune on a fully lightend bottom end to make it survive high revs. I have seen standard cranks that have been nitrided, survive 200bhp+ and still going, reason, they are rev limited to 6500 but can produce the power due to forced induction. Also the standard flywheel is a big no no on high revers, go for a lightweight (not ultra light) steel item

If its normaly aspirated then the 286SP is as far as i would go on a cam for a road car used in traffic, the 1380cc tames the ropey idle down as well as having more torque below the start of the rev band. The 286SP cam was specificaly thought out with the big cc engines in mind.

Hope that helps some what

Edited by Mini Sprocket, 12 May 2007 - 10:47 PM.

[mini-majic]

big help mate cheers! thats what i needed to hear. this is what i was trying to find out from my research but couldnt my spec is still changing with the information i am finding so this was just a rough set up of what i wanted and now its being fine tuned to get me what i want. this will be the first a-series i've modified like this so am always open to any sort of advise.

one thing though, you say about the 276sp is the scatter of the injection cam. i wont be doing this on my injection engine. it will be on a carb. can i still use this cam or is it purely for the injection models?? (might seem stupid but like i said its my first )

Cheers again, James.

[TOMMO0302]

From what i understand, the 274'i' is for injection, whereas the 274'SP' is the scatter and suited to your carb'd engine

[mini-majic]

nice one, thanks mate. oh an love that avatar, didnt get it at first but when you look closer makes laugh.

[Sprocket]

From what i understand, the 274'i' is for injection, whereas the 274'SP' is the scatter and suited to your carb'd engine

Any of the 274 cams by Kent, the MD274 or the MD274SP are specificaly designed for the injection engines. The 274SP is the lowest spec scatter cam on the market. Just because its labled as an injection cam doesnt mean that it wont be suitable for anything else. These injection cams are ideal for forced induction with a limited valve overlap and a large amount of exhaust valve duration compared to the inlet valve, the scatter profile makes better use of the time the valves are open due to the five port head design, reducing the effects of charge steeling or port robbing as some call it. Forced induction engines do not respond well to racey cams as the valve overlap is large, a lot of the charge that enters the cylinder is blown straight out of the exhaust, reducing the power potential and increasing the emissions. There is no need for large inlet durations as the charge is being forced into the cylinder, but the exhaust needs all the help it can get to expell as much of the combustion gasses as it posibly can so that it doesnt contaminate the new intake charge, hence the longer exhaust duration.

Hope that clears up any confussion

[Sprocket]

one thing though, you say about the 276sp is the scatter of the injection cam. i wont be doing this on my injection engine. it will be on a carb. can i still use this cam or is it purely for the injection models?? (might seem stupid but like i said its my first )

I mentioned the 274SP cam, Kent do not do a 276SP, the 276 cam is one of Kents run of the mill fast road cams.

There is always some confusion whith this as there are still a lot of people unaware of the 274 cams and get confused easiy with the 276 which deffo will not work on the Injection engines.

As I said before, theres no reason why you cant use the 274 range of cams on non injection engines, good performance with drivebility from 1500 through to 7000rpm on a 1380, the torque spread is huge. My 1399 produces 58lbft torque at 1700rpm peaking at 87lbft at 4800 rpm and falling off to about 75lbft at 6800 rpm, and that is on the 274 cam, the scatter profile will give more torque lower down. It idles real nice and will drive happily in traffic. Power figures are meaning less, its all about the torque.