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256 Mechanical Camshaft views and adjustment

Posted: Mon Jun 18, 2012 8:26 am
by K4000JB
Hi Guys
Does anyone have any experience of a rover v8 with this cam fitted, how does it drive like in your vehicle, and does anyone have any cold tappet clearence that will help with fitting it to a cold engine.
Thank You
James

Posted: Mon Jun 18, 2012 12:15 pm
by kiwicar
Hi
Usual caveats on this, I've not used this in a rover, however I have a 256 263 on an LSA of 112 degrees mechanical roller cam in an SBC of 6.3 litres, I was going to use it on a road car, weighing less than a ton I think it would have been just about managable, provided I didn't try and take it into London! I am now going to use that engine with that cam in a slingshot dragster. . . make of that what you will!
I would think it would make a good circute race cam on engines up to 4.3 litres on webers or individual port EFI on a 4.6 or 5 litre it would probably also work as a drag race cam or a hill climb jobbie. For road use it would need atleast 6.5 litres (as it is non roller and will be on a tighter LSA) and that is not possable on a rover engine, anyway the heads would be so miss-matched . . . . . .
To get it to work you will need good heads and lots of compression (12:1+) and a proper induction set up.
Best regards
Mike

Posted: Mon Jun 18, 2012 1:09 pm
by K4000JB
Thanks Mike
Your engine sounds interesting, :D
The cam power band is stated as 4000-7400 in a 3500cc rover V8 I intend in running it in a 4500cc which may lower the curve a tad, the heads will be either JE UBV or TVR BV's, the induuction will be a twin plenum fed by (wo seperate feed pipes ingnition and fuel controlled by an omex 710 ecu.
Is there anyone out there running a 256 out there that can help with the tappet clearence when the engine is cold, just to get me up and running please
Thanks
James

Posted: Mon Jun 18, 2012 1:39 pm
by kiwicar
Hi
Sorry missed off that bit, I am running 22 thou (cold) as a starting point (comp cams recommended starting point for the lobe) you can usually run a bit tighter than that safely, down to about 15 thou, I think some on here say 12 thou (hot set) personally I think 18 to 20 thou should be quite safe.
I think 4500cc on that cam will be a handfull on the road, a good track cam though.
Best regards
Mike

Posted: Mon Jun 18, 2012 2:40 pm
by K4000JB
Thanks again Mike that's most helpful, I am planning on running a mcleod alloy flywheel (11lbs in weight) do you think this will make the vechile less driveable with this cam?
James

Posted: Mon Jun 18, 2012 3:17 pm
by kiwicar
Hi James
is this a race car? just if yes then yes. . . . If you hope to run it on the road then I would have a bit more weight in the flywheel.
Personally on a race engine I think you want all the rotating assembly as light as poss, even down to using a 7 1/4 inch multiplate clutch, the lot, a circute car is much nicer if it has a quick throttle response. A road engine is a different beast and you have to be able to drive it on light throttle and at lower revs, then you need a bit of help or you are forever working the clutch and ratling your teeth.
Best regards
Mike

Posted: Thu Jun 21, 2012 8:58 am
by K4000JB
Thanks again mike for your help :D