The V8 Owners Forum -

Hi..

I just receive V8developments M238cam

Solid Lifter Profile camshaft

Duration at .050” lift = Inlet. 238 & Exhaust. 238

Valve Lift = Inlet. 13mm & Exhaust. 13mm - clearance 0.2mm (assuming 1.6:1 rocker ratio)

Rpm Range for optimal power delivery is between 3000 and 6000 rpm.

The Cam should be timed at 103 degrees after top dead centre. The lobe separation angle is 108 degrees.

The recommended valve clearance setting are 0.2mm when cold.

Question:
If have to time cam to 103deg? Is it too earlier for 5.2litre stage 4 Rover v8? I usally see approx ~108deg for every cam what are used in Rover v8?
I have got in place Kent M228 (280/290duration @0.004" lift. valve lift is 11,78 and 11.94mm inc 0,55mm clearance)and it is timed to 108deg and engine dosent rev more than 5-5500rmp max.
So if this new cam is approx 290/290deg @ 0.004" lift, i will think engine cant rev more than 5000rpm? I will estimate that 105deg should be better idea? I want that engine will rev approx 6000rpm without proplem.
So what do you recon..?

And what do you think of 0.008" valve clearance? 0,2mm? Kent cam recon usually 0,55mm clearance..

Or is this wrong info for this camshaft?

I suspect the clearance figure is to be set cold. On a hot engine they will open up. When running a solid cam we always set tight to start and then adjusted hot. Follow the instructions then measure when the engine is hot, I bet you will be close to the other setting. Valve clearance depends heavily on ramp design so can vary from manufacturer to manufacturer. If you find a cam runs out of steam too early try retarding it 4 degrees, if you want more bottom end try advancing 4 degrees. This only moves the curve around and is no substitute for a big enough cam in the first place. Always check piston to valve clearance if you change the timing. The timing figures given may be a compromise to allow the cam to run without piston mods. Not necessarily optimum for best power. All engines are a little different so its a place where there can be a lot of power to be gained by experimentation.

Yes they are quated when engine is cold. and i usually set up them when engine is approx +20c, because then i have got more time to adjust them.. So what you recon when engine is hot?
i´m not sure Kent cams clearances are they quated cold or hot? I think cold?

I want more top end power. Now engine power band is approx 800-5000-max 5500rpm I want to rev it more than 5000.. So i think 105deg would be better for my aplication?

I may be missing something here, but that clearance seems tight to me and it would get even tighter when the engine is hot wouldnt it?

I have a 248 cam and the clearance .022" hot. I set them at .025" cold.

Steve