11 replies to this topic

[Surfbluegarage]

please help me i purchased a kent 266 cam today for my 1275 im new to the world of cams but basically my understandin was that the bigger the lobes the longer the valves open and so on i.e better perfromance. But why does my original metro cam seem to have bigger lobes by about 2 mil. please help im confusled..

[Purple Tom]

The height of the lobes only determines the distance the valves open. Its the shape of the lobe thats important, the overlap between inlet and exhaust, the duration etc. Its this that determines the profile.

Are you measuring the cam using anything precise? Or just a tape measure or similar?

I've heard tell that the Kent profile's aren't the best as the original base is quite old now, but I wouldn't worry. I had a 266 in an otherwise standard Metro 1275 and it was great.

[Surfbluegarage]

yer we measured it with a digital vernier gauge and the lobes on the kent are more pointy and are smaller than the lobes on the metro cam i thought it was the bigger or more domed the lobes are the better the performance i.e more fuel and what not..

[dklawson]

A lot of cams are made from "re-ground" stock cams so by definition they're going to be "smaller" than a stock cam.

It's not the physical size of the lobe (point to point) that's important, it's the lift off the baseline diameter. What this means is, you can't measure the lift using dial calipers per se. A better method would be to slowly spin the cam while it's supported on centers. Zero the dial indicator when you've found the low spot, then turn the cam and measure the maximum lift above this datum.

If you don't have this, the best you can achieve with dial calipers is to measure across the cam lobe along the "narrow" axis (perpendicular to the lift. ) Record this value. Now measure the maximum dimension from the tip of the lobe to the far side (along the axis of lift. ) Subtract the first measurement from the one taken in the direction of lift. The difference between the two should be close to the maximum published cam lift.

However, as stated above, it's not jut the lift of the cam that's important, it's how the lift occurs... the profile of the lobe. The only way to measure that is with a degree wheel and dial indicator.

[Road Runner]

yer we measured it with a digital vernier gauge and the lobes on the kent are more pointy and are smaller than the lobes on the metro cam i thought it was the bigger or more domed the lobes are the better the performance i.e more fuel and what not..

Don't think you can go by that as the metro cam may well be worn so will give a false impression.

[minimanclive]

I might be wrong but I think I read in one of the Vizard books that the Kent 266 was designed to be used with 1.5 ratio rockers. That would get your extra lift.

[Surfbluegarage]

i know what your sayin about the metro cam may be worn but even if it is its still bigger than the kent one. would i still have to use 1:5 roller rockers or can i use normal 1275 rockers. are the rockers just to get max performance or is it a must have please help?

[alexcrosse]

the 266 is a bit of a tame cam. Thats why. The fast road one is the 276, fast road / rally 286. 266 is just a lil more overlap i think. Again, quite tame tho.

[The Matt]

i know what your sayin about the metro cam may be worn but even if it is its still bigger than the kent one. would i still have to use 1:5 roller rockers or can i use normal 1275 rockers. are the rockers just to get max performance or is it a must have please help?

As DK has already explained. A normal Kent Cam would be a re-profiled camshaft. Your Metro one will be made from a blank.

Basically, they take a cam like the one you have, grind it down to a different profile, then put it in a box. The lobes may be smaller, but the lift will be different.

[Surfbluegarage]

thanks very much guys anyone know the situation witht e rockers am i still good to use mine?

[Surfbluegarage]

hello again can anyone tell me if i can time my kent 266 cam up usin the standard timing points found on the timing gear the picture below is of my new duplex timing gear and has the standard timing spots marks on the gears, will these marks be ok for timin or would it need special timing. thanks alot

[The Matt]

The standard dot to dot timing procedure will work OK, but it will not maximise the performance of the cam at all. It's simply not accurate enough. You can use them and use offest woodruff keys if you want to get the timing spot on. Or you can get an adjustable timing gear setup.