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MG MGB Technical - Kent 715 Cam

Is this Cam rubbish?

My engine has never run well since it was built 5000 miles ago (lack of go) its a 18v taken out to +30 with a 715 Cam, Big valve stage 2 head, new HS4's, High lift Rolling Rockers(tried standard ones as well), Aldon Dizzy + electronic ignition and sports coil Janspeed manifold and K&N filters.

Needles I've tried AAA and AAU's Timing is set at 14 bdtc @ 800 rpm 24 @ 3000.

I've checked and rechecked things but it still does not respond no matter what I try!!

I keep coming back to the Cam and if its suited for that head? Can anyone offer a opinion.
K Harris

Was your camshaft degreed upon installation? If not the cam timing could be off considerabaly causing a loss in power. RAY
RAY

i have a 715 kent cam in my 1950 ,i think the cam timing is set at 106 atdc when the inlet valve on number one is fully open,
i run a weber 45 dcoe, tickover is not to good ,so i tryed twin su's back on it ,it was so slow on pickup so i put the weber back on ,i'll put up with the poor tickover cos it go like hell with the weber,
ignition timing i just put it back untill it stop pinking,
good luck with it.
da wright

I've got to second on the cam timing. At least check it.

I bought a Piper HR270 for my '73 some years ago and it dialed in somewhere around 11 degrees retarded with stock gears and chain. So with a multi-index timing set, using a tooth off the timing marks and 8 degrees on the timing set, I was able to get 1 degree advanced. Works well.

I put a Kent 714 (regrind) in my stock '75 about 20 years ago (OMG) and as far as I am concerned, it's like a good stock cam. I wouldn't think that a 715 is that much more radical and should work with your parts. Unless the compression ratio is way low due to low compression pistons and large combustion chamber. Bigger cams tend to need compression to work.

Wayne
Wayne Pearson

Sorted maybe, the cam had slipped and retarded in the vernier pulley meaning the exhaust valve was open at the wrong time thus the low compressions, now in the process of changing the cam for a Piper 270 (as PB recommended on the phone) I hope this sorts the bugger out!!

Anyone thinking of use sidedraughts Weber's after a cam thats suited to that application? give me a shout..

Cheers for posts..
K Harris

This thread was discussed between 13/10/2008 and 14/10/2008

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