Can I have your cam specs?

No 🙂

We all see things from a different point of view, here is mine.

I get asked this time and time again, here is why I don’t:

The first and most obvious reason is when you’ve spent thousands of pounds developing unique and winning profiles you are not about to advertise them so they can be copied! People rip off other peoples ideas and designs all the time, I know all about that. I do have my own spec of cams, they are absolutely not ‘off the shelf’ grinds available to anyone. They are made to order, I do not usually have stock.

Secondly, what will do with the figures? Is 8, 9 or 10mm lift on the exhaust better than 11? Do you know what your exhaust port flow is and how to match a cam from that? Is a 250 or 270 duration better? When would you have 1mm of inlet valve lift at TDC or 3? If you know all the answers to this then you can design your own cams so i’m unsure why you would be asking me for the figures. Well ok I do, see paragraph 1 ^

Now you’re thinking here that you want some specs so you can compare it to others, but here is a thing, you don’t know what method of measurement I or anyone else uses, so a direct comparison is impossible.

Lancia for instance measured the advertised duration of their cams with a shim clearance of .8mm. In reality a standard engine runs with .35 and .4mm of clearance so any published figures weren’t relative nor comparable to anything! It’s still the same now. Take a C&B cam with an advertised 265 degrees. Is that 265 with any valve clearance, no valve clearance, how much valve clearance? At .1mm of lift, at 1mm of lift or (if it’s how the Americans quote it) at.050″ which is 1.27mm? The cam card doesn’t tell you. Ask them and it’s unlikely they will tell you (I asked, they wouldn’t), if they do would you believe them anyhow?

A cam duration figure ‘seat to seat’ with no clearance coupled with a duration figure taken at 1mm (or 1.27) gives a much clearer representation of a cam yet C&B don’t give you all that info.

If a cam has a duration of 265 then the valve may only see 245 of it after lash is set.

If you set the lash tighter than standard then the valve may see 255 degrees from open to close.

Is quoted lift at the valve or cam with or without clearance?

Should you use standard valve clearances on a modified engine with bigger cams?

I’m guessing that 99% of the people reading this have no answers to most of this, yet still they ask for cam specs. If you don’t know what you’re talking about why are you asking?!

It’s like going to buy a new Ford car and asking them what size valves or what cam duration it has. A. they won’t know, and B if they did, what would you do with that info, compare it to Nissans? You just have to accept that they know what they’re doing and buy the car.

The third reason is this and i’ve proven it time after time over the years. The people that ask all the questions before buying anything were never going to buy anything anyway. Also the hours I’ve spent answering their endless questions I could have been earning money building an engine or something. I am an engine builder, i’m not a salesman.

Last of all is this: As you just learned I am an engine builder and specifier and not a salesman. My message to you is this, if I’ve done all the hard work (and I have had many years of experience with just this engine) I am offering you the chance to buy the parts which I know work; my winning recipe. You’re getting the chance to either have a proper engine built and specified or buy those same bits to do it yourself. You can also go elsewhere, have less power than expected or completely mess it up yourself. That’s fine, it’s your choice to make. That’s how I roll, the offer is there for you to take it or not and that is your decision, I can’t make it for you.

So to answer your question, my favourite profiles have a lift of 12 and 11, a duration of 255 and 275. So now armed with that info make a decision 😉