what is the highest duration/lift cam I can fit to my 2.7?

[oakey]

In short:
I need to know how "lairy"-a-cam It is possible to run on a 2.7 m20 without valve/piston contact or any other issues?
Also how high will my bottom end be able to rev up to without breaking stuff?

many thanks
Dave

[maxfield]

What's in there now?

I assume your going ITBS.

So you need something to make full advantage of them.

PM Ant for advice and i'm sure he can get custom ones done.

Not sure about your bottom end.

[chu346]

The most i've seen done on the zone without going silly is 288, whilst most people go for 284/272 on engines with the 325i pistons with the valve cut outs. I would imagine a 288 with eta pistons would mean contact.

[oakey]

I have JE custom pistons in mine.
Is there any way of testing it to find out?
what sort of rev range will a 288 shift the peak power to?

[Simon13]

all the way up top!

will idle like a dog and emissions for MOT might be an issue if you can't sort the mapping for it. the others know more but it's the most extreme road cam out there. After that your looking at 304/304! which is madness!

[oakey]

all the way up top!

will idle like a dog and emissions for MOT might be an issue if you can't sort the mapping for it. the others know more but it's the most extreme road cam out there. After that your looking at 304/304! which is madness!

I want madness
i will be running itbs so hopefully the idle wont be too bad.

what would be involved it fitting a 304/304 simon?

[maxfield]

The idle will still be quite lumpy!

304/304 you would need a high rev limit to take full advantage of them.

[oakey]

the others know more but it's the most extreme road cam out there

who are the others?

[oakey]

i wouldnt mind a lumpy idle at all.
i quite like the sound of a lumpy idle

[Simon13]

you have heard my touring!

others as in the guys who know lots more than me!

you'll need better valve springs, best talk to bexleys about safe rev limits on the bottom end as they built it?

[oakey]

you have heard my touring!

Yup

you'll need better valve springs, best talk to bexleys about safe rev limits on the bottom end as they built it?

Yeah I will. Im just lazy and posting on here is easier.

Will i need to get the pistons machined to run a 304 cam?

[maxfield]

Ask bexleys on that again as we don't know engine specs what valve cut outs etc

[Ant]

the big question is, Eta crank or TD ? if its an ETA, 7K max, so powerband 3-6.5K ish would work best,

[oakey]

Ok I'll get on the phone to bexleys today and post up in case anyone else is interested
I think I have the eta crank. I dont remember any talk of a TD crank. 7k sounds good enough though.

[Jhonno]

7k is 288 territory really

if you have custom pistons you may have larger valve cut outs but without seeing or knowing more cant tell

remember it isnt just about duration numbers - there is lift to take into account, you can have 2 very different cams with the same duration

[oakey]

7k is 288 territory really

if you have custom pistons you may have larger valve cut outs but without seeing or knowing more cant tell

remember it isnt just about duration numbers - there is lift to take into account, you can have 2 very different cams with the same duration

Im not very mechanically minded so I am not too clued up on duration/lift etc.

Is "duration" how long the valve is opened for???
and is "lift" the amount of distance the valve is opened????

Do both of these affect piston contact or is it just the "lift"????

educate me...

[Templ8e30]

7k is 288 territory really

if you have custom pistons you may have larger valve cut outs but without seeing or knowing more cant tell

remember it isnt just about duration numbers - there is lift to take into account, you can have 2 very different cams with the same duration

Im not very mechanically minded so I am not too clued up on duration/lift etc.

Is "duration" how long the valve is opened for???
and is "lift" the amount of distance the valve is opened????

Do both of these affect piston contact or is it just the "lift"????

educate me...

Spot on mate, both affect piston contact. Too long a duration and lift means piston/valve clearance issues.

Cheers,

Iain T

[oakey]

to answer my own question:
I spoke to them today and:
The engine was prepared to run a 288 cam apparently. so thats what I'll be going for.
It will rev to just over 7k.
sweet