cam timing on 318is

[Dan318-is]

i wonted to replace cams on my IS but the prices are ridiculous

iv read in a couple of threads (which i now cant find) and some other sites that the inlet cam timing on a 318is can be advanced by 6 degrees to improve low down power?

can anyone advance on this as i dont no much about cam timing etc

[tomstickland]

The cams are both on adjustable pulleys so doing timing adjustment is a simple job. I've no idea how much valve-piston clearance there is though, so care must be taken.

Adjusting cam timing normally gains some torque somewhere but loses it somewhere else. The balance of numbers can only be determined by dyno testing the engine really. There might be a few more BHP to be had by adjusting the cam timing off the factory marks. All depends on how accurately BMW ground the cams in the first place.

Physically making the adjustments is a 15 minute job. I'd be very interetsed to hear if anyone has ever done it and gained anything.

[Demlotcrew]

Ive done it, pulls really well to 7k now with on loss of power, but it has produced a flat spot at around 3.2k-4.4k rpm. You will gain lots top end and not really loose much else where.

A

[Dan318-is]

demlot, 6 degress on inlet ye?

[Demlotcrew]

Five on inlet.

A

[Dan318-is]

ok mate thanks i mite look into it

did u do it yourself or get a garage to it, how much did it cost

[Jimbob]

If it's so good why didn't BMW just do it in the first place?

Fair enough Andrew we know yours is meticulously maintained so is in a better state for the adjustment, but others - who knows

[Dan318-is]

you could say that about loads of things hto

throttle bodies for instance???

[Jimbob]

There's a difference in increasing airflow and retard the timing!

[Dan318-is]

i no that

but im saying why didnt they just put bigger throttle bodies on like people on here do, the arguement is the same for cam timing

fair play they didnt do it from the factory, but why put an adjustable sprocket on there?

[Jimbob]

They have loads of reasons for certain restrictions, I suppose the bigger throttle body wouldn't have suited the rest of the (standard!) engine.

I'm no pro on the M42 (mine was wank!) but maybe the adjustable sprocket is to ease the adjustment of cam timing etc when new belts go on, and perhaps something to do with the hydraulic tappets (probably not mind LOL)

[Dan318-is]

yours is wank ?

iv had mean a week an its got oil in a spark plug and has a fuel leak

im going to go to bmw and ask them what they think today

thanks guys

[Demlotcrew]

There's a difference in increasing airflow and retard the timing!

All it does is increase valve over lap so its like getting schrick cams in there.

It makes the engine really buzy, it shakes quite a bit when cold.

A

[Dan318-is]

mine does anyway

isnt overlap what makes cars get fire out the back of the exhausts ?