timing to fit with piper 296 cams

[Callum]

Does anybody on here know how i can get my hands on the info needed to set the timing up correctly to fit with the piper 296 cams in my 1380. Thanks very much. Callum

[Innovator]

If you need to know the actual recommended timing then I would contact Piper.

If you need to know how to do it then I learnt from books (soory cant remember which) but now the info will be on the `net.

http://www.burtonpower.com/tuning-guide ... iming.html from a quick search.

One of the best tips I learnt when finding TDC is to actually position the piston say 0.2mm below TDC and note the angle, then take the piston past TDC to 0.2mm and note the angle. TDC is midway between the angles. Much more accurate than just using the dial gauge to find TDC.

I also made a bolt on plate and marked the flywheel with TDC



This little piece of steel bolts on and lines up with marks on the
flywheel to give me top dead centre, full inlet lift and full exhaust
lift on cylinder one. It is very useful and saves having to find TDC
everytime.

[bmcecosse]

You will need a dial gauge and lot's of patience - the adjustments are tiny and need to be done very accurately. Of course - unless you have access to a dynamometer - you will never know what is the 'best' setting for your engine spec. One engine may work best with the cam slightly advanced - another may work better with the cam slightly retarded. One setting on the same engine may give best ultimate power, but another setting may give better low down torque......... A 296 is pretty much a 'racing' cam - so has the engine been built with high revs and reliability in mind ? I suggest it will need to be fully balanced and lightened - with a hardened crank and a centre main strap - to be able to use that cam to advantage!

[MartinB]

As long as the cam timing is within a couple of degrees you won't notice any difference. The most critical thing you must establish is the valve to piston clearance, probably not to much of an issue with an A series, but critical with a 4 valve head. The best way to time a cam in in my experience is as John mentioned above.
Advancing or retarding the cam will just alter the rpm at which peak torque and peak power is reached, provided that the valve to piston clearance is adequate then 5 degrees either way can be tried. I tried all sorts of cam timing with my atmo 16 valve Fiat engine altering valve overlap (twin cam is easy), advancing/retarding up to 10 degrees! In my view too many people search for the 'magic' cam spec where as I believe getting the head to flow better is much more important with the cam matched to the head flow characteristics e.g. no point in having a cam that lifts the valve to 360 thou if the head flow peaks at 420 thou or vice versa etc. You can of course optimise the porting to match a certain cam as well though.
Sorry went a bitof topic there!

[bmcecosse]

I agree completely Martin - but when I say something like that on a Mini forum they all go wild - they are completely anal about getting the timing correct to the degree and hate anyone suggesting otherwise!

[MartinB]

I agree bmc, a lot of people get way too caught up in the cam timing accuracy thing and don't realise that there is probably a couple of degrees flutter through the timing gear/belt/chain/tensioner etc and that it varies according to rpm and harmonics etc.
I would go for the best flowing head with the mildest cam you can get away with for the power band you are after and of course everything optoimised to suit what the engine will be used for (road or race etc).