5 replies to this topic

[majorslinn]

hi,

Just in process of rebuilding the 1972 a series engine. Here the engine spec.

Overbore to 74mm

Satge 3 cylinder head 36in/30ex

1.5 rocker

Piper BP285 camshaft.

So as you can see that i,ve fitted BP285 cam with Dowel adjustable timing gears. I do have all tools (dial guage and 360 degree protractor) i need for cam timing i just need a step by guide to correctly timed the cam.

Mant thanks

Christian

[bmcecosse]

Have you any idea what setting you want the cam ? Are you going to set it to give equal overlap at TDC??

[majorslinn]

well i am quite new to this i like to be good performance engine so what it would be best timing for it?

[dklawson]

Piper a-series cam specs can be found in the link below:
http://www.pipercams...p...4&engine=62
They say the cam angle should be 107 ATDC.

To understand how you use that figure, borrow a copy of Vizard if you don't already have one and read through the explanation and procedure. It will make a lot more sense if you can read text accompanied by pictures.

[mini13]

as above but basically the procedure is...

bolt a big protractor to the crank with a pointer and set it to 0 deg at tdc, to do this accurately get the dti on no 1 piston and check the dti reads the same before and after TDC (say 20 deg)

then get the dti on no 1 inlet, turning the engine the engine slowly in the correct direction note the degrees on the protractor 10 thou before and after full lift, add the two figures together and divide the answere by two, this will give you the angle the cam is set to.

your cam should be set to 107 degress after tdc, although i would suggest setting it to 105 to allow for chain wear.

[majorslinn]

hi,

Thank you, i've done it set at 105.

cheers

Christian