PDA

View Full Version : Cam timing, vernier adjustment amount?


Tony Walker
19-09-2012, 21:34
Quick query, does anyone know how much adjustment in degrees is available on the piper vernier puller from full one way to the other?
GTphil
19-09-2012, 21:42
I have only done it once but I would say a lot for full ajustment one way or the other, probably to much!
Tony Walker
19-09-2012, 21:46
I wasnt happy with the delivery so i adjusted mine but went the wrong way and i ended up fully retarded on my vernier, and it was at the point it was just about idling. so that was the limit of retarding the cam lol so i advanced it 2/3rds of the adjustment which i think is around 10ish degrees and it drove much much better but its still too laggy for me compared to how it was before i rebuilt it.
rs250nut
19-09-2012, 21:50
Have any of you guys checked your p2v clearances when messing about with the cam timing?
Tony Walker
19-09-2012, 21:51
nah just turned it over then revved to 7000? :)
GTphil
19-09-2012, 21:54
Nope:wasntme: but my pistons have been dished and I have revved well beyond 7k a few times on the strip and it's still in one piece :laugh:
Tony Walker
19-09-2012, 21:54
i think the pistons where probably helping my valves close, its the new way to stop valve bounce.
Tony Walker
19-09-2012, 22:22
Anyone?
groky
19-09-2012, 22:30
i'm sure that its around 18 deg about the same as one tooth.
Tony Walker
20-09-2012, 08:15
Yeh o had a guess at 20. Anyone ever retarded it to the point it wouldn't run right? How far out was that.
Brigsy
20-09-2012, 08:38
You need a dti and wheel on to time it up properly. Chances are you will be miles out if you guess
Tony Walker
21-09-2012, 19:53
yeah i did that and didnt like the way it drove. then just adjusted and tested. it was at the point where id come on boost 18psi at 4300 then you could feel it come "on cam" at 5000 and flew effortlessly to 7k in 4th , it was also a little bit flat and a little rough idling.
Ive just advanced it about 7 degrees and its driving much better turbos in around 4kjust under and pulls evenly throughout to 7k without dropping off. i may retard it slightly but i wanted power lower down for track use rather than revving it so hard.
Brigsy
21-09-2012, 22:55
Retarding the cam shifts the power up the rpm range:scratch:
rs250nut
21-09-2012, 23:57
Advancing cam timing.

Begins inlet event sooner

Builds more low end torque

Opens Inlet valve sooner

Retarding cam timing.

Delays inlet event

Builds more top end power

Keeps inlet valve open later.

http://www.webcamshafts.com/
Tony Walker
22-09-2012, 07:42
Retarding the cam shifts the power up the rpm range:scratch:

lol yeah i meant advanced it.