jeff652

iTrader: (1)

Hello Forum,

I am hoping for a sanity check as this is the first time I have degreed a set of cams. I 'finished' today and had a couple observations I am hoping that others can comment on.

I installed the s2p2 cams and degreed them using the peak lift numbers (Intake 99o ATDC, Exhaust 106o BTDC). Both cams have dwell at max lift (moreso the exhaust) so I noted the crank angle 3o before and after the peak lift range and split the difference to get my centers.

After completing the process as per 1_2_NV and Skunk2, I noticed a couple things:
1) With my peak lift 'centerline' set correctly, my opening and closing angles are way off what the Skunk2 tech sheet says they should be, around 10-15o earlier than indicated, IIRC. Is this common?
2) My exhaust is advanced 10o over my intake. In my particilar case, I have a stock B20 bottom and ENDYN head, neither have been milled. I am running a 2 layer OEM (GE) head gasket. My intake is at -1 and my exuast is at -10 or -11 (it is out of range on my cam gears, they only go to -5). This seems extreme to me, is it?

I am just surprised that I have to adjust the exhaust cam that much to get the centerline correct. Has anyone else had a similar experience? What did your gears end up at after degreeing your s2p2 cams?

I know the gear setting don't really 'matter', but it has me a little uncomfortable as I seem to be dialing out a lot of overlap . . .

Thanks in advance for any input
Jeff



P.S. - I have ordered a set of Pro Series cam gears and will re-degree the whole setup when they arrive, but I am hoping to gain some comfort from your experience prior to then.

Again, Thanks!

DDTECH

s2p2's need to be adjusted that much

i'll give you a hint tho.. Your exhaust cam will be WAY more advanced.. then your intake.. IF your degreeing numbers are correct.. you should end up with the exhaust at +4 and the intake at....? I'll leave the rest for you to decide... but your -10 .. is off. and your obviously not using the pro series cam gears which are setup for these cams.

stumpyf4

My suggestion to get around the dwell at peak lift, take note of your peak lift measurement i.e. 0.500". Take note of the angle at 0.490" before peak and 0.490" after peak... then split the difference.

ef92b

i haven't have experience dialing a S2P2 yet but have done couple of other cams in the past using Belben's kit.

two things i can think of now...

1. are your valve lashes set to 0?
2. are your dial gauges mounted properly? parallel to the valves thrust angle?

before setting the gears using the peak lift method, make sure you read/acquire the right values(duration), as per spec sheet, when cams are completely rotated. that from 0.05" opening and closing.

flesh199

I degreed my pro2 cam and pro cam gear last month...With 0 valve lash like ef92b said.

With the peak lift method i am at +4 exhaust a +2 intake.Keep in mind that my cylinder head is milled(15 thou)

DDTECH

.. your exhaust will always be more advanced then your intake on these cams , if they are dialed in properly.. keep that in mind folks.

jeff652

iTrader: (1)

Thanks guys for all the feedback! I sincerely appreciate it. I am continuing to research and analyze what I did wrong and will surely post back with an update when I fix/determine the issue.

Jeff

Natural Aspirations

Sounds like your timing belt is off a tooth, what are you using to set tdc? Locking Vtec?

Most will come "close" to the quick settings S2 provides.

Taylorej1-93

what degreeing kit is that and where did you get it?

gstrudler

Xenocron carries it; check out the "cam fixtures kits".

SR20S13

Mine was +1.5 intake +3.5 exhaust

vteczone

Vtec engaged when you degree them?

pithor-c1

iTrader: (1)

Specs on this motor pliz...pro series cam gears?

odz-fab

from the original post i dont believe you are finding your centerlines correctly. if the intake is -10 than try holding the cam in place, loosen you cam bolts and jump it a tooth in the right direction. not the actual cam just the gear. just an idea

unusual71

Someone correct me if i'm wrong, but the asymmetrical cam profile of the S2P2 might cause a problem finding the center line if you are comparing lift points before and after peak lift.
I haven't actually gotten to installing my P2 cams but I am familiar with the process and this was just an initial speculation I had upon inspection of the cams.
Anyways the possible error or discrepancy between expected and calculated center lines comes from this factor as well as others, the important thing is to check for clearances so you know your safe setting range. Let the dyno or track dictate where the cams need to be for the most power

mark@silbernage

I was thinking the same thing - I don't think the ramp up to peak lift and the ramp down are the same, so the center won't be "half way".

However, if the cam card gives you options then following those instructions should work if done correctly.

When I degreed mine (DD Tech), I used open/close @ 1mm to time them - and not the centerline.

Mark

SR20S13

ummm b18c with CTR pistons and RLZ port job, deck the block/head just to make it straight, and we had a TON of room to work with both P2V and V2V

odz-fab

exactly why you must find centerline from base circle and not max lift of the lob. different cams have different duration etc. yes the dyno/tuner may find a better suited cam degrea that the engine set will like more but it will be close to the cam card settings. id rather take the extra time to double check degreas than spend an hour on the dyno trying a plethra of cam settings

Rocket

Donf told me that all the Pro cams he degreed had to have the exhaust advanced (quite a bit) to hit the numbers specified on the timing card S2 provided.

I would contact Skunk to verify.

gmsii

if you are having a hard time finding peak lift because of the 'preceived' dwell, you can jot down the crank position for a certain lift value on either side of peak lift and mathematically determine the peak lift location (center). for example, if you have a cam that has a peak lift of 0.500", i would take the measurements at 0.497 or 0.498" on the opening and closing sides and do the math to find the 'center'. The closer those lift points are to peak lift, the closer your mathematical 'center' will be to the actual peak lift position. If you were to choose lower lift points, lets say .400" or .450", your mathematical 'center' may be off from the actual 'center' due to the asymmetry of the opening and closing lift profiles (only if they were designed as being asymmetrical)

DDTECH

Great way if you're pressed, Good advice.

Pippen_001

Good advice indeed, Thanks!!