I have few unanswered questions about this note that I got from my engine builder. Can anyone decifer it?

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Crower 62404 Cam Specs (for B18A/B Non-VTEC):
(Measured at 0.040 LIFT)

IN:
OPEN 8° BTDC
CLOSE 40° ABDC
DURATION (at 0.040 LIFT point) = 228°
LIFT 0.417
LOBECENTER 106°
PISTON-TO-VALVE at 10° ATDC (Overlap) = 0.160 plus
0.006 LASH

EX:
OPEN 36° BBDC
CLOSE 6° ATDC
DURATION (at 0.040 LIFT point) = 222°
LIFT 0.403
LOBECENTER 105°
PISTON-TO-VALVE at 10° BTDC (Overlap) = 0.150 plus
0.008 LASH
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Relevant parts listed: Endyn RW high N/A pistons, Eagle rods, head milled to medium (30-35 thou), Ferrea 1mm ovesize intake valves, stock LS exhaust valves, Crower 62404 cams/springs/retainers, race P&P head, balanced and lightened bottom-end, everything blueprinted.

My questions are:

1) How can the Piston-to-Valve clearance be that big?

2) What is its compression ratio?

3) How are these Non-VTEC cams compared to the VTEC ones of the ITR's, Toda's, Jun's, etc.?

 

Anyone?

 

Vtec cams have higher duration and lift.


[Modified by machaf, 3:14 AM 12/9/2001]

 

1) specs never say if that is the CLOSEST valve and piston come together. Likely using stock parts for measuring, which you have changed.

2) since you've milled head and changed valves, gonna have to spec out everything yourself. Might wanna clay the setup before running.

Be prepared to have a high 1200 rpm idle with the 404's as they will not create enough idle vacuum to satisfy MAP sensor.

This goes back to tuning big cams in V8's, same thing applys.

 

The engine is already running. It was blueprinted so I'm sure the parts are within specs. I'm just curious why the piston-to-valve clearance is so big with the parts I have installed.

[quote]Be prepared to have a high 1200 rpm idle with the 404's as they will not create enough idle vacuum to satisfy MAP sensor.

This goes back to tuning big cams in V8's, same thing applys.

Actually, the car does idle at 650-750 rpm with the fuel lean out 25% at 1000 rpm with the S-AFC, but I've raised it to 1000 rpm recently. The only problem is that it fluctuates up and down from 1000 to 1500 rpm. Is there a way to stop or decrease this fluctuation?