Jason M
09-29-2011, 05:36 PM
Camshaft timing results for 240 intake 248 exhaust JWT adjustable gears & also JWT 272's. I'am going to edit this page as I collect a little more data & find my pic's of my degreeing setup...
Exhasut cam advanced 5 deg's, I had **assumed** that I needed to spread out the overlap. I did this before I new the measurements earlier this year. Valve clearance around .013"-.014". & yes I have used a piston stop to verify the TDC mark on the OEM crankshaft pulley. Nissan did a good job!
Shelf welded onto a spare pulley
http://i1217.photobucket.com/albums/dd398/conedodgers/022.jpg
Fowler Digital Angle Guage...
http://i1217.photobucket.com/albums/dd398/conedodgers/021.jpg
Big peice of steel clamped onto the intake manifold for a solid base for the Dial indicator.
http://i1217.photobucket.com/albums/dd398/conedodgers/014.jpg
248 exhaust 5 degree's advanced
EVO
.001" lift 72 deg's BBDC
.010" 61.5 deg's
.020" 57 deg's
.030" 54 deg's
.040" 51 deg's
.050" 48.2 deg's
EVC
.001" lift 9 deg's ATDC
.005" lift 5 deg's BTDC
.010" 9.15 deg's
.020" 14.05 deg's
.030" 17.8 deg's
.040" 20.7 deg's
.050" 23.35 deg's BTDC
IVO 240 deg's OEM
.001" lift 2.235 deg's BTDC
.005" 1.35 deg's ATDC
.010" 4.7 deg's
.020" 9.3 deg's
.030" 13.2 deg's
.040" 16.4 deg's
.050" 19 deg's ATDC
IVC
.050" lift 37.05 deg's ABDC
.040" 40.05 deg's
.030" 42.8 deg's
.020" 46.2 deg's
.010" 51.2 deg's
.005" 56.72 deg's
.001" 71 deg's
In short @ .050" lift, the Exhaust valve opens @ 48.2 deg's BBDC, closes @ 23.35 BTDC, Intake valve opens @ 19 deg's ATDC & closes @ 37.05 deg's ABDC
Measured peak lift for IV 120.65 deg's ATDC, peak lift for exhaust valve occured @ 124 deg's BTDC.
Online calculator gave me these numbers.
Camshaft Calculations - Lobe Center / Duration
Your OEM 240/248 has an Overlap of -42.35 degrees and has in Intake Duration of 198.05 degrees. The Exhaust Duration is 204.85 degrees. The Inlet Cam has an Installed Centerline of 118.03 degrees ATDC. The exhaust cam has an Installed Centerline of 125.78 degrees BTDC.
JWT 272's ( I spread out the overlap a little on each cam but did not make notes as to how much)
@ .050" lift EVO 49 deg's BBDC, EVC 4 deg's BTDC, IVO 12 deg's ATDC, IVC 56 deg's ABDC.
Exhasut cam advanced 5 deg's, I had **assumed** that I needed to spread out the overlap. I did this before I new the measurements earlier this year. Valve clearance around .013"-.014". & yes I have used a piston stop to verify the TDC mark on the OEM crankshaft pulley. Nissan did a good job!
Shelf welded onto a spare pulley
http://i1217.photobucket.com/albums/dd398/conedodgers/022.jpg
Fowler Digital Angle Guage...
http://i1217.photobucket.com/albums/dd398/conedodgers/021.jpg
Big peice of steel clamped onto the intake manifold for a solid base for the Dial indicator.
http://i1217.photobucket.com/albums/dd398/conedodgers/014.jpg
248 exhaust 5 degree's advanced
EVO
.001" lift 72 deg's BBDC
.010" 61.5 deg's
.020" 57 deg's
.030" 54 deg's
.040" 51 deg's
.050" 48.2 deg's
EVC
.001" lift 9 deg's ATDC
.005" lift 5 deg's BTDC
.010" 9.15 deg's
.020" 14.05 deg's
.030" 17.8 deg's
.040" 20.7 deg's
.050" 23.35 deg's BTDC
IVO 240 deg's OEM
.001" lift 2.235 deg's BTDC
.005" 1.35 deg's ATDC
.010" 4.7 deg's
.020" 9.3 deg's
.030" 13.2 deg's
.040" 16.4 deg's
.050" 19 deg's ATDC
IVC
.050" lift 37.05 deg's ABDC
.040" 40.05 deg's
.030" 42.8 deg's
.020" 46.2 deg's
.010" 51.2 deg's
.005" 56.72 deg's
.001" 71 deg's
In short @ .050" lift, the Exhaust valve opens @ 48.2 deg's BBDC, closes @ 23.35 BTDC, Intake valve opens @ 19 deg's ATDC & closes @ 37.05 deg's ABDC
Measured peak lift for IV 120.65 deg's ATDC, peak lift for exhaust valve occured @ 124 deg's BTDC.
Online calculator gave me these numbers.
Camshaft Calculations - Lobe Center / Duration
Your OEM 240/248 has an Overlap of -42.35 degrees and has in Intake Duration of 198.05 degrees. The Exhaust Duration is 204.85 degrees. The Inlet Cam has an Installed Centerline of 118.03 degrees ATDC. The exhaust cam has an Installed Centerline of 125.78 degrees BTDC.
JWT 272's ( I spread out the overlap a little on each cam but did not make notes as to how much)
@ .050" lift EVO 49 deg's BBDC, EVC 4 deg's BTDC, IVO 12 deg's ATDC, IVC 56 deg's ABDC.