Originally Posted by
AndreasSomeone needs to talk to Kelford and have them make these cams on Nissan standard base circles. ( This is a must )
This would make things very simple for everyone.
Originally Posted by
5speed They do.
Simple reason why BlueRb240,Donttazembro, or anybody else would have to reshim is because they had a valve job.
Cutting the valve seats will cause the valves to sit higher in the head and therefore change the lash clearance.
The latest set of Kelford cams are not quite what i would call "correct". The base circle on the cams is smaller than stock by almost .25-.5mm small lobe and big lobe.
These cams were degreed into another motor and the last was set to the specs as given by kelford on the spec card. The intake cam duration was pretty close to what they said, but the lift was way off. This set of cams can not be run on stock rocker arms. they must be modified to clear the rotation of the cam lobe because the lift is .521" (13.23mm). the most that will clear stock rockers is .498" or 12.65mm. The exhaust cam is the problem. The valve lash for the exhaust i believe is .40mm spec (.016") The exhaust cam was then degreed and checked and the exhaust valve opening at .004" lift is 104 deg BBDC. that means the exhaust valve is opening before the piston is 1/2 way down the bore. Then the max lift was .486" or 12.34mm which will clear the rockers so that is ok, the exhaust valve closing was 65 deg ATDC which was way too late. So that means the exhaust cam has 349 deg duration at .004" lift. Something seem wrong to anyone?
Exhaust (.016" lash)
349 @ .004"
303 @ .015"
255 @ .050"
109 C/L
Intake (.008" lash)
318 @ .004"
291 @ .015"
256 @ .050"
105 C/L
The exhaust was way over spec on duration. After checking the opening and closing ramps I measured the base circles and found them to be smaller than stock. 32.20mm I think for the exhaust. That is a .30mm difference from the factory. I decided to set the exhaust valve lash to .025" (.635mm) and try it again. this time I got more "normal" numbers
313 @ .004"
284 @ .015"
249 @ .050"
109 C/L.
The exhaust valve opening went from 104 BBDC to 86 BBDC. Almost 20 deg just from loosening the valve lash. These numbers are very close to what is listed on the spec sheet ( if that is what they are supposed to be).
After seeing these results, I would love to try loosening up the valve lash on the N1 exhaust cam to see if it gains power by not opening the exhaust valve so soon.