Thread: dropped a valve in 3 diff motors what am i doing wrong PLEASE HELP

u should still check ur pistons to see if they are done correctly or installed correctly....

what about the donor motor and the motor i boguth i never messed with the bottom end only the head?

Are you using the head with the bigger valve on all these motors? If so the head is no good.
Also where did you get the N1 cams from?

am using the same head that came with each motor individually and i bought the cams from greg spec

Try them with the stock valve see what happen.

what valve clearance are you running?
Are they genuine nissan N1s or aftermarket n1s?

i bought the n1 cams from greg spec original n1 cams

on the donor motor i used the same donor vvl head super tech dual v/r

an the motor i built i used the full built vvl head with bigger vlaves with super tech dual v/r

and on the motor i bought i used same head that came with this motor on stock prings and ret

no changes to the head suface i used cosmetic head gasket on built motor and donor motor ans till have the same prob in all 3 motors using the same cam points to assamble and still dont understand what am dojng wrong am doing everyhting that is done to properly install n1 cams

********help me********

This looks like your own with this one. A bad tensioner could cause this problem too but I don't about getting 3 bad ones in a row. Have a different machine shop look at the head if you used the same one for the 1st 2.

did you check the valve clearance on any of the motors? just cause they are nissan N1s you cant ncessarily assume they are drop in, maybe they are on the outer limit of the manufacturing tolerance which means your valve clearane is a too tight hence the dropped valves?

Do you have a stock motor with stock head no valve job no N1 cams put that in see how it works then if no problem drop in N1 cams if that works then your problem is in the heads on all those motors.
Do 1 step at a time so you can pinpoint the problem too much going on at one time.