questions about LT1 SR motor and power
#21
Moderator
iTrader: (242)
I meant what procedure did you use to adjust the lash? For example, rotate the motor till both valves are closed then do the lash?...etc. When in the rotation of the motor did you adust the lash?
It should've been done like this.....
Rotate the motor till the exhaust valve begins to open....at this point adust the intake valve lash.
Then rotate the motor till the intake valve starts to return from full lift....at this point adjust the exhaust valve lash.
Doing it this way will ensure that you are on the bottom of the lobe of the cam. Adjusting them both while both valves are closed does not ensure that you are on the bottom of the lobe. (Just an FYI)
It should've been done like this.....
Rotate the motor till the exhaust valve begins to open....at this point adust the intake valve lash.
Then rotate the motor till the intake valve starts to return from full lift....at this point adjust the exhaust valve lash.
Doing it this way will ensure that you are on the bottom of the lobe of the cam. Adjusting them both while both valves are closed does not ensure that you are on the bottom of the lobe. (Just an FYI)
This method is right on and the only way to really ensure accuracy in setting lash. Also, was the lash recommendations from the cam manufacturer given in "hot" or "cold"? Most manufacturers give them in "hot"....but in my opinion it's better to recalculate those measurements and set them when the engine is cold. The engine cools quite a bit in the first 30 minutes of turning off (from full operating temp).
#22
9 Second Club
iTrader: (7)
This method is right on and the only way to really ensure accuracy in setting lash. Also, was the lash recommendations from the cam manufacturer given in "hot" or "cold"? Most manufacturers give them in "hot"....but in my opinion it's better to recalculate those measurements and set them when the engine is cold. The engine cools quite a bit in the first 30 minutes of turning off (from full operating temp).
#24
10 Second Club
iTrader: (26)
if it gets faster with tighter lash, i'd retard the cam, and if you still pick up your engine wants more camshaft. measure the lash at full operating temp, then measure it with the engine cold so you know the difference between the two on YOUR MOTOR. Head deck thickness, rocker material, valve material, etc will all change how much the lash moves around with engine temp changes.
#25
9 Second Club
iTrader: (7)
if it gets faster with tighter lash, i'd retard the cam, and if you still pick up your engine wants more camshaft. measure the lash at full operating temp, then measure it with the engine cold so you know the difference between the two on YOUR MOTOR. Head deck thickness, rocker material, valve material, etc will all change how much the lash moves around with engine temp changes.
#31
10 Second Club
iTrader: (26)
I'm guessing you're close on the exhaust, or is it intake as well? With that single plane and converter you can spread the lobe centers, and add intake duration. So you're effectively keeping overlap relatively the same, but more exhaust biased. With the single plane the pressure differential will hold on longer after TDC, so you don't NEED to jump start the intake charge so early especially if it's on a street driven application. You're not hurting for compression or head flow so it'll still make plenty of torque, but I'll scream for a BROAD range of rpm up top.