Looking at the WSM (and maybe I missed the answer to my question).- 238 duration intake IVO 16btdc IVC 42abdc 252 duration exhaust EVO 56 bbdc EVC 16 atdc What valve lift to match the above?
Thanks, I understand the above. What I'm trying to figure out is at what lift is the stated duration? Intake supposed to open 16deg btdc at what lift
For example, I see the valve events of some of the older models measured at .5mm. Measuring at .5mm is not getting me actual results that match the WSM. When I test as above the intake valve at TDC is 2.24mm which should be about 14.5deg intake valve open. When I measure at .5mm I get Intake valve open- 16.5 btdc Intake valve close- 45 abdc 241.5 degree duration. Measured lift 9.1mm Exhaust valve open 57.5 bbdc Exhaust valve close 17.5 atdc 255 degrees duration . Measured lift 9.42mm Center intake valve open- 5 btdc Center intake valve close- 56.5 abdc 241.5 degree duration. Measured lift 8.96mm 11.5deg retarded from outer intake valves Measuring at .5mm it is ending up with more duration than listed and center intake valve more delayed than listed. I tried at .6mm and still has more duration than listed.
Have you considered that this is a hydraulic valve lifter design and as soon as the oil pressure is built up, there is no move valve clearance? The specs must be set up for that.
I think you are confusing older solid lifter motors with the 355 with hydraulic lifters. On, for example, the 308 QV the valve clearance is set to 0.5mm and when so set the intake will begin to open at 16 BTDC, for example. Another way to do it is to set the clearance to zero and then the intake would be 0.5mm open at 16 BTDC. In either case, after setting the timing the clearance has to be set correctly. On the 355 the clearance is 0 mm as it has hydraulic tappets. On the 355 when the intake is open 2.41 mm (or rather the tappet moves down 2.41mm) with the engine at TDC the intake actually begins to open at 16 BTDC. Similarly, with the engine at TDC the exhaust valve tappet moves down 2.29mm which means the exhaust valve will be closed at 16 ATDC.
I am aware of the difference in tappets. Also understand that when 2.41mm as measured on the intake at TDC it should open the valve at 16 deg btdc. (measured at what lift?) Regardless of it being a hydraulic cam there should be a lift specification for the stated duration/valve events no? It's not matching at .5mm, .6mm and certainly isn't absolute (very start of movement) As a comparison, any cam I measure after having made for a cam in block engine, the duration is at .050in lifter movement. So if I check a hydraulic or solid cam by the lifter body the duration matches the cam card at .050in lifter movement. Image Unavailable, Please Login
