Is This Calculation Correct

[png godzilla]

i searched & searched the forums on how to identify cam shaft lift, didn't find the proceedure as such but found the Tomei factory cam shaft specs. for RB26DETT is 8.58/8.28 IN/EX

then i searched Google on how to measure. rocker armed engines use lobe lift & rocker ration from what i can gather.................makes sense.

where OHC engines it appears the measurement from the backside of the lobe over the top of the lobe, minus the base circle = lift.

so if my cams in my RB26 are 41mm over the lobes & the base circle without the lobe is 31.2mm does it mean the lift is 9.8mm, or am i missing something here??

can anybody sched some light please?

[blind_elk]

Calculation is correct. Maybe misread the vernier? Otherwise you have one lumpy cam there.

[png godzilla]

OK, they don't look aftermarket (not that i really know what i'd be looking for) but here's a pic.

does this help at all?

[Adriano]

Turn the motor over, and see if the cam has any writing cast into it

[png godzilla]

the paint on the cams depicts that they are stock GTR so i found out.

but also the sock base circle diameter is 32mm, so looks like they might be some sort of re-grind.

i'll set up a dial indicator on the bucket & measure the lift, i guess is easiest..

interesting what you find in imported cars, it's like a lucky dip some times