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insane524td wrote:ive got it marked where its supposed to be with the dial. but just was testing.

it can be easily 0.50mm wrong with mark... or even more...
think by your self... you can put your mark about 2mm wrong.... and that will be destructive failure...

and this effects a lot with power and engine endurance...
my friend has learn this by the practice when engine exploded...

we went only testing hes car... and after 1.5km and the gasket blowed out... so dont even test your car...

wrong timing gets burning pressures and heat go nuts....

after 5years of working on these shit piles has taught something...

ok i understand, what is a safe rpm to run it at?

insane524td wrote:ok i understand, what is a safe rpm to run it at?

it depends about injection pump...

with 12mm rotorhead and stock cam plate 6000rpm is good limit... (or even with 2.0mm cam plate from electric pump, like my friend has)

with 10mm rotorhead up to 7000rpm....

but in both cases you must use stiffer springs for rotorhead...

or rotor head can make floating effect... (maybe)

i dont have personal experience about steeper cam plates... than vw 2.2mm

one problem with high rpm m21 is that valves can make contact with pistons... so i recommend to time your cam shaft little bit earlier... it also make compression rise little bit... so turbo spools little bit higher...

but this valve contact is not always in all m21 engines... like mine... i doesnt make this...

but i recommend test your pump advance like .... first 0.75mm after that test 0.80mm and 0.65mm.... you can see from you dynoresults what makes it work better...

with 10mm you may need use higher advance like 0.90mm or more... but that cummins cam plate can make some differencies about that...

how much you cam plate has lift?