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mb230sl · 03-21-2018, 04:34 PM

i just hope that given the back story, we don't hit an errant kangaroo during its inaugural drive through the countryside!

i downloaded the 987 manual which i figured might be more relevant to the engine. the 986 manual only seems to cover the five chain engines. i don't recall such a resource being available when this project started nearly 2 years ago , and all for the princely sum of $20.

anyway the specs there suggest the following -

2.7 -

intake opens early/late; 21 before TDC/19 after TDC
intake closes early/late; 9 after BDC/49 after BDC
outlet opens ; 39 before BDC
outlet closes; 8 before TDC

3.2 -

intake opens early/late; 26 before TDC/14 after TDC
intake closes early/late; 20 after BDC/60 after BDC
outlet opens ; 39 before BDC
outlet closes; 6 before TDC

the calculator i've been using can't deal with inlet opening after TDC, so now i'm stuck.

i do notice the 3.2 has larger valves, that the 2.7 generates more hp per litre than the 3.2, and both have their torque band between 4700 and 6000.

all very interesting but it is a lot of work to swap cams over if the outcome is a flop.

03-21-2018, 04:34 PM	#3
mb230sl Registered User Join Date: Mar 2018 Location: australia Posts: 8	i just hope that given the back story, we don't hit an errant kangaroo during its inaugural drive through the countryside! i downloaded the 987 manual which i figured might be more relevant to the engine. the 986 manual only seems to cover the five chain engines. i don't recall such a resource being available when this project started nearly 2 years ago , and all for the princely sum of $20. anyway the specs there suggest the following - 2.7 - intake opens early/late; 21 before TDC/19 after TDC intake closes early/late; 9 after BDC/49 after BDC outlet opens ; 39 before BDC outlet closes; 8 before TDC 3.2 - intake opens early/late; 26 before TDC/14 after TDC intake closes early/late; 20 after BDC/60 after BDC outlet opens ; 39 before BDC outlet closes; 6 before TDC the calculator i've been using can't deal with inlet opening after TDC, so now i'm stuck. i do notice the 3.2 has larger valves, that the 2.7 generates more hp per litre than the 3.2, and both have their torque band between 4700 and 6000. all very interesting but it is a lot of work to swap cams over if the outcome is a flop.