Serpentine engine???
Discussion
Hi Mark, Welcome to PH, 
Im sorry that no-one has answered till now. I confess I am curious to know why are you asking (not that there is any problem with that) You dont say if there is a problem or whatever (fitting a new dizzy, engine rebuild, for instance). Optimal ignition timing isnt necessarily a fixed value for a model and will vary between individual engines for a miriad of reasons. What you are looking for is the least amount of advance required to give the highest smooth idle and freedom from significant pre-ignition at full throttle and low rpm. In general the static advance for the RV8 is somewhere between 10 and 16 degrees with the smaller capacity engines requiring the higher advance settings. The mechanical advance mechanism adds about 22 degrees of advance by 4500 rpm. So typically for a 4.0 (3.9) litre you are looking at about 12 deg static (or in reality at below 1000 rpm anyway) increasing smoothly to 34 degrees at 4500 rpm. Dont forget to DISCONNECT the vacuum advance(and plug the tube)when doing this.
I assume you have a suitable strobe and can mark the front pulley (Tipex is good) etc. A word of warning however - some engines have been found to have inaccurate timing marks on the front pulley, so TDC needs to be checked and verified before relying on the calibration. I did this on my 450 before checking the timing and found it to be spot on (use a dial-gauge with an extension through number 1 plug hole to find true TDC). You can fiddle with timing to advantage but you need to understand (as you may do) the implications as getting it seriously wrong which could be very costly if you run into detonation (or high rev pre-ignition which can be difficult to detect).
Hope that helps.
Im sorry that no-one has answered till now. I confess I am curious to know why are you asking (not that there is any problem with that) You dont say if there is a problem or whatever (fitting a new dizzy, engine rebuild, for instance). Optimal ignition timing isnt necessarily a fixed value for a model and will vary between individual engines for a miriad of reasons. What you are looking for is the least amount of advance required to give the highest smooth idle and freedom from significant pre-ignition at full throttle and low rpm. In general the static advance for the RV8 is somewhere between 10 and 16 degrees with the smaller capacity engines requiring the higher advance settings. The mechanical advance mechanism adds about 22 degrees of advance by 4500 rpm. So typically for a 4.0 (3.9) litre you are looking at about 12 deg static (or in reality at below 1000 rpm anyway) increasing smoothly to 34 degrees at 4500 rpm. Dont forget to DISCONNECT the vacuum advance(and plug the tube)when doing this.
I assume you have a suitable strobe and can mark the front pulley (Tipex is good) etc. A word of warning however - some engines have been found to have inaccurate timing marks on the front pulley, so TDC needs to be checked and verified before relying on the calibration. I did this on my 450 before checking the timing and found it to be spot on (use a dial-gauge with an extension through number 1 plug hole to find true TDC). You can fiddle with timing to advantage but you need to understand (as you may do) the implications as getting it seriously wrong which could be very costly if you run into detonation (or high rev pre-ignition which can be difficult to detect).
Hope that helps.
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