Subaru Timing

[mrford61]

Could anyone tell me how to correctly time a standard ea81.At the moment it is at 10 deg BTDC while "idling" at 1000 rpm.The motor idles sweeter the more I advance it from 10 deg? I have the vacuum advance hooked up.Any help much appreciated.Mark Clifford

[asra]

Hi MarkMark here from memory the timing of the different ea81 motors goes up to 24 degrees at idle. The japanese gt and the turbo were 16 and 24 degrees but this is from distant memory. The total advance of them all is the same to within a couple of degrees. For more torque and power you may want to get you distributor regraphed and then set your advance higher. I had a subaru brumby and wound the timing up and it had plenty more go but I coudn,t afford the dizzy regraphMark

[Tim]

G'day Mark. Most think that the advance keeps increasing as the rpm goes up. This is not the case. The vacuum and mechanical advances are only there to aid starting, smoother idling, better pollution control and to stop pre-ignition at high load low rpm situations. None of these situations are critical in gyro applications. All the advances are fully "in" by 3500rpm and from then up the timing remains the same. The best way to set the timing is to run the engine up to over 3500rpm and set the advance to 28 to 30 degrees and lock it there. This is true for most 4-stroke engines. With a standard Subaru, if the engine is bought back to idle, it should come back to 8 to 10 degrees, but you cannot rely on setting it there initially because of wear and the use of different distrubutor components over the years. (many have replaced parts from different distributors with different part numbers)The timing marks only go up to 20 degrees so you will have to measure around and mark a 30 degree line.Hope this helps.Tim McClure

[asra]

Tim is correct do Not exceed 33deg of advance We have just done some dyno testing of EA81's & found that they DO NOT make any more power beyond this advance only heat & high probability of detonation.With a bigger cam, after seting this max advance will give a very poor idle as EA81 dizzys have to much tolal advance disconecting the vac advance may help & is what I do this has been a problem BUT I'm working on a solusion with a veiw to different dizzy Butch

[mrford61]

Thanks for the help.It makes sense now to what is going on.Mark.

[mrford61]

Another question:Should it advance well past 30deg as you power up and settle back to 28-30 as the revs climb to 3500+? Thanks againMark.

[asra]

NO Butch
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