Distributor Curve - 2.0L Non S

[B D]

First off call to Barry Hershon is already in...

I've got the stock 2.0 specs for the 130 HP E cam motor but was wondering if there is any changes with unleaded gas and the reduction in octance.

The stock specs are:

idle 5 degrees ATC
2800-4200 - 17-26 degrees BTC
5K - 21-28 degrees BTC
6K - 30 degrees BTC

I had a quick check done and the advance curve starts at 1200 and I am getting 18 degrees BTC at 2,600 RPM, thoughts?

[brads911sc]

If you want max torque/power... the 5 ATC is fine, but you want to be all in earlier. Id go all in (30 degrees) at 3k rpms if it was me...

[B D]

Thats a few degrees beyond the curves range.

[brads911sc]

Yes. I didnt know you wanted to increase the degrees.

Ill let the experts weigh in... Can probably do greater than 30 degrees with no issues. whatever degrees you choose, you want to be all in earlier. long before 4500 RPM. I think even at 30 degrees Id be running 93 octane fuel...

[B D]

Ill let the experts weigh in...

When and where?

[lindy 911]

I would make a call to Henry @ Supertec. He has a ton of experience with the earlier motors.
My experience is with a 3.0 SC motor so I don't know about your 2.0 but I have never heard of idle timing ATDC. From what you posted the total timing in your dizzy is over 35 degrees. I know my twin plug dizzy has about 10 degrees less than that. I set idle at 5 BTDC and all in by 3500, 30 degrees total.

Lindy

[lindy 911]

Arron Burnham would also be a good sounding board; do you have your ears on Master Burnham?

[BURN-BROS]

Originally Posted by B D

First off call to Barry Hershon is already in...

I've got the stock 2.0 specs for the 130 HP E cam motor but was wondering if there is any changes with unleaded gas and the reduction in octance.

The stock specs are:

idle 5 degrees ATC
2800-4200 - 17-26 degrees BTC
5K - 21-28 degrees BTC
6K - 30 degrees BTC

I had a quick check done and the advance curve starts at 1200 and I am getting 18 degrees BTC at 2,600 RPM, thoughts?

The settings you have posted are for a 911L with smog control 901/14 and 901/17(smog pump)

For a conservative E spec 2.0 liter, I would use a Solex Type distributor and run initial of 0 deg @ idle with 30-32 @6000rpm.

A slightly hotter setup would be 67S curve and setting but Dynamic compression is high in the E compared to the S. Be mindful of the 2.0 liter combustions chambers as they are prone to detonation.

A problem with the early distributors is the lack of ability to change the curve significantly.

[B D]

Originally Posted by BURN-BROS

The settings you have posted are for a 911L with smog control 901/14 and 901/17(smog pump)

For a conservative E spec 2.0 liter, I would use a Solex Type distributor and run initial of 0 deg @ idle with 30-32 @6000rpm.

A slightly hotter setup would be 67S curve and setting but Dynamic compression is high in the E compared to the S. Be mindful of the 2.0 liter combustions chambers as they are prone to detonation.

A problem with the early distributors is the lack of ability to change the curve significantly.

Thanks! The car is a 911L no smog pumps anymore though and I've got the later aluminum body dist. The 0 at idle and 30-32 at 6K seems reasonable but what about other RPMs, when should full advance take place some say 3K others say over 5K? I am getting a lot of conflicting opinions...

[BURN-BROS]

You are fine with the settings you have now. They are not ideal, but are acceptable. No more than 20 deg@ 3000 rpm. Keep in mind, the graph posted is rpm and advance @ the dizzy. You have to times by 2 when measuring with a timing light @ the crank.

You are stuck with 5 deg ATDC with that distributor. I would like to see 0 or even 5 deg BTDC, Throttle response would improve.