[AdamIsAdam]

Originally Posted by HWYSTR455

Scope creep.

I had to look that one up!

You should really start a new thread for tuning, think the oil psi thing has been resolved.

Will do. I know it will open up a can of worms, so I'll get my facts straight and work out a few things before I do this.

Surge at 3k RPM would have nothing to do with where your vacuum can is hooked by the way.

What causes surge at 3k cruising? I can get it to almost go away by just backing out the adjusting screw on the crane vacuum unit.

This statement confuses me: 'So I have initial set to 12* and added 24* with the adjustable unit using MVA.' . A vacuum can isn't adjustable for the amount of advance it adds, that is a static value, and the adjustment is when it starts opening, like at a particular amount of vacuum. In order to limit the amount of timing it adds, you have to have a limiter. The crane units come with a cam that can be adjusted to control the amount of timing the can adds. Is that installed?

Yes, I have the notch plate/adjustment cam. I used that to get the timing from 12* to 36* at idle since 36* is my car's sweet spot. then I was using the adjustment spring to fine tune that. I guess what I'm doing is fine tuning how much vacuum advance is coming in at idle and part throttle because as I turn it, I brought the initial timing (with vacuum advance connected) from 36* all the way down to 20* in order to get rid of the bad surge and also the slight part throttle ping. However, the engine really runs best and is most responsive at 36* at idle with MVA connected. Only down side is that surge.

Just to say, the adjustable can has a range of 9.5 turns out (CCW) from the bottoming point (CW), and if you exceed the 9.5 turns, the adjustment screw pops out, and it's a biotch to get it started again. Most of the time it falls out, and you need to buy a new can. So turn it all the way in (CW), and if it doesn't bottom, it's fallen out, and it's junk and needs to be replaced.

I think I've turned it more than 9.5 turns CCW already I'll close it (CW) and start again. I've read that about the screw coming out.

Best way to test what the total amount of advance a can adds, hook up a vacuum pump with a timing light hooked up and suck the can down, watching the timing mark. That will tell you total advance a can adds.

I don't have a vacuum pump. But I know that the notch plate/cam on the Crane gives 2* for every notch. It seems pretty straightforward and easy to get my initial timing connected to 36* at idle.

Vacuum is the last adjustment you make when doing a timing curve. Initial, total, and rate are the 3 items you adjust before you even hook the can up, and generally in that order. Initial is obvious how you adjust that, total is by limiting travel or by the center cam and weights, rate is by the springs.

My timing curve has been checked by Richie as being good. It's 12* initial, 32* total at 2,800 RPM and about 20* at 1,800.