[HWYSTR455]

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

As for manifold vs ported, you are going to get a lot of opinions there, but my personal experience has always to run full time/manifold. The exception is when you have a radical cam, and make little vacuum at idle. Just to say though, manifold/full time does help idle temps.

There is some true about the adjustable vacuum cans, since the adjustment isn't linear, like, a 1/2 turn may give you X, but the next half turn can give you XXX. You can still get reasonable results with them though, and they seem to work well for me.

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

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?

Remember, the can is just a diaphragm with a spring, and the adjustment controls the tension on that spring.

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.

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.

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.

Plot your curve. Use a piece of graph paper, on the left do degrees, on the bottom, do RPM, and go in 500 RPM increments. With a dial back light, step the RPM in 500 increments, and write down the advance, all the way up to 4500 RPM or so. That's your baseline. That should be done with the vacuum can disconnected. All adjustments should be made to initial, mechanical, and springs with the can disconnected.

Oil weight depends greatly on engine clearances, wider clearances require heavier oil, and the general indication is seen by oil psi. If you're getting 15-20 at idle hot with 20-50, then run 20-50. You don't really want anything lower than that.

.