Barring mechanical failure, keep in mind that as boost builds, it gets harder to ignite the mixture. Your ignition system may not be able to maintain.

CJ

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Part of Tyrde-Browne Racing

Ceej,

No ignition problems yet, but we have only run 10 pounds of boost so far.

As we eventually raise the waste gate limit to 15 and then 20 pounds, eventually, that could surely happen.

Here's what we are currently running:

MSD 6-AL digital (but, not programmable) module with an MSD Blaster II coil.

TAYLOR cable 'resistance' spark plug wires (the instructions that came with the MSD unit said, in no uncertain terms, that it won't work with solid-core wires.) I had already bought a set...

We have the system set to deliver 18 degrees (at the crank) spark advance, from a Chrysler lean burn distributor that has no on-board spark advance mechanism of any kind... no mechanical advance mechanism and no vacuum diaphragm, so it is essentially a locked plate with the amount of advance set, manually, at 18 degrees from which it cannot move. It seems to work very well, with excellent starting and drive-ability, and spark-advance related detonation has not been an issue... ever.

We use some NGK racing plugs (non-projected tip) that are the coldest available on the Internet, gapped at .022".

I have never heard a misfire under any conditions from this setup, but, that may well change as we increase the boost. We are currently trying ten pounds and will attempt to increase the waste gate setting to fifteen, and ultimately, twenty pounds, at a later date once we get this O-Ring issue ironed out.

This car will never see street duty (just a fun, race car) so a spark advance curve that might enhance driveability, and fuel economy, are not issues we need to address.

Any advice would be appreciated.

Bill

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1964 Valiant 4-door sedan, 225 turbo/904

I know I express muself clumsily, but I thought you understood that my suggestion for having a dynamic spark advance curve, was intended to make power, not enhanced drivability or economy.

If you run at a fixed rpm, and with a constant boost pressure, down the strip, you may only need a fixed, preset ignition timing to maintain your preset power level. All other instances will benefit from some adjustment of the timing curve, even if your 18° will be correct at some points.

As they say, even a broken watch is correct twice a day!

Olaf

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Aspenized

True...

But when this ignition system is not "correct," it can cause catastrophic engine failure, unlike a watch that simply gives you the wrong time.

I fully understand that optimized ignition timing is most likely a fluid setting that needs to change with differences in RPM and boost levels. I am not suggesting that I believe that ignition timing, ideally, is a "one-size-fits-all" scenario that is the optimum system for this engine.

Hardly.

What I AM suggesting is that the overall situation involved in developing an ignition curve that might could pay benefits in terms of torque and horsepower, is a diabolically-complicated problem that an individual like myself (lacking the education, engineering tools and instruments, such as an engine dyno, exhaust temperature probes, accurate air/fuel ratio input, and a whole host of other "engineering aides",) stands about as much chance of designing an opitimal spark advance curve for this engine as he would designing an anti-gravity machine in a darkened room.


I have NO DOUBT that the engine in question could make more power overall, with an "active" spark advance system, because as ignorant as I am, even I realize that the "locked plate" approach is likely giving away tons of power at this rpm or that, but with my limited experience and diagnostic resources, I have no way to know what to do to design an active advance system that will produce more power without, at some point, creating an opportunity for detonation.

The amount of research necessary to determine the vagaries of an engine like ours with regard to spark advance/detonation potential is way beyond the realm of what is reasonable for an old duffer like me. I am 74 years old and would LIKE to see this bucket of bolts make a trip down the drag strip under power, before I shuffle off this mortal coil.

Looks like maybe a 50/50 chance at this point...

I could spend an easy ten years trying to determine a working, not "dangerous-to-the-engine," spark advance curve for this motor and maybe pick up two tenths in the process.... and, maybe more, but for a guy like me, who has spent his last dime to bring this project to fruition... it ain't gonna happen.

The chances of detonating a piston, or rod, into oblivion, are just too easy to envision, for me to want to take that chance.

And, when you play around, experimenting with boost/spark advance, it CAN happen... in a heartbeat...

So, I am not a very good candidate for ignition experiments, even though I realize they could pay dividends. Call me "chicken".... LOL!

So, for now, we'll stick with the "locked plate," cognizant of the fact that we are likely leaving some power on the table.

By the way, your English is beyond EXCELLENT!!!! It is astounding to me that someone who writes so very well in English could speak it as a second language. Just amazing... English is a monster and extremely hard to learn, for a million reasons.
You should be VERY proud of your English capabilities. It is quite easy, reading your posts, to forget that you are not writing in your "native tongue." That's how well you do it...

You should see my "Norwegian"... LOL!

Folks who speak more than one language are said to be "multi-lingual."
Folks who speak just one language are said to be "American."

Sad, but true...


Bill

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1964 Valiant 4-door sedan, 225 turbo/904

Olaf

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Aspenized