how much initial advance for a SBF ?

[zrayr]

Originally Posted by kiwigt

Newb here, resurrecting a (slightly) old thread and seeking your collective assistance. I have a 66 Mustang GT Fastback with a Roush 342R stroker engine.
I am installing a brand new set of Jim Inglese 48 IDA's.

Jim advises I want to start at 8-10 degrees initial timing advance, and deliver a total of 38 degrees at the crankshaft, this would be 4-5 degrees initial lead and 19 total degrees of advance in the distributor.

I'm using an MSD distributor. Can anybody advise on bushing / spring selection based on the above please?

I have a set of Jim's 48 IDA's on a 289 HiPo engine, and am using msd dist. and digital 6 box. I was experiencing an off idle bog that no amount of experimentation with jetting (under Jim;s guidance) was helping much. He was also wanting me to increase the initial timing from the stock 12 degrees. That helped a little, but not significantly. (A HiPo 289 K code engine has initial timing at 12 degrees and 40 degrees at maximum advance). No adjustment of the full advance timing was doing much either. Finally I started experimenting with the advance springs. Bingo. Best performance was obtained by using the lightest advance springs, AND starting with 19 degrees initial advance and going with the 21 degree bushing, ending up at the stock 40 degree full advance.

With the stock 10.0:1 HiPo pistons, I have zero evidence of detonation or pinging. For ease of starting and to reduce the load on the starter I have the msd box set for a 20 degree start retard.


Z.

[kiwigt]

Thanks for your reply zrayr - that is an interesting insight. I will bear that in mind with my settings, and if its ok I may PM you for further information once I get this installed....

[zrayr]

the beauty of the webers, and the msd system as well, is that you can do a lot of experimentation in a relatively short time.

Z.

[kiwigt]

"With the stock 10.0:1 HiPo pistons, I have zero evidence of detonation or pinging. For ease of starting and to reduce the load on the starter I have the msd box set for a 20 degree start retard".

I only have an older MSD 6 (non digital). Can you explain the 20 degree start retard function of the digital 6 MSD please - I might look into getting one.

The manufacturers specs on my Roush engine call for 18 degrees at 900 rpm initial timing....

[zrayr]

Originally Posted by kiwigt

"With the stock 10.0:1 HiPo pistons, I have zero evidence of detonation or pinging. For ease of starting and to reduce the load on the starter I have the msd box set for a 20 degree start retard".

I only have an older MSD 6 (non digital). Can you explain the 20 degree start retard function of the digital 6 MSD please - I might look into getting one.

The manufacturers specs on my Roush engine call for 18 degrees at 900 rpm initial timing....

The start ignition feature is pretty cool. The unit has a couple of dials for setting rev limiter and another one for matching the msd unit to the number of cylinders the engine has. the same dial can also activate the start retard. Below 800 rpm it retards the timing 20 degrees. Once the engine goes past 800 rpm the feasture is de-activated.

I had the msd box for several years and didn't think to use the start retard. Then one summer it was hotter than usual and the car wasn't liking to restart after it had been turned off for a bit. The starter was turning over the motor really slow before it would finally catch.

So I thought to try to start retard. WOW. The same starter now spins the engine about two to three times faster. It's a dramatic difference. With the timing retarded the 20 degrees the load on the starter was just so much less I had envisioned and hoped for. I'm sold on the digital 6, and kept the unit when I sold the car it was on, a '66 GT350. It had been on that car about eight years, and I have it on my current '65 K code Mustang.

Z

[kiwigt]

zrayr, I'm looking for ideas / locations to mounting the fuel pressure regulator - can you advise where you placed your pressure regulator please?

[zrayr]

Originally Posted by kiwigt

zrayr, I'm looking for ideas / locations to mounting the fuel pressure regulator - can you advise where you placed your pressure regulator please?

using the regulator and regulator bracket supplied by Jim Inglese.





Z.

[kiwigt]

Many thanks - looks good ...

[Snakebit]

331 with Webers running a Compcams 282S cam. Timing is 20* at the crank with 16* in the distributor. All in at 2800 rpm for a total of 36*. Webers love lots of advance and premium fuel

[PANAVIA]

What is the fuel pump system like >? -- curious