compression, timing, fuel

[boss429kiwi]

Hi

Prior to me purchasing my Superbird, the engine was rebuilt by Ray Barton.
On the spec sheet it stats it was rebuilt with flat top pistons, bored .030, W/73cc, 11.6:1 compression.........................really 11.6:1, why!

I am not an engine guy, so why would the timing be set at 0? because any change makes it ping. With 11.6:1 compression, surprise surprise it has alway had bad dieseling.

6 pack, 4 speed

[Fred]

Have you considered putting a solenoid on your carby? That would stop the dieseling.
Or turn the motor off with the car left in gear.

In my opinion the compression is way to high.  Have you got aluminium heads?

[boss429kiwi]

Hi

Yes, always turned off in gear and looking at connecting the solenoid up.
Timing at 0?

The engine is all stock except for some internals.

[Fred]

Hi


Timing at 0?

No that can't be right. You need to have that checked.
Who knows what they did when they built the engine.

[justcruisin]

Can't imagine a motor built to stock specs having that high compression, have you done a compression test? If it has a stock cam and 11.6:1 you are going to see some pretty high readings. Not sure what you reading you will get, depends on a few variables but my 440 has 180psi with 10.2:1 static compression and a 230 @ 50 cam.

[boss429kiwi]

Just going by the spec sheet.
As mentioned, internals are not stock. Cam stats Ray Barton custom grind 490 lift.
11.6:1 compression etc

[elacruze]

If Ray Barton built it, dyno'd it and says it wants 0* timing, bet on it being right.

Timing by itself is meaningless; the function of timing is to time the peak cylinder pressure, not specifically to time the spark itself. The crank angle at which the cylinderpressure maximizes is a function of dynamic compression, piston speed, and increasing pressure from the burning mixture. All of these things change with RPM. Piston speed increases, dynamic compression goes through a change curve, and mixture burn time remains largely the same.

With so much static compression, the engine likely wants little timing at low RPM because the pressure rises very quickly in relation to crank angle.

[charger_fan_4ever]

Usually the wilder the combo the more initial timing required and less advance. All out motors run locked timing 36+ degrees.

Whats the total timing by say 3000-3500 rpm ?

Must have worked the distributor to make some major advance if initial is zero. My last mustang with a HCI 357W I had a mechanical MSD distributor with 18 initial and 18 advance.

[justcruisin]

My take on what you have said is that it wont run without detonating unless timing is set at 0. I doubt that the engine was built with 0 degrees initial in mind. Was is stated on your spec sheet that 0 degrees is required or is that where it is set so it will run on pump gas. Do a compression to get a better idea. What heads are on it, if they are iron with 73cc chambers it will be difficult to run on pump gas with a zero deck, best bet pull them and do some measurements, chuck a set of eddy's with 84cc chambers at it. That will net you between 10-10.3 at zero deck.