Ignition timing on HP 500 -97 and later?
 

Does anyone have the specs for the ignition timing on HP500 carb engines with Thunderbolt V module (-97 and later)?

This module has a 'dynamic timing curve' function which adjusts the spark advance depending on load and acceleration. The module has to be set in 'base timing mode' to be adjusted but I can't find either the base timing point at idle or max advance @ x rpm :confused:

32 degrees over 2400rpm

My 98 carb 500HP's were 34 advance above 3000 and 14 base with the purple/white wire grounded.

Is 2400 rpm's really the break point for maximum advance?
Sounds a little low to me since the older Thundebolt IV HP module hits full advance @ 3000 and other 'standard' V8 T'bolts even higher ...

Sounds accurate, does the info come from the label on the engine, service manual or from testing?
Seems like I was a little on the safe side with app. 32 deg around 3200 rpm ...

Btw, a service manual for this engine seems impossible to find, only older HP500 manuals found so far. I know there was one for the T'bolt V system only when it was new but it is now NLA.

The 97 should have a TB IV ignition. It should be stamped "TB IV-HP",

My ignition modules were square Thunderbolt V. They were mounted on a plate with the knock sensor module on the stbd head underneath the coil.

Set them to 34 advance at an rpm > 3000.

The TB IV module were used up to serial no 0F877722. I don't know exactly what date the break was but later on they used TB V

That's what I did with my 98's

Actually, the knock sensors should be able to rescue the engine if the ignition ends up a little on the wild side.
I do run it with both AFR and exh. temp gauges during initial break in and propeller testing.

(To confuse you a little the engine is a brand new 454 Gen VI with same spec's inside as the 450/500 HP's. The TB V system used on the HP500 seemed to be a good choice due to the 'adaptive' curve settings and the use of knock sensors. It wasn't on the market when the 450 was, but it replaced the TB HP module later, which were used on early 450/500's)