Spark Advance on Hi Compression Head

[Bruce Adams]

I have noticed that if I advance my spark lever below 9 o'clock with my high compression head, I get a noticeable PING or some such noise.

The car did sixty MPH for a couple of hours straight, last week,(GPS verified), with its touring cam, balanced crankshaft, and high compression head, so I figure the spark lever works OK at the nine o'clock position while at speed.

I checked it last night, timing pin in the indent, rotor to number one, and my NuRex timing tool right on the number 4 distributor peg as per the NuRex instructions, with the spark throw going full in the distributor, .022" on the points.

Is this typical, or should I set it back to conform to the standard head's spark advance? Is it too far advanced at start while up at 11 o'clock so it might hurt the Bendix or something?

Thanks

[MrTube]

I wouldn't think you would want your base timing any more retarded then 0 degrees regardless of the head you are running.

[pat in Santa Cruz]

HC heads use less advance. (With the possible exception of a Lion Head). The Brumfield and Snyders I have run best at half mast, and a click or 2 more at highway speed. Rich Falluca recommends no more than 27 degrees advance with a Snyder head. If yours pings, that's too far advanced. To protect the bearings from getting flattened by pre detonation, you might consider placing something on the register or on the distributor plate to prevent over advance if you think you might accidentally go too far. I would not retard the spark more than zero.

[Bruce Adams]

Thanks, Pat and Mr Tube.
Pat, I think I just might try a block in the distributor to prevent any accidental over-advances.
Have you seen anyone who has done this?

[PC/SR]

I saw somewhere that Winfield had a block for the advance with his HC head but no one now knows what size it was.

[MrTube]

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Aww what fun is that? That takes the skill out of driving just as much as rev limiters.

Ok I'll admit maybe I would speak differently if it was my engine I was risking damage to. But for now I hold my ground .

[V4F]

i run a 6-1 head . timing is 5* retard ... 35* advance . no problems ............ done with timing lite .................. steve

[Jim Brierley]

The important thing is to not let it ping, babbitt will pound out in a hurry if it does ping.

[Marco Tahtaras]

Originally Posted by steve norcal

i run a 6-1 head . timing is 5* retard ... 35* advance . no problems ............ done with timing lite .................. steve

Are you running a distributor with manual spark advance or centrifugal advance? If it's the latter we are comparing apples and oranges. If it's the former then you are handling the lever well it seems.

[Bruce Adams]

Originally Posted by MrTube

Aww what fun is that? That takes the skill out of driving just as much as rev limiters.

Ok I'll admit maybe I would speak differently if it was my engine I was risking damage to. But for now I hold my ground .

Yes, When I hear the ping on acceleration, my memory is quickly refreshed that I have a HC head and that its too far down.

I am sure I will not put a block in the distributor to prevent me from being too far advanced, but it seemed like something to know about.