model A head

[old Tom]

The cyl. head on my Model is cracked I have a good red Winfield 7.1 head that I purchased in 1955 and never used. Would in be advisable to use this head? Would it be to much compression for a stock A? Are those old Red Winfield heads worth anything?
Thanks

[alexiskai]

I'm about to put a repro Winfield on my stock A, I'd say go ahead. Or sell it and buy a Snyder's 6 if you're nervous.

[Jim Brierley]

Winfield heads were the best head available at the time, and are still very good. Most guys will tell you that 7:1 is too much, I say it is not. I ran a 7.4:1 Cyclone head on my widebed for several years with no problems. The thing to watch is that higher compression needs less spark advance, or detonation will occur, and likely cause engine damage. The Cyclone is like the Winfield "crows-foot" head. Probably no more than 26 degrees of total spark advance should be used. That head and a bigger carb will result in a huge increase in performance. It has good value, up to $600.

[alexiskai]

Originally Posted by Jim Brierley

The thing to watch is that higher compression needs less spark advance, or detonation will occur, and likely cause engine damage.

This might be a good place to ask something I've been wondering, which is how to tell if you're getting close to detonation. I have the Nu-Rex auto advance on this motor I'm about to put the Winfield on. Am I probably good if I just set the baseline a bit more retarded? What would be my cues that I should back it off?

[Jack Shaft]

Mr Brierley is correct,he actually did write the book red head,FSI mechanical advance electronic distributor,late B cam and single 97 (running a 94 now)and a reds 4 into 2 header..I found timing best at 1 degree per 100 rpm. What's amazing is the engine runs cooler and is more efficient than stock.

[Jim Brierley]

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Detonation is usually easily heard, called "engine knock". It is very damaging to babbitt rod bearings, and actually gives the engine less power and fuel economy.

[Y-Blockhead]

Originally Posted by alexiskai

This might be a good place to ask something I've been wondering, which is how to tell if you're getting close to detonation. I have the Nu-Rex auto advance on this motor I'm about to put the Winfield on. Am I probably good if I just set the baseline a bit more retarded? What would be my cues that I should back it off?

PM sent.

[Ranchero50]

Originally Posted by alexiskai

This might be a good place to ask something I've been wondering, which is how to tell if you're getting close to detonation. I have the Nu-Rex auto advance on this motor I'm about to put the Winfield on. Am I probably good if I just set the baseline a bit more retarded? What would be my cues that I should back it off?

Find a long hill, pull it at a constant acceleration and change the timing until you find the sweet spot where the engine seems to pull the best, that's your ideal timing at that RPM. As you go more advanced the engine will feel lazier as the spark is firing too far before the piston reaches the top. If you go far enough the spark pressure will crash with the mechanical pressure and it'll audibly knock. With a 6-1 head I'm only coming down about 4-5 notches on the timing adjustment. Nowhere near horizontal on the lever.