high conpression head ??

[PC/SR]

I run a vintage Weiand head, 6.8 CR. On an engine dyno best HP at the flywheel was at 22 advance. The total advance for the A distributor is 40. Run the spark lever at about half way down on your total range. Every head and engine set up is different, but this should work for general usage. Mechanical or vacuum advance is going to take some work to modify depending on the type of distributor you have.

[Bruce of MN]

This is how I limit advance for my 6:1 head:

https://www.fordbarn.com/forum/showp...2&postcount=23

[nkaminar]

Hitman, That would depend on how you time your engine. If you use a timing light and degree wheel then your method is good, especially if you have a distributor with automatic timing. You also have to know what degree advance to set the timing at for your particular engine. If you use the method of finding the knee in the advance curve by experimentation, then timing your engine (with a high compression head) using the lever 3 notches down will work just fine. The setting of the distributor when retarded is not important. It is the timing where the engine is run that is the important part. In my case I retained the manual adjusted distributor advance and I adjust the timing depending on conditions. After 60 years driving Model A's, this is what I am used to.

[Boston Bruce]

Originally Posted by Pete

Winfield red.

winfield_17.jpg

[Hitman]

Originally Posted by nkaminar

Hitman, That would depend on how you time your engine. If you use a timing light and degree wheel then your method is good, especially if you have a distributor with automatic timing. You also have to know what degree advance to set the timing at for your particular engine. If you use the method of finding the knee in the advance curve by experimentation, then timing your engine (with a high compression head) using the lever 3 notches down will work just fine. The setting of the distributor when retarded is not important. It is the timing where the engine is run that is the important part. In my case I retained the manual adjusted distributor advance and I adjust the timing depending on conditions. After 60 years driving Model A's, this is what I am used to.

I get what you're saying, and if it works for people, that's great. I just wouldn't provide advice like that on the forums without huge caveats. Even between 28/29 and 30/31 styles, the steering column assembly can be different, the top portion with the groves is different, the levers are different, and even distributor bodies are different across the years. Throw in reproduction parts and it's anyone's guess. Add in other variables like head compression ratio, fuel used, worn parts, etc., and there's no one size fits all approach.

The best recommendation you can give would be time it by the manual and how current day manuals recommend. Start there and see how the car performs, find where the spark advance lever runs best in your application and tweak as you go. Monitor detonation, gas mileage, engine temps and other things to determine if you have it set properly.

[40 Deluxe]

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Originally Posted by Hitman

Never time a car to this. Your three notches are different than mine, your horizontal level is different than mine. Even 28-29 vs 30-31 columns are different as well as their notches. Since the cam and rotor are adjustable, there’s no way to standardize the timing by notches, position, feel or other things.

Always time the car with a light, ideally setting the timing for total advance. Depending on factors, should be 26-32 degrees. I aim for 28-30 deg at 2500 rpm for a mild street engine.

This assumes, dwell, shaft bushings, and other factors are properly set.

Here it is: The best timing advice ever! It is amazing how well Model A engines tolerate ham-fisted mechanics using old seat-of-the-pants methods! However, higher compression and other mods limit the tolerance factor. Time to get scientific!

[Jyromefedx]

Are there any spec sheets that break down how the individual heads increase performance?

[Pete]

Originally Posted by Jyromefedx

Are there any spec sheets that break down how the individual heads increase performance?

Yes. I have seen a few in magazines or advertising. They are usually based on a stock a displacement engine but there have been a few based on various oversize engines.
Most people have only heard the old myth about boring a block just enough to clean it so there is plenty for the next rebuild. HOGWASH!!
How many of you have ever rebuilt the same engine 2, 3, 4 times??
If you bore to the limit as determined by ultrasound and
reduce that number by .030 you will have a block that can be rebored 2 more times and will produce enough more hp that you will be smiling all the way.
This is a far cheaper way to get the same results as a high compression head for a mild street engine.
If you want to add a head on top of this, then you are getting
into the realm of hot rodding and should be well aware of the other things involved in this modification.

[nkaminar]

The effect of different modifications can be seen here: https://www.modelaparts.net/dynoshee...ynosheets.html

[Gene F]

Originally Posted by nkaminar

The effect of different modifications can be seen here: https://www.modelaparts.net/dynoshee...ynosheets.html

This is some nice info. Thanks.

I always wondered how much adding the second Zenith carb impacted performance. (~10 HP). I spent a lot to get 13 extra HP. This would have been nice info to have when deciding what I wanted in an engine package.

[OldIronRookieDriver]

Question for all: Our Model B engine has a Winfield 6.5:1 Aluminum head... we're replacing the gasket now and have just noticed that there are small coolant channels that come up from the block and thru the gasket only to be blocked off at the head (ie. there is no hole that continues)... It appears in the pic above that the Brierly head above also does the same. There are 6 of these holes like this.... Wondering if anyone knows of the explanation, but it seems they reduce the circulation of the coolant thru the block in this design.

[ModelA29]

The one that got away. Early Winfield Super 7.0:1. Crowfoot combustion chamber. The early ones weren't marked "Super" and used the standard Model A size spark plug. I wavered on buying this one because I have a Brierley on order.

[nkaminar]

In my opinion, for what that is worth, that looks like a nice combustion chamber design. It looks like there would be no problem for the air/fuel to turn down into the cylinder during intake. But it looks like custom pistons would be needed because it appears that there are no pockets in the head.