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03-08-2024, 11:52 PM | #21 |
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Join Date: May 2010
Location: Santa Rosa, CA
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Re: high conpression head ??
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.
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03-09-2024, 06:38 AM | #22 |
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Re: high conpression head ??
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03-09-2024, 06:40 AM | #23 |
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Join Date: Jan 2012
Location: Western North Carolina
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Re: high conpression head ??
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.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
03-09-2024, 09:06 AM | #24 |
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Location: Maine and SC
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Re: high conpression head ??
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03-09-2024, 01:31 PM | #25 | |
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Re: high conpression head ??
Quote:
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. |
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03-11-2024, 12:04 PM | #26 | |
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Re: high conpression head ??
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03-17-2024, 08:37 PM | #27 |
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Join Date: Mar 2024
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Re: high conpression head ??
Are there any spec sheets that break down how the individual heads increase performance?
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03-18-2024, 10:16 PM | #28 | |
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Join Date: May 2010
Location: Wa.
Posts: 5,423
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Re: high conpression head ??
Quote:
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. |
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03-19-2024, 05:15 AM | #29 |
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Re: high conpression head ??
The effect of different modifications can be seen here: https://www.modelaparts.net/dynoshee...ynosheets.html
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
03-19-2024, 02:00 PM | #30 | |
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Join Date: Mar 2012
Location: Ohio
Posts: 2,057
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Re: high conpression head ??
Quote:
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. |
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04-05-2024, 08:14 PM | #31 |
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Join Date: Apr 2024
Posts: 1
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Re: high conpression head ??
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.
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04-05-2024, 09:12 PM | #32 |
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Join Date: Sep 2022
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Posts: 637
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Re: high conpression head ??
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.
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04-06-2024, 06:25 AM | #33 |
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Location: Western North Carolina
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Re: high conpression head ??
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.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
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