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05-27-2010, 05:31 PM | #21 |
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French dual spark plug head
At Rétromobile in Paris, France last year I saw this rather interesting Model A head. It was made by the "Etablisement Veyet", Lyon, France.
What does the extra set of spark plugs do? I believe it might have been an attempt to squeeze a little more power out of the smaller AF engine that it is mounted on. The engine is located in central France. His asking price for the entire engine as pictured is 1500 Euro ($1875.-) and he does not know what the condition of the engine is.... Fordially, Brad |
05-28-2010, 05:09 PM | #22 |
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Re: High compression heads?
Bassman,
I'm running a Winfield head, and have been very pleased with the performance and reliabilty. Cheers Bick |
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05-28-2010, 05:13 PM | #23 | ||
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Re: French dual spark plug head
Brad - My guess would be that the engine you are looking at was either originally a fancy speed (they have been made with dual spark plugs for speed. Look at the modern Lion Head)
OR an airplane engine head. redundancy is nice to have in the air, and airplanes had two sets of magnetos. One electrical system goes out, switch over to the other and keep 'em flyin' I also found this on a Harley website: Interesting Info: Quote:
Quote:
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-------------- Drive it like you know how to fix it! DMAFC / OILERS CC-MC Last edited by Jason in TX; 05-28-2010 at 05:31 PM. |
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05-28-2010, 05:54 PM | #24 | |
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Re: High compression heads?
Quote:
Dan told me how to modify one of his heads to get 10 to 1 compression. After welding the chamber up completely you machine it to look exactly like a flathead V8 Edelbrock head chamber. I ended up with 11 to 1. Here's a pic of the V8 chambers..The 4 bangers looks identical. |
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05-28-2010, 06:47 PM | #25 |
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Re: High compression heads?
I just put on the Snyders 6:1 head with a touring cam. I can run 65 mph all day and not hear the motor run. Best money ever spent. I also run a 4 speed overdrive.
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06-09-2010, 03:30 PM | #26 |
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Re: High compression heads?
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Larry Brumfield |
06-09-2010, 05:10 PM | #27 |
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Re: High compression heads?
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06-09-2010, 05:16 PM | #28 |
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Re: High compression heads?
Larry, Nice to see you posting on the "Barn" again. Have missed your posts.
Paul in CT |
06-09-2010, 05:38 PM | #29 | |
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Re: French dual spark plug head
Quote:
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06-09-2010, 10:50 PM | #30 |
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Re: High compression heads?
i have tested for compression on 3 different heads .
stock - 55# 5.5 - 75# 6.1 - 85# hope this helps .......... steve
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10-11-2018, 06:54 PM | #31 |
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Re: High compression heads?
Are they 94 Holleys and what jet cofigurations are you using. I have a Riley 2 port head and having trouble tuning them. I've been told that the power valves are the wrong size
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10-11-2018, 07:05 PM | #32 |
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Re: High compression heads?
In my tourer, which you know, Lawrie, I get more than others here have said they get - high 90's. Very close to 100 psi in each. That's higher than I would have expected from 5.5:1 compression ratio but that's what it is! Bores are 60 over, FWIW.
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10-11-2018, 07:40 PM | #33 |
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Re: High compression heads?
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10-11-2018, 08:28 PM | #34 |
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Re: High compression heads?
Compression (PSI) / 14.7 = compression ratio. Good for rough estimate, no lab glassware needed.
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10-12-2018, 12:11 AM | #35 |
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Re: High compression heads?
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10-12-2018, 11:57 AM | #36 |
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Re: High compression heads?
Just a comment, the pics posted by Jason, niggled, etc. appears to be more like a Winfield chamber. The original Thomas tended to detonate, Winfields did not. On dual plug heads, I ran a big Hall-Scott (5 3/5" bore) on a chassis dyno years ago. They had dual plugs, one on the left side of the head (OHV) one on the right. Each bank was on a separate switch. At idle there was a difference in RPM when one bank was shut off, at full throttle there was no difference in power!
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10-13-2018, 11:47 AM | #37 | |
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Re: High compression heads?
Quote:
Compression ratio, on the other hand, is based on two simple measurements: the volume of the combustion space with the piston at BDC, and then the combustion volume with the piston at TDC. Then simple division gives you the correct ratio. |
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