Model A heads
 

I just purchased parts from a fellow model A enthusiast. Amongst the assorted parts was a new aluminum head. It has no markings on it. Just wondering who made these, besides Winfield. Also how would one determine the compression ratio? This was from his estate.

Re: Model A heads
 

A photo would help.

Measure the volume of the combustion chamber by turning the head up side down and, with plugs installed, pour water into the combustion chamber. Pour from a measuring cup or beaker so you know how much water goes in. The combustion ratio is the displacement of each cylinder divided by the volume of water. The volume of each cylinder is about 200 cubic inches divided by 4 or 50 cubic inches which converts to 27.7 fluid ounces.

The top of the piston is inside the combustion chamber at TDC, displacing about 4 cubic inches or about 2.2 fluid ounces. Subtract this from the volume of water you measure. So if you measure 7.2 fluid ounces of water, subtract 2.2 to yield 5 fluid ounces to get 27.7/5 or 5.5 to 1. The results are approximate. It is more accurate when measured with the head on the engine. I hope this all makes sense.

Re: Model A heads
 

Don't you use the "total" volume when calculation the compression ratio? Cylinder volune plus head volume divided by head volume?

Re: Model A heads
 

Good point, thanks.

Re: Model A heads
 

This link may help you...


https://www.fordgarage.com/pages/hea...ssionratio.htm

Re: Model A heads
 

Aluminum "Winfield" heads are all repops. His were cast iron. You could probably count all the different designers, casters and cloners of Model A flat and OH valve or cam heads on 20 or 30 hands.........
Since most wanted their product to look like an original they didn't mark them. Some are known to be bad or marginal but without knowing the maker it's hard to know what you have.
The pinnacle of the A flathead has to be a Brierley. It's 7:1 with a thick deck and taller height to increase cooling. It also has a very efficient combustion chamber.

Re: Model A heads
 

That's nice. Does Jim still sell his heads?

Re: Model A heads
 

Ruth - ask him. I'll PM you his email. I had him do a cam for me a year or so ago and it's great.

Re: Model A heads
 

Start with his book. [email protected]