Rebuilding my engine. Head choice?

1928 Sport Coupe

1928 Sport Coupe

Member
1930 Model A Town Sedan
I got the engine running for a couple days after sitting for 20-30 years before I removed the engine and disassembled it. I found the rear main bearing was cracking, leaking head gasket, stuck valves, and the stuck rings. The cylinders had been bored 0.040 and the pistons were knurled. I took the engine to the local engine machine shop for rebuilding. He magnafluxed it after cleaning and found no cracks. He bored it out to 0.080 because of rust pitting at the bottom of #2 cylinder. He should get it to the babbet guy soon for pouring bearings. I think the crank should be done soon also.
I will be using a Burtz cam and Snyders modern valves, along with Snyders pistons and a B carb. Which HC head would be recommended for this? Snyders 5.5:1, Snyders 6.1:1 or Burtz 6.5:1. I have read the Snyders heads are 3/16" short and do not line up with the block. I wonder about the gasket sealing. Would the Burtz be too much compression? Which gasket would be best to use with these heads? Would there be any concern about an oversized gasket at 0.080 over bore?
I do not plan on running the engine hard or on long tours, mainly within a 30 to 40 mile trip at a time. I just want to have a little extra power if I need to get on the highway.
Thanks for any advice.
 
All the heads above are good. The 5.5 seems to seal a little better than the 6.1.
If your going to use the Burt’s cam then you might as well order the Burt’s head.
We have used them all and that Burt’s cam and head are a sweet combination.
 
I don't know whether it's true or not but I heard that the 5.5 head is no longer available. I run a Snyders 6.0 head on one of my cars with no problems whatsoever but I had to make sure the ignition was not too far advanced, FWIW, The higher the CR, the fussier the engine is about the advance.
 
100% Burtz head. Well within the capacity of a rebuilt engine. Better cooling than stock but looks identical.
 
I would do a stock head, easier on all the moving parts and the low compression gives you the multifuel capability, if you raise compression you lose that, if you just HAVE to have high compression, get a police head
 
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Sunny the Model A said:
I would do a stock head, easier on all the moving parts and the low compression gives you the multifuel capability, if you raise compression you lose that, if you just HAVE to have high compression, get a police head
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I understand this perspective, but it is odd to me to make this decision based on something you might do later under radically different circumstances. I might run on diesel or kerosene someday, maybe – but I pull out into traffic literally multiple times a day. The benefits are immediate and tangible.
 
I daily my A, and I run multifuel regularly, saves me vast quantities of money, since I run used motor oil through it. I drive 45-50 all the time, no problems.
 
The A-6050-B Hi-Compression Police Head (5.6:1) is scarce and of aged / tired iron. A new 6:1 head has similar performance to the A-6050-B Head. The principal benefits of running the Snyder's 6:1 Head are more power using less gasoline, cooler running, better gas mileage and zero time fatigue life. The stock 4.22:1 head was right for its time when gasoline was of low octane & poor quality. To the contrary, get the far better energy efficiency from modern 87 Octane gasoline with a higher compression cylinder head. From my experiences, the Models A & B engines with babbitt bearings work well with the 6:1 head.
 
Higher than stock compression and a bigger carb are the two easiest and quickest way to get more power in the A/B engines, and I believe more enjoyment driving them. Yes, pay attention to the amount of spark advance you use. The Burtz cam is also a good choice.
 
Might I ask the reasoning why Old31? what is there to gain by raising compression? You can no longer run on multifuel, it would be extremely difficult to crank start the engine in an emergency, it increases stress on the moving parts, and it is hard on the starter. Unless you want a moonshine car that'll do 80+ to outrun the 5-0, I just don't see a reason to bump it up to almost 90 psi.
 
Bob Bidonde said:
The A-6050-B Hi-Compression Police Head (5.6:1) is scarce and of aged / tired iron. A new 6:1 head has similar performance to the A-6050-B Head. The principal benefits of running the Snyder's 6:1 Head are more power using less gasoline, cooler running, better gas mileage and zero time fatigue life. The stock 4.22:1 head was right for its time when gasoline was of low octane & poor quality. To the contrary, get the far better energy efficiency from modern 87 Octane gasoline with a higher compression cylinder head. From my experiences, the Models A & B engines with babbitt bearings work well with the 6:1 head.
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I make my own fuel that sits right around 65 octane and My pickup loves it. I pull about 20 around town and 23 on a long trip at 50 mph. My a is the most fuel efficient car I've ever had. My "modern" '53 chevy 210 with a 235 and a 3 speed gets 11 city 14 highway on a really good day. '91 S-10 is not much better. These cars have high compression and cost me dearly in gas money. My A has been run on pretty much anything I can throw in the tank. only things it balked at was 70% diesel 30% gas and 30% motor oil 70% gas. I had to put a thermostat in my A to get it up to temperature, it seems to be cold natured.
 
Sunny the Model A said:
Might I ask the reasoning why Old31? what is there to gain by raising compression? You can no longer run on multifuel, it would be extremely difficult to crank start the engine in an emergency, it increases stress on the moving parts, and it is hard on the starter. Unless you want a moonshine car that'll do 80+ to outrun the 5-0, I just don't see a reason to bump it up to almost 90 psi.
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The engine I have used for about 60,000 miles in our long distance tourer started its high compression life with a 5.5 head. Now, with 0.060" oversized bores and the head planed a few time before refitting it, it cranks 105-110 psi on all cylinders and I'm NOT going back. I notice the better fuel efficiency, power and cooler running than I had before moving out of the early 20th century.
 
Bob Bidonde said:
The A-6050-B Hi-Compression Police Head (5.6:1) is scarce and of aged / tired iron. A new 6:1 head has similar performance to the A-6050-B Head. The principal benefits of running the Snyder's 6:1 Head are more power using less gasoline, cooler running, better gas mileage and zero time fatigue life. The stock 4.22:1 head was right for its time when gasoline was of low octane & poor quality. To the contrary, get the far better energy efficiency from modern 87 Octane gasoline with a higher compression cylinder head. From my experiences, the Models A & B engines with babbitt bearings work well with the 6:1 head.
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Bob - Not meaning to pick nits, but I was under the impression that the "Police" head was 5.2:1, not 5.6:1. I have an aftermarket "Model A" head with heart-shaped chambers that according to Vince Falter's site was a copy of the "Police" head at 5.2.
 
I think it is great that Sunny can mix up a batch of low-cost fuel and burn it in his Model A. But it is not for me. With today's traffic where I drive I need the extra umph of the high compression head. It also means that I can tour several hundred miles away from home and pull into a gas station and fill up without having to haul around my home made fuel.

Compression ratio is not everything in a head. The shape of the combustion chamber and the transition to the cylinder are also important. In my opinion, none of the heads manufactured today have the optimum combustion chamber and transition area shape. Look at the racing Harley or B&S heads.
 
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nkaminar said:
I think it is great that Sunny can mix up a batch of low-cost fuel and burn it in his Model A. But it is not for me. With today's traffic where I drive I need the extra umph of the high compression head. It also means that I can tour several hundred miles away from home and pull into a gas station and fill up without having to haul around my home made fuel.

Compression ratio is not everything in a head. The shape of the combustion chamber and the transition to the cylinder are also important. In my opinion, non of the heads manufactured today have the optimum combustion chamber and transition area shape. Look at the racing Harley or B&S heads.
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Bingo!!
 
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