Highest Reliable Compression Ratio

Ed in Maine said:
I am amazed with all the interest in high compression heads. How fast do you really have to go in a Model A? My Victoria has a touring cam and it idles lousy. Ed
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You only have to go as fast as you want to.

If your "touring" cam idles lousy, it was either ground by the wrong guy or installed by the wrong guy.
A quality "touring" cam will idle SMOOTH at 400 rpm.
 
Ed in Maine said:
I am amazed with all the interest in high compression heads. How fast do you really have to go in a Model A?
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There are two reasons to put in a high compression head:
1. Torque
2. See reason #1

I’m not trying to hit 70, I’m trying to get out of my driveway.
 
Maybe in Maine and alot of other spots in the country a stock model is adequate..here in suburban Northern CA A stocker running without convoy protection is at the mercy of the yahoos..
 
johnneilson said:
X3 here in Cali, lunatics...
But, it does go noticed when you pass a BMW on the freeway, or pull up next to him.

J
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That is fun, especially if they want to try you out and you just drive away.
I have the B engine out of my 2 door right now and have a 450 hp crate engine in it. It will do 155 and is just like a Sunday drive on the freeway.
 
Pete said:
That is fun, especially if they want to try you out and you just drive away.
I have the B engine out of my 2 door right now and have a 450 hp crate engine in it. It will do 155 and is just like a Sunday drive on the freeway.
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Good clean fun, you bet!!
I don't know about where you are, a Sunday drive on the freeway down here is playing miss all the bumper cars and don't get run over...

J
 
Ed In Maine, I am driving my Victoria to the 2021 New England Meet in Newry, Maine from Long Island, so I need to cruise along the interstates to get there. 50-55mph is a must do, and a hi-compression head improves the efficiency of the engine to do it. There are thousands of Model "A" drivers who drive to out-of-town functions, and they must be able to do it on main roads. Do you drive your Victoria anywhere of significant miles from home?
 
I agree with Brent, plus gas mileage goes up with higher compression. Compression and a bigger carb are the two quickest and easiest ways to more power, cam is next but not near as effective per dollar and time invested. The very latest B cam has more lift and slightly more duration than a normal B, and makes a great touring cam.
 
johnneilson said:
Good clean fun, you bet!!
I don't know about where you are, a Sunday drive on the freeway down here is playing miss all the bumper cars and don't get run over...

J
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Yes, I hear you there. That was a figure of speech but I do have a dash plaque from the SCTA that says, 154.7.
My point was that while a stock model A body has an extremely poor drag coefficent and lots of frontal area especially with fenders on, it will handle very good at speeds over 100.
If your car wanders or shakes at 65, something is worn out or out of adjustment.
 
BRENT in 10-uh-C said:
A typical 'touring camshaft' should never make an engine idle lousy.

I agree.

I have a "Touring cam in a B engine with a 6.0:1 head and it consistently idles very smooth at 350 RPM. If I go up into the mountains where the air is thinner, it will idle at 290 RPM.

Chris W.
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Its important to note making these changes on a stock model a engine raises the engines efficiency. Higher compression, adding fuel, using a mechanical advance distributor and making it breathe better results in better economy and a cooler running engine. That's something most model a guys don't get, they feel you are ruining the engine 'hotrodding' it. banging the bearings out of it, causing it to run hot and increasing wear..
Actually the opposite is true, raising efficiency extends engine life, upper cylinder issues decrease as well,rings seat better, less exhaust heat due to a better burn saves valves..Alot of the common issues with a stock engine disappear...exhaust manifold drooping, burned exhaust manifold gaskets,engine temperature issues...gone.
 
Camshaft choice I have a story to tell about that. Many years ago I got a phone call from a guy wanting to buy one of my cams. He had a (heavy) fordor, all stock but wanted more power. We talked for quite awhile and I thought I had convinced him to not change his cam, he was running a B cam at the time. Well ... a month or so later I get a call from a guy complaining about one of my cams having no power. It took me awhile to realize it was this same guy. He had gotten one of my cams from another source, I have no idea which grind it was. He had a test site that he uses, up a steep hill, in high gear, starting from 5 mph, said it was slower with my cam than before. When I finally realized it was this same guy, I said "didn't I recommend staying with your B cam". There was a long silence on the phone after that!
 
Jack Shaft said:
Its important to note making these changes on a stock model a engine raises the engines efficiency. Higher compression, adding fuel, using a mechanical advance distributor and making it breathe better results in better economy and a cooler running engine.
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As early as 1933, stock V8s were shipping with poured bearings, mechanical advance, and a 6.3:1 compression ratio. If anything, the A was under-compressed for its time.
 
alexiskai said:
As early as 1933, stock V8s were shipping with poured bearings, mechanical advance, and a 6.3:1 compression ratio. If anything, the A was under-compressed for its time.
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Look no further than the 'new and improved' 4 cylinder engine introduced in 1932..other than just a mild compression increase it incorporated all the upgrades Ford engineering noted as necessary from 28 to 31
 
New A owner here….... have had the car since last June and was in overall decent shape, or so I thought. Once I got it home I could tell the car suffered from a lack of TLC.

Major items done include new front tires with balance beads added, toe in adjusted, brake inspection and adjustment, new front shocks and links, tie rod ends rebuilt, remove and correctly reinstall pitman arm bolt, front spring shackles…...etc, you get the point.

Anyway, the engine ran great, smooth idle, adequate power, no smoke out the back. Did discover an exhaust leak, so decided to go with opened up intake for model B zenith compatibility and new exhaust manifold and Aires muffler. Currently using a Marvel-Schebler and very happy with results.

Head-gasket (Felpro copper) blew between 3&4, all apart, cleaned up and wondering if this is a good time to install a higher compression head and what the Barn community might have to say! Have read many opinions, thinking of the Burtz 6.5. I don’t drive like I stole it, but very hilly around here and I’d like a bit more power for that………. Thanks all!
 
Skycop - Welcome from another relative newcomer. My car needed a thorough mechanical rebuild front to rear. The engine block was cracked and I replaced it with a rebuilt unit and added the Burtz cam and 6.5:1 head. Also a counterbalanced crank and lighter flywheel. No changes to the carb, ignition, or manifolds. It all looks stock. I have not encountered any problems caused by the head, and the increased torque makes the car much easier to drive in local traffic and pull hills without downshifting. A couple of differences no one else seems to mention: the engine is louder, and deceleration is much more sudden when I lift off the throttle. I suspect the rapid off-throttle compression braking is partly due to the lightweight flywheel as well. Not a drawback, just an observation.
 
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alexiskai said:
My personal opinion is that crypto-HC heads (heads that are HC but look stock) are OK but one needs to be extra-careful to document them. You won't own the car forever, and whomever you pass it on to will need to remember that their car will behave differently than one with the stock head. A 5.5 head can probably pass without documentation, but certainly once you get to 7 you should either mark the head visibly or keep good records.

That's one reason I like the Winfield head – it keeps the stock shape, but it says Winfield on it and the spark plug locations are different, so anyone buying the car will be able to identify that it's a 6 or 7 head without taking the head off.

Also I painted mine fire engine red, but that's just me.
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We all know that fire engine red produces 5 more HP above the Winfield.:cool:
 
Sky, I would definitely go with a HC head. They make a big difference on climbing hills and your take-off speeds are quicker.
 
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