Looking for a Consensus
 

I just came from my Model A club meeting, and got two completely opposite opinions on buying a higher compression head. I was advised against it by two fellows, since I have a babbitt engine. They both independently told me that the higher forces would crystalize the babbitt and destroy it.
Two other guys told me the opposite. They said (and rightfully so?), that the police head (5.3:1)was used successfully with babbit for years with no problems. A fifth guy said that there have been high compression race cars with babbitt, and no big issue.

I realize people have had different experiences, or heard/read different stuff about this, so I respect ALL INPUT. "There's wisdom in a multitude of council" - (the old black book)... So I invite any input here. Thanx in advance... Chuck

Re: Looking for a Consensus
 

Have no fear with using a 5.5 head. If the babbit goes, it was junk anyway.

Re: Looking for a Consensus
 

Not exactly sure what the CR of an original CRAGAR head is, but I drive the snot out of my Babbitt equipped A in my avatar. I also have an A with inserts and a Brumfield Superhead and both cars perform great. The quality of the Babbitt is the key.

Re: Looking for a Consensus
 

Sort of what I figured. The quality of the babbitt is probably the "yea" or "nay" for some experiences. I've done a superficial study of babbitt, and some babbitt is made with lead, but not so with Henry Ford. His was 86% tin, 7% antimony and 7% copper. Nickel was not used, nor lead. I've read where the lead mixed babbitt would indeed crystalize and crumble. It's hard to find anyone to do babbitt anymore, so maybe some folks have used the wrong mix, and thus had bad reviews.

Re: Looking for a Consensus
 

Re: Looking for a Consensus
 

"They both independently told me that the higher forces would crystalize the babbitt and destroy it."

avoid these guys

you have one of the best rebuilders only a few miles from you, what does he say

Re: Looking for a Consensus
 

the mains checked out at .0020, .0015, .0020. I have no idea when the rebabbitting was done, but I'm sticking with it!!! My engine was worn to 3.975" with ONE CYLINDER SLEEVED for some reason. I'm putting it all back together with "new" sleeves rebored to original std 3.875" Snyder pistons and rings, new std valves, guides & springs (original keeps) adjustable lifters, a B camshaft, and same rods. Although the original camshaft was fine, I was tempted to get more performance from the B camshaft. Now, a 5.5 hc head is tempting. Other members tell me to get a 6.0 for another $25. I don't want to overdo modification. It is a fine Model A, and I am fine with some basic mods, but not too much. I am tempted to do a Mitchell O/D, but then ya gotta get new wheels... Sheesh!!! It's a driver, but I still want it to remain a Model A.

Re: Looking for a Consensus
 

Are you referring to Larry Azevedo in Corrales, Empire Engines on Alemeda or John Cosper (at Pete's)?

Re: Looking for a Consensus
 

I've heard there is junk babbitt work out there.

Re: Looking for a Consensus
 

Try it...you'll like it... These cars really like and respond to a compression boost.
Even the difference from 5.5 to 6 to one is noticabel. If your worried go 5.5 but I wouldn't
Be afraid to go to 6-1.
Just learn to drive with less advance and don't lug it. You could also use a automatic advance dist.

Re: Looking for a Consensus
 

I would love to give it as much push as the babbitt will allow (and I really think I have an outstanding babbitt job). Members are trying to convince me to go with a V8 light flywheel, or have mine cut (good luck finding that kinda work). I've read where it won't sound like a Model A anymore... Over-sentimental? Maybe, but that's where I draw the line.

Re: Looking for a Consensus
 

Re: Looking for a Consensus
 

I was referring to John Cosper.
He also can cut your flywheel and machine to a V8 clutch, but you really don't wanna do that if you don't have a counterweighted crank.
Flywheel changes won't change the sound of the motor; but the cam change you are talking about (which will really wake up the motor) will alter the sound somewhat. But you will still know it is an A. It is the shape of the muffler that predominately causes the characteristic sound that you hear

Re: Looking for a Consensus
 

What is more critical is the balance and grind of the moving parts and how you use the spark advance. Plus the quality of the babbitt.

If the crank is not ground right you can have the flywheel off center causing vibrations. You could have mains not ground on the same center line. The throws could be differnet lengths too. It will also need to be balanced well.

Then the rods need to be accurately balanced at each end. Factory was +-1 gram.

An engine not built with a lot of care to detail will have many different interactions that could cause the imbalances that will hurt the babbitt over time.

Then there is the babbitt. People who do not understand the rules for babbitt pouring will pour babbitt that will not hold up. This is way more common then you might expect. Does not matter what head you have on it, the babbitt will come apart. Of course, it is easier to blame the high compression then to take the time to figure out all the other things that were done wrong. It is always easier to come up with a higher power to make an explaination then to dig and find what the real cause is of a failure.

Finally, some guys do not understand what to do with their spark advance. Anytime you cause advance ignition you put stress on the bearings.

If the engine is built like factory - which is more like building a race car engine- then you should expect and engine to run 55 MPH all day long and get well over 50,000 miles on the babbitt.

Re: Looking for a Consensus
 

Here is a couple of thing to think about ! How well do you know about the in's and out of your motor ,do you feel it's a strong engine ,how much faster do you think it will be ,if your motor is an older than just leave it alone .if it's strong or newer buy the head it will make some improvements .

Re: Looking for a Consensus
 

I've used high compression heads, 5.5, 5.9 and 6.1 on babbitt engines for years with no problems. I probably have a lot more miles on my cars than they guys telling you not to do it. My sedan has over 40,000 miles and is babbitt with a 5.5.

Re: Looking for a Consensus
 

I have a Fordor 29 which is a heavy car. All is bone stock, I see absolutely no need for more pep. Get along just fine with my forty horses! That being said, I live in the backwoods of the middle of no where so usually have the road all to myself. I can drive to alexandria, 35 miles, and often only passed by one or two cars. Usually stick to about 45mph. So for me, my forty horses are just fine. Last fall I passed an old farmer in a new pickup, he was only going 35. My wife commented "bet that's the first time you did that".

Re: Looking for a Consensus
 

I've always heard that babbitt limit is 8:1, but, it may be an old wives tale.

Re: Looking for a Consensus
 

If you call an experienced engine rebuilder, such as Mr. Ron Kelley in Texas, (who rebuilds many engines "after" Babbitt has been ruined by Model A owners), he will advise that when you run a Model A engine, with the spark advanced too much, you can beat the Babbitt out of an engine with just an original head.

Please don't forget that over recommended advanced timing is extremely harmful to Babbitted engines.

Re: Looking for a Consensus
 

I asked similar questions primarily about blowby and oil /seal leakage for the 5.5 head. I've noticed a healthy flutter given the bag test and changed to a '32 filler tube which hopefully allows for increase in the pressure/volume though it's difficult to measure. Also have the auto advance ignition and haven't found any problems.