Drilled crank

J

jfreddie

Senior Member
I have a cutdown, drilled Model B crank that I just put in my babbitted engine.

It was cut to Model A std size.

I thought about plugging the oil holes in the crank but decided not to thinking
that the holes would fill and be an oil reservoir after running for a while.

It's back together and runs fine now but thought I'd ask for opinions on leaving the holes open.

Maybe temporary balance issues? Oiling changes in the rod journals?

Thanks.
 
I don't want to worry you but it is well known that a Model A crank is prone to breaking if drilled. Now that you have reduced the B crank to the size of an A, I wonder whether you might have set yourself up for the same problem. I guess that would depend on a number of things including what metal is used in the B crank vs the A and how it was drilled. That is, were the oil holes drilled at an angle to get from the main bearing journal to the big end journal or were they done with a series of vertical and horizontal holes intersecting and the ends plugged.
I'm sure others will chime in with info on the materials used in the cranks.
 
Yes, bad idea. Back in the day drilled crank was thought to be the thing to do. Real world it weakens the crank. Have fun modelAtony tony white Lafayette, LA
 
The above answers do not answer jfreddie's questions! I once bought a C engine with a drilled crank but otherwise stock oiling. This engine had been raced but on inspection there was no damage to any of the bearings. I would run it as you now have it and not worry about anything. The dippers assure that the rods get oil immediately on start-up and the mains will still get oil from the valve chamber, all should be OK. Balance should not enter into the question.
 
Jim Brierley said:
The above answers do not answer jfreddie's questions! I once bought a C engine with a drilled crank but otherwise stock oiling. This engine had been raced but on inspection there was no damage to any of the bearings. I would run it as you now have it and not worry about anything. The dippers assure that the rods get oil immediately on start-up and the mains will still get oil from the valve chamber, all should be OK. Balance should not enter into the question.
Click to expand...

Yep,..it will oil good too the rods!
 
hardtimes said:
Hey Vince,
Thanks for the crank info in your 'garage' ..very informative :) !
I'm curious to know what it cost , back when, to make a '32 style drilled crank and why such a crank can not be made today at a reasonable cost :confused:
I agree with you that this new A crank seems reasonably priced and looks great !
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I will step out in front of the Firing Squad for a few nano-seconds here and make a LONG post:

1. It is not that the prices today are out of line!

Yes it seems that things years ago were cheap.

But if you look at how long a person had to work to earn the $525 for a new Coupe in 1929 at $2.50 to $5.00 per DAY, it is obvious that the problem is that the money was worth a lot more 86 years ago.

In 1961 a new VW Bug with a sun roof was $1600.

In 1969 a new VW Fastback with Fuel Injection was $2300.

[In 1968 I was making $307 a month as an E5 (with less than 6 months time in grade) including Combat and Proficiency pay.]

Now granted the tent, food, 55 gallon drum shower, the piss tubes and the out houses were paid for by the Army, but we did have to burn the contents of the out houses when they filled up! A little Army humor!
 :D

In 1973 a new VW Square Back was $3300. Only reason that I traded was that I needed a station wagon for work and the dealer gave me $3100 for the '69 Type 3 FB.

By 1979 a new Chevy Malibu with A/C and few extras was $6300. A Wagon was about $6500.

I will bet that no one has bought a new car for anywhere near those prices lately! :D:D

Prices due to inflation just keep going up!
 
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Benson said:
In 1969 a new VW Fastback with Fuel Injection was $2300.

[In 1968 I was making $307 a month as an E5 (with less than 6 months time in grade) including Combat and Proficiency pay.]
Click to expand...

$2300 is what I paid for my '68 VW Squareback, I was making $3.10/hr.

(Only brand new car I ever bought)
 
I've always said that the only way to price an item is how long you have to work to pay for it. When you're born, you have nothing but time in the bank. As you go through life, you gradually spend your allocated time till you have none left. There are no top ups and no refunds.
 
I greatly appreciate all your responses.
The oil holes were drilled diagonally.
I had it cut down to std journals, flange faced, and balanced...all for $500. Very affordable compared to new.
I also had the flywheel lightened to 43#, so I'm cautiously optimistic.
We'll see, thanks again for input.
 
jfreddie said:
I greatly appreciate all your responses.
The oil holes were drilled diagonally.
I had it cut down to std journals, flange faced, and balanced...all for $500. Very affordable compared to new.
I also had the flywheel lightened to 43#, so I'm cautiously optimistic.
We'll see, thanks again for input.
Click to expand...

Hey Freddie, your actions and $ outlay seem right on to me (for brevity censors) !

Answer for you and interested, eh :)
In my opinion, there are a lot of unknowns (to us) about you and your drilled crank, to make a helpful reliability statement. For instance, how long had this particular crank been used...and how used (think metal fatigue) ? I know of NOS B cranks which should take a lot of work and a long time to fatigue, even if drilled and (gulp) cut down. After all, Ford made his cranks of the best available materials and processes...I've been informed. On the other hand, take a drilled C crank that has made incredible runs at B-Ville any number of times..until its' tail was twisted off ...ouch :D. Which example would you choose to buy for , say, longevity , the NOS B or the much used (or cut down)/repaired crank (prices will vary, of course) ? Ironically, I felt fortunate enough to buy both and both are in use:eek:.
However, I have considered buying a new crank with CUT DOWN bearing surfaces, say B to A...and have come to conclusion that I won't ever do so. Why? Without naming crank maker, I've taken pictures and have seen even more pictures of what I call 'puny' sized rod throws..cut down and/or newly made, that BROKE in the same spot every time.

Now for your habits , as to longevity of your crank. If you drive without excessive speed and rpms, with proper lubrication, your cut down crank may last a very long time. Best of luck to you :)
 
I'm running an early B crank with welded on counterweights, already drilled when I bought it at a swap meet. It had .040-under mains and .010-under rods. It magnafluxed good so I turned the mains half way between A and B, had it babbitted. Mild 4-port Riley on top. So far so good!
 
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