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Old 07-11-2017, 11:06 PM   #21
Tom Wesenberg
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Default Re: 60 mile per hour all day long?perhaps..

What make of engine is that broken crank from?
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Old 07-11-2017, 11:30 PM   #22
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Default Re: 60 mile per hour all day long?perhaps..

When I worked on big trucks and construction equipment years ago I saw a lot of broken crankshafts. Some engines are just known to do it if they were ran at too low a RPM, (Cummins). Some engines if they had a bent or not straight crank would struggle for power, (Cat 3408). A lot of crankshaft failures were the result of a bad damper on the front of the crankshaft, (Cummins). Some dampers were oil filled and would leak, (Cummins). It amazes me how seldom you hear of a broken crankshaft in a Model A engine given the problem with the center main bearing failure. Haven given a lot of thought about this flywheel lightening, I don't think I'd want anymore taken off the flywheel then the difference in a stock Model A crank and a counterbalanced crank. And everything would have to be balanced. It bothers me whenever I see an engine with the pan off and 2 rods with the same number. To me it wouldn't cost too much to remove the numbers and renumber in correct location when it was rebuilt. I saw a lot of factory flaws also, casting flash in the cylinder head causing over heating problem, somebody forgetting to install the valve stem seals. Huh, what are those?

Last edited by denniskliesen; 07-11-2017 at 11:39 PM.
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Old 07-12-2017, 01:00 AM   #23
H. L. Chauvin
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Default Re: 60 mile per hour all day long?perhaps..

For many years, many in any business have noticed that no matter what type of work we are engaged in, if we concentrate on trying to master what we are doing, charge descent prices, and treat clients and customers with respect, we will always have more work than we can handle in just correcting what others continue to screw up with their carelessness and mediocre final results.

Works not just with good Model A engine re-builders; but also for plastic surgeons, cosmetic dentist, locksmiths, roofers, electricians, mechanics, and yes .... even bird dog trainers.

Last edited by H. L. Chauvin; 07-12-2017 at 01:02 AM. Reason: typo
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Old 07-12-2017, 07:41 AM   #24
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Default Re: 60 mile per hour all day long?perhaps..

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Originally Posted by Tom Wesenberg View Post
What make of engine is that broken crank from?
SCAT cranks in Vw engines,its a common occurrence.

In my opinion balancing is critical for engine and drivetrain life.Adding rotating mass like counterbalancing can be offset by flywheel lightening but if your not building for speed why?the additional mass has a dampening effect of its own.Kinetic energy is stored in rotating mass,to translate that into operator terms more kinetic energy means smoother clutch function and shifting,torque transfer impulse is moderated by the weight.

The engine I first worked on as a boy,that propelled me into a career, has taught an old dog a new trick.Till the last week i never knew babbit can de-laminate from tinning..that reason alone has changed my mind about babbit and precision insert bearings,Ive never seen this type of failure from inserts.

To add to Mr.Chauvins axiom,a customer trained in the use of measuring tools will rarely fall victim to slipshod engine builder practices..unless such provider hasn't mastered pouring bearings,you cant catch that mistake prior to failure.
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Old 07-12-2017, 09:45 AM   #25
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Default Re: 60 mile per hour all day long?perhaps..

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Schwalm's/Ora Landis





Thats kinda what I think I'm leaning towards. It appears they do a proper job and have been adding counter weights for quite awhile.
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Old 07-12-2017, 09:47 AM   #26
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Default Re: 60 mile per hour all day long?perhaps..

I'm one that happens to like the heavy flywheel but have always heard that at least 12# needs to be cut from it when adding counter weights. Just another ole wives tale I guess.
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Old 07-12-2017, 10:03 AM   #27
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Default Re: 60 mile per hour all day long?perhaps..

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SCAT cranks in Vw engines,its a common occurrence.

In my opinion balancing is critical for engine and drivetrain life.Adding rotating mass like counterbalancing can be offset by flywheel lightening but if your not building for speed why?the additional mass has a dampening effect of its own.Kinetic energy is stored in rotating mass,to translate that into operator terms more kinetic energy means smoother clutch function and shifting,torque transfer impulse is moderated by the weight.
Food for thought while eating breakfast: A heavy flywheel has a dampening effect, stores kinetic energy, and smooths out firing impulses. The thing is, each firing impulse tends to briefly speed up the crankshaft but that heavy flywheel prevents this, so something has to give! What is the result? Torsional twist, or flex, of the crankshaft. So a heavy flywheel stresses the crank more than a light one. It's not just the weight, it's 4 cylinders each trying to speed up the crank while that big flywheel resists.
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Old 07-12-2017, 10:43 AM   #28
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Default Re: 60 mile per hour all day long?perhaps..

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Food for thought while eating breakfast: A heavy flywheel has a dampening effect, stores kinetic energy, and smooths out firing impulses. The thing is, each firing impulse tends to briefly speed up the crankshaft but that heavy flywheel prevents this, so something has to give! What is the result? Torsional twist, or flex, of the crankshaft. So a heavy flywheel stresses the crank more than a light one. It's not just the weight, it's 4 cylinders each trying to speed up the crank while that big flywheel resists.
Yep, what we need is a spring center flywheel, like the clutch disc.
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Old 07-12-2017, 11:09 AM   #29
H. L. Chauvin
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Default Re: 60 mile per hour all day long?perhaps..

Possible Most Ingenious Model A Engine Balancing Statement of the Year:

"The spring provided on the bottom of the Model A oil pump was carefully designed to absorb all Model A engine vibrations!"
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Old 07-12-2017, 07:16 PM   #30
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Default Re: 60 mile per hour all day long?perhaps..

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Food for thought while eating breakfast: A heavy flywheel has a dampening effect, stores kinetic energy, and smooths out firing impulses. The thing is, each firing impulse tends to briefly speed up the crankshaft but that heavy flywheel prevents this, so something has to give! What is the result? Torsional twist, or flex, of the crankshaft. So a heavy flywheel stresses the crank more than a light one. It's not just the weight, it's 4 cylinders each trying to speed up the crank while that big flywheel resists.
It not prevention of impulse,its a moderation of impulse,20 pounds of counter reaction against torque..the additional 'drag' has its greatest impact on the first revolution,but like a hit and miss engine,as it fires continuously the momentum generated by the mass of the flywheel dampen the impulse further.. basically Ill stipulate to initial crankshaft stress due to spinning the larger mass,but a counter acting reduction of stress as opposed to a lighter flywheel when running.
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Old 07-13-2017, 04:07 PM   #31
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Default Re: 60 mile per hour all day long?perhaps..

Thanks Railcarmover, You've just severely dented my feelings about the reliability of my motor which has all new components in it.
We'll just have to keep our fingers crossed every time we use it!
Cheers
Keith
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