Pulling Forum - flat plane cranks and crossplane cranks

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flat plane cranks and crossplane cranks

Printed From: Unofficial Allis
Category: Other Topics
Forum Name: Pulling Forum
Forum Description: Forum dedicated to Tractor and Garden Pulling
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=59490
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Topic: flat plane cranks and crossplane cranks

Posted By: mlpankey
Subject: flat plane cranks and crossplane cranks
Date Posted: 05 Nov 2012 at 5:16pm

flat plane cranks are what inline allis four cylinders have . crossplane is your american v8 with large counterweights. Ferrai v8 is flat plane with little to no counterweights because pistons cancell out each other. They are used for quick acceleration and high rpm applications.

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people if they don't already know it you can't tell them. quote yogi berra

Replies:

Posted By: Rod B
Date Posted: 06 Nov 2012 at 7:01pm

Onk key piece of information you leave out is that ferrari has a main berring for each pair of cylinders where allis does not. That extra support is needed to controll crank flex. Counterweights are not needed to balance, but without support from extra main crank flex will be excessive unless counterweights are used to aid.

This is why so many of the top competing antique 4 cyl pulling engines are going for counterweighted crankshafts. This is also why some chose to build additional main berring supports in engines that lack them from original design.

So you don't have to try and fool the uneducated reader into thinking that an allis can rev like a ferrari without extensive work.

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for the money there is nothing better than provoking idiots and posers

Posted By: mlpankey
Date Posted: 06 Nov 2012 at 7:46pm

Its just because they are not current on the latest rage. Rod you can now research linginfilters ls6 turbo camaro with flat plane crank. Keeping bob weight mass close to cranks centerline reduces forces on crank and if its balanced at 5500 then vibration will start at a higher rpm and increaae proportionaly with increase of rpms.The only way counterweights would reduce second vibrations would be if they were position on the side of crank throw instead of opposite of rod and piston. Then theres the vibration that doing that creates.

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people if they don't already know it you can't tell them. quote yogi berra

Posted By: mlpankey
Date Posted: 06 Nov 2012 at 8:01pm

Even nascar realised that you can over mass a counterweight when they experienced bearing failure when engine rpms left the 8grand and went into the 9200 area. Holding a ball in your hand rotating it around above your head doesnt generate near the force the same ball on a three inch string generates through the same motion.

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people if they don't already know it you can't tell them. quote yogi berra

Posted By: Butch(OH)
Date Posted: 07 Nov 2012 at 12:37pm

Your forgot a couple

Air plane cranks is what you put in a airplane motor no matter if in-line or out of line.

Those of you considering an air plane crank should be forwarned that there are some imposters around. These are known as hot-air plane cranks by those in the know. They look like regular airplane cranks but they are not!! Always test an air plane crank to see if it is full of hot air before using it!!

Posted By: mlpankey
Date Posted: 07 Nov 2012 at 2:38pm

yeah if your plane is like butch's and cant leave the ground

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people if they don't already know it you can't tell them. quote yogi berra