Crankshaft end play. I think this is to much. What do you think.

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don january

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I think it is'nt right to have end play on your crank and useing washers to get it out. Thats wy VW and Corvair need a new block built. I dont know about you but I've had to install the spacer's it's a waste of energy IMO, BUT NEEDED...CROSS VW 3.jpg
 

Pops

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The book says .003 to .006. If you have the end play too tight the crank and case expands at a different rate and the gap gets smaller as the engine gets to running temp. If the end play is to tight the engine will bind up when it gets up to normal temp. I have always set the end gap at .005/.006 . Also when running the space between the 3 end play shims will be filled with an oil film from a oil hole in the case and at oil pressure reducing the end play gap. Remember you are seeing the cold end play gap, not the end play gap at normal running temp.

Doesn't look to bad, I would measure it and record the end play gap and at the next annual inspection compare the two measurements. Bet they will be the same. If I were Scott, I would also set it a little on the loose side in case a buyer had poor air cooling to the engine that could result in an engine locking up due to the uneven expansion rate of the case and crank.

When building a VW engine you measure the end gap without any shims and then put 3 shims in where the thickness of the 3 shims gives you the proper endplay. You can buy the shims in several thickness. Never use less than 3 shims. With the oil between each shim they act as a endplay bearing as each turn at different speeds.


Dan
 
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N8053H

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Pops just what I wanted to know. I believe it was like this when I took this engine out of the crate for the first time. I will record this end play and check it next year. Thanks Dan.

Tony
 

Dan Thomas

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That looks like .040" to me. Pretty big slop. Best to at least get a dial gauge on it and find out exactly what it is if you're not going to fix it, and check it again in ten hours or so to see if it's getting bigger.
 

Dana

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That looks like a lot more than .006 or even .010, hard to say from the video but it looks like .030 or more. I wonder if you had some excess wear when you were having the oil issues? But ask Scott Casler since he built the engine.

Dana
 

ekimneirbo

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Movement of .006 or less would be difficult to see unless pushing straight toward the engine and straight back. Rotating the
flywheel to get the movement should make difficult to see it. In this case it is easy to see, so I have to agree with the guys who
feel its far greater than .006. My guess would be .030 or more. I would not fly with this engine until I had verified the play.
Have you checked the oil and filter for any shiny particles?
 

Daleandee

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I think it isn't right to have end play on your crank and using washers to get it out. That's why VW and Corvair need a new block built.
Excessive end play on a Corvair is not nearly as common as on VW engines ... or at least that's been my limited experience. When it is found on a Corvair it is usually corrected with a new set of crank bearings (thrust bearing wear is mostly the culprit).

Looking at the video does make it seem that your end play is excessive although I have known builders (drag racers) that would set it a bit loose for engines that were going to be subjected to higher temps. Maybe a call to Scott to ask what he sets his engines at during the build, that way when you get a measurement you will know how much it's changed ... if any at all from where it was.

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
107.8 hours / Status - Flying
(Myunn is in the "Completions" section of Kitplanes for November 2015)
https://www.youtube.com/channel/UC49h6Qijc17_Ebfz0CbRFtg/videos
 

TFF

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If it has always been that way, call Scott Casler. If it is new, something is wrong for sure. Hard to know if it is a trade secret or sloppiness of building. I see it open up when turned, does it do the same if grabbing prop from front and pull in and out? Will it do the same when rotated the other way?
 

ekimneirbo

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Besides the fact that excessive end play will allow damage to the main bearings is also the consideration of what effect it
may have on rod bearings and wrist pins, timing gears, etc. I would not take the situation litely. Even if it can be fixed with
new shims, I would have to ask why it happened to begin with. Insufficient oil flow to the rubbing surfaces???? Wrong oil
choice??? Too much thrust pressure ???
 

Pops

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I have seen VW engines in Bugs with 250k to 300K miles on the engine with 1/8"+ crank end play and still running fine. VW type 1 engines are built loose, just like all aircooled engines compared to modern water cooled engines.

On the cut case 1/2 VW engine that I built, I used the #1 bearing in place of #3 bearing and machined for the shims. Don't know how Scott does the 1/2 VW engine that he builds, but he has a reputation of selling good engines.

Dan
 

StarJar

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I have seen VW engines in Bugs with 250k to 300K miles on the engine with 1/8"+ crank end play and still running fine. VW type 1 engines are built loose, just like all aircooled engines compared to modern water cooled engines.

On the cut case 1/2 VW engine that I built, I used the #1 bearing in place of #3 bearing and machined for the shims. Don't know how Scott does the 1/2 VW engine that he builds, but he has a reputation of selling good engines.

Dan
Ya, it might be fine and built that way.
I doubt the play could change much in a couple hundred hours.
It might be fine since it's not frequently getting shoved by a clutch.
 

Dan Thomas

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Ya, it might be fine and built that way.
I doubt the play could change much in a couple hundred hours.
It might be fine since it's not frequently getting shoved by a clutch.
Clutch forces are intermittent and probably less than constant thrust forces.
 

Dan Thomas

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True, but I was referring to the awkward strain it would impose on rod pins gears etc. The prop thrust, being rather constant is without that.
It wasn't linking it to spacer wear issues.
The crank can slop back and forth in flight with power changes. Depending on how the thrust bearings are set up, too much slop could cause trouble with their locations. It's been 40 years since I fooled with a VW engine and don't remember if it has separate thrust washers located in a recess, or if they're part of a main bearing. Separate washers can fall out of position if the crank moves enough to let them out of their recess. Can get nasty.

The other issue with too much slop involves cocking the pistons when the engine isn't running, as in the video. If the rods decide to stick a bit on the wrist pins, someone pushing back and forth on the prop could damage a piston or a rod bearing.
 
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