a question

[rodbolt17]

to anyone that is experienced with babbit bearing crankshaft 4 stroke engines. what would you think of .022" on crankshaft end play?

[99yam40]

it has been way too long since I worked on an automotive babbit bearing motor.
Back in the early 70s and I do not remember very much from back that far

what type of motor are we talking about.
heck the old old ones you could make do with just about anything if you could get some oil pressure

[99yam40]

Are we talking about insert 2 piece or poured babbit

My mind took me back too far I guess

[donsmarine]

4 stroke outboard?

[rodbolt17]

4.2L v6 Yamaha 300.came in for maint and we noticed the belt was missing aabout 1/2 its width.
checked shaft endplay with a dial indicator at .022".
about the most endplay ( ever saw on auto engine rebuilding was a max of 8. any engine I built with a manual trans my max was .004.

[boscoe99]

What is the Yamaha specification for thrust bearing tolerance?

[panasonic]

Seems a bit much for any crank. Model T ford engine end play spec is something like .005 to .010"

Horizontally opposed Aircraft Engines can have quite a bit ..up to a Max of .020" I belive, which seems like a lot when you grab the blade roots pushing the aircraft backwards and it goes "clunk"

I would be surprised if it was any more then .005"

But we don't know what you are talking about here....let us know.

posted this earlier then when you replied with what you where working on...lol

[99yam40]

Guessing the reason the belt was chewed up is the shaft movement

I only pay attention to clearances when I build stuff.
it has been a very long time since I built a motor.
since I started buying new vehicles back in 79, I have not had a need to

[boscoe99]

The 4.2 liter blocks are (were) known for thrust bearing failures. Originally there was only a two piece bearing used. Then they went to a four piece bearing. Finally they changed the bearing material.

Found some data in a Suzuki SM. Notice the correct use of torque.

[boscoe99]

Seems a bit much for any crank. Model T ford engine end play spec is something like .005 to .010"

Horizontally opposed Aircraft Engines can have quite a bit ..up to a Max of .020" I belive, which seems like a lot when you grab the blade roots pushing the aircraft backwards and it goes "clunk"

I would be surprised if it was any more then .005"

But we don't know what you are talking about here....let us know.

posted this earlier then when you replied with what you where working on...lol

Lycoming

[panasonic]

Now I had to go back 30+ plus years and look through a IO-360 maintenance manual.






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crank 2.JPG

[Sheff 69]

Depends how much noise you are willing to put up with?
Had a 71 Dodge station wagon with a 318 slant 6 engine.
At 250K miles the crankshaft end play was such that it would ride on the flat, and down hill OK, but up hill the crankshaft and flywheel would slide back and hit the transmission shield causing a very loud noise.
Pry-bar between the transmission lower shield and the flywheel would open up the gap and I could get another 10K miles on it before it would do it again.
I believe I was at about 0.060" wear on the side thrust bearings before I had to scrap the engine.

[panasonic]

Depends how much noise you are willing to put up with?
Had a 71 Dodge station wagon with a 318 slant 6 engine.
At 250K miles the crankshaft end play was such that it would ride on the flat, and down hill OK, but up hill the crankshaft and flywheel would slide back and hit the transmission shield causing a very loud noise.
Pry-bar between the transmission lower shield and the flywheel would open up the gap and I could get another 10K miles on it before it would do it again.
I believe I was at about 0.060" wear on the side thrust bearings before I had to scrap the engine.

Now that is funny....lol

[pstephens46]

Honey grab the pry bar. Not that one, the other one.

[99yam40]

I would think the flex plate on a automatic would keep that from happening , but not sure if the pilot bushing would have enough room to allow the crank to move that far on a standard trans motor but it might

thinking about it a little more it would allow all sorts of movement back