cleaning crank before instal...good idea or bad??

[meandmyz]

so went out to my local performance shop and was advised to soak my used crank in diesel and wash it well to clean all the crap out, then spray whit lithium grease in all the bearings before install...was an older gentleman who claimed he worked at our old local dealer and said that was what they did with every rebuild they did....so I came home with new seals and followed his advise, however now I am wondering if it was a smart decision as bearing felt much more smooth before and now make more noise while spinning by hand....did I just remove all the original pre packed grease ad make an anchor out of my crank???I know they get lubed by 2 stroke oil, just weird that the bearings are louder now...did I just listen to the wrong dude or was this good old school advice....thanks

just seems its the two inner bearings that are making all the noise, before I cleaned them I spun them by hand and they felt good and noise free, so is it just the tolerances I can here with the bearings all clean??

 

[68ragtop]

Everything needs to be as clean as possible. If its a used crank, no question I would clean it, & then clean it again. When bearings have zero lubrication in them, its not abnormal from them to make a little noise when you spin them. But they should still feel very smooth & a few drops of injection oil should quiet them right down. They should have no rust on the races or the balls. I would only use injection oil to lubricate all the bearings once its clean.

 

[Coastiejoe]

I have rebuilt HUNDREDS of automotive engines and probably 20 or so small engines. I have have always cleaned the crank with diesel fuel. I have use White Lithium grease to instal bearings, but I normally use a Pre-Lube grease. It is heavier and will lube the bearing until the oil from the crankcase get to it and does the job.

 

[Nike12000]

I agree I'm a ford mechanic and we use a parts washer with solvent so same idea but then we use lithium or break in lube like stated above holds up better till system primes. make sure all bearings are torqued correct pattern and tightness to spec doesn't take much to throw stuff off.

 

[mikidymac]

Since these cranks use ball bearings all they need is some 2-stroke oil to lube them and try to work some down into the seals so they do not dry start and burn up. A syringe works great for this. I would use the grease or even better actual assembly lube on babbitt bearings like the automotive ones but not on these.

 

[Coastiejoe]

With crank seals, I have always put a grease on them before I install them as well as on the shaft they will slide over. Seals are pretty amazing in that they last as long as they do and don't allow oils and lubes to pass by them. Which is the amazing part as they have a VERY small amount of oil to lubricate and cool them. So I always start them out wet,,,

 

[mikidymac]

Sorry Joe, you are correct.

I was speaking about the inner seals if it is a cleaned used crank. They are hard to grease so I use the oil. The outer seals get grease.

 

[Coastiejoe]

Sorry Joe, you are correct.

I was speaking about the inner seals if it is a cleaned used crank. They are hard to grease so I use the oil. The outer seals get grease.

If you can't get to them, then it is what it is.. Maybe a squirt can and 2-stroke oil if possible. All you can do is try...

 

[meandmyz]

okay thnks guys, I I normally use lucas for my sbc, bbc assy lube and love the stuff and only have about 5 2 stroke rebuilds under my belt, all skidoo stuff so still learning a ton about this 2 stroke world.....bearings feel smooth so I will just try it out and worst case sbt gets my business, I got a 91 xp and gonna have under 250 into it and should be a fun toy to add to the collection...thanks again for the fast reply's....I have tried a few other forums during this project and this one is def the winner....fast good knowledge.....thanks again
cheers!

one last thing....what is grease of choice for outer seals....I have some kluber here for my doo stuff but damn expensive and hate to use it on this budget beater if there is other good stuff out there....and I can also switch for the doo too and save allot of money in the future

thanks
cheers

 

[68ragtop]

Keep in mind whatever you lube the ball bearings with will be broken down by the injection oil & burned. Seeing its a crank that already been run, I would just use injection oil to lube things. Thats how they come right from BRP new. Quite a different animal over oil pressure style multi-metal bearings.

The inner seals, oil them best you can like coastie says, but the center rv chamber will be flooded with oil before you run it as well, so I wouldn't get too worried. I use molykote on the outer seals because I have it. But you could use a quality synthetic grease. just fill the inner "cupped" area of the seal & you should be fine. be sure to use a good product like three bond to seal the crank halves. Using the wrong stuff like permatex is just asking for an air leak IMO.

 

[Dr Honda]

Personally.... I wouldn't have wasted my time with a used crank. The reason is... there's a high probability that it came out of an engine that was old, and blew a top-end. Both are reasons to NOT use it.

1) if the inner seals are bad... that's a lot of wasted time to find out on it's first run.

2) If the inner bearings are bad (sounds like they are) then the engine will eat it self in short order. And if that happens, it's a waste of time and money since you will loose the top end too.



Try to re-clean it... but if you feel ANY grit... then don't even waste the time of installing it. (that gritty feeling is pitted balls or the race) They should feel smooth even dry. With that said... a little grease will keep the seals safe on the start up, and it is recommended. But putting grease in the bearings of a 2-stroke to make them feel smooth, is just masking the issues.


So... put it on the shelf, and get a fresh re-built crank.



I hate to be negative... but it's the truth.