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BS350 lab seal?

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I thought some of the more experienced members of the site might be able to offer me some advice.  I have a 350 crank assembly that I suspect needs a rebuild.  I've only had one other 350 engine completely apart and the crank lab seal didn't make the noise and move like this one does (see video).  Also, but not mentioned in the video, the two inner bearings seem to have a little slop in them and when wiggled will rock back and forth on the crank slightly, as I show at the end of the video.

Let me know what you think!  Thanks.  (Click on youtube link below).

Couldn't tell you whether it's good or bad, but I can tell you that I just checked a lab seal on a crank I happen to have out and it makes the same sound when slid sideways like that.

So....   popcorn

That labrynth seal is probably good. When the engine cases squeeze together it will not move side to side anymore. I don't know how you are going to get the o-ring that goes around the lab seal over the crankshaft counterweight though. You just want to make sure you cant move the seal up and down on the crankshaft. You don't want too much clearance between the seal and the shaft going through it.

Also, for your crank bearings. If there is a little bit of axial play (which you are showing at the end of the video) that is ok. To check the bearings, make sure they are oiled and clean and slowly spin each bearing all the way around, while putting slight pressure on it with your fingers, and make sure you don't feel any roughness or hear any noises. Each bearing should be quiet and smooth. Harry

Jeff Bar:
Personally I would replace the labrynth seal as they wear on inside not on sides, just way too much trouble to get to it later , I bought a spare from
Richard some time back, not sure if he has them or not

Jeff Bar

I think this all boils down to whether you intend to rebuild the crank or not. If not, you can probably get away with using the lab seal and bearings as they are. I don't expect you intend to race/abuse this motor, so with proper lubrication they should do fine. I like the checking technique Harry recommends above before you commit to reuse.
There is a trick to stretch the o-ring over all the stuff that seems to large the get past. I have never done it myself and don't know the details, but I'm sure someone on here can add some instructions for that. Steve Reed did this o-ring stretch on a crank that he did a partial rebuild on for me.

Good luck Roland!



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