my crank shaft wont turn

[sno_boarder4343]

ok so i installed the pistons and rods to the crank and it turned on so i torqued everything up to specs wit hthe pistons and the mains and it still turned but slower. then i added the rear oil seal and now i cant turn it with all my weight.

 

[92AWDHX40]

something is binding, tear it apart and look again.

 

[bullettdsm]

You do know your rod caps are directional, correct? Tangs should be on the same side.

 

[spooln4fun]

I agree with Bullet, check them b/c I learned that lesson the hard way.

I had my caps in the wrong way/order, after I got them correct it spun freely as it should

 

[david-b]

I'm having the same issue actually on my 420a. It's on a stand all built. When the crank was in with no pistons attached it spun freely. After I put each piston on, it got harder and harder. Now, I can only turn it by hand about a 1/4 turn before I need to really use a lot of pressure. Rod caps are on right, since there really wasn't an option, caps were numbered to the correct piston, and the the bearing were all lubed up really good. Oil was also poured over the pistons before they were installed. Any other ideas?

If I have time this weekend I'll tear it down and see what I can find.

 

[Redwidow]

Did you guys plasti gauge and make sure all of your clearances are in spec, to make sure you have the correct bearings. Also did you use plenty of assembly lube?

 

[david-b]

Did you guys plasti gauge and make sure all of your clearances are in spec, to make sure you have the correct bearings. Also did you use plenty of assembly lube?

I'm using the Clevit 77 bearings I believe. Everything checked out good and was a freshly rebuilt motor when I got it (stock, .020 over). How much is plenty? I put a decent amount on them and then spread with finger for a fine "glazing" for lack of a better word. Wasn't swimming in lube, but seemed decent.

 

[Redwidow]

Ok well first the Clevite 77 Bearings is like a "brand". They come in many different sizes for polished cranks or ones that have been cut. I would recommend you to go get some plasti gauge and check to make sure you have the correct bearings first. As far as assembly lube goes just use common sense. But remember, assembly lube is made to break down once it comes in contact with the oil. It will blend so its not like you can use too much as long as dont use a whole bottle. Just use common sense and you will be okay. But go get plastigauge, its the best way to make sure you have the correct bearings.
Good Luck
-Andy

 

[david-b]

Ok well first the Clevite 77 Bearings is like a "brand". They come in many different sizes for polished cranks or ones that have been cut. I would recommend you to go get some plasti gauge and check to make sure you have the correct bearings first. As far as assembly lube goes just use common sense. But remember, assembly lube is made to break down once it comes in contact with the oil. It will blend so its not like you can use too much as long as dont use a whole bottle. Just use common sense and you will be okay. But go get plastigauge, its the best way to make sure you have the correct bearings.
Good Luck
-Andy

Ya I'm at work so I don't know what sizes or whatever they were. Was recommended by the company that I was going through for parts. When moving the pistons, are you supposed to be able to hear the rings against the pistons? Obviously it's metal on metal, but even oiled up really well still is pretty noticeable.

 

[Redwidow]

Did you buy your rings seperately or did they come with the pistons?

 

[david-b]

Did you buy your rings seperately or did they come with the pistons?

Came with. Bored 0.040" over. Gapped properly too.

 

[Redwidow]

well when you get home check your bearings with plastigauge and start with that. Let us know.
-Andy