Bottom end help!!!!

[Tmac26]

I'm rebuilding an extra blaster engine. the engine was locked up. I have the cases split and the crank rotates so far then it stops. it seems like there is some thing in the gears but i can't find anything and all the gears look good. does anyone know what my problem is?

 

[stabor1122]

Bad bearings probably.

 

[sicivicdude]

Sounds like small aluminum particles in the main bearings. If a bottom end comes apart (piston disintegrates and the bottom end is locked up as a result) you should probably replace the main bearings while you are in there.

Now that it's already open, you can TRY flushing the bearings to free them up. It's still recommended, even if they start to turn that you replace them.

 

[Tmac26]

will change the berings for sure but i have one more question. how can you tell if the crankshaft is good or bad?

 

[2smoker85]

up and down play of the crank is not good, minimal side to side play is ok and if ur rebuilding it why short urself now? u already have it apart and might as well put a stroker in it... or a new crank, that way u will know the thing is good and wont have to wonder if it is going to last, up to u

 

[sicivicdude]

The rod should have less than .001" up and down play.
The big end of the rod shouldn't have more than .028" side to side play.
The small end bearing and wrist pin should not be able to "twist", only rotate smoothly. The small end of the rod shouldn't be able to be pushed side to side more than .039" The overall width of the crank webs shouldn't be more than 2.281"

All of the specs I just quoted are available in the service manual downloadable out of the "general support" section of this forum.

 

[Tmac26]

okay thanks guys and think I'm going to get a new crank but idk bout a stroker bc you have to get your cases machined and i don't have money for that.

 

[sicivicdude]

The vito's +3 stroker crank doesn't necessarily have to have the cases trenched but to extract the maximum advantage out of the modification you need to have your cylinder ported for the increased stroke.

 

[Tmac26]

well maybe i will get a stroker then!

 

[sicivicdude]

Watch that mod bug... it's a nasty disease you won't be rid of once you start.

 

[Tmac26]

I know haha I hope I don't get too crazy. this is just an old engine i had laying around and thought i should fix it to sell or keep as a back up

 

[sicivicdude]

Well, I have a stock length usable crank for sale if you would be satisfied with stock length.

I bought it as a spare in case my 4 mil long rod came apart but I don't need it now.

It's just a stock used crank in usable condition. If it sounds like it's up your alley, check out my "blaster internals" post in the for sale section

 

[Tmac26]

thanks but I also have a good stock crank that came out of the engine i have in my blaster now.

 

[sicivicdude]

Well, unless you plan on getting the cylinder ported for the stroker kit, you might want to just pop that stock stroke crank in the other bottom end for a spare.

 

[Orleymtnez]

Watch that mod bug... it's a nasty disease you won't be rid of once you start.

Agreed It Gets Expensive FAAST!!!

 

[Tmac26]

I'm probly going to put the stock crank in it and port and polish

 

[sicivicdude]

Are you talking about getting it professionally ported? If you are... go ahead and drop the coin for the stroker kit. It costs about the same to get it ported for a stock stroke and get it ported for a 3 mil stroker and the 3 mil stroker will put out more power when it's all done up.

 

[Tmac26]

today i finished breaking down the cases and i figured out that one of the transmisson gears was not where it was supose to be. that is why the engine could not make full rotation. i solved that problem but i also found out that the shifting rod was not working. idk how to fix that. can anyone help?

 

[Tmac26]

can anyone tell me how to get the shifting rod back into place?

 

[sicivicdude]

Do what?! You were missing a gear and had a problem with the shift rod? Sounds like you need to go back to the manual and re-read the transmission section.

I'll need pictures to figure out what you've got going on. I mean there are two fork shafts, a shift drum, and a shift shaft. Which one are you talking about?