30 replies to this topic

[Dusky]

Hi there! In installing my crank, but or locks up when I install the last bearing cap.
However, If I leave the locating rings out between the block and cap I can torque it without problems. It looks like I cant push these rings deep enouh? Any ideas?

[peter-b]

By rings I assume you mean hollow dowels?

[peter-b]

If it locks up with them in it looks like the caps either on wrong or machined wrong. Did it get line bored ?

[Dusky]

Didnt got it line bored no, but its weard that they are not seating fully

Edited by Dusky, 19 April 2015 - 10:56 AM.

[Dusky]

Does it take long to line bore a block?

[69k1100]

Pretty expensive option to throw out before the problem is even identified. Line boring isn't cheap, it is last resort.

Are the caps on the right order? Are the bearing shells the correct size? Are they correctly seated? Are the caps the right way around?

does the crank jam? You haven't made this explicitly clear, first you say t locks up but then you talk about not being able to seat the dowels properly, so which is it?

Building an engine isn't as easy as ripping it apart then slapping it back together. Certain machining operations were carried out with parts of the block assembled, the caps were line bored assembled, so they have a specific order and must be the right way around.

[Dusky]

Caps are on the right way, dont think you can fit them in the wrong way? When tightened the crank locks up on 1 specific point. So i can turn it for like 120° then it comes to a point where of locks. Standard size bearings wich are seated well.

[dklawson]

OK... you say the caps are on the right way.  However, as 69k1100 asked, are they on in the right order?   Did you mark the bearing caps for position before removing them the first time?

 

Did you measure the crank journals before placing it on the shells?  Did you measure the bearing shell thickness to confirm they are all the same?

 

Line boring is not typically required on a regular rebuild of a street engine.  It is an expensive process that is dictated for certain conditions but it isn't automatically part of a rebuild.

[gazza82]

We assume that the crank, main caps and block are from the same engine? Any machining been done to crank?

[Dusky]

This is how I put the caps.
I do think everything came from the same engine, bought it in bits though.
https://www.dropbox....172047.jpg?dl=0
https://www.dropbox....172052.jpg?dl=0

[Dusky]

No machining to the crank

[Yoda]

I do think everything came from the same engine, bought it in bits though.

 

Hmmmmm. bit of a clue here i think. NO?

[Dusky]

I do think everything came from the same engine, bought it in bits though.

 
Hmmmmm. bit of a clue here i think. NO?

What should the young padewan do when it wasnt from the same engine? Line bore?
Strange thing is that I can turn it fine when I leave those dowels out on the 'conflicting' cap

[Guess-Works.com]

The dowels are there for a reason, but make sure they are not misshaped..

 

then check that they are the right caps... 

 

Also now you've had a play check the shells for witness marks/rubs.

 

What I would do is measure the main bearing for ovality with a micrometer and if you have access, put the crank between two centres and rotate it with a DTI on all 3 mains... check for straightness and run-out. 

[Dusky]

But what should I do if it are not the right caps? Will check for the marks etc