New main bearing problem

[DangerousDerek]

I am refreshing a 4.6 and had the crank ground +10thou at Chesmans.
I bought a set of +10 bearings but the centre main thrust bearing is very tight to the block. When I measured it with a vernier it measure 8 thou narrower inside width?

Am I missing something here?

[Engineer1949]

derek had similar probs just take the wearing side down slowly on wet and dry 600 grit till you get the right clearance then a quick rub on 2000 to get a good finish.


john

[DangerousDerek]

Engineer1949 said:

derek had similar probs just take the wearing side down slowly on wet and dry 600 grit till you get the right clearance then a quick rub on 2000 to get a good finish.


john

Hi John
outside width is fine, its the inside to the block itself that's too tight.

[Chuggaboom]

Unless things have changed over the years, when you have a crank reground, the grinder doesn't touch the thrust faces unless they are badly scored or you ask them to.....its more work that naturally attracts an additional cost.

[Engineer1949]

ok not seen that before probably got an early 3.5 thrust in there somehow


john

[DangerousDerek]

Chuggaboom said:

Unless things have changed over the years, when you have a crank reground, the grinder doesn't touch the thrust faces unless they are badly scored or you ask them to.....its more work that naturally attracts an additional cost.

I think there is some confusion here.
The bearing outside width is fine and fits perfectly to the crank. The problem is the inside width to the engine block itself.

[carsy]

I cant see how it can be anything other than the wrong shell.

I wouldnt modify it. Take it back and ask for another.

[DangerousDerek]

After a little careful fettling the crank is in and turning.
Just checked endfloat with a dial gauge and get the minimum 4 thou at a push but it settles back to 3 thou.
Is this too tight or can I put it down to the thick sticky assembly lube I have used liberally?

[DangerousDerek]

[TVR Beaver]

Sure that will be fine... I had less on mine but it's only soft white metal thats controling this... put the clutch in a few times when built and running and it will soon free up....

[DangerousDerek]

Actually getting somewhere today

[Pupp]

What's the stud hanging out the centre of the inner rear main cap for? Was looking at mine today after dropping the sump and although there is a threaded hole in that cap (only), there has certainly never been anything like that in it...

Is a cross-bolted block

I also think you'll be fine with that clearance

[Boosted LS1]

DangerousDerek said:

Chuggaboom said:

Unless things have changed over the years, when you have a crank reground, the grinder doesn't touch the thrust faces unless they are badly scored or you ask them to.....its more work that naturally attracts an additional cost.

I think there is some confusion here.
The bearing outside width is fine and fits perfectly to the crank. The problem is the inside width to the engine block itself.

Why's that a problem? The measurement you need to be concerned about it the end float of the crank. This is the gap between the crankshaft and bearing thrust face when the crank is pushed fully in one direction. I doubt for one minute the shells will be compressed and damage the block. They don't rotate either. You have .003", that'll be just dandy.

Edited by Boosted LS1 on Saturday 11th March 23:16

[Boosted LS1]

Pupp said:

What's the stud hanging out the centre of the inner rear main cap for? Was looking at mine today after dropping the sump and although there is a threaded hole in that cap (only), there has certainly never been anything like that in it...

To locate the oil pick up pipe?