6 replies to this topic

[scottyboy805]

Crankshaft has previously been reground I believe and am just trying to work out by how much. I was expecting to see something like 020 but I am not too sure what these numbers are telling me. 
If I had to guess I would say +10, but it would only be a guess so hopefully someone with more experience can offer some insight. First picture (With `LOWER` marked) is the main bearing, and second is a big end bearing, but I assume they will be ground the same amount.

 

 

[nicklouse]

Can’t tell you the sizing. But never assume that they will have been ground the same. Also I would be having the crank measured to check it does not need any work or different bearings.

[Spider]

There's a few ways of working it out, but without know if you have small or big bore engine;-

 

Small bore BE shell (wall) thickness is 0.0719" for a std shell
Small Bore Mains are 0.0722"

Big Bore BE shell is 0.0719 (1.625 nominal journal)

                                0.0718 (1.750" Nominal)
Big Bore Mains are 0.0720"

add 0.005" to these for each step up in undersize.

[scottyboy805]

Thanks for the help.

I should have said but it is a 1275 block. 

 

I guess the numbers don't indicate anything about the size then, or at least no one knows the meaning of them 

In that case I suppose I will have to take it in to be measured and checked properly, thanks again.

[Shooter63]

I've just done a search on here, it's suggesting that they are STD bearings ( HL20260 ), personally I would fit them in the block and measure them properly using the appropriate equipment ( bore gauges and a micrometer)

Shooter

[MrBounce]

As a guess, could the "05 10" be a manufacturing date?

[scottyboy805]

Looks like Shooter was on the right track. Borrowed some tools and did some measuring earlier and seems they are standard size after all. 

I just assumed it had been reground because they were not marked std.

 

Checked the crankshaft journals and they are spot on with the standard size I found listed in another post, on the higher end if anything. 

Also had some old std con rod bearings stored away in a box, so I fitted a set of those plus the bearings in question to a con rod, torqued up and measured each.

Both were identical in size so mystery solved and it is 100% standard size for both the main and big ends. 

 

Thanks for the help all.