Readings on 3 x 390 crank journals

[winr1]

#1 Mains: 2.715 ....... Rods: 2.418

#2 Mains: 2.725 ....... Rods: 2.425

#3 Mains: 2.713 ....... Rods: 2.424


All the journals look good, bearings were fine as well



Ricky.

[blykins]

What did you measure with?

[FrozenMerc]

Not to put words in Brent's mouth, but what I think he is driving at is that it would be rather odd that some machinist would cut one of the mains at -0.020" and the others at -0.030".  You would then have to buy multiple sets of bearings and play the mix and match game.  So, are you sure you measured accurately?  Also, what were the rest of the journals cut at?  Do the bearing shells have their size marketed on them?  If so, do they match your measurements?

[winr1]

Starrett 2" to 3" mike, measured 3 times

As to each crank, all the mains and rod journals are the same

These came out of running engines and were not turned

Have had over 50 or 60 cranks with the mains and inserts different sizes under



#1 Mains: 2.715 ....... Rods: 2.418 ......  .034 under and .020 under

#2 Mains: 2.725 ....... Rods: 2.425 ...... .024 under and .015 under

#3 Mains: 2.713 ....... Rods: 2.424 ...... 0.36 under and . 014 under

The under numbers have given me pause




Ricky.

[Lg57]

To clarify, are you measuring three different crankshafts or different journals on the same crank? Sounds like you know what you're doing but I'm confused.

[FrozenMerc]

I am confused now too.  The way I read it yesterday was that you measured the first 3 journals on a single crankshaft and came up with different sizes between each of the first 3 journals.  Or was it as Lg57 implied that you measured 3 separate crankshafts and reported average numbers for the rods and mains?  In which case, what is the question?  0.0025" to 0.003" clearance is generally considered nominal, looks like you are at 0.004 to 0.006" on your mains. 

[Falcon67]

If it's one crank - Sounds like a 400 I was given (some time way back) that came out of a service truck.  Ford Reman tag on the side.  Some bores were .030, some .040, , one .060, deck height varied by hole, some down .070, most around .050.  Never got to the crank, never broke it down - it went as a unit to the scrap yard for .017/lb. 

[winr1]

Sorry guys :-)

There are 3 390 cranks... 2 are 2U and 1 2UA

The 5 crank journals are the same per crank
Same for the rods

............................................................
#1 crank has all 5 mains at 2.715

#1 crank has all 4 rods at 2.418
..............................................................


#1 crank  Mains: 2.715 ....... Rods: 2.418 ......  .034 under and .020 under

#2 crank Mains: 2.725 ....... Rods: 2.425 ...... .024 under and .015 under

#3 crank Mains: 2.713 ....... Rods: 2.424 ...... 0.36 under and . 014 under


The under number is from an un turned crank

The clearances are what are odd .......... I cant find my mike pins to check if they are off

I will check and see if I need to calibrate my mikes :-)



Ricky.

[My427stang]

I misread it originally too.

I think you need to check your mic though.  Consistent weird measurements across many cranks is usually due to the tool (LOL read that in any context and it is correct)