Thrust Washers
Turbo Mini Forums

Hey chaps,

So I'm about to buy a new set of thrust washers for my k-build. The crank has been bought from Carl at Force racing. So its not the block's original crank.

With the standard (old) set of thrust washers that have been dismantled from the block and Carl's crankshaft, the end float measured with a dial gauge is 0.36mm. Haynes manual says that crank endfloat should be between 0.051mm to 0.076mm.

To get the required endfloat I need a total of 0.36mm-0.051mm= 0.31mm (11.8 thou) oversize thrust washers. The problem is that it seems that for a 1275cc engine, only +3thou and +30thou are available. Am I calculating this correct or no ? When they claim thrust washers to be +3thou for example, does it mean that each thrust washer is thicker by 3thou ? Or the combination of the two sets of washers give +3thou ? Excuse my stupidity in the matter, but never done this before XD

Thanks in Advance

They are sized in + sizes per side, so if you put STD on one side and +0.003" on the other, it will adjust by 0.003". Likewise if you fit +0.003" on both sides it will adjust by 0.006".

You can get +0.005" but the +0.030" I've had surface ground down to the desired size before now. If you do similar, make sure your machinist uses Loctite or Permabond to glue the bronze thrust face onto the table and surface grind the steel back down to the right thickness.

Edited by Sprocket on 11th Dec, 2017.

I haven't understood your last sentence Sprocket. Isn't the thrust washer fully made out of bronze ? What do you mean by grinding "steel" ?

the back of the bearing is steel, the face of the bearing is bronze.

A decent machine shop will have a machine called a surface grinder. It is a machine used to surface blocks and heads to ensure they are perfectly flat.

Don't try and grind the back off of these bearings with a bench or angle grinder

the thrusts have a thinish layer of bronze on a steel backing, the bronze is probably in the order of 10-15 thou thick tops, at a guess.

Oh I see . Didn't know the back of the thrusts was steel... slways thought it was fully made out of bronze. Thsnks guys. So I guess the best bet is to get the 30thou oversize and machine them.

What is the recommended end float ? Haynes suggest 0.051mm to 0.076mm, however in one of Matty's threads he suggested 6 though for revvy engines.

Do you guys happen to know what should be the exact thickness of a new std thrust washer ? Cause I'm thinking that my measurement might be biased with my "old" and possibly a bit worn atd thrust washers.

Why not measure the end float with no thrusts in, and go from there?