Crankshaft thrust washers

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alex_holden
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Crankshaft thrust washers

Post by alex_holden »

I have here an unused crankshaft for a 1098 engine that came in an original BMC spares cardboard box, still coated in hard brown anti-rust gunk. I've measured the bearing journal diameters and compared them to the figures in the manual, and ascertained that they have been reground to -20 thou.

As best as I can measure it without a suitable internal micrometer, the distance between the central thrust faces is 1.257". The manual doesn't quote a standard figure for that dimension and I don't have an un-reground crankshaft to hand for comparison. I'm guessing it is likely to be 1.25" because the bearing diameters are all common fractions.

If I'm right, that would mean the thrust faces have each had about 3.5 thou removed. Does that sound right to you? ESM list +3 thou thrust washers but they are currently out of stock. Bull Motif only list standard ones. :-?

While I'm here, does anyone happen to have a spare pair of -20 main bearing shells they'd be willing to sell me? The crankshaft came with four but obviously you need six for a full set.

Incidentally, the counterweights have machining marks very similar to those discussed in the "Balanced crank?" thread. :)
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Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
bmcecosse
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Post by bmcecosse »

Alex - stick a pair of thrusts into the centre main in the block with some grease - and measure the gap between them. I would say standard thrusts will be fine - but that size will tell you how much end float the engine will have.
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Kevin
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Post by Kevin »

Hi Alex you overlooked the biggest supplier of engine parts
http://www.minispares.com/Product.aspx? ... %20washers...

And in case no one has a spare pair of mains (which I doubt)
http://www.minispares.com/Product.aspx? ... 98/1100+20
Cheers

Kevin
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alex_holden
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Post by alex_holden »

Kevin wrote:Hi Alex you overlooked the biggest supplier of engine parts
http://www.minispares.com/Product.aspx? ... %20washers...
"This item is no longer available." :(
And in case no one has a spare pair of mains (which I doubt)
http://www.minispares.com/Product.aspx? ... 98/1100+20
I know I can buy another full set if it comes to it; I'm just being a bit stingy/thrifty. I've got a similar problem with an incomplete set of +20 piston rings...
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Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
Kevin
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Post by Kevin »

Opps sorry about that Alex, it could still be worth giving them a call as when items from original suppliers run out they normally get the manufactured for themselves so it could be worth asking.
Cheers

Kevin
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alex_holden
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Post by alex_holden »

Perhaps I could buy a standard set of thrust washers, measure the end float with feeler gauges, and if necessary make a couple of shims from 0.1mm (4 thou) copper foil.
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Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
bmcecosse
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Post by bmcecosse »

Don't worry about it Alex -on high power engines the thrusts are left loose anyway, so no great harm in an extra couple of thou float. Measure it - as I suggested earlier! Then decide what needs doing. Shims would never stay in place - unless you soldered them on the thrusts - and the heat of that may do something strange to the running surface.
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