At 01:03 AM 7/21/2000 +1000, Neil Cotty wrote:
>What is an optimal end float figure to look for? Book says 2-3 thou "End
Clearance", but also quotes "Running Clearance" - ?
Da book sez: 2-3 thou, which is 1.0-1.5 on a side, which is very similar to
he clearance in the rod and main bearings. "End-clearance" is the total
clearance for both sides of the thrust surfaces combined, often refered to
as "end float". Note that when you have an oil film in a gap this small
there will be virtually no detectable end flost. The "Running Clearance"
noted in the book is the radial clearance in the rod and main bearings.
>My machinist who has made my Mk2 crank fit the Mk1 block says he's looks
for 6 thou. I am having to get special thrust washers made up to suit you
see, so if anyone has an optimal figure please shoot me an email. Right
now, with the stock washers I have 10 thou.
It appears that your machinist is not so hot after all? A few thousandths
extra end float isn't going to hurt anything, and in fact is where you get
to after a little wear on the thrust washers. But 10 thou sounds like way
too much to me, and that much axial motion in the crank can cause clutch
There are over-thickness thrust washers available (at least here in the
states), for .005" and .010". The ones listed as .005" are actually .0025"
on each side, and the ones listed as .010" are actually .005" on each side.
By mixing and matching parts from different sets you can adjust the end
float in .0025" increments. See Moss Motors parts listing.
For a street engine I'd stick with the 2-4 thou range. For a race engine
maybe a couple of thou more, definitely not in the 6-10 range, but I ain't
no race engine expert.
1958 MGA with an attitude