Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess on
the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair

"Alistair Ross" wrote in message
...
Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess
on the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair



http://mgaguru.com/mgtech/clutch/ft_101a.htm

Good start.

--
Jeff R.

"Alistair Ross" wrote in message
...
Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess
on the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair



No, but years ago when I made a steel flywheel I shrunk the ring gear on and
then put a few small mig welds on it to make sure it stayed put.

On Mon, 11 Jan 2010 19:32:09 +0800, Royston Vasey wrote:

"Alistair Ross" wrote in message
...
Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess
on the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair



No, but years ago when I made a steel flywheel I shrunk the ring gear on and
then put a few small mig welds on it to make sure it stayed put.

I had a car where the ring gear was slipping; the mechanic, rather than
remove and dis-assemble the entire engine removed the sump and did much the
same through a small access. This was only a temporary solution as the
seal failed sometime after; he said it was due to the unavoidable loss of
balance as the welds were not exactly evenly distributed.

"_" wrote in message
.. .
On Mon, 11 Jan 2010 19:32:09 +0800, Royston Vasey wrote:

"Alistair Ross" wrote in message
...
Anyone know the formula, rule of thumb regarding the shrink fit
tolerance
for fitting starter rings to flywheels? My feeling is to leave the
recess
on the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools
it
'nips' up, without too much stress on the ring but with enough 'nip' so
as
not to work loose or spin.

ttfn....Alistair



No, but years ago when I made a steel flywheel I shrunk the ring gear on
and
then put a few small mig welds on it to make sure it stayed put.

I had a car where the ring gear was slipping; the mechanic, rather than
remove and dis-assemble the entire engine removed the sump and did much
the
same through a small access. This was only a temporary solution as the
seal failed sometime after; he said it was due to the unavoidable loss of
balance as the welds were not exactly evenly distributed.

That sounds like a reasonable quick fix.

I did maybe 4 small tacks. I had the whole thing balanced as an assembly
afterwards.

On Mon, 11 Jan 2010 09:19:25 -0000, "Alistair Ross"
wrote:

Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess on
the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair


I can't help with a rule of thumb specific to starter rings.
Machinerys Handbook has tables on classes of fit, along with examples
of their application and caveats regarding materials and part size. I
think the formulas for calculating stresses in interference fitted
parts is in MH as well.

Here are three online calculators. I haven't verified any of them, but
they're on the web, so they must be right g.
http://www.engineersedge.com/calcula...calculator.htm
http://www.tribology-abc.com/calculators/e3_8.htm
http://www.meadinfo.org/2009/07/pres...-optimize.html

--
Ned Simmons

On Jan 11, 2:19*am, "Alistair Ross" wrote:
Anyone know the formula, rule of thumb regarding the shrink fit tolerance
for fitting starter rings to flywheels? My feeling is to leave the recess on
the flywheel 'up' by say 0.010" (.25mm) so as the starter ring cools it
'nips' up, without too much stress on the ring but with enough 'nip' so as
not to work loose or spin.

ttfn....Alistair

..001" per inch of diameter on shrink fits was what I've read. Guys
have also put regularly spaced tack welds on both sides just to make
sure. I'd rebalance afterwards, in any event. Haven't had to do
either, VW parts were plentiful when I built my air-cooled engine.

Stan