I've stripped an engine down for a rebuild ready for Snetterton this year only to find that whoever last built this engine has fitted the crank shells incorrectly damaging them.

As per the title of this thread, has this rendered the crank as bin fodder? The shells still turn freely on the crank but I'm worried that it's just because they've been "machined" round again by the rotating crank meaning I'll end up with unwanted movement in the crank when I put it all back together.

Am I worrying unnecessarilly or is it replacement crank time?

Thanks in advance.

spanners,
as far as I'm aware, the end float of a crankshaft is determined by the front bearing, so if you clean that rear bearing shell up and locate it on its dowel correctly when reassembling, all should be well.

edit: by 'cleaning up', I mean filing out the original hole into which the dowel fits.

ken.

There's also that "dink" in the front shell too as in the first picture......

That said, I like what you're saying Ken.

re dink in the front shell, if it hasn't seized yet, any part which was standing proud will have been smoothed off by now.

Is the original dowel hole still OK on the front shell?

Both shells turn perfectly freely on the crank so with a bit of luck then, it'll be okay.

This is good. We have another crank but I'd rather not have to chuck a crank away.

If it is to be used in racing I wouldn't risk it. Street car no worries.

Apologies spanners,
short break in service whilst watching Spain prove that the octopus never lies...

No luck needed, if that crank has already been run with the dowels out of position on the shells, any danger is now passed.

All you need to worry about now is that the #ent cam doesn't cast its evil spell on your labours.
That's the main reason why I stopped building race engines.

ken

Thanks for the words of wisdom Ken, I "filed" the hole back out with an M3 bolt in the absence of any needle files here at Spanners HQ!

Anyway, I got the crank to seat nicely along with the afforementiond #ent cam so all will be well I hope. Right up until it's run for the first time.

Incidentally, I was looking through all the boxes of bits Simon brought up to me, I found the remnents of another engine including 2 very bent valves and an utterly destroyed follower, almost brought tears to my eyes in anticipation!

Yep,
that's the bit that's least fun, holding it at around 2,500 rpm for at least 10 minutes on first start up, to break in the new cam and followers.

Just got to grit your teeth...



No big problem there,
the driver will blame the spanner monkey...


...and the spanner monkey blames the driver.

ken