Crank Query

[AlfaLofa]

I've removed the crank from a 701M block and fortunately (to my untrained eye) it looks pretty good.

The main bearings show no wear.

They are stamped as per photo which I assume means the crank has been re-ground by 10 thou.

Can't even guess what the rest of the text means.

However the crank does have striations (which can be felt with the fingers) where one of the thrust washers locates adjacent to the centre journal.

The other thrust washer surface is perfect.

I assume these surfaces can be easily machined by a decent machine shop?

[Chancer]

Its only the rear facing thrust bearing that does any work, it resists the force when you disengage the clutch, the rest of the time it just locates the crank without any significant thrust load like the front one.

Hard to see from the photo but it looks quite normal to me and no cause of concern, back in the day I would just swap them front to rear and not even replace them.

[types26/36]

I would agree, from the pic it does not look bad (I've seen worse and still used) although I would fit new thrust washers but first check clearance with a feeler gauge and even if in spec still fit new washers .......they are not expensive (or wasn't last time I bought any)
Then get yourself some PLASTIGAUGE and check main and big end clearance, you can then decide if you want to replace the bearings.
You could also get your friendly garage man to mic up the crank if you feel it is necessary.
Don't forget to check the crank spigot bearing.....its a lot easier to replace now then later.

[AlfaLofa]

Hopefully here are some better pictures of the scoring on the crank where the rear thrust washer locates.

Also there are pictures of the washers as removed - showing that the scoring is sufficiently deep to remove the punched text.

The "gouging" on the crank is equivalent to that on the washer.

I've added Plastigauge and the spigot bearing to my shopping list

[rgh0]

I would grind the thrust face on the crank and fit an oversize thrust bearing to keep the clearance right

cheers
Rohan

[oldelanman]

Thrust washers I've seen have always had oil grooves in the wear face and the stamping on the back - do yours have the grooves ? If so it looks like the worn one has been fitted the wrong way round.

[alan]

if the stamped text is worn they were fitted the wrong way round

[AlfaLofa]

At least I'm innocent - I'm just taking it all to pieces

And yes both the thrust washers do have the oil cut-outs.

So as deduced by you all, the badly worn washer was fitted the wrong way round.

When I get everything checked out I'll add machining the thrust face on the crank to the list.

Afterthought:
I read somewhere (I think) that both the thrust faces on the crank have to be equally machined.
Is this correct?

[Elan45]

If you read the thrust washers print, they are already oversize, so your thrust surfaces have already been ground. I'm not sure if they are available in varying thickness. Check with Burtons, a Ford supplier.

Roger

[AlfaLofa]

Hi Roger,

Burtons list them at 10 thou and Miles Wilkins in his book suggests that the various thicknesses can be mixed and matched to obtain the desired result (although he doesn't mention the 10 thou version).

I'd be interested to hear what people here think about this.

[promotor]

An engine reconditioning company near to me claim that they can rectify anything like this with custom bearings after grinding the grooves out (providing they aren't too deep - I seem to remember being told 2mm was no problem).
I was told that they could make the bearings to suit.

So if they can I'm sure most machinists could do this (if you get someone who's actually interested!!)

Aside from that in answer to your question you don't need to fit identical size bearings either side - as long as the running clearance is correct and the crank is sitting near where it should be ie central and without hitting anything (or being too close to block etc) then any combination is fine.

[rgh0]

Yes I agree with Promotor that a good old style machine shop should be able to build up the white metal on a thrust bearing to what ever thickness is required. The Datsun L16 steel crank crank conversion requires a thicker thrust bearing as the thrust faces are about 1mm further apart than the orginal Ford crank and I routinely get these made at the egnine machine shop i use here. i normally use the standard thrust bearing on the rear thrust face to take the clutch load and the thicker white metal built up bearing on the front face that carries no load but you need to check the crank postion to make sure this is OK for clearances and alignment of the crank logitudinally in the block .

cheers
Rohan

[nomad]

If all else fail's you can have the crank welded up and re-machined. Not cheap but I'm having the seal face on my crank welded right now and I've had another crank welded on the trust throw with good results.

Kurt
26/3754