Bearing renewal?

[swampy42]

I'm about to put the engine back together and I'm wondering if I should replace the bearings? I would rather not as it's more cash, so how can i tell if my existing bearings are OK? There is no play in them and they don't, to my untrained eyes, look unduly worn. Is there a way of visually telling? I have only run the car for a matter of a few minutes (a few years ago) since owning it and I don't recall any untoward knocking. Any advice appreciated.
Russ

[bmcecosse]

You say they don't look unduly worn....how do you know? Have you inspected them? Best clue is to whip the sump off - and remove the centre main cap - and show us a picture of what you find!

[swampy42]

Here you go. This is one of the end bearings.[frame][/frame]

[les]

Usually that sign of copper breaking through is indicative of wear but if that is the only area, you're probably ok to assemble. It's a shame not to replace this sort of stuff though, especially as the engine is in bits but it's a personal choice. I would have to do it! If the crankshaft is not scored or oval you may get away with just shells, in which case would not be over expensive.
On assembly it's a good plan to smear the shells with some sticky oil, you can purchase stuff for the job, engine oil is ok if the engine will be used right away.

[bmcecosse]

That doesn't look too bad at all - the centre one is the most 'telling' though... General rule is that if you disturb the bearings - then you should fit new ones...... However the price of shells these days is just not funny any more......so - provided the others look no worse, and it's just a 'standard' engine - I would clean everything carefully and reinstall. How about the big-ends ?? Again one fed from the centre main (so 2 or 3) is most at risk....so let's see one of them.

[swampy42]

Thanks guys. I think a few of the bearings have slight amounts of copper showing, but nothing more severe than this. No sign of the crank being oval - it turns really smoothly without noise or lateral movement. Hang on - i'll go and take a pic of the big end.

[swampy42]

It turns out that the central bearing is a bit worse, as shown. Pic of con rod bearing to follow.[frame][/frame]

[swampy42]

Here's a pic of the con rod bearing on number 2 piston.[frame][/frame]

[philthehill]

If that is the copper backing showing through and not just oil stain I am afraid bearing renewal is required
What is the crankshaft like?

[swampy42]

It looks fine to me. Are there tell-tail signs I should be looking for, if the crank shaft is likely to have issues.

[philthehill]

Scoring is the obvious sign. Run your finger nail across the journal. Can you feel any ridges?
In reality the only way to check for wear is to measure with a micrometre.
The crankshaft bearing journals may look good but they could be oval and using the micrometre will confirm whether they are or not.
A photo of the crankshaft journals would be helpful.

[swampy42]

OK, I'll take a pic tomorrow if I get a chance. and dust off the micrometer. Hope to post back tomorrow evening. Thanks guys.

[bmcecosse]

New shells required I'm afraid - the centre main is always the worst - but the wear is just that - no obvious scoring - I'm confident the crank will be fine ! I would also consider a new oil pump - but have a look inside yours and decide. Also check that the oil filter is all there (plate and spring under the element) before rebuilding...

[alexmcguffie]

New bearings needed. Your best bet is to take it all to a good machine shop and have them meaure up exactly what you need. They may also do you trade prices on bearings which still arent expensive compared to many 'affordable' classics.

[bmcecosse]

Don't get me wrong - if it is a standard engine - and only being run on 'light duties' - you could re=assemble what you have (including the piston ring - which was probably broken at the last rebuild) - and the engine would serve you well for many a happy mile - as long as it was driven reasonably 'carefully' - not hammered up the M/way for mile after mile. But a new set of bearings at this stage will see the crank fit for a long long time - and hopefully someone will come up with a ring for you!

[swampy42]

I think that would be a wise move. Might as well while it's stripped down. Someone mentioned that the copper colour could be oil staining - is that a possibility? I've measured all the journals and they are pretty much spot on standard diameter, with no signs of ovalling (is that a word?).

[les]

New shells well oiled, would seem all you need.

[bmcecosse]

It's certainly not 'staining' It has worn through the lead/indium layer into the leaded bronze layer below. You've caught it 'just in time' - with new shells the crank assembly will be good as new. DO however check the oil filter to MAKE SURE the plate and spring are present and correct - otherwise it's running on unfiltered oil - possibly leading to the wear you see here......

[swampy42]

Many thanks indeed. I will make doubly sure that the oil filter is all present and correct.
Russ

[bmcecosse]

It is of course also critical to NEVER allow the oil level to fall low enough to cause 'surging' on cornering. The slightest drop in oil pressure is absolute death to bearing shells........