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Big End Shells bearings

Posted: Mon Oct 14, 2019 9:02 am
by Rev Light
Okay, I am pulling an engine apart to investigate its serviceability.

The engine was pulled as it was 'making a noise', a knock, apparently.

Many theories were put forward, but nobody really knew, until the engine was stripped.

So hear we are.

The engine is on a stand, the heads are off and the piston are out.

But at first glance the standard shells seem to be in good condition, with only some light marks on them. Shiny white metal as opposed to dull white metal, mostly around the edges. No deep scores (using the finger nail test).

But one does look as if something has passed through, with a very light scoring that can just be picked up with the finger nail.

My question is what are these shells made of? What type of metal is the white metal bonded to? Bonded is probably the wrong word, but I though the white metal was melted onto a copper substrate? But are more modern ones aluminium.

Does not look like the engine has done much mileage. Crank not out yet.

Cheers

Steve

Big End Shells bearings

Posted: Mon Oct 14, 2019 9:15 am
by philhoward
A picture will tell a thousand words with the bearing surfaces.

Whilst it applies to diesel engine bearings (which have a much higher loading), this is a pretty good summary: http://www.marinediesels.info/2_stroke_ ... erials.htm

In short, there isn't a "one size fits all" bearing material but copper is normally a substrate used to get the bearing material to stick.

Measurement of the crank journals is the only real way to tell - the engine could have had new shells fitted to a slightly worn crank at the edge of the tolerances and the slight wear you now see has taken it out of tolerance. If you want to check the bearing clearance, get some plastigauge strips: https://www.ebay.co.uk/i/173609836432 (other sellers are surely available - this was just the first one that cropped up). I'm pretty sure the bearing clearance is in the manual?

Big End Shells bearings

Posted: Mon Oct 14, 2019 9:20 am
by philhoward
Found them:

25. Big-end bearing clearance 0.018/0.063mm.(.0007/-0025in.)
31. Main bearing clearance 0.01/0.058mm. (.004/.0023in.)
From here:
http://laffhog.com/ford/v4v62.html

Big End Shells bearings

Posted: Mon Oct 14, 2019 10:20 am
by Rev Light
I will try and get a picture or two up in the next day or two. Being foiled by latest security policies at work and a useless phone.

Noggin night tonight for Wiltshire, will try and get some opinions form noted experts there.

The journals have some marks on them, but nothing I can feel with my finger nail. I have not measured them yet, ad I have to measure the crank end float also.

Expensive business rebuilding an engine. I have not spent anything yet, but if I have to get the crank reground it soon starts adding up.

1. New Gasket set.
2. New rings
3. New Shells

Plus whatever is actually wrong with this engine.

Big End Shells bearings

Posted: Mon Oct 14, 2019 10:35 am
by Rev Light
Is it recommended that I change the oil pump also, as I am in there.......Been on the 'tube'.

I should add, I am an 'engine rebuild virgin'

Big End Shells bearings

Posted: Mon Oct 14, 2019 10:46 am
by philhoward
Some light reading for you: http://www.marcoscars.net/v6_rebuild.pdf as there's no such thing as too much research - think it might be in the Practical Classics book sold by the club?

Big End Shells bearings

Posted: Mon Oct 14, 2019 11:41 am
by scimjim
Only you (and your budget) can decide where to stop - gaskets only or machining, crank bearings, piston rings, oil pump, oil pump drive, water pump, camshaft, camshaft bearings, clutch - £300 or £1300?

Big End Shells bearings

Posted: Mon Oct 14, 2019 11:50 am
by Rev Light
Yes Jim, and your spare engine is in the background mocking me......

Big End Shells bearings

Posted: Mon Oct 14, 2019 12:08 pm
by willholderogri
see you at the noggin tonight I have some new shells at home they owe me £35 a box

Big End Shells bearings

Posted: Mon Oct 14, 2019 5:19 pm
by TrevorG
I remember that rebuild article....
didn't they advocate that if the fibre timing wheel teeth are still sharp, don't change it!! :w :dh

Big End Shells bearings

Posted: Mon Oct 14, 2019 5:21 pm
by philhoward
Some of the advice might be a bit out of date...

Big End Shells bearings

Posted: Mon Oct 14, 2019 6:07 pm
by scimjim
There’s people on Facebook saying that to this day :D

Big End Shells bearings

Posted: Tue Oct 15, 2019 8:08 am
by Rev Light
And you can still buy them second hand on ebay.....