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Crank Case Compression

Posted: Sat Sep 14, 2013 8:01 pm
by mickeytwonames
I seem to have a case of 'Crank Case Compression'. This seems to be the cause of my previous thread 'Texas Tea' about oil smoke coming from the breather tube on the rocker cover. It's been darkly hinted that it is 'yer piston rings.'
Dose anyone have experience or advice of this 'Gold Seal Syndrome'?

Re: Crank Case Compression

Posted: Sat Sep 14, 2013 8:11 pm
by bmcecosse
Have you carried out the test - with hot engine, oil filler cap removed -and revved up? If there is a plume of smoke/fume - then yes indeed the rings/pistons/bores are worn or damaged.....

Re: Crank Case Compression

Posted: Sat Sep 14, 2013 11:00 pm
by mickeytwonames
Yes - they're worn on number 4 cylinder. is there any big danger in short journeys till i can sort the problem out?

Re: Crank Case Compression

Posted: Sat Sep 14, 2013 11:01 pm
by mickeytwonames
Is it an engine out job?

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 12:36 am
by bmcecosse
How do you know it's #4 cylinder? No 'big danger' but oil consumption will be heavy.... You can pop out the pistons with the engine in place - take the head and sump off.

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 5:26 pm
by mickeytwonames
I replaced the head gasket thinking my problem lay there - it didn't but other issues were fixed and all gaskets changed etc.
I've got time on a ramp - I'm going to replace the shells and rings. Everything is OK above the sump - is there anything else I can usefully do with the crank case off?
Also - Best Practice - do you do one cylinder at a time or go for all four.
Lastly - Do you need to run piston rings in?
Again, many thanks for your support

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 5:31 pm
by mickeytwonames
And, Blimey
Bull motif sell:-
948cc Piston Ring Set(standard)
948cc Piston Ring Set(+20)
948cc Piston Ring Set(+30)
948cc Piston Ring Set(+40)

Which do i need?
When I had the head off (I think) I remember the letter 3 stamped on the block

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 10:27 pm
by bmcecosse
You need to see the tops of the pistons - they will be marked STD or 010 or 020 etc to indicate size.. same with big-end shells - you need to see the back of the old shells to see what marking they carry... You would do all 4 pistons at the same time... The bores should be 'glaze busted' - and yes you would take it easy on new rings first few miles... You should understand - new rings in old/worn bores are not going to make a huge difference - and any improvement won't last long. But if you only do a v limited mileage - that could be a few years, and may be what you are happy with.

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 10:39 pm
by mickeytwonames
Many thanks - what is glaze busted?
The pots look clean and are not scoured and there is no piston movement/wobble - it that just an illusion to their wear?

Re: Crank Case Compression

Posted: Sun Sep 15, 2013 10:41 pm
by JOWETTJAVELIN
The bores need checking by a professional for ovality, amongst other things. If they are ok then indeed deglaze and a set of Cords if you can get hold of them.

Tbh, you're getting into full-blown rebuild territory here, or at least might as well do.