Burning Oil

[Paul from Derby]

I am going to submit this at the risk of being shot down in flames by the moderators, as it concerns a corsa 1.0 engine, not a Vectra (I do own a Vectra as well!). The reason I have submitted it here is to hopefully get some experienced advice from proper mechanics etc, as the Corsa forums are populated by airheads and are a waste of time. So, here goes:

Engine in question is a Z10XE 1.0 ltr. The timing chain slipped causing a coming-together of the pistons and valves, resulting in a damaged head and 2 holed pistons. I obtained another engine that had suffered a similar fate but not so excessively, and used the head and 2 pistons from it to repair the original engine. The block identifying letters were a bit confusing but I very carefully measured the pistons and bores (using proper instruments) and they all are the same on both engines. After fitting a new timing chain and tensioner, the engine is now running really well, I have done a compression test and all is good - but, the engine is burning oil. I have checked the valve stem seals against a new one and they look fine, no deterioration and as tight a fit on the valve stems as a new one. I did actually replace them on one cylinder which wasn't easy with the head in place but decided due to the condition of the existing ones it was not worth doing the rest. I reckon it's burning about a litre every 750 miles. I am wondering if using pistons from another engine, albeit the same mileage and size etc, is causing oil to bypass the control rings and get into the chambers, but it seems like a lot of oil is going that route if so?? any ideas anyone???

[Big Sig]

Did you not change the piston rings for a new set then?

[Paul from Derby]

Do you mean compression or oil control? Compressions are fine under test but no, original rings were used.

[Big Sig]

if you didn't change them could that be a reason the oil is getting into the cylinder? All cylinder bores wear differently and i am wondering if the old ones are ever so slightly different to your engine bores allowing oil through?

(oil control)

[Paul from Derby]

Yeah well as far as i can see it's either got to be going in at the top or up via the bores but it just seems like a lot of oil is getting through. As far as I am aware the only lubrication is the oil that is splashed onto the bores as the crankshaft rotates it not like its under pressure?? I am wondering if the oil control rings might wear to the shape of the bores after a time???

[Jezzy]

What colour is the exhaust smoke?

[nikroc]

personaly ida thought that piston/ring/bore wear would be specfic to each set of pistons/rings/bores...and if you replace a set of pistons and rings into a different set of barrels/bores then they would be oil tight..

[Paul from Derby]

Good point regarding the smoke. Usually there is none at all on either start up or when the car pulls off. BUT - there is occasionally a bit of smoke on startup, although I must say i have not noticed this for a good while now, which would suggest to me that the stem seals are OK. Regarding the rings I think Jezzy has a point, if the compressions and therefore the compression rings are OK, you would think the oil control ones would be as well? Has anyone heard of any method to find out which cylinders are burning oil? The plugs all look similar upon removal.

[Grumpy1954]

The reason I have submitted it here is to hopefully get some experienced advice from proper mechanics. So, here goes:

Are you sure about this?

[cont1204]

Have you tried posting this on corsa-c.co.uk? Apart from the messing about in off topic chat etc they know Corsas well and you'll probably get a good reply in the technical areas. On the oil burning issue, that's alright for a worn engine. The 1.0 is quoted by Vauxhall to burn about a litre of oil every 1000 miles. Mine drank a bit of oil too (owned a 1.0 Corsa before the Vec and a member on Corsa-C).