16 replies to this topic

[AVV IT]

My recently fitted MG metro engine appears to be going through an excessive amount of oil. There are no visible leaks, so I assume it must be burning it. It's not smoking on start up, or tick over, but I do keep noticing the occasional puff of blue smoke in the rear view mirror, particularly after a period of high revs followed by easing off then applying the power again.

Any thoughts??

[jonny d]

could be worn valve stems or oil seals or it could be the oil control rings have you overheated the engine at all?

[AVV IT]

No it's not overheated at all, and the head was reconditioned with new valve seats and seals etc by a reputable engineering company a few hundred miles ago.

[old original]

It's worth checking the stem seals again, they can come adrift

[AVV IT]

It's worth checking the stem seals again, they can come adrift

Thanks I'll give that a go!!

First place you want to be checking, are the engine breathers.........there most likely blocked

The breathers are clear and also fairly new as the engine only went in recently. You'll have to explain how that would cause oil to enter to the pistons in order to be burnt though, as that has me confused!!

[bmcecosse]

It's due to worn bores and/or piston rings. If you can't live with it - it's engine out time.

[AVV IT]

I certainly hope not, it's a recently rebored block with new rings and pistons, it's only just gone in a few hundred miles ago!!

Edited by AVV IT, 04 August 2012 - 09:06 PM.

[Jordie]

had the engine tuned correctly? sounds like bore wash due to excess fuel. plus it will take a little time for it to bed in fully and seal, so might be a little oil passing.

[bmcecosse]

'Maybe' it's just running in........but I doubt it.

[mk3 Cooper S]

What oil did you run it in with?

[Jellevandok]

Where was the engine rebuild?

[Yoda]

It does sound like some stem seals have popped off or maybe the valve guides are just a bit too worn. If i am right, the MG metro had 8mm exhaust stems and later seals do not fit well, if you find they have lifted, fit Vicon seals. MRA used to sell them, it might be worth giving Martin a ring. But just remember, worn guides will need replacing for a proper repair.

(edit)

Just had a re read, you state that the head was rebuilt. did this include new valve guides / valves and recutting the seats to match? if so you should be able to run without seals if the job was done properly. I have heard that Turbo conversions have valve stem seal issues and the cure is usually to have new guides, valves etc and run without seals.

Edited by Yoda, 05 August 2012 - 07:21 AM.

[AVV IT]

I believe that the head was reconditioned by Ivor Searle of Ely, and was a complete refurb including valves, guides, seals etc. Unleaded seats were also fitted as it was an early MG metro pre unleaded head. The engine was the built by reputable local guy who works on classic cars and specialises in classic minis. The guy who built the engine did the tuning once it was fitted, this was just static tuning though as it hasn't been on the rollers yet. I believe it was run in with Millers classic 20/50.

[Yoda]

Was it run in nice and hard, say 2000rpm for half hour after initial start and warm up then on the road for an hour of thrashing?. If not it could be needing rings and a hone if it aint the valve stems. I know that sounds a harsh way to treat a new build, but i am sure a few others will agree its the new way to get going for a good engine.

[jaydee]

3000 rpm in two runs of 10 mins each is essential for camshaft and followers run-in.
That wouldnt explain the consumption of oil though
What oil have been used for running in? Synth oils are usually not very good for that purpose, and can be burnt off by the engine..