BMC 1.8 using oil

[jimfin]

As some of you my remember I did a lot of work on my 1.8 over last winter.

Since then it has been using lot of oil. I'm only guessing but I would say about 2 pints in about 10 hours.

There are no leaks from the engine. I think it's coming from the breather into the air box. I have read some older posts and suspect timing!!

The engine starts and go's well. I have taken the breather pipe off while running and there was a lot of mist. The air box is black with oil.

If it is timing what way do I turn the pump? Looking down on the engine do I turn it towards the engine or away from the engine? Hope this makes sense.

[Flyboy]

Possible causes :- Over filled with oil.

Pressurising of the crankcase by piston ring blow by.

Oil control rings.

Valve stem oil seals.

I can't see how the timing would have any effect on oil consumption.

[Tony Brooks]

It depends if you want to advance or retard it. If your diagnosis is correct, and I am not sure it is, then I suspect you need to retard it a little but I feel that as you have done a lot of work you really should get the timing pointer (on the pump mounting block) set with the proper gauge so that all the slack in the camshaft and pump drive is taken into account. You will probably have to pay someone to do this

[RLWP]

Remind me - new rings?

 

Richard

[Mikexx]

Since then it has been using lot of oil. I'm only guessing but I would say about 2 pints in about 10 hours.

 

 

Since then it has been using lot of oil. I'm only guessing but I would say about 2 pints in about 10 hours.

 

That is a lot of oil. Can you confirm there is a lot of blue smoke out of the exhaust?

 

If not can I suggest you look at where else you can lose this amount of oil?

[Tony Brooks]

Remind me - new rings?

 

Richard

 

And was there not something about turning the pistons to get rings that "fit"?

 

 

Was it re-bored? If not you have removed all the old caked carbon that was forming a seal on the piston/rings.

[RLWP]

 

And was there not something about turning the pistons to get rings that "fit"?

 

Oh blimey - forgot all that

 

Jim, your rings are bedding in - don't panic!

 

Richard

Was it re-bored? If not you have removed all the old caked carbon that was forming a seal on the piston/rings.

 

Was it honed?

[jimfin]

Yes. I got new rings but could not get bmc one's. The ones I got did not fit exactly and I had to get the pistons machined to take in new rings. The job was done by a competent engineer.

Another engineering friend helped me carefully fit the pistons in the cylinders.

I bought a honer and honed the cylinders.

Have done about 150 hours

[Tony Dunkley]

If it's burning all the oil it's using, then you would be getting quite a bit of noticeable blue smoke when running.

 

Is it sending much blue smoke out of the exhaust ?

Edited September 4, 2016 by Tony Dunkley

[Mike Jordan]

Is there any evidence of oil in the exhaust system?

[Mikexx]

Have done about 150 hours

 

Would that be 30 pints of oil?

[jimfin]

 

Oh blimey - forgot all that

 

Jim, your rings are bedding in - don't panic!

 

Richard

 

Was it honed?

How long should it take for the new rings to bed in. Yes I did hone the cylinders.

 

I think it's coming from the breather pipe. I took it off yesterday and there is a lot of smoke / mist. Also there is a lot of oil around the air intake.

Edited September 5, 2016 by jimfin

[RLWP]

Blow by. Until the rings seal, you get gasses passing from the cylinder into the crankcase

 

How long to bed in? It depends...

 

Are you using running in oil? Are you working her hard? Does she get nice and hot? What is the spec and source of the rings - are they of good quality?

 

Richard

[crossley]

If you've just honed the bores and re ringed the pistons, then it may take a while before the rings bed in.

Honing won't restore the bore geometry to any extent,as the stones are spring loaded and follow the existing shape. Only the proper delapena or Chris marine honing machines are able to true up bores to a small extent,and they need diamond stones to do it.the actual honing pattern produced has a very profound influence on oil consumption. Give it jolly good blast at high load to get those rings bedded in to the walls.

I assume all the clearances are correct in your re machined ring grooves and you have gapped the rings?

[jimfin]

Was talking to another guy today and he also said to give here a bit of stick and heat her up.

 

Is there any way to to route the breather pipe so as not to burn so much oil!!

[Tony Brooks]

 

Was talking to another guy today and he also said to give here a bit of stick and heat her up.

 

Is there any way to to route the breather pipe so as not to burn so much oil!!

 

Get a longer one and route it to a bottle stood in the engine tray. It won't stop the fumes but will keep the air cleaner oil free.

[jimfin]

 

 

 

Get a longer one and route it to a bottle stood in the engine tray. It won't stop the fumes but will keep the air cleaner oil free.

 

The fumes are not that bad. I could pipe it outside but the oil would mess up the outside. Any way to filter it before it goes outside!!!

[RLWP]

The fumes are not that bad. I could pipe it outside but the oil would mess up the outside. Any way to filter it before it goes outside!!!

 

Yes - route it into a bottle! The oil gets caught and the gasses pass out

 

Richard

[Geoff Taylor]

Hi, Just a guess, if you are running with a paper air filter it is possible that the excess oil from the breather has blocked it and the alternative is to create more suction by the engine getting its air from the crankcase therefore causing the excessive oil consumption.

 

If that is not the case then I am afraid that something a lot more serious is wrong especially having to have modified the pistons to take different rings etc.

 

Were the bores checked for ovality after the honing?, was the wear lip at the top of the bores removed or the top rings stepped to miss them, otherwise the top rings will break up very quickly, (I have witnessed this on quite a few occasions with both petrol and diesel engines) were the rings fitted the right way up?, is the ring circumference exactly right for the bore?, the engineer who machined the pistons would not know this if he did not personally try the ring fit in the bore, many questions I know but thats engine building.

 

 

Hope some of this info helps you but my fear is that you will have to endure another stripdown in order to find your problem.

[jimfin]

Thanks for all the advice guys. Think I will keep going and see if the rings bed in a bit more.

 

Don't fancy a strip down this winter again!!! We'll see how things go.

[Chalky]

When you rebuilt the engine did you clean the oil separator in the crank case breather? On my engine (B series petrol) the breather is one of the tappet chest covers. It consists of a "wire pan scraper" and is designed to separate oil vapour. Washing it in petrol cleans the congealed oil off and lets it work properly.

[jimfin]

 

Yes - route it into a bottle! The oil gets caught and the gasses pass out

 

Richard

So. Would you put some kind of filter in the bottle. Thinking about a bottle with 2 tubes. One in and one out, and some kind of filter to catch the oil

[Cheshire cat]

Someone asked about running in oil and didn't get a reply. Whenever I've had an engine rebuilt I was required to use running in oil to aid the bedding in. I was told it will never bed in if its using a modern oil.

[jimfin]

Blow by. Until the rings seal, you get gasses passing from the cylinder into the crankcase

 

How long to bed in? It depends...

 

Are you using running in oil? Are you working her hard? Does she get nice and hot? What is the spec and source of the rings - are they of good quality?

 

Richard

Well Richard. Whats this running in oil!!!!

[bizzard]

The best and quickest way to run an engine in is to start up and go for short trip, but only until the engine has reached its normal running temperature and then stop it and let it cool right down. start up and do the same, over and over again.

This procedure allows the different expansion and contraction rates of the associated metals to settle down, reform into loving compatibeness. with each other. Just running the engine for hours on end without stopping, putting hours on it, doesn't really do much more than just shave a thou or two of unwanted proud bits of metal off. This procedure really only applies to fully reconditioned engines though which have had their cranks re-ground, new bearings. re-bored, new pistons, ect, ect.