Frothy oil

[Zetomagneto]

I my experience would suggest it is never wise start an engine that has stood for years without first removing the head to inspect bore's and grind in valves, removing the sump, cleaning and checking the oil pump, etc. I have found a surprising amount of corrosion in some engines, it is also worth removing the two water manifolds as these are often clogged as well. I know that some will say, oh we simply changed the oils started the engine and it has been fine ever since, well you may have done so, but you may also have been lucky. The pictures attached are of an engine that has been through my workshop recently, it was apparently completely rebuilt not many miles before being laid up 20 odd years ago......would you want to have started it??

Ian, I am definitely with you on this one.


I love this forum, specially noting the proper engineers from the untrained/ inexperienced/bodgers

I recently stripped an engine so called rebuilt, it had been rebored,pistons,white metalled just poorly reassembled,not particularly well cleaned.It would have run, but not as well as it did after I reassembled it properly

[Ian Williams]

I am dismayed by the responses of some on here, but as Hedd says it is all down to what floats your boat. Personally I like to use my cars as much as possible and my Nippy is my daily runner, however I spend a huge amount of my time helping club members get, and keep their car's running, and in all honesty a lot of that time is spent fixing ill advised actions and bodges. The engine in my pictures was back together and running happily within a week and is still going strong, personally I am relieved the owner followed my advice and we took the head and sump off revealing the horror within, had we not done so I doubt it would be quite so healthy now and would have undoubtably cost more in the long run. It take's very little effort to remove the head and sump, both can be done in the car, if all is well then you will have spent a couple of hours and a couple of gaskets, if things are not well you will save yourself a whole world of pain.

[Colin Reed]

HI Ian,
           All anyone can do is offer advice based on experience .
           the advice you gave in this case is spot on in my opinion.

[Nick Salmon]

I'll leave to one side the debate about dealing with long unused engines. Suffice to say that I know the car from a while back and had sump and head off before it came to me so I had a visual on the internals which were fine. The water was not in it long.

Meanwhile, back at the oil question it has been suggested that the oil pressure relief may be stuck open - which would give a lower than normal pressure reading at startup and might account for the frothing. I am going to take a look see at that first, then if necessary go for the oil pump vanes/springs and will report back in due course.

[Derek Sheldon]

Well I’m with Ian on this one. Foolishly expensive route to take in my opinion but it’s good that we are different, wouldn’t it be bloody boring if we were all the same. 
Nick, the pressure relief springs and balls are only a few quid from Jamie and after advise from Ruairidh   I change them as a matter of course on a rebuild. Check that the ball seats well with no obstructions. If it ends up with further strip down it would be worthwhile to have the pump bored out to get greater pressure, something else I do as standard.

[Nick Salmon]

Yesterday I decided to have another look inside the sump (the oil pressure relief being in such a daft place to get at that I thought I'd just check on the obvious things again first).  Lo and behold - water.  Despite having thought all of it was out, and having done two oil changes, a small quantity of H2O was evident. Cleaned everything, turned the engine over several times on the handle, put it all back together, fresh oil. Voila. 10lbs+ on startup and 5lbs on warm running. No sign of frothing. Happy days. Thanks for all suggestions.