Apologies for the long post but I could really do with some help and advice.

I bought an NC that had just been engine swapped for a lower mileage 2.0 on 55,000 miles.

The engine had been stripped down fully, cleaned, checked and rebuilt with all new bearings, gaskets, valve stem oil seals, thermostat, aux belt and a few other bits. ( I am not sure if the piston rings or oil rings were replaced at the time )

I bought the car from the person that did the engine swap and it had run for 20 miles and was still on its mineral running in oil. After about 600 miles of spirited driving up to the limiter regularly I decided to check the oil, to my surprise it had gone from full to only just touching the bottom of the dipstick and well below the minimum fill level. I would guess this is around 1 to 1.5 litres/quarts under the max fill line. I had been thrashing the car for some time unaware that it was burning a lot of oil and below the minimum fill line.

At this point I changed the oil for some good quality fully synthetic 5-40 and have kept a very close eye on the oil level before and after every drive.

I have continued to drive the car hard through the gears and it seems to be using just over a quart/litre of oil every 100 miles/160 km. The car is smoking very very slightly at max revs and is clearly spitting oil through the exhaust ( which is mainly a straight pipe with a de cat manifold and muffler delete )

I took the oil cap off and did a rubber glove test, the glove inflated quickly indicating that there may be blowby or a faulty pcv valve stuck closed.

I haven’t had chance to speak to the garage I bought the car from who did the work amd when I do tomorrow I will be asking them if they changed the piston and oil rings when the engine was rebuilt. I would hope that they did as they are specialist Duratec engine builders/tuners with a reputation to keep.

I am really hoping the issue is just the PCV valve and will be replacing it next week in the hope that completely cures the issue but I’m worrying it’s something more serious.

What do you think the cause of the excessive oil consumption could be??

Thanks in advance!

 

assuming no oil leaks that you know of.......

1) Check compression. Read how to properly do a compression test. DO NOT EXCEED 5 revolution per cylinder and duplicate the same revolution with each cylinder.
2) Perform a cylinder leak down test.
3) scope the cylinders.

You will find the answer to your question.