Glazed bores = high oil use

[Tony Martyr]

My rebuilt engine was run after build on 5/40 synthetic. The new liner bores were much more polished at new than the originals which had marked hone cross-hatching. I noticed the black deposit on piston crown during the strip due to ingesting airbox nut and replaced the oil with a straigh Halfords mineral oil in the hope of getting the oil control rings to bed in better. Without much luck.

Oil consumption is high and although the plug points look OK you can see the piston crowns are oil wetted.

With Le Sept starting this weekend I have reverted to synthetic oil and will take at least one spare set of plugs.

What can I expect?

In addition to very high oil consumption on the track I can't see I will do other damage that has not already required a re-hone during the winter.

Any informed comment welcome

[Peter Carmichael]

Any oil vapour present in the combustion chamber will tend to bring on detonation.

[Rob Walker]

Tony

 

If the plugs look Ok I would not worry too much. Excessive oil contamination of the mixture does reduce the octane rating which could lead to detonation but this would be evident on your plugs and you would feel it under hard excelleration. What sort of oil consumption are you getting ?

See you next week, should I bring a gas mask along?