Horton

Right about 6 months ago I had a spare head rebuilt ,skimmed and put it on my car. Shortly after I noticed the car smoking and burning oil. I then decided that this was because the oil control rings were gone so I have just rebuilt the bottom end with all new genuine Mazda parts which cost a fortune.

Ive just taken the head that I had rebuilt 6 months ago off the old bottom end and put it on the freshly rebuilt spare bottom end. Then put that in the car and it's still smoking the same.

Whilst I had the rebuilt head off I noticed that cylinder 2 had oil deposits on it already. Bare in mind this head has only done 1000 miles max. All other 12 valves look mint still.



Ok I thought, 1 of cylinder 2s new valve seals must have been dodgy. No big deal I'll swap out all 4 seals from new ones ASAP.

So I've ordered the valve seals and they should arrive Wednesday. However I have just looked back through pics of when I split the spare engines bottom end and head originally and you guessed it cylinder 2 had heavy oil deposits on it back then.

^ hope that all makes sense

Soooooo now it seems very unlikely (but not impossible) that the new valve seals have failed on cylinder 2 when the original valve seals on this head had also only failed on cylinder 2.

All the valve guides were measured when the head was rebuilt and they were all fine.

What could this possibly be? Very minor cracked valve guide maybe? Fingers crossed we find an obviously failed valve seal above cylinder 2?

Anyone who has any input please help as I've just spent a couple of grand rebuilding an entire engine and I feel like setting the whole car on fire.

chrisgtx

I know the feeling,my engine smoked after I had it rebuilt,but all the cylinders are equally carboned up.
It's terrible when cold but not so bed when warm and everything tightens up.
I can only assume the bloke i took the engine to cocked up on re boring it.
But,back to yours,I guess a cracked valve guide could lose a lot of oil down the stem.