Ive been having an intermitent rattle/knock/pinking sound, seems to happen when warm and on light throttle.
I noticed today that when it happens and i come off the throttle there was a puff of blue smoke, pretty large to be fair.
Im worried it could be the rings?

Its a 1.6 focus 2003 114k miles.

 

Update -

Did a compression test today and the results where -

1 - 158psi
2 - 151psi
3 - 121psi
4 - 178psi

Seems a bit all over the place but seems No. 3 is the issue. I just now need to try and find out if it's top or bottom end where the problems Lies...

 

Could be a burnt valve and worn guide on that cylinder, you need to do a cylinder leakage test really to be sure

 

not uncommon for these engines to wear the stem seals, I have had 2 of these engines in a focus and have both used oil.

 

Well believe it or not i (sceptically) ran an engine flush through on the weekend and re-checked the compression it now reads -

1 - 180
2 - 175
3 - 181
4 - 173

Weird but if its worked im happy!

The only issue i still have is that there is a very loud clattering noise when im at between 1500 - 2000 rpm on light throttle, its driving me insane and i dont know what to do, i would really appreiate the help

Thank you for your replys so far

 

Had this on my rs2000 and the rattle was the cam followers.

 

Could well be, how would i tell and if so whats the fix?

 

Unless this is actually 'pinking' although I thought this occurred under load?

 

Had the smoke appear again yesterday, always seems to do it while I'm going down hill.
I wasn't touching the throttle at all and as soon as I do I get a cloud of smoke behind me.....any ideas before I go down the replacement engine route?