Why do CVH heads always gunk up so much?

Is it because people use crap oil and don't change it often enough?

Or is it a breather problem?

Just re-done a 1400 cvh head after the cambelt snapped and bent a couple of valves. Only done 89k but there was so much gunk under the rocker cover. All the other cvhs i've ever worked on have been the same.

In comparison, a zetec head of the same mileage will be clean as a whistle?

Any one ever got to the bottom of this?

 

My CVH was 75k old when i replaced the cylinder head with a stage 3 head

Before that I took the std head off and it was very clean. Light brown colouring on the metal but i believe that comes from using mineral oil at some point in the cars life. No gunk. The car had had reguylar servicing.

Then the new head went on and it was subject to my servicing standards which were very high. Regular oi changes always full synthetic and use engine flush just as I changed the oil.

When the head was removed at 160k or whatever the car made it to, it was steal cast clean and not a drop of gunk in sight.

So regular servicing is the key

RW

 

zetecs in general run fully synth dont they? so probably get away with the service intervals much better.

 

Apparently the oil control rings going hard is a comon problem with the CVH and this causes them to gas and get gunged up.

But as Steven said, if the engine is serviced properly and looked after, there shouldn't be a problem.

Kirk

 

Pretty sure Zetec E, the stuff that Ford sell is semi synth.

 

Ok, so it seems pretty oil/service dependant.....

So what is the best oil for a CVH?

 

Do you mean the the valve stem seals?

 

My findings on my S2 are pretty much in line with Stevo RW. Prior to my Stage 3 head the car had been on mineral oil from Ford and there was a light brown colour to the metal but other than that there was no gunk. After alot of miles on the stage 3 head using Mobil1 it was like new.

However.........my first car was a 1.4CVH Orion and I thrashed it from cold, hardly ever changed the oil, made short journeys etc. The rocker cover was coated with a very thick layer of hardened crap. Both breather hoses were blocked solid with what appeared to be an almost coal like substance - the guy at the garage said he'd never seen anything like it. I learnt to look after my car after that!

 

Mine has never had gunk - cold running contributes to gunk

 

Agree with RW as well (dont laugh Steven ) its regular servicing that keeps them good. I had to take the head off my previous S2 when I'd not long got it and it was in perfect condition at 98k all down to regular oil changes and servicing as well as letting it heat up, cool down properly

 

My XR2 engine with regular oil changes

 

as said regular oil changes is the key

 

my xr2, after i got it from my sis (no oil changes etc) was FULL of gunk, but my cabriolet and especially my RST looks good, must be to do with servicing it well

 

as most of the other guys have said regular oil
and filter changes it also helps to give the engine
a flush with diesel , when doing an oil change just
drain half the oil out then a about 2 litres of diesel
into your engine and run it for about 15 minutes
before changing old oil and filter
that will keep all the breathers clear and your engine
sweet and you should use mobil 1 oil its quite expensive
@ £35 for 4 litres but is the best oil for the job
hope this helps mate

 

is that my old 1???

 

noooooooooooooooooo

 

ive owned loads of cvh and the only thing that gunks them up is not changing the oil its as simple as that i run semi synthetic magnetec and if changed regulary the head will go a nice gold colour

andy

 

Never had any problem with gunking up.

Cheers

Steve

 

I meant the lower piston rings, although the valve stem seals are a problem as well apparently.

Kirk