I know there are a lot of threads on this, and i've read them all (i think!), but there's one question (edit: okay, 2) nagging at me that i seem to be unable to find an answer to and i hope somebody can explain ...

What's the difference, besides colour, between a black and silver top? Also, i've noticed some of these cam covers have their oil caps right at what would be the back of the engine bay in a sierra, whereas other have them closer to the pulleys. Why's that? Closer to the front would obviously make filling easier, so: Is it important?

I reckon i can complete the conversion, and i'm sure it'll be facinating, but having never owned a zetec engine i'd prefer to know what's what. Whatever - something's gotta be done, i don't think i can scrape the old CVH through anoither emissions test.

Can someone knowledgable help me out?

Much thanks in advance.

 

Blacktop head has better flow also blacktop block is better than a silvertop, in NA form differences are minimal however when you go turbo route the differences come about thats why when uou look more silvertops go bang than blacktops which is down to oil pump failure caused by crank flex. Oil filling doesnt really matter other than obviously being easier to fill being near pulleys

 

silvertops you can use escort or fiesta waterpumps which turn clockwise blacktop you got to use a pulley system for reversing waterpump

 

Can you please stop giving duff information in threads?
Where did you get the idea that Silvertops are the ones that break and Blacktops don't? Also the oil pump failures are believed to be down to resonance at high rpm, and can occur in both the Silver and the Black tops!

 

to answer one of your questions the silvertop has a cast alloy rocker cover where as the blacktops are plastic.. silvertops are early engines,ranging from early to mid 90's where as the blacktops are made from then on. blacktops have solid lifters where as silvertops are hydraulic. blacktops also have a longer con rod/shorter piston. depending on what you intend to use the engine for blacktops are more readily available and can still be bought new.

 

its not just high rpm's that kill the oil pump's the n/a zetec's can rev to 8.5k on the standard oil pump and have no problems

 

You can't just say the blacktop block is BETTER. , why is it better? ???

 

Wrong, on just about everything you've written.

Large differences on N/A, Silvertops aren't suited to high revving because of the hydraulic lifters.
Oil pump failures are pot luck, as has been said, it's generally believed to be the resonance created by high revs.


IIRC, Silvertops were first introduced in mk5 Escorts, RS1800 Fiestas and mk1 Mondeos. Blacktops were introduced with the Focus I think. Not 100% on that though!

 

silvertops better to turbo than blacktops in my opinion

 

ps barny chicken soup lol

 

Okay, thanks for the replies, and sorry to cause such a kerfuffle. Clearly there are pro's and con's to both, so I'd better explain my intention more completely...

What it is, the current CVH is burning oil, and my suspicion is the lambda is becomming poluted, and that's why the emissions test was so bloody difficult to pass last year. I scraped it through, but only just.

So, yeah, i could replace the rings, etc. But if i'm gonna do all that i'd rather do it to a newer engine that hasn't done 200,000 miles, and i reckon the zetec is the way to go. I'm not looking at massive power, frankly 120bhp in something that isn't cluttered up with power steering, air-con, etc will be adeqiately fast for my needs. High revs aren't important.

So why not just buy a mondeo or similar? Frankly, payload. There's not much i can't throw into the old sierra and it'll just carry it happily. I love the flat-bed it turns into when i put the rear seats down, sheesh, it's practically a pick-up with a roof on. There's a lot to like about the old girl.

What i do want is fuel economy, so fuel injection is a must. Not bothered about a turbo. Not quite sure how i'll go about connecting the engine management computer, i'm assuming i'll need the one from the donar zetec car and fudge it in somehow ... i'll cross that bridge when i get to it.

Not keen on the idea of a plastic rocker cover, either.

Can anyone expand on this? Thanks guys.

 

Blacktop zetec mainly use a plastic cover, they are fine, but you could find one of the early Ali blacktop rocker cover,
By the sounds of it, you will be ok with either type of zetec,
Most things have been covered already,
As for black top blocks being stronger, I will clear it up, later engines came with a two piece sump (girdle) which ford said was designed to stop block flex, any how that boring,
Get a zetec and pop it in, wat about mega squirt?

 

with regards to your conversion, you'll need to:

make one side engine mount (cvh mount will fit other side)

fabricate or buy (£200!!!) a water rail to relocate the thermostat OR modify the bulkhead to allow clearance for the original item.

use cvh sump and pickup pipe if using a silvertop, on a blacktop, they need modifying a little to fit correctly.

you can use the sierra flywheel and clutch, but will need an alternative trigger wheel for the management system (the cvh front pulley can be used if you space the other pulleys out a little)

you will need an efi type fuel tank, either cosworth style with external pump, or late efi style with an internal pump.

wiring is easy really, you should only have around 5 wires to connect the engine into the car. if using a late mondeo loom, you'll need to keep the key strapped to the immobiliser.

as you're using a standard engine, both early and late will be fine, but early is probably the easiest to fit.