Zetec/CVH hybrid engine for the Quantum

MOT passed on 24th July 2001, The engine has now run for 8000 miles including a almost non stop John O Groats to Lands End run in 20 hours.

Now been rolling road tested at Owen Developments, running with 10Psi boost the power output was 226bhp at the wheels, estimated 259 bhp at the engine, 260 ft/lb of torque at 5520rpm.

Block.

The oil return galleys don't line up with the head. 4 of the oil galleys need plugging as they are under coolant holes in the head.
The 4 holes that need plugging are on the bottom in the pictures.
They are highlighted in green in the LH picture.
Luckily the head bolts and oil feed do line up.
The holes have been blanked off with press fitted brass plugs.
The holes aren't drilled at 90 to the block surface unfortunately so the block needs skimming off to make them flush.
When this was done it turned out the block surface varied by about 3 Thou, low around the bores and waterways and high round the edges.

I only found this potential problem area fairly recent when i had the cylinder head off to change the head gasket (which had blown due to the engine running weak).

There is a water passage in the Zetec cylinder block which is very close to the oil way hole in the CVH head gasket, look at the pictures and you can just see the impression of where the gasket has squashed into the hole in the block, it's only about 1.5mm from the edge of the of the oil passage opening in the gasket, nasty.

My fix was to fit a 'O' ring into the hole in the gasket to stop oil pressure reaching as far as the thin section of gasket. The 'O' ring wants to be slightly thicker than the gasket and of a suitable size for the hole in the gasket, mine stayed put in the hole quite happily without popping out. I don't know if this will be a problem on all engines, it may just be the combination of the gasket I've got and where passages are in my block but check them to be sure.

Cylinder head.

The cylinder head doesn't actually need modifying to use it on the ZVH but it makes sense to improve the head to help it match the increased capacity of the larger bottom end.

My head has been modified to pretty much the maximum possible by Dave at Pumaracing but it cost £700 inc.

I think it was worth it, he's done a great job.

First time I've had modified spring seats and valve caps to take the dual springs properly which is more than can be said for Piper kits.

Pistons.

If it's a Turbo CVH that's being converted the Zetec pistons may need replacing depending on the amount of boost you want to run, Burton sell some Accralite pistons specifically for the ZVH conversion.

However, Paul Rye is apparently running a ZVH Turbo  with the original Zetec pistons and 1 Bar boost. The compression ratio with the standard 2.0l Zetec pistons and a standard 55cc CVH turbo or 1600i head works out at 8.6 to 1 which is really too high for a turbo. Initially I'd hoped to reduce this by getting Dave to enlarge the combustion chambers in the head but it's turned out to be too much to gain that way (he got 57cc) so I've skimmed 0.5mm off of the top of the pistons, this drops the compression ratio down to 8.2:1 which is about what I want. Apparently the Zetec pistons skimmed 0.5mm like this are ok up to about 1 bar boost.

These are details of some Accralite 2.0 pistons from Burtons web site, the 1.8 would needs 81mm diameter pistons but these aren't mentioned. These ones cost £450 a set and they come with unmachined 12mm crowns.

	Car/Engine type:	Cyls	Capacity	Bore size	Comp.Ht	Crown	Part No
	Ford CVH/2.0 Zetec conversion	4	1997	85	35	Flat	FZ142

There has also been mention of using Calibra pistons with a 1.8 block bored out to 83.5mm (from 81) giving 1.9 L and also of  using Celica GT4 pistons in a 2.0 block bored out to 85.5mm (from 85) giving 2.1 L

 

Piston Rings.

 

While I had the pistons apart for skimming I checked the ring gaps as Dave was worried that they might be a big tight as standard for a Turbo engine. Probably a good thing he did as the top ring gaps were 10 to 12 thou, lower than the minimum gap specified in the Haynes manual and almost certainly to small for use with a turbo. I machined a groove in a piece of alloy the same size as the bore and used that to hold the ring and act as a guide for a 20 thou thick cutting disc in a mini drill. This gave me a nice ring gap of 25 thou The 2nd and oil ring gaps were fine as they were.

Use a CVH water pump, the Zetec Mondeo one spins the wrong way and the Zetec Fiesta/Escort one is no good as the water pump is driven from the alternator belt which means the pulley on the water pump fouls the side of the engine bay.
I initially didn't want to just drill the block for the CVH waterpump as where the new holes need drilling the block appeared only a few mm thick so I made up an adaptor plate from 2.5mm thick stainless steel with 3x 6mm studs Loctited in to take the CVH water pump.
This method didn't work, the plate distorts too much when the pump is bolted on.
After a well timed email from Clint Gaskin (thanks) and a bit more research I've concluded that I was trying to be too clever and I should just drill and tap the block for the 3 new CVH mounting holes required.
I can still use the adaptor plate I made but without the studs, just holes straight through.
By mounting the pump at an angle I was able to use one of the existing Zetec pump mounting holes, this hole has a M8 to M6 stepped stud fitted. The top left hole one breaks through into the end of the head bolt hole at about 10mm deep, luckily below the end of the bolt.
The bottom left one is only in about 3mm of metal and is the one most likely to give problems.
The bottom right hole I drilled about 10mm deep without breaking though.
A hole the same size as the tapping drill (5mm) in thick lump of steel was used to keep the drill straight, the hole in the steel was then opened out to 6mm and was used to keep the tap straight as well.
I wanted to avoid modifying the CVH water pump if at all possible to make it easy to replace with a standard pump if it fails, I ended up having to remove a small amount of metal to clear the head of one of the plate mounting bolts but it was only a few mins work with a carbide burr in the electric drill.

A CVH cambelt tensioner is used, one from the 1300 CVH, as it's smaller than the 1600 CVH one.
But depending on exactly where the water pump is fitted there may be enough room for the 1600 CVH tensioner..
Needs bolt holes drilling in block using the same method as the water pump, using the thick block of steel to keep the drill and then the tap straight.

Pulleys and spacers.

Top left engine mounting.

The Zetec oil filter comes straight out the rear of the oil pump, a completely different place to the CVH one but at least it won't pour oil all over the driveshaft when you change the filter.
If you are doing this conversion on a Fiesta (maybe Escort as well) I believe you need to replace the Mondeo oil pump with the Fiesta/Escort Zetec one which angles the oil filter in and clears the chassis rail on the side of the engine bay
There's enough room on the Quantum for me to use the Mondeo one.
However the CVH engine has an oil to water heat exchanger fitted between the oil filter and block and that doesn't fit so I'll replace it with a external oil cooler, using a remote oil filter as well.

I'd been told the  sump may have to have a little machining done to give the downpipe a little more clearance but it doesn't need any modding on the Quantum so I'd have thought most Escorts and Fiestas should be ok as well.

The Mondeo has it's crankcase breather outlet on the centre front of the block.
Unfortunately this is direct under the turbo manifold, so I've made a blanking plate up to cover it, including some nice semi CSK allan bolts.
This also means I need 2 new passages into the block, 1 for the Turbo oil drain and 1 to replace blocked crankcase breather.
I was going to drill through the rear of the block to fit a breather outlet where the CVH one was but luckily I didn't as I now want to use a gearbox from an Mk5 Zetec Escort which has the starter at the top rear of the engine. Right where I would have drilled the hole.

Alternator mounting.

Use the CVH alternator mounting bracket, it bolts straight on.
The dipstick does clear it which is good.
This is the overhung alternator bracket, used on most Mk3/4 Escorts, there's also an underhung bracket which is used on most Mk2 Fiestas, this is the one I've used.

The Zetec block has the start of the head bolt threads 14mm below the top of the block as opposed to the CVH head's 3.5mm
As a result the CVH head bolts are now too short.   
The normal head bolt thread engagement on a CVH is ~17mm, using the same bolts on the Zetec block would only give 6mm engagement or 9mm you replaced the 5mm thick CVH washers with 2mm ones.
9mm isn't enough engagement to be sure of not stripping the block threads when tightening the head bolts. Nasty !
I need 145 to 150mm bolts to give me at least 17mm of thread engagement.
The Zetec bolts don't even make it through the head.
I bought some 150mm long HT cap screws, gives me about 25 mm thread engagement in the Zetec block.
Dave has recommended tightening them to 75 lb/ft.

The 1600cvh Bore is a fraction under 80mm, the 1.8 Zetec is 80mm so you can use the 1600CVH head gasket with no problems on the 1.8 ZVH.
Unfortunately the 2.0 Zetec bore is 84 mm so you can't use the CVH head gasket as the edges of the gasket will be exposed and will burn away.
You can use the 2.0 Zetec head gasket but it's oil passage goes of of the edge of the CVH head so it needs the edge of the head built up with weld and the head skimming flat again.
I've found a suitable gasket, thanks to Dave at Pumaracing, a Felpro competition gasket, used on American 2.0 Litre CVH engines.
Felpro part No. 9303PT2 but I believe part No. 9309PT is the same.
86.7mm bore and 1.83mm thick, perfect.

The 1.6 and 1.8 Fiesta/Escort Zetec flywheel takes the same 220mm dia clutches as the 1600 MK4 Escort so any heavy duty clutches for the Escort RST will be fine.
I ordered a Heavy duty AP clutch centre and cover from from R.S Cosworth specialists, a very helpful company and very good prices as well.
N.B I had big problem with this clutch not releasing, more info here on the main Quantum page.

The deep section is in the wrong place on the Mondeo

The thin Spacer plate from between engine & gearbox (different shape). 

Different shape needed to fit the new sump. 

Dipstick & dipstick tube. 

I've actually cut the bracket off of the 1.8 dipstick and made a rather excessive complete new one from aluminum but most ZVH's seem to just have a bit of metal strip between the bracket on the dipstick and the top left exhaust stud.

Flywheel. 

The 2.0 Mondeo one is too big to fit in the CVH gearbox bell housing.
I didn't realise this initially and chucked the one from the 1.8 Zetec I got the sump etc from in the skip down the breakers ARGH !

Got another Fiesta 1.8 Zetec flywheel from Bridges for £25+vat.
The CVH one will fit (with the bolt holes opened out to 11mm) and work but doesn't have the holes on the back (unless you get one from an EFI CVH) for the ECU sensor which I want to use.
I recently been informed that the later Zetec flywheels are thicker than the CVH ones, this possibly only applies to engines with MTX75 gearbox's. 

This is the engine exactly as it came. 

Click on these thumbnails for 1200x1200 pixel images (~320K)

After 29,000 miles no measurable wear.