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CVH oil / coolant guide 2019 update

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Thought i would make a small guide on engine oils and coolants for CVH engines for you all, the same questions get asked over and over.

I do not claim to be a professional expert, but i have been studying on this on my own, for more than 3 years now, reading lots of literature on engine lubrication and cooling.

I do not write this with the intention of this being some sort of bible, just something to guide you based on my knowldege of these subjects.


Some people might say you can run classic cars like Escorts and Fiestas on any oil you like, wrong!

The main reason for that statement being wrong is called :

( ZDDP )

Zddp, Zddp is a molecule or compound or whatever you want to call it of Zinc and Phosphorous.

Zddp does one main thing in engine oil : it protects the flat tappets and cams in older engines like the CVH from wear.

The way it works is the Phosphorous reacts chemically in areas where there is high friction and heat inside an engine, and the Zinc which is attached to the same molecule forms a sacrificial protective layer between those parts that acts like a microscopic cushion and keeps them from wearing.

The contact between the camshaft lobes and their respective tappets are the part of the engine by far with the most friction inside an engine, the pressure in small spots between the cam lobe and its tapet can exceed 100.000 PSI!! yes, one hundred thousand pounds.

In the CVH this is even more critical due to the CVH's extrmely stiff valve springs, which produce 220lbs of pressure at full valve lift, these high valve spring pressures combined with the CVH's not so good valvetrain oiling system, and possible neglect in terms of oil changes over the years, leads to the common cam and tappet wear problems the CVH is known for, and the nasty rattling that goes with it.

So what is the matter with Zddp?
Zddp used to be added in engine oil in generous amounts, between 1000 and 1400 parts per million during the 70s and 80s.

However in the 90s it was found that Zinc was damaging to catalytic converters, so for the past 20+ years the amount of it in most oil has been getting lower and lower.

Modern engines don't need Zinc almost at all, because the camshafts are roller type with low friction.

We are at a point now where most oils contain between 800 and 900 parts per million of Zinc, some as little as 600, 1000 is acceptable for our engines, but 800 or 600 are far too little.

Over the last years more and more classic cars are reporting issues with camshsaft and tappet wear due to this.

----------- Viscosity : -----------------

The CVH was designed in an era where 20W-50 was almost universally used, however the CVH being an overhead cam engine with hydraulic tappets, it needs a thinner oil that will get to the top of the engine fast enough in cold temperatures but will also keep the tappets pumped up and working properly when hot.

Because of this a 10W-40 Semi-synthetic oil or 15W-40 Mineral oil is the best choice for you run of the mill CVH that is sued on the street.

if you have an engine that is old, and leaks or uses a lot of oil, you could run 20W-50, as long as you are very gentle when the engine is warming up.

-------- RS Turbo Escort / Fiesta engines : -------------

RS Turbos need a more specific oil choice, these engines run very hot and are usually driven hard.

If your engine is standard and you don't beat on it too hard, you can get away with a 10W-40 Semi synthetic or full synthetic oil.

If your engine has somewhat more power than standard and you drive it hard, you shoud probably use a 5W-50, 10W-50 or 15W-50 full synthetic oil.

For really crazy builds running say +250hp and lots of boost, 10W-60 Full synthetic would be a good option if your oil temps are very high, 10W-50 or 15W-50 if you they're not so high.

-- Here is a list of oils that are known to have high Zinc and would be good for CVHs --

For standard N/A CVH engines :

1 - Comma X-Flow Type XS 10W-40 ( Semi Synthetic, 1100ppm Zinc )
https://www.amazon.co.uk/Comma-XFXS5L-X-Flow-10W40-Litre/dp/B00DYTO5VE/ref=sr_1_2?s=automotive&ie=UTF8&qid=1536228284&sr= 1-2&keywords=comma+xflow+10w40

2 - Comma X-Flow Type MF 15W-40 ( Mineral, same Zinc as former )

3- Classic Oils Hot Hatch 10W-40 ( 1300ppm Zinc )

4 - Morris Multivis 10W-40,

5 - Millers CSS 10W-40 :

- For Turbo CVH engines :

1 - Millers CFS 10W-40 Full syn.

2 - Valvoline VR1 5W-50 Full syn.

4 - Mobil 1 5W-50 FS-X2 full syn.

5 - Millers CFS 10W-60 Syll syn.

6 - Mobil 1 10W-60 Full syn.

-------- COOLANTS --------

If you have a copper type original radiator, use Comma Super Coldmaster, change every 2-3 years


If you have a modern alloy or aluminium / plastic radiator, use Comma G40, change every 4-5 years.


Keep in mind when buying concentrate the coolant has to be mixed in equal parts with distilled water ( 40 / 60 would be ok too ) 

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