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CVH o.k to run on unleaded???? Advice required please.


retrogeezer

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This Escort I've just bought was built in 1984 and apparently only engines built 85 onwards could run unleaded with no valve damage.A couple of other sites on the t'internet say that it makes no difference, they have had CVH engines from all years and they are all the same i.e no change in hardened valves/seats etc.Anyone had personal experience of this? And should I run it on normal unleaded/super unleaded or should I get some additive?

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Get some FHVBC approved additive and bosh that in with 95RON unleaded - I used to do this with my old Opels. Castrol Valvemaster rings a bell. Probably best not to take the risk with just slopping in unleaded, although if you're not using it much and not revving the bejesus out of it, the lead "memory effect" might still see you right. That said, it's a long time now since 4 star (or even LRP) was freely available.

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I ran my wifes T reg (78) Fiasco ffor about 10K miles on unleaded without any issues at all. It was only terminal grott that signed its death warrant. It was a LC engine though, so that may have had some bearing on the running as it was designed for 2 star petrol.

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From memory the Haynes manual says that pre 85 "hemi head" CVH motors can run UL if the letters LPG are cast into the cyl head. I have run early 80s Fords without even thinking about the lack of lead in the fuel! I guess I didn't once worry about it because in the back of my mind I knew that if the worst happened I could always lob in a late 80s leanburn XR2 engine with the hardened valve seats. dont think you can swap leanburn head with the hemi tho as the pistons are shaped differently and would probably foul the valves, if not then the CR would doubtless be all to pot.

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Yep - I can't see LPG on the head anywhere but not really sure where it should be stamped. There is a small flate plate with C82 or something on it.Anyway, this is what I found from a google search so I don't really think I need to worry too much, just wondered if someone had run an 80-84 engine continuously on unleaded really.

We've just been through this at length for someone else but just to re-iterate.The official advice is what ford offer. The practical advice is this: All CVHengines have adequate seat inserts to run unleaded. There was never any changeto the valve or guide spec. I have seen no major change in seat inserts between1980 and 1989. They all cut the same on the valve seat machine and they alllast perfectly well in road use. Some heads I see have bronze exhaust seatinserts - they can be found in any year of head - no particular pattern to itre make or year of vehicle.Use unleaded and maybe knock the timing back a degree or two if it pinks.Otherwise just don't worry.Dave Baker at Puma Race Engines (London - England) - specialist flowdevelopment and engine work.

and:

However imho any CVH will be unleaded safe as it's a ally head therefore would in theory have hardened valve seats or the valves would just beat the sh!t out of the head casting. Exactly what i've said every time this thread has popped up. Not like my opinion counts for sh!t, but I was told this by the guy who runs RPM who do lots of CVH head work, and he writes for Track and Race Car...so I think he'd know!!!

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