Am I right in thinking the later type X-flows
had unleaded heads ?
If yes how do you tell the difference ?
Thanks.

No crossflows have unleaded heads , the valencia engine fitted to fiestas etc that was similiar, did on the later models, but I dont think they are interchangable.
I have a crossflow and use castrol valvemaster additive , it is a lead replacement and octane booster and appears to work well .
Paul

I had my 1977 1300 converted to unleaded, cost about £200 including some other work (porting etc..)if that's any help.

Cheers

I had mine converted to unleaded. I now run it on super unleaded most of the time, so that I can run the standard ignition timing, but on occasion when I've only been able to get standard unleaded I've not really noticed any problems.

David

I'll second the castrol valvemaster plus, works very well. Nearly 10k on my car with no head problems. Can use normal unleaded too as its an octane booster.

Thank you all for your answers, its just I have been told the heads of the ford Ka.
are unleaded and they are /were the same as the old Escort heads.

It's a long time since I came on here - got fed up with mis information and advice being offered by people who knew dangerously little to those who genuinely needed specific advice.

Anyway I'm back for a bit anyway, at least whilst I recover from pneumonia!

LUKEFAB, you should understand that the generic term X'Flow refers only to the engine type fitted in Mk1 & 2 Escorts, early cortinas, some capris etc up to about 1979. When someone says "1600 Crossflow", it is to this engine type they are refering.

None of these were manufactured with hardened valve seats and suitable for unleaded fuel (at least without running an additive).

You are confusing these to the much later HCS type engine fitted to Fiestas and Escorts (1100 and 1300) from about 1987. The ones without a distributor, just a coil pack bolted to the rear of the engine. All but the earliest of these (for about 1 year I recall) were unleaded friendly. The same/similar basic engine was fitted in the later Ford KA. There is no similarity or interchangability with the X'Flow

Its nice to see you back on here David with some sound advice as usual. Welcome back.

David,
Thank you for putting me right.
Its the same old story, some bloke in the pub knows some one, whose grandad's brother, swears blind you can use the Ford Ka head on the old Escort crossflow.
So thank you again.

P. S. Hope you get better soon.

I had mine converted years ago by Vulcan.

early fiesta had crossflow.

none as far as I know had hardened seats.

very early crossflows had chamered heads (this shorter valves) which apparently are a better design.