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Crossflow - unleaded fuel?
Mike Wood - 23/11/24 at 05:27 AM

Hi

I am new to Ford Crossflow engines and am planning to initially fit a standard 1300cc Escort Mk2 engine to my Locost project - would you expect to need to get the cylinder head modified with hardened valves/valve stems to run unleaded fuel or at the very least run an additive such as Castrol Valvemaster in the fuel?

And I guess the timing info in an old Haynes manual would be subject to tweaking too?

It is funny to ask this question now as Unleaded has been around so long, the short-lived Lead Replacement Fuel (LRP) long-gone and E5 and E10 here. I remember there used to be a network of a few garages still selling leaded 4 star - Pace Petroleum?.

Cheers
Mike

[Edited on 23/11/24 by Mike Wood]

cliftyhanger - 23/11/24 at 07:53 AM

I have been invo;ved with Triumphs for years, with engines from the same era as the crossflow.
If the head has not had seats recut etc, it is likely they have "lead memory" and will be OK, especially with some lead replacement stuff added. Teh concensus is that IF the head starts to suffer valve seat recession, then get the seats done.
I am currently pondering my early 60s 6 cylinder engine. It has a low CR and very very mild cam. I intend to swap to a later cam and skim the head to raise the CR. Do I fork out for valve seats at the same time?? I ought to get a quote....

Mike Wood - 23/11/24 at 08:54 AM

quote:
Originally posted by cliftyhanger
I have been invo;ved with Triumphs for years, with engines from the same era as the crossflow.
If the head has not had seats recut etc, it is likely they have "lead memory" and will be OK, especially with some lead replacement stuff added. Teh concensus is that IF the head starts to suffer valve seat recession, then get the seats done.
I am currently pondering my early 60s 6 cylinder engine. It has a low CR and very very mild cam. I intend to swap to a later cam and skim the head to raise the CR. Do I fork out for valve seats at the same time?? I ought to get a quote....


Thanks, that was my thinking too. I am more used to A Series engines in Minis and Sprites where the same thoughts on lead memory are applied with use of an additive and then if you go to refurb or modify the head for other reasons - burnt valve is a favourite for a standard engine and road car, or perhaps a warped head needing a skim, or wanting to get the head flowing better with changes to the combustion chamber and perhaps larger valves as part of other engine mods - then take the opportunity to sort out the valves to suit unleaded.

gremlin1234 - 24/11/24 at 05:41 PM

ok Ill try again, my message seemed to be double posted, so I removed one, and now its gone.

basically, I was saying that doing the work after it fails is about the same amount of work as doing it in advance,
but I would recommend doing it:
before say a 2000 mile journey,
or if the head is off for any other reason.

[Edited on 25/11/24 by gremlin1234]