SD1 Cylinder Heads - do all have hardened valves/seats?

[ricky8664]

I've mentioned in threads elsewhere that I acquired a pair of SD1 cyl heads about 10 years ago. As my plan is to get them overhauled and fit them to my engine (either as it is if I can re-start it or to a rebuilt Bottom end if the pistons remain stuck) I thought it worthwhile checking that what i was sold as SD1 heads were actually that.

Fortunately, both are stamped ERC 0216. This number was used for both carb engines and later EFi models. The latter had cut outs in the inlet manifolds by where the injectors are located. The casting numbers in the EFi heads also seem larger in size than those on my heads.

My pair have nice rectangular inlet holes with rounded corners but no cut outs nor any holes for the injectors. So I assume I have the earlier carb versions. Actually, I'm not certain the heads had the holes for the injectors anyway - they may have been in the EFi plenum/induction manifold - but I/m assuming I have the non EFi heads.

In which case, do all the early ERC 0216 heads have hardened valves/seats? 

[lagain]

No idea, but as they are alloy heads they will have hardened inserts. If there was a problem it would only show itself if you took the car on the motorway and spent all day at 70 mph. However if you have the heads checked they should be able to tell you. Generally alloy heads will need a light skim before fitting back on the engine.

[enigmas]

All Rover V8 heads have hardened seats. As the cylinder head is alloy, hardened seat inserts are fitted. Cast iron cylinder heads prior to the use of unleaded fuel often cut the seats directly into the cast iron of the combustion chamber. Some engines, primarily American V8s from my recollection had the exhaust side induction hardened. It's only the exhaust side that's an issue as obviously it's the side subject to the most intense heat. Exhaust valve material is another issue if you really want to delve into this subject. AFAIK from guys in Oz running P5Bs on LPG and other non-leaded fuels for years on end, there's never been an issue with exhaust valve seat recession.

As an aside, don't fit or run restrictive exhaust systems, as these systems though quiet contain the heat laden exhaust gases right back to the exhaust valve face. Retarded/late or slow ignition timing won't benefit the engine either.

[ricky8664]

My reference to hardened valves/ seats etc was concerning whether the engine would run on unleaded fuel without an anti knock additive using SAD1 heads.

Neither do I intend to convert to LPG. Sorry if I wasn't clear about that.

[enigmas]

My reference to LPG fuel is that it's effects are similar to that of using an unleaded fuel (petrol), not converting your engine to LPG.

Hardened exhaust seats are required for both fuel types. Fortunately Rover cylinder heads and valve seat material suit both of these fuels.

Pre-ignition and or pinging/pinking/knocking (or whatever you want to call the phenomena) is down to fuel octane, compression level, ignition curve design and cylinder head combustion chamber design.

Know what causes it and then configure the engine accordingly to avoid knock.
Good luck with your project.