Standard new AEA434 exhaust valves work fine in a road smallbore motor, with hardened seats.
It's the head that wears, not the valves.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

ah ok. I'll keep that in mind. I've just heard of instances of valves burning, and most engine builders recomend going to stainless for unleaded conversions...

For what it's worth, I used BP ultimate and flashlube valve saver everytime I filled up - drove for 5+ years doing this and had no problems.

Had head rebuilt a few years back (due to valve guides which had always been worn) and converted to unleaded at same time - but at time of rebuild I was told there was no evidence of damage to valves from use of unleaded.

Unless you desperately want to install an unleaded head, I don't see why you couldn't just stick with the valve saver fluid (I buy the Flashlube in the 1L bottles so it works out at around 1c / litre). When the head eventually needs rebuilding due to general wear, have it converted then.

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Dave - 64 Nurburg White Morris 850 & 67 Morris Mini Deluxe (Bro's Car)
Previous Rides - 62 Morris 850 (Sold '03 - Now 'Lulu-62') & 76 Clubman S (Sold '99 - SFW-863)
+ Too many other classics

Once the head is converted:
1. Do you still run on premium unleaded? and,
2. Is it still better to add the valve saver anyway? or would it be a waste of money?
or,
is it better to not convert the head and continue running premium with valve saver even if you are rebuilding the engine? Can the hardened valve seats cause their own set of problems.

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Flute - 68 MK I Cooper S
Member: VMCI #2474
Member: International Mini Model Collectors Club

I believe you still need to use premium, as it has the higher octane rating - depending on how your engine is tuned regular unleaded can cause knocking/pinging/rough running because the octane level is lower than what super/leaded used to be.

I still add the valve saver fluid - and I know some of you out there will probably blast me for this (why are you still using it if you have an unleaded head? etc etc) but as far as I can see any extra upper cylinder lube can't hurt. Besides, the fuel bill for a standard 850 that gets driven once a week is not very much, even when paying for PULP and extra flashlube...

As for whether to rebuild the head or not, personally I would be doing the conversion if you are rebuilding the motor - but it depends on how worn it is - only negative I can see is that if it does wear and you have to replace it down the track, it would have been cheaper to have done it while the rest of the engine was apart.

You should probably get a few other opinions on this - it will also depend on your budget - but if the engine was not blowing smoke after long downhill runs and the engine still had good compression, I don't see why the existing head wouldn't last for several more years on PULP and plenty of valve saver additive.

On the other '62 850 we had for 4 years, we never touched the head and had no problems with just using the additive - that was a daily driver too.

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Dave - 64 Nurburg White Morris 850 & 67 Morris Mini Deluxe (Bro's Car)
Previous Rides - 62 Morris 850 (Sold '03 - Now 'Lulu-62') & 76 Clubman S (Sold '99 - SFW-863)
+ Too many other classics

That's because you didn't follow the instructions.

Thanks ddk848, very helpful. I will discuss this more with my mini mechanic. I am due for a full rebuild on my daily driver and the more I know the better.

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Flute - 68 MK I Cooper S
Member: VMCI #2474
Member: International Mini Model Collectors Club

What instructions???
I set out to prove that, if you drive a Mini `normally' (ie rev it a bit and use the available performance) with a reconditioned stock iron head using unleaded fuel (it was 95, by the way) without additives, the `seats' in the head will wear. And, they did.
Morris 1100 trots his antique 1100 out to `prove' you don't need any additives, but it never gets a decent rev and the lead encrusted valves have never been out of it.

OK, we may as well continue on with myths and legends as we're now into it, so who is running the snakeoil canisters, eg Fuelstar that `put tin into the fuel'... and have you ever removed the head for a looksee after considerable miles?
More importantly, have any been weighed before and after?

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

And it works.

Why not try the same experiment without reconditioning the head first and see how long it lasts. There is no point in removing all the hard metal from the valve seats and then say that the reason if failed was lack of an additive.

[/quote]Why not try the same experiment without reconditioning the head first and see how long it lasts. There is no point in removing all the hard metal from the valve seats and then say that the reason if failed was lack of an additive. [/quote]

Your on the ball there M1100. Most cast iron heads (eg Mini, old Holden etc) have electrohardened valve seats from the factory. The more times the head has been reco'ed over the years the more the cast iron valve seats get thinner & softer. The advent of ULP only, started a lot of burnt out valves & valve seats. I have reco'd hundreds of cast iron heads and i agree, a original untouched mini head will last longer on ULP than one that has had its valve seats cut. Valve guides also wear, when a head is fitted with inserts, the valve guides need to be K lined as well.

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Have a Nice Day.
If already having a nice day please disregard.

Point 1.
Point taken with the lead deposits in the head, but it's pretty hard to recondition a head properly without cutting the valve seats. By the time the valves are burned the `seat' is neither round, or anywhere near the right angle.
Point 2.
I have experienced real `electrohardened valve seats', Mercruiser 4 cylinder marine heads have this done when new. They have concentric heat temper marks around the seat and are hard as buggery. These are so damned hard that you cannot machine them with hand cutters at all. Unlike either old grey Holden heads or A series ones.... yes, years ago I have recut both these by hand in `untouched from new' motors.
Maybe you are talking about later Holden heads (V6 or V8 maybe?)

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yes most "red" Holden engines inc V8. New V6 heads you can see the electrohardening around the valve seats. Not sure what the "grey" heads had done to them & i doubt you would find a untouched grey motor head these days. I do have a new 12G940 head in the shed, ill go and have a look to see what it has.

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Have a Nice Day.
If already having a nice day please disregard.

Here'tis. Cant tell cos its got its protective wax all over it still. I do remember we had a few "injected" new mini bare heads at NMP a few years ago and i can remember them having hardened valve seats.

_________________
Have a Nice Day.
If already having a nice day please disregard.

Looks standard to me, have the seats been machined or ground? They look machined... same as the intakes.
I've had and seen lots of 940 heads over the years but never found one with electrohardening.
The hard ones (late Rover) all have inserts.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.