Redex Lead?

Hi Ian,

My local firm who recondition my Scimitar heads for me say as a rule of thumb that the reliant alloy heads, since they already have an insert in them, ought to be OK on green petrol. I've been running my Rebel 700 estate on a mixture, one tank full of LRP, one tank full of green. So far - no problems (but only a few hundred miles to judge it by). I'd suggest you try the redex. If the tappets start closing up you'll only have to replace an insert or two, not scrap the head.

I've been running an unconverted Scimitar for 40,000 miles now on either LRP, or Wynn's 4-star additive with green petrol. No sign of tappets closing up, and the Wynn's hasn't got approval either. IIRC only Millers VSP and Castrol Valvemaster made it through the tests.

Adrian_S

PS when are you going to drive that Rebel saloon down to Oxford for me to buy it ?

For some reason, Reliant are quite emphatic that my tricycle needs leaded petrol, although I agree with you and your reconditioners. Maybe it's to do with non-head bits: I'm told that some seals don't like the benzene in unleaded.

Aaaaaaaarrrrrrgggghhhh. It took me six months to get the bloody head off when the gasket went. Well, OK, quite a lot of that time was spent thinking "what the hell do I do now", but it's not my favourite job. Though the Reliant engine is absolutely lovely!

Oops. I'm afraid that one's gone ... I could do you a very nice Rebel estate in kit form ... for a very, very reasonable price!

Ian

Dam - snipped too much - yes, there was a spate og rubber hoses and diaphragm failures when unleaded first appeared, and I think I've just got exactly that in the Rebel now - it's dribbling petrol from the accelerator pump discharge tube at idle. Howver, most repair kits now are using a better grade neoprene, and modern rubber fuel hose is obviously OK to use.

It took me a few hours to get the head off my Rebel. I had to use stud-extractors to wind some cylinder head studs out of the block and head together. Had no-one heard of copperslip before the 90's ?

And yes, it is a "classic" engine in superlight form.

No thanks, one estate is enough for me. I want a saloon now :)

Adrian_S

I think they're just being prudent - to themselves. If they say their engine is OK on unleaded then they lay themselves open to claims if something goes wrong for whatever reason. So far safer to say it isn't.

Exactly the same applies to early Rover V-8s. Now if you ignoring octane ratings and compression ratios, it comes down to the hardness of the valves and seat inserts.

Rover were adamant that early engines couldn't be run on unleaded. But a metallurgist member of the P6 club actually tested the hardness of the valves and seats on an early engine and they were exactly on the borderline, which meant that short of running at full power for sustained periods - unlikely given the 120 mph+ top speed, they'd be fine for even hard use.

I had a P6 3500S and used to drive it very hard using Super Unleaded - at the time it was a higher octane than 4 star leaded and it ran better. No problems at all.

Do you know the spec of the valves and seat inserts? They will have an EN number. I've got the lists of what is and isn't suitable (only as a rough guide) somewhere.

: Do you know the spec of the valves and seat inserts? They will have an EN : number. I've got the lists of what is and isn't suitable (only as a rough : guide) somewhere.

Unfortunately not. But I do have access to a Vickers hardness testing machine, so some experimentation on a spare head may be in order ...

Ian