Fuel Additive

[d_harris]

At the moment I am relying on 'lead memory' with the trav but would rather be using the correct additive.

So is it valvemaster/valvemaster plus I should be looking for?

[IaininTenbury]

Whatever you want really. I find Zero Lead (Morris Oil product) to be one of the most economical to buy. Look at how much you get and how much you need per tankfull they're all different. Supply is also an issue, if you can get Valvemaster at your local shop it may be better for you to use that.
Its not recomended to change between different types - some of the active ingredients aren't compatable, though I'd imagine a tank full of untreated fuel between different types and you'll be ok.

As an experiment I ran my convertible on 'lead memory' ever since 4star went out and not had a problem. Its done the JOGLE 3 times and been to Essen Classic Car show in Germany once and the top end seems fine. Crankshaft bearings were sounding a bit tired so I changed the engine last week for the Roses Run, but until then it still pulled well.
I worked on the theory that if the valve seats did give trouble, then I'd take the head off and get it converted but up until then I may as well use it.

Older cars with sidevalve engines and more complex engines, I run on Zero Lead just to be on the safe side....

[grumpygrandad]

use valve master plus ,,grandad

[bmcecosse]

There really is no need for anything! Just set the exhaust gaps to 15 thou and keep an eye on them. If they start to close up, then re-adjust them ! I haven't used any additives for the whole 8 years i've had my car - no problems at all - not even gap closing. If you really feel strongly about using an additive - then the only one worth worrying about is Tetra-boost ( http://tetraboost.com/) which is the ONLY one with tetra-ethyl lead in it and therefore replicates genuine 4 star if added to normal unleaded fuel. The others are [Moderated - due to breach of T&Cs. Ray.]. But really - you don't need anything - just run it on unleaded and keep a weather eye on the exhaust valve gaps!

[IaininTenbury]

Quite. Unless you're doing 1000s of hard motorway miles per year, just run it. Spare heads are plentiful if the worst happens and having 4 hardened valve seats fitted at an engineering shop is cheap enough.
As I said I only bother with additives for older / more complex / expensive engines such as Hudson straight 8 sidevalve / Wolseley 6 OHC etc.

If you're happier using an additive, any of the brands that passed the FHVC test a few years ago will do the job or as bmcecosse says, use tetraboost and give it some real lead. It all comes down to price and availability. Look at how much you get in the bottle, and how much you need for a tank full and do the sums. Cheapest can may not be the cheapest to use.

[IaininTenbury]

Quick web search gives
Castrol Valvemaster at £10 per 150ml treats 250 litres =25p per litre
Morris Superblend Zero Lead at £7.00 250ml treats 150 litres = 21p per litre
So same sort of thing really. I expect both would be cheaper if you buy in bulk and both have a good reputation. Both are phosphoric based too so are compatable with each other.

[rayofleamington]

Castrol Valvemaster at £10 per 150ml treats 250 litres =

???
that works out to 4p a litre!

You used to be able to buy it mail order from Castrol - when I last looked the one without octane booster was £6 making just over 2p a litre.

[alanworland]

I have used Valvemaster since I have been unable to obtain 4 star as I wish to avoid the dreaded valve seat recession!
Has any one experienced this problem with the sidevalve engine by not using an additive?

[bmcecosse]

Sidevalve engine was designed in the days of 'Pool' petrol - I doubt it had lead tetra-ethyl in it! So really - it shoudn't need anything. But - I grant you if it did go wrong in a side valve it would not be easy to fix - so may be worth the slight cost to prevent sleepless nights. Still think if adding anything (and I don't) that Tetraboost would be the one to use. It has real tetra-ethyl lead in it!

[Matt]

Valvemaster comes in 250ml ;)

[MikeNash]

Erm,
I'm not sure your right here, bmc. I think you'll find that some pool petrol was so poor that it was leaded up to the eyeballs just to get it to the low (84?) octane required then.

BUT, like you I agree that additive use is questionable. I drove my Trav for some 15,000 miles without additive with the intention of replacing the head anyway, and I wound up WILLING it to die just so I could justify the change. If you're hard up, do as bmc suggests. Regards, MikeN.

[bmcecosse]

MN - you may well be right - but I thought I had read that lead additive in petrol was post war thing.

[MikeNash]

Exactly! Pool petrol was that "pooled" for domestic use through middle and end of the war and on through rationing period until (I think) the early 50s. (We're talking of World War 2 here, don't forget!) MikeN.

[IaininTenbury]

Ok forget that earlier post!

Zero lead is as follows from one supplier:

Size: 500ml
Pack size: each
Price: £7.38

and Valvemaster is:

Product Name: CASTROL VALVEMASTER - 250ml
O.E. Part No: -
Alternate PartNo: -
Application: ADDITIVE
Your Price (Exc VAT): £7.95

Cant find the site where I picked up the earlier info from... Obviously rubbish.
As you can see, I rarely use the stuff myself. Certainly not in Minors which is what I use for most of my mileage.

[IaininTenbury]

I thought lead in petrol was more of a '30s thing. Earlier cars shouldn't need it, but mass produced 30s cars onwards were certainly designed to use leaded petrol. A quick web search found this:

"In 1922, an American called Thomas Midgely (who also invented CFCs) found that if tetraethyl lead, Pb(CH2CH3)4, was put into petrol, particles of lead and lead oxide PbO are formed on combustion. This helps the petrol to burn more slowly and smoothly, preventing knocking and giving higher"

[rayofleamington]

I thought lead in petrol was more of a '30s thing. Earlier cars shouldn't need it,

I didn't think pre-30's cars were expected to do tens of thousands of miles without needing an engine rebuild anyway?

It always makes me chuckle to see the high speed endurance testing of the early Minor 1000s in the mid 50's - they ran flat out for 10,000 miles (on the German autobahns) expecting some problems then had to do another 10,000 because the engine was barely worn!
Expectations were certainly not that high...

[bmcecosse]

Well found Iain - that's in the States I guess - dunno when it would spread to the UK though, and be put into general use.

[MikeNash]

Re octanes, found this in "Carburation", three volumes published in 1963 by C.H. Fisher.

"Prior to the commencement of the 1939-45 war the average octrane number of the cheaper brands of motor spirit was of the order of 70, while the better quality was in the region of 80. During the war, however, special fuels used in some of the higly supercharged aircraft engines were rated as high as 120 and 130.
For some years after the war, the only pump fuel available for road vehicles in this country was the so-called Regular (generally known as "Pool"). This had an octane number in the region of 72 (Resarch) [ie the test method]. In 1953 premium fuels were introduced, with octanes around the 90 mark, but the lower rating regular fuels were retained , being sold at a lower price." Regards, MikeN.

PS I wonder if this will trigger bmceccosse's 10000th posting?

[alex_holden]

How did 2 and 4 star petrol fit in with this?

[MarkyB]

I seem to remember 5 star was 100 octane.
Not so sure about 2 star 95? 93?