Additives

[andybeta]

Can anyone whose running a VX engine that has used additives to substitute for the loss of lead give me some pointers as to the better brands for this engine. I've previously not bothered adding any which might have been foolish. Conscience is geting the better of me despite the sodium cooled valves etc. The long term plan is to end up with the head converted to unleaded, but don't want the valves to disintegrate in the meantime. Only done about 25,000 miles on unleaded fuel, now just over 100k in total.

Thanks,

Andybeta

[Hamish]

Millers VSP lead replacement and octane booster is the one I use :wink:
The VX absolutely loves it :twisted:

[Will]

Since you are in the UK, I turn up:
Millers VSP Plus, (manganese)
Millers Oils Ltd. Freephone 0800 281 053
* Red Line Lead Substitute, (sodium)
Delta Oil Ltd. 01476 861 195
* Superblend Zero Lead, (potassium)
Superblend Lubricants Ltd. 0116 291 1700
* Castrol Valvemaster & Valvemaster Plus (phosphorus)
Castrol Ltd. 01793 452 222
* Carplan Nitrox 4-Star (potassium) & 4-Lead (manganese)
Carplan Ltd. 0161 764 5981

From what I've read up on, the additives aren't quite as good as leaded fuel, dropping about 2oct points. (leaded stopped being sold in 2000 in the UK?)
The only possible problem appears to be seats, the valve guides needn't be replaced, as it is only the seats that become recessed through micro-welding to the valve. Additionally, this is a phenomenon that exhibits itself on the more ductile iron heads, but may not manifest itself on a harder steel or cast valve insert.
Also, if you are using stainless valves, the common consensus seems to be that you are safe as well. might pay to have one of the valve inserts rockwell-tested to determine if it's necessary on the motor, if you have it apart.
If you do decide you need the additive, hopefully the above numbers will be useful. You may need to slightly retard the timing as well.
-Will

[andybeta]

Just to let anyone who's interested, the Volumex loves Miller's VSP in combination with super unleaded.

Andybeta