Lead Replacement Petrol

[IMPI]

I have just spent another 2 hours trying to start a brand new engine which just did not want to run. as the engine had four seemingly brand new plugs I thought of saving a few bucks by reusing them. I cranked the hell out of the ngine and could not get it to run. since everything else was brand new I decided to fit four new plugs. She started first time. This isnt the first time this has happened either It took me three days to get the SP2 to run after it was in hibernation for about 2 years same problem same fix.

The LRP petrol sold in SA conforms to the following std:
6 Permitted metal-containing petrol must conform to South Afiican
National Standard, Leaded Petrol, SANS 299 provided that-
(1) the RON rating must be either 95 or 93;
(2) the maximum permitted traces of lead as contamination must not
exceed 5 milligrams per litre;
(3) manganese based additives must not exceed 18 milligrams per litre;
(4)-potassiunbase&additivesm ust not exceed -1 0 milligrams per litre;
(5) phosphorous based additives must not exceed 14 milligrams perlitre;
(6) only one of the additives referred to in sub-regulations (3), (4) and
(5) is added to such petrol;
(7) the maximum permitted content of aromatics is 42% vlv; and
(8) the maximum permitted benzene content is 3% v/v.
Petrol zones
7 Permitted metal-free petrol grades may be sold throughout the
Republic.
8 Metal-containing petrol with a RON of 95 must only be sold in the
coastal zone.
9 Metal-containing petrol with a RON of 93 must only be sold in the
inland zone.

Since I have been using this type of fuel in my old cars I have noticed the following traits.
No visible valve seat recession.
The stuf seems to go off very soon
very little of it evaporates when left in the open the oily residue is extremely resistant to burning.
If the car stand for any time it refuses to run right
Plugs seem to die more easily I have found electronic ignitions to help in this regard
Fuel hoses seem to deteriorate more

My theory:
Modern fuels are made with Fuel injection in mind that is: they musnt evaporate easily (causes vapour lock) and must be atomisable in a fuel injection system. thus the requiement for les evaporatable compounds.
The aditives used manganese, potassium, and phosphorous based additives coat the whole combustion chamber including the valves seats and plugs. I believe that coating the plugs is where the problem lies If you do not have high powered ignition the plug eventually gets coated to such an extent that the spark cannot jump.
I have found that using Unleaded in a ratio of 1 to four tanks of LRP seems to help and causes no serious side effects
Anybody with other ideas
Armand

[Tom Bishop]

The LRP from about two years ago was bad.

Plugs dying, normally cylinder 3. And if the stuff evaporated in the bowl, you were left with a sticky goo.

[jmvv]

I have a 1992 Ford Sapphire (DO NOT LAUGH) with fuel injection and was using LRP in it because of the cast iron head and valve seats.

With LRP every time when you started the car and let it run for only a short while (less than 5 minutes) like when moving it out of the carport etc, it would flatly refuse to start again and I would end up changing all four plugs.

An article was published in CAR magazine about this and it seems that when the engine is stopped before it had reached normal operating temperature, some of the metals in the fuel is deposited on the plugs, thus shorting out the electrodes. When normal operating temperature is reached, these deposits are burned away allowing the plug to operate properly at the next cold start.

I've since had the valve seats changed to accomodate Unleaded fuel and the problem has dissappeared. (I had the head skimmed to bump the compression a bit and use 95 unleaded)

[Dawie]

Changed about a year ago to unleaded, no LRP fills inbetween ever. Regularly check valve clearances with a feeler gauge. No signs of valve seat recession so far. Seems to run better with unleaded.

Had a problem with run-on after switching off when still using LRP. (No idle cutoff valves in carbs). Unleaded seemed to have reduced this. Also found that knock/detonation occurred easier with LPR. Had to reduce timing 2-3 degrees with LRP.

Seems it causes deposits in the combustion chambers,that causes pre-ignition when hot. Been to a cylinderhead machining place and the owner showed me the deposits that started to happen in some heads soon after LRP was introduced.

[1972]

have heard of engine kits that allow the engine to run off unleaded petrol what would a kit like this cost and is it worth doing this modification to your engine??

[Tony Z]

go look at the other threads on this topic.

What mods do you need to do to run a beetle engine on unleaded.
In brief... fill up with unleaded.
The engine is ready for unleaded fuel and has been for the last 40 years
Unless someone put the wrong valve seats in during an overhaul