However, I know from physics lessons at school [!!], that the big problem with using unleaded is valve seat recession..[VSR] this is due to higher temperatures during the combustion cycle, the valve seat fuses to the valve, and then when the valve opens again, it tears some of the valve seat away with it... through time, the seat wears down... now old british cars with cast iron blocks and heads have soft valve seats, so that the valves dont stick to the seats under heavy loads and high revs, and its these cars that will suffer from the lack of lead to lubricate the seats.

Aircooleds have soft aluminium heads, and so need hardened seats for them to be able to stay put.. a soft seat in a soft head would fall out, and as the name suggests, hardened seats are ideal for unleaded motors, as the valve seats wont wear as quickly.

New Mexican heads are the same as the original german ones in every way, but have been changed slightly for use with fuel injection, and low grade fuels. Mexico hasnt got the best fuel in the world, and most owners out there cant afford it anyway!! some distill their own fuel from potatoes [IM NOT JOKING!!] its pretty much the same as methanol!!! they dont seem to suffer too many ill effects, so if thats not a sign of a strong head and valve seat i dont know what is!!!

So why are Traders selling "unleaded" heads? Whats so different about them? Well theyve usually been machined so that they run a lower compression ratio. This is no bad thing, but is it worth sppending all that hard earned cash on when the highest stock compression ratio for an aircooled was only 7.0:1 anyway??? I dont think so! compared to most other cars this is very low, hence why aircooleds never feel that fast when in stock form! save your money! spend the £300 or so on something more pressing

SO! now were OK with our valves, and our compression ratio, whats next? Timing!

So it seems that our old veedubs are already halfway there... halfway?! well actually they ARE there!! the only other problem to address when converting a car to unleaded is the ignition timing... if its too far advanced, the engine will run hot, and problems arise. But as we all know, aircooleds are pretty low tuned cars, and the timing isnt particularly aggressive.

So as long as you check your timing and make sure its spot on according to your manual, [no more than 32 degrees @ maximum advance on most late engines] youll be fine! some people who are running an elderly engine may wish to err on the side of caution and retard the timing by a degree or two, thats fine, also if you hear "pinking" a slight rattle under acceleration, you should retard the timing slightly...

Fuel catalysts are junk, dont even waste your money... they are just tin pellets in a wire gauze. the theory being that the pellets dissolve into the fuel and act as a lead replacement, lubricating the valve seats. but the truth is that most of them do nothing. Some, like the "Broquet" do work, but they only increase the octane of the fuel, making it burn cleaner, and as aircooleds only need 91RON octane fuel anyway, and pump unleaded is 95RON, these seem like a waste of time and money too!! Forget 'em!

Additives are good, they do work, but they really are pointless in an aircooled... they dont need it!! unless youre running some hi-po large displacement engine that again, needs the octane boost? in which case, you should know all this anyway!!

LRP is not much cop, its additives havent even been awarded a B.S. mark yet, and once again, youre just paying for something you dont need... high octane..

I'll tell you what i did to mine... 2 years ago I filled up with unleaded, set my timing spot on.. :i.e. no more than 32degrees at max advance, 30 if youre feeling cautious, and set all my tappets/ valve clearances to 0.20mm or 8thou... [slightly more than normal, its safer that way.. less chance of valve drop and better exhaust scavenging-less heat build-up] ...and then drove it!! I've probably saved myself about £20 a month by changing, and there was NO outlay...!

If you need any more convincing of a non technical nature, just ask any German or American VW driver... they havent had leaded fuel for years! do you think they wasted their money on tin pellets or overpriced de-tuned heads?! I dont think so!!

Just service your engine, get everything spot on, then fill up with the green stuff and have a healthier wallet!!!!

happy dubbing!