Unleaded petrol conversion

[1973JPS]

. Hi Guys .... what is the opinion on having the head on a twin cam set up for unleaded petrol...conflicting reports  so confusion sets in.... 

https://www.pistonheads.com/gassing/topic.asp?h=0&f=14&t=1573860

[jbcollier]

Simple.

- If you are going to potter about, seldom missing a cafe, and only drive in anger when returning home from where the judges fail to see the Light, then there is no need to fit hardened valve seats.

- If you plan on driving hard, for long periods of time -- high speed, flat out in the mountains, track days -- then you'll need hardened seats.

- If the head is off for work already, fit hardened valve seats

Most of us fall somewhere in the middle.  Then you might want to wait and see.  If your valves close up, then you should look at hardened seats.

SPECIAL NOTE

Lotus TC heads are fragile, easily ruined and expensive to replace.  Only take it to a machine shop experienced with Lotus TC engines.  You have been warned.

[EuropaTC]

I remember contributing to that thread on Pistonheads (I'm b2hbm there) and it did change my views on our unleaded petrol.  I can't help but think one of the posters there got it right when he talked about people/companies using the uncertainty to push for conversion work.

Now I don't do a lot of mileage and most of that is just pottering about so I'm like John in the "wait until you see something happening" camp. When leaded petrol disappeared I religiously added the unleaded substitutes every tankful but after learning that the US guys didn't seem to have a problem with their unleaded I changed to only adding octane booster. 

After that pistonheads thread I'm not even sure about that now because it does seem to work without although I'll add that my engines are in the 9:1 (ish) range rather than the higher sprint spec of 10:1 (?)

Brian