How would you convert a 221ci to unleaded, would it just be a matter of changing the valves and seats???
Basically, yes that's what you have to do, but if its a reco motor chances are the compression ratio will have increased. It is unlikely you will be able to run regular unleaded, you will need some sort of premium and/or an additive. You can also just add an upper cylinder lubricant to the petrol tank if you like.
If the motor is ok, just stick in unleaded and use it. If you have to beleive all the B.S. that is printed by people trying to cash in on everyday peoples paranoia, then invest in a Flash Lube setup. It's probly the cheapest way to do it.
My 351 clevo has 4v big port heads, is set up as a pretty goey motor, has closed chamber heads and flat top pistons, so comp is pretty high. I use electronic ignition etc and Holley 750 vac. I have had no mods done to the heads to run unleaded, and have run regular 92 ulp and the 98's etc for 5 long, hard thrashing years with no problems at all. (upto 6500rpm type thrashing) and no additives, or upper engine lubricants.
My engine builder has a worked 351 clevo in his f100 truck, is on straight gas, has done mega klms, and done nothing at all to the heads(as like mine), and it is still going strong. Gas runs a lot hotter than ulp, and is harder on internals too.
Don't be a victim of all the hype and panic, it only helps the coffers who make the crap....
Your engine will already run on Unleaded,but it just won't last as long as it would have on the old Leaded or Super as the Lead was a Lubricant for the Valves amongst other things as far as I know.That is why fitting Hardened Valve Seats is recommended and say Stainless Steel Valves. I think I have also heard of people using Brass Valve Guide Inserts for this conversion aswell? Chrome Moly Ring's would also help for Engine durability for this situation IMO.I have also heard that Unleaded Engines use lower Compression,but my friend runs his XC 6 Cylinder on Unleaded all the time with no problems and his motor is'nt Low Compression...So maybe that does'nt matter so much??Goodluck !!
u could run a fuel star which is installed into your fuelline before your carb it is like a canister with lead pinaccles in it ,as the fuel runs thru it picks up a bit of lead. quite expensive but probably cheaper than getting your seats and valves done
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