Simon.AU
Enthusiast
- Messages
- 116
I did start replying to Steve's reply in the R4 upgrade topic, but figured it would be going a bit too far OT.
What is the concensus on unleaded though? On my R4 with a 1964 type 800-01 three bearing motor, with 8.0:1 compression (checked when rebuilt, very close to) that has been run exclusively on 91 octane unleaded with no additives since it was rebuilt 20,000 miles ago. It has been used in extremes from town to fast intercity trips (500-800 miles at a time, around 60-70mph).
I've also got a 1975 R12 with 810-05 Sierra motor, basically a "big block" 4GTL motor. That has been run exclusively on unleaded for the last 20,000k's (12,000 miles), mainly as an unleaded experiment on 98 octane with no additives, again in a number of extremes, and again no signs yet of VSR.
I've tried cross referencing things like R5 Series 1 heads, but have drawn a blank as I've not got a parts catalogue for the US Le Car unleaded versions. Things like the Renault 15/17 used a completely different head for the US market unleaded versions, and valve seats are not listed separately so that didn't help either.
Hence the using of my 12 as a personal unleaded test bed, also no pills potions, lotions, or Ebay sourced magnetic additions have been added on the 12, it is basically stock with nearly 300,000km's on the clock. The motor having been rebuilt 120,000k's ago, the valve seats were unchanged, but new stock valves were installed at that time, and it was still running on leaded petrol.
What is the concensus on unleaded though? On my R4 with a 1964 type 800-01 three bearing motor, with 8.0:1 compression (checked when rebuilt, very close to) that has been run exclusively on 91 octane unleaded with no additives since it was rebuilt 20,000 miles ago. It has been used in extremes from town to fast intercity trips (500-800 miles at a time, around 60-70mph).
I've also got a 1975 R12 with 810-05 Sierra motor, basically a "big block" 4GTL motor. That has been run exclusively on unleaded for the last 20,000k's (12,000 miles), mainly as an unleaded experiment on 98 octane with no additives, again in a number of extremes, and again no signs yet of VSR.
I've tried cross referencing things like R5 Series 1 heads, but have drawn a blank as I've not got a parts catalogue for the US Le Car unleaded versions. Things like the Renault 15/17 used a completely different head for the US market unleaded versions, and valve seats are not listed separately so that didn't help either.
Hence the using of my 12 as a personal unleaded test bed, also no pills potions, lotions, or Ebay sourced magnetic additions have been added on the 12, it is basically stock with nearly 300,000km's on the clock. The motor having been rebuilt 120,000k's ago, the valve seats were unchanged, but new stock valves were installed at that time, and it was still running on leaded petrol.