leaded
Posted: 16 Sep 2010 08:15
Morning Gentlemen
I need the help of the clever guys, my apologies if this has been covered before. For some time now I have been worried about this, and it finally happened last night:
How will my old-tech 4.2 petrol handle unleaded fuel if LRP becomes unavailable.
I remember several years ago this was a hot topic in the British magazines that cater for older cars, and if I remember correctly there were two possible problems arising from using modern unleaded fuel in old engines:
1) Valve Seat Recession, which is the valve seats getting bashed into submission by the valves closing because they are operating at higher temperatures, which in turn is due to the shielding/cooling effect of the lead not being there anymore.
2) Some of the rubber/sealing elements perishing more quickly.
Now in terms of the first point, this was only seen as a problem on cast-iron cylinder heads with integral seats, but our engines already have aluminium heads with pressed-in seats, however when I asked Nissan they said I should avoid unleaded fuel, but they could not or would not tell me what was going to go wrong.
Does anybody on this forum have any knowledge of what will go wrong in the Y60 engines (and older) if they are run extensively on unleaded?
Thanks
Peter

I need the help of the clever guys, my apologies if this has been covered before. For some time now I have been worried about this, and it finally happened last night:
How will my old-tech 4.2 petrol handle unleaded fuel if LRP becomes unavailable.
I remember several years ago this was a hot topic in the British magazines that cater for older cars, and if I remember correctly there were two possible problems arising from using modern unleaded fuel in old engines:
1) Valve Seat Recession, which is the valve seats getting bashed into submission by the valves closing because they are operating at higher temperatures, which in turn is due to the shielding/cooling effect of the lead not being there anymore.
2) Some of the rubber/sealing elements perishing more quickly.
Now in terms of the first point, this was only seen as a problem on cast-iron cylinder heads with integral seats, but our engines already have aluminium heads with pressed-in seats, however when I asked Nissan they said I should avoid unleaded fuel, but they could not or would not tell me what was going to go wrong.

Does anybody on this forum have any knowledge of what will go wrong in the Y60 engines (and older) if they are run extensively on unleaded?


Thanks
Peter