Correct fuel for 3500S

W

wilkinson92

Member
Am I able to run my '73 3500S on 95 RON unleaded? I read somewhere the V8s prefer to run on 100 octane fuel, so I thought I'd try and find out for certain

Thanks
 
Depends on your engine. If it's a 10.5:1 engine then super unleaded will run far better. If it's a 9.25:1 engine it will behave just fine on 95ron.

Rich
 
Hi, check the engine number and compression ratio on the left hand side of the engine
by the dipstick. Or on the off chance the engine has been changed for an earlier one
behind the left hand head on the block by the bellhousing bolts.

Colin
 
Hi for what its worth I always stick some lead additive in just to be on the safe side. Some on here seem to think its a waste of time but as I am unsure what work has been done to the heads and carbs I would rather cover all bases. If you know your heads are 100% fine with unleaded then go for the premium as said. It might also pay to invest in either Esso or shell premium as they are reportedly ethanol free for the time being.

hope this helps
coop
 
wilkinson92 wrote,...
Am I able to run my '73 3500S on 95 RON unleaded? I read somewhere the V8s prefer to run on 100 octane fuel, so I thought I'd try and find out for certain
Click to expand...

Your engine may ping running on 95 RON, given it has (originally) a 10.5 : 1 CR engine. The recommendation for less than 100 octane fuel is to set the initial timing to TDC @ 600rpm.

The change over to the lower compression engine took place around the middle of 1974, certainly that was what happened here in Australia. So here you can have two 1974 models, and each will have engines of different compression as well as changes to instruments, switches and interior fittings.

Ron.
 
My 3500 auto is a December 1973 one and has the 9.25 engine and BW65 box, boxpleat seats etc. It is full 1974 spec.

Does seem happier on the higher octane stuff, but I mainly use it due to the promised lower ethanol content
 
Ok well according to my research the heads on rover V8's didn't have hardened valve seats till Oct 1985, so I've no idea what to believe.....I'll just chuck in some lead additive in future, with super unleaded
 
wilkinson92 said:
Ok well according to my research the heads on rover V8's didn't have hardened valve seats till Oct 1985,
Click to expand...

They're OK with Unleaded from the point where Rover tried to sell the NADA cars in the US, so roughly 1968/9 ish onwards.
 
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