Petrol type

[vampire222]

Hey, just bought my 350i!!!

Now im wondering, the previous owner always put lead substitute in, is this really necessary? I'll post a pic or two later

[mrzigazaga]

..Congrats..I do believe that all the V8 wedges had hardened valve seats fitted so the higher the octane the better..Super unleaded or 97-98 ron will be fine..You will need to check your timing though as it may need retarding from 8 degrees to 4 degrees BTDC..Im sure someone else can confirm..Hope your miles are smiles..Ziga

Edited by mrzigazaga on Tuesday 29th November 13:41

[broadside]

Fuel injected Rover v8's were designed to run on unleaded fuel so no real use for a lead substitute. By all means use super unleaded fuel for the extra pops bangs and a bit more oomph!!

[vampire222]

broadside said:

Fuel injected Rover v8's were designed to run on unleaded fuel so no real use for a lead substitute. By all means use super unleaded fuel for the extra pops bangs and a bit more oomph!!

Always fill it up with the best available, always have with my sports cars

Good to know i wont have to fiddle around with lead substitute tho! Thanks!

[rocky65]

Hello chaps.I was going to ask this question at some point before I put mine back on the road,what about the 280i its an 83 I read that it can depend on the year anyone know.

[mrzigazaga]

Hi mate..Apparently cars made up to 1983 dont have hardened valve seats so every fourth tank needs a lead replacement additive..Cars made after 1983 have hardened valve seats if fitted with unleaded heads, There is either a letter D or E stamped on the cylinder head exhaust flange upper face..Near the middle spark plug although sometimes the engine code and engine number can be mis-read as they sometimes contain the same letters..For normal unleaded retard the timming to 9 degrees BTDC or if using super unleaded leave at 12 degrees BTDC you will still need additive..If you have unleaded heads i dont think using an additive will hurt but as i have found out the sealing compound between the metering head can become liquid causing minor leakage due to injector cleaner or lead additive..Also if you have soft valve seats and are not using additive then it wouldnt be major as you can go 100s of thousands of miles before valve recession begins..Hope this helps..Ziga

[voltage_maxx]

Any fuel injected Rover V8 will be fine to run unleaded, as will most other Rover V8's as they have aluminium cylinder heads and hence by default, hard valve seats.

As regards fuel type, the 3.5 engine is a Vitesse spec engine running 9.75:1 compression ratio. In order to run a decent amount of ignition advance without encountering 'pinking', I'd advise running on super unleaded.
I shall be doing the same with mine when it's on the road (fond of Tesco's 'excellium' - 99 Octane!).

[RCK974X]

Time to keep up my 'geek' reputation !!

I don't know about Rovers but I DO know about cologne V6s, probably a bit too much....

2.8s made before 1985 are definitely not made for unleaded. A few later heads did have hardened seats, and they have a small 'D' stamped on the [head] exhaust port flange. You can of course get hardened inserts put in if you really want.

The real info though is -

If you tend to drive with a light right foot (Yeah, Yeah, I know) your engine may never have a problem even without additives, as valve seat recession is more or less linked to load.

If your engine has been driven for a long time on leaded fuel, the lead actually hangs around in the head casting, causing a 'lead memory' effect. This lasts for approximately 20,000 miles, and so chances are you won't have any issues.

Obviously this is going to vary from engine to engine, so it's general advice...

The Cologne likes to run slightly 'tappy' , i.e. DON'T run less than recommended valve clearances.
If you get valve seat recession it will go quiet, and then misfire/ run rough at low speed first.

Unleaded gas does burn differently (slower ? not sure), so you may still have to fiddle with the timing to get it just right.

Here in New Zealand, the gas comes in standard unleaded (91 octane) and super (95 Octane), and BP sell 98 Octane, which is same as 4 star. I run my wedge on 95, with the static timing retarded to 10.5 degrees (half way between recommended 4 star (12) and unleaded (9)) - it seems happy.

I did have to disconnect the vac advance completely though, otherwise it misfires at low throttle low speed (e.g. in traffic). On a run recently it returned 28 mpg, so it's got to be pretty close to ideal...

There's also different engine blocks, depending upon year....[ CUT !!! CUT !!!]
OK, I have more info if needed, I'll just say that and stop.

Edited by RCK974X on Wednesday 30th November 04:20