What fuel for a V8

C

campingstoveman

New Member
Gentlemen,

As of last Saturday I am now a proud owner of a white 1969 P6 3500 V8, could somebody tell me what I can run it on and do I need additives in the fuel or do the heads have steel inserts.

Thank you,

Martin Perman
 
Hi Martin,
Congratulations on your new purchase, now a rare beast indeed!

Some people do run their V8's on standard 95 octane unleaded. But personally I would use Super-unleaded (preferably Shell V-Power) as well as an additive. Especially as you will most likely have the 10:1 compression ratio engine.

When I had an early 'S', I ran it on super unleaded and Castrol Valvemaster Plus with very good results.

P.S. Any pics of your Three Thousand Five that you could post on here?, I for one would love to see it. :D
 
Martin,
I also used Castrol Valvemaster Plus with Super unleaded in my Three Thousand Five.
If you send me an e-mail via club officials with your e-mail address on it (not thro' FORUM as I cannot attach anything) I will send you my article from P6 NEWs entitled "Fuels, Combustion and Consumption" which was published in April 2003 and has since been updated to mention the modern higher octane fuels available.
Regards, John
 
Martin,
You need to open an account (free) with something like photobucket (www.photobucket.com) and then upload pics to it from your computer. You can then insert a link into your post on the forum that will show the picture.

Regarding additives, some people have found their cars run ok without additives, but some have also found that not using them has ultimately lead to valve recession and pinking etc.
I personally regard that it's not worth the risk and so use additives.
 
Gentlemen,

I bought the car off of my brothers partner, it belonged to her father until he died just over 18 months ago, it has been on SORN ever since and garaged, I went to the garage last Saturday and my brother and I checked it over drove it to a garage and one hour later she was MOTed by lunch time she was also taxed.

My brother over the last eighteen months has kept the battery charged and has driven her around the yard once a week.

I have loaded some pics hear.

http://s181.photobucket.com/albums/x145/campingstoveman/

Martin P
 
JC,
I am afraid that you are wrong - The heads are most definitely NOT suitable for unleaded !
Martin's Three Thousand Five was built for 5 star fuel and has a compression ratio of 10.5 : 1
The reduction from 5 star to 4 star meant that the static timing was reduced from 6° btdc to tdc and unleaded fuel had a lower octane rating again as well as no (actually only 1/10) lead content.
It has neither hardened valve seats or guides and The Rover Company does not recommend unleaded fuel unless used with an additive - lubricant, anti-knock agent and octane booster.
There is a difference of opinion about SD1 heads needing additives (or not) but there is no doubt that any engines built prior to SD1 (1976) would not be suitable for unleaded.
Hope this helps, and my previous offer still stands.
Regards, John.

There is plenty of information and guidance on this website (and others) for Martin
 
Nada cars obviously ran on unleaded in the states with no lower compression mods etc... so why can't ours?
 
PeterB76 said:
Hi Martin,
Congratulations on your new purchase, now a rare beast indeed!

Some people do run their V8's on standard 95 octane unleaded. But personally I would use Super-unleaded (preferably Shell V-Power) as well as an additive. Especially as you will most likely have the 10:1 compression ratio engine.

When I had an early 'S', I ran it on super unleaded and Castrol Valvemaster Plus with very good results.

P.S. Any pics of your Three Thousand Five that you could post on here?, I for one would love to see it. :D
Click to expand...
 
With the high CR engines I would either run highest octane available with timing at 6 BTDC, or lower octane at TDC - depends on what you can afford and what sort of driving you enjoy. In this sort of car the cost of fuel is relatively insignificant. With alloy heads there must be valve seats harder than alloy fitted to provide a useful life , even if they are not technically 'hardened'.
 
I have ben runnin my 300S on Super- unleaded , mostly from Sainsbury's, since leaded disappeared. So fa , no problems, but I do not do many miles and dive gently.. Ignition timing has been set by engine tuner.
 
Never had a problem with my non high compression V8 on UN leaded RON 91 fuel, 10.5 to one would be a different matter.

Owned it since 1987.
 
Have to be careful comparing fuels, as one country's definition of a given octane isnt necessarily the same as others. Here in Oz we typically see octanes listed as 91, 95 and 98. I tyically run 98 in my turbo cars (Subaru 2.5 GT and Clubbie (lotus 7 clone, Mazda 1.8 with turbo), 95 in the P6B (9.25 CR). Wont use 91 as it has a rep for being dirty. In my actual experience the 9.25CR version of the v8 has the best overall power/torque curve, as the 10.5CR version is a bit peaky for my likes.
 
as fuels here at least in UK are marked E5 or E10 ( petrol) its about the amount of ethanol added to petrol and octane rating that have biggest effect. I only use E5 rated and always seek the more expensive 'super' type too. I also have those metal fuel tables in tank that give a slight octane boost. I once drained half a tank of fuel when using then E fuels you have to buy ( was lining fuel tank to prevent corrosion) and after 2 days checked container and was disheartened by amount of water mixed with fuel . easily see top half was pure fuel and lower almost half was like looking at millions of water droplets suspended in the petrol. needless to say I only use date top half when refilling! I also found with the slower burn rate (I am told) that modern fuels have I advanced ignition a bit .can't say exactly what it is now as did it by trail ( hand advance of dizzy a bit and locking back up) car has a lot more oomph now and goes much better.easy to start even when cold with choke but the after just starting choke in half way . after 3-4 mins it idles much better too. Cr is if I recall correctly 9.75:1
 
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