Unleaded.

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peterbaker
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Unleaded.

Post by peterbaker » Mon Aug 07, 2017 7:21 pm

I'm sure this has been raised before, but can my 1937 12hp P2 be run on unleaded (Super)?

TonyG
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Re: Unleaded.

Post by TonyG » Tue Aug 08, 2017 10:42 am

Peter, I would happily put super unleaded in my '37 P2 or my '36 P1 if that was what was available. I tried it once with my P1 to give it a treat and it was hard, if not impossible, to tell the difference. That said, it has a high compression head and twin carbs so it is already quite lively. Aside from performance, it may run smoother as it does with modern cars so perhaps I will try again now that my engine has done a few miles. In theory the higher octane should suit the car and back in the 70s when it was available I used to put 4* in. Nowadays, it is likely that the ignition timing will be set up for best running on regular unleaded, which is why I didn't notice any difference. However, given that our cars have the manual advance/retard capability specifically to deal with occasions of poor quality fuel (back in the day I think it was quite variable and in places it was a matter of using what was available), it seems likely that Rover built the engines to cope with any octane grade of fuel. Regarding valve seat wear, the same issue exists as with regular unleaded.

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

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luli
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Re: Unleaded.

Post by luli » Wed Aug 09, 2017 8:26 pm

See also here: http://wp.me/pXLKy-2lJ
Rover 10 1946 RHD
Rover 10 1947 LHD
Rover 12 1947 tourer LHD
http://lulisml.wordpress.com/

MarkK
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Re: Unleaded.

Post by MarkK » Thu Aug 10, 2017 7:38 am

I've heard many times that these old Rover engines are fairly indestructible and will run with adjustments no matter what quality of petrol is used. This has been the case with the various P4s I've owned over 30 years. But were our prewar engines really designed with enough foresight to cope with unleaded fuel, full stop?
I have my engine on a stand, stripped to pieces, so I am lucky that it will be a straightforward job to replace the valves, valve seats and guides. If I were not so lucky I might chance it until I noticed something but only if I weren't depending on the car. At one stage I used my P4 daily and as an orchestral musician I was touring a great deal, many miles. P4s were all built with hardened valve seats in the factory but I don't think P2 was.

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luli
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Re: Unleaded.

Post by luli » Thu Aug 10, 2017 4:58 pm

The P4 engine has hardened exhaust seats that can withstand unleaded petrol. The P2 does not have them. Ihe head is made of soft steel and the seats will burn over hard use.
Rover 10 1946 RHD
Rover 10 1947 LHD
Rover 12 1947 tourer LHD
http://lulisml.wordpress.com/

dhbuchanan
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Re: Unleaded.

Post by dhbuchanan » Mon Aug 14, 2017 9:52 pm

I always put 97 RON super unleaded in my P2, following the advice of a friend with vast experience and knowledge of these matters who told me that 97 burns cooler than 95. As far as I'm concerned, anything that reduces the significantly increased amount of heat emanating from the (converted) engine of my '39 20 HP since the abolition of leaded petrol is more than welcome. He also told me that super contains a smaller proportion of ethanol, stuff which can damage the fuel lines of old cars, an effect which I attempt to counter with Flexolite Ethanolmate additive, particularly when the car is laid up over the winter.
Thanks to the tree-huggers and the anthropogenic global warming campaigners, the amount of ethanol in our petrol will be hiked up even more when E5 replaces E10 in the near future. Right now, 46% of all the palm oil used in Europe ends up in the tanks of road vehicles. What the arboreal advocates don't seem to understand is that much of this same palm oil is produced as a result of the extensive destruction of irreplaceable virgin rainforest in the developing world. This process will shortly be going into overdrive when the petrol formula changes.
1939 20 H.P. Salmons Tickford D.H.C.

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