1935 12 which fuel

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kevh
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1935 12 which fuel

Post by kevh » Fri May 31, 2019 9:02 pm

I suppose the question has been asked 1,000 times before but which fuel should I put in my 1935 12, or does it not matter?

Kev
1935 Rover 12

kevh
Posts: 32
Joined: Mon May 27, 2019 3:19 pm

Re: 1935 12 which fuel

Post by kevh » Sat Jun 01, 2019 7:07 am

I meant is it ok to use the standard unleaded at my local garage, or is a different grade required for an engine which would have been designed to run on leaded fuel?

Kev
1935 Rover 12

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47p2
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Re: 1935 12 which fuel

Post by 47p2 » Sat Jun 01, 2019 8:37 am

If the valve seats are original non hardened it's recommended to use a lead additive with unleaded fuel

TonyG
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Re: 1935 12 which fuel

Post by TonyG » Sat Jun 01, 2019 9:22 am

Kevin,

Unless you are likely to be doing a lot of miles in your car it probably doesn’t matter. Pre war steel was high grade and it would take a long time to burn out your valves. When I rebuilt my engine I had the head checked and skimmed by Coltec near Woodbridge (formally Holbay Engineering) and I asked about the need for hardened valve seats etc I was told not to bother. As such, I don’t use additives in my 12s and they run ok. I put Super in the Tourer because of it’s high compression head as it goes better.

I suspect Petrol will become hard to find and electric cars the norm long before our Rover engines give in to unleaded fuel!

All a matter of choice.

Tony.
Tony Gilbert

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

TonyG
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Re: 1935 12 which fuel

Post by TonyG » Sun Jun 02, 2019 8:35 am

Kevin,

Did some further research last night on this subject. Petrol didn’t have any lead in it until the 1920s when a chemist called Thomas Midgley, working for GM and Standard Fuel Co in USA, developed it as a way of reducing ‘knock’ and thereby allowing higher compression engines.

Leaded Petrol reached the UK in 1928 and was available from Pratt’s, which later became the Shell motor spirit company I believe. By the outbreak of war leaded fuel was greatly used in aero engines to raise performance and was very much the norm from then onwards.

It’s debatable whether engines made in the 30s were designed for leaded fuel or not but the vehicle handbook I have does recommend upper cylinder lubrication, which wouldn’t be needed with leaded fuel I’d have thought. As such, it’s probably wise to add lead replacement to our fuel but damage through not adding it will be minimal and slow on a low compression, low mileage vehicle. Hardened valve seats and valves will protect against valve damage but lead replacement is still required to reduce heat and damage to pistons, especially in performance engines. Also an octane booster is a good idea in such engines as it avoids having to retard the ignition, which will make it run hotter.

Interestingly, Midgley went on to develop the CFCs used in refrigerators. He later contracted polio and devised a system of ropes and pulleys to help get in and out of bed. Sadly he got tangled in them and hanged himself!

I hope that helps. I will investigate lead replacement types for my car to use when filling the tank.

Tony.
Tony Gilbert

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

kevh
Posts: 32
Joined: Mon May 27, 2019 3:19 pm

Re: 1935 12 which fuel

Post by kevh » Mon Jun 03, 2019 11:03 am

Thanks Tony,

Interesting read, I will need use the additive as I expect my 12 will be high performance when completed and it is best to be safe.

I will also bear it in mind if I ever need to construct any kind of a pulley system in the bedroom.

There are some things which you know you shouldn't laugh at but can't help it.

Kev
1935 Rover 12

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