likaleica Posted May 23, 2015 Report Posted May 23, 2015 This is one for the technical fuel junkies: Being new to my 1939 Plymouth sedan I'm not sure if it needs a lead replacement fuel additive such as Redline or Wynns. I've been using Redline - but I've just seen an original Plymouth sales brochure highlighting the fact that the '39 models had hardened exhaust valve seats as standard. So I'm wondering if I need any additive at all to protect the engine ? There is also a choice of gas. Here in the UK our unleaded fuel is 97 octane but to achieve that is full of Ethanol. We do have a slightly higher 98 octane Super Unleaded with lower Ethanol content. Is Ethanol bad for these cars so I should use the Super fuel? All advice gratefully received as ever, guys! Quote
james curl Posted May 23, 2015 Report Posted May 23, 2015 I have run my P-15 on unleaded gas for twenty years with no additives without problems. 2 Quote
Plymouthy Adams Posted May 23, 2015 Report Posted May 23, 2015 (edited) the lower the CR ratio of your engine the less need it has for high octane gas...read up on octane and how it works..you will probably be quite surprised..additives..none unless your car sits for long periods unused and then make the call on a fuel stabilizer..many people get a warm fuzzy putting this stuff in their tanks..the makers get a fat wallet,... Edited May 23, 2015 by Plymouthy Adams 1 Quote
TodFitch Posted May 23, 2015 Report Posted May 23, 2015 Older (pre 1990 or so) fuel system rubber components may be affected by modern gas additives including ethanol. If you are unsure of the age of your fuel flex line (from the frame to the engine), the fuel pump diaphragm or, if so equipped, the rubber tip on the float value in the carburetor then you should keep an eye on them or replace or rebuild them with more recent materials. It seems that modern gas additives have a limited shelf life and the expectation is that you will use all the gasoline within about 6 months of purchase. If your driving style is such that you will have a tank of gas for longer than that then a fuel preservative like Plymouthy Adams suggests may be helpful. Other than that, your car will run fine with no damage on the lowest octane, cheapest petrol/gasoline you can buy with no additional over the counter additives. 1 Quote
likaleica Posted May 23, 2015 Author Report Posted May 23, 2015 This is great news guys and frankly not quite what I was expecting - thanks indeed! Owning my '39 is now even more affordable I don't need to spend out on expensive additive As my car is pre-1960 I don't need an annual safety test (MOT) certificate As it is pre-1973 I do not have to pay Road Tax (saving over $330 a year) Classic car insurance (limited to 1,500 miles a year) is about $220 a year Quote
Ian Crombie UK Posted May 23, 2015 Report Posted May 23, 2015 $220 for yer Insurance....check out R&H next time...£85 for me Quote
Ian Crombie UK Posted May 23, 2015 Report Posted May 23, 2015 Thats with 3000miles and no questions asked for club /odometer/endorsments etc. Quote
DJ194950 Posted May 23, 2015 Report Posted May 23, 2015 $220 for yer Insurance....check out R&H next time...£85 for me Do they do business is the U.S.?? 1 Quote
doctor dirt Posted May 23, 2015 Report Posted May 23, 2015 87 oct. in my 218 1951 Plymouth P22 and no problems with it. Insurance this time around I went back to Grundy (go back and forth with Grundy & Hagerity) and pay 182.00 per year for 100/300 and a replacement value of 15,000. I think all the companies are very fair these days. Doc 1 Quote
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