I was reading that the 1930's Plymouth L-6 engine has hardened valve seats,etc. and doesn't require lead additive to run on modern unleaded gasoline. Is this also true for the 28 L-4? Or should I use lead substitute as this chap in Grand Bay (met him on the weekend he has a 28 as well, but someone else rebuilt it.) recommended?
I don't want to do any damage by trying to run her without lead... maybe it's when in doubt - add lead?????? I picked up a bottle just in case at Canadian Tire.
Help?
Thanks,
Chris
The 28Q and 30U did not have hardened valve seats. There are many diferent opinions on lead substitute additives. I use Bardahl Instead O' Lead on my 29U. However, I do not use the octane boost version - these cars ran on much lower octane than we have today, so you do not need an octane boster.
I'm not sure if it's also an octane booster, but from what you say running regular is all that is needed and wanted?
Thanks,
Chris
Yes - just run it on regular.
Even at that, you will find that if you try to set the timing by the owner's manual, it will run rough, if at all. Reason is, fuel in 1929 had a much lower octane and so ignitied much faster than today's fuel. There are no timing marks on the 28Q or 29U. You will have to adjust the timing by ear, advancing it somewhat. So, if you try and set it by the manual, and it refuses to run, advance the distributor a little and try again. The simplest method - once you get her running - is to adjust the distributor at idle to obtain the fastest rpm, then turn it back just a hair. You can also attached an RPM meter (set for a 4 cylinder). There are other methods, and I am sure you will hear from others.
Good luck.