Posted by 74merc (IP: 207.157.60.19) on June 27, 2000 at 18:29:04:
In Reply to: Re: Lead Additive? posted by Joe Divito on June 27, 2000 at 18:17:33:
several different engines, a couple of which the car was imobile, just keeping the engine from rusting up and such, the valves started chattering after a few hours of running unleaded.
My cousin's 68 289 however, did fine for about a year before his valve seats went south...
I say get the hardened valve seats...
: : What is everyone's opinion on add Lead Additive to the unleaded gas we currently run. The engine's an original 302 with 89K on it, should I be using an lead additive and if so what type and for what duration. Every fill up, every other. Thanks in Advance.
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: If the engine was built after about '74 or '75 (depending on whether it was for sale in California or 50 states), it WILL NOT require lead, period. Hint: if it has catalytic converts, your should never use lead. Of course, a previous owner may have removed the cats, so go by the VIN number (since the engine's an original) and see when the car was built.
: Even if it's pre-emission, you can still get away without using lead additives if the engine isn't going to be run hard. By this, I mean no towing, nothing over 65MPH on the highway (especially in excessively hot weather), and no hard acceloration. There was an article about this several years ago in Popular Science, back when lead was going the way of the dinosaur. The conclusion was that even for '60s engines, unleaded wasn't a problem unless you did any of the above things. Then you needed the lead deposits to cusion the valves.
: If you want, you can discuss with a machine shop about the installation of hardened valve seats. Since the engine is so low mileage, this may be cheaper in the long run than buying lead additive. From what I understand, it's not a big deal to install hardened valve seats that can take unleaded gas. Then you can run the engine hard all you want.