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Why you shouldn’t cold-start a long-dead car

For any engine unused for ten years I would assume the gaskets are unreliable. Don’t bother trying to start. Tear it down and install new gaskets and seals.

Another fun item is a vehicle whose gas tank was last filled with fuel containing MTBE. When the fuel evaporates, the MTBE remains, leaving a gum that looks like silicone seal. This sometimes is left in the fuel lines, plugging up the lines. It can be removed with compressed air. When fuel is added to the MTBE, it will re-dissolve into the fuel and eventually be burned up.

when attampting to assess an ‘unknown’ long dead vehicles mechanical condition, its important not to ‘overdo it’ and waste meterials > often there is a reason it was parked in the first place… commonly because something broke, or it became impractical to repair it… first step I alwasy take with engines is to check they turn freely…if so, next stop is to judge if it has even compression check for spark…remove spark plugs and spray some penetrant (minimal amount)… I’ll often replace points etc…check there is oil and its up to level ( add if required) then clean out carb and add fuel.( or you can try and spray some ether to see if it fires first… be aware that this DOES load up things more and will expose any major weaknss) . the fist initial ‘dry start’ will tell you a lot… if it has the ‘death rattle’ for worn rods and mains… IF it seems good and runs evenly for few seconds…THEN and only then should one take the time to change for fresh oil and make sure clooant is present and suffient to run the engine up to operating temp for next round of tests… engines are tougher than most imagine… it makes no sense to mollycoddle an ‘unknown’ dead engine and waste money on new oil an coolant until you have some idea of its overall condition…best to find out if its serviceable by starting it up first…
almost all engines that have stood for more than 6-7 yrs will need a teardown and refresh in order to be ‘right’ … if you have one or more stuck pistons and are able to free it up…teardown and rebuild is essential…

My 76 Corvette sat for 10 years in the garage. I knew the gas and tank was bad and just wanted to start the engine before going any further with a rebuild. I took out the spark plugs, sprayed in penetrating oil, hand cranked the engine to verify not seized. Then put in new plugs, battery, oil and filter. We pushed it out of the garage and ran a new fuel line from the carburetor to an external electric fuel pump then to a can of fresh gas. We turned on the fuel pump, turned the key, and the engine started right up like at ran yesterday.

Take a tip from aviation engine maintenance and get a borescope. Now days they can be as cheap as $30 and attach to a smart phone. They greatly simplify cylinder inspections and any other inspection that involves getting into tight quarters and looking around. I’ve even used them to find the proverbial lost nut. I use this one connected to a notebook computer on planes, cars, and motorcycles:

https://www.oasisscientific.com/vividia-va-400-rigid-usb-articulating-borescope-videoscope-inspection-camera.html

I just bought a 1990 ZR-1that has been sitting for over 5 years. The guy I bought it from had the cylinders filled with marvel mystery oil. I’m taking my time with her, I plan on making a nice driver out of her. I don’t think she was abused just neglected. I’m going through all the systems with a fine tooth comb. Can’t wait to get her going, she deserves some tlc and I’m going to do it right.

So much good advice except for one bit. As others have suggested, I don’t agree with turning the engine by hand before anything to see if free. I’ve revived many old vehicles, and most have iron rings. Chances are all ring types are stuck to the cylinder bore, but unlike moly rings, iron rings are brittle and will break immediately. Then you start the car and find a bad cylinder and say that’s why it was parked. I’ve seen it from many shadetree mechanics. Oil the cylinders and change oil & filter before you dare budge the engine, and delicately at that. If I can, I’ll even lightly tap on the piston with a brass rod through the spark plug hole to encourage the rings to break free. Then you have a fighting chance at a revived engine.
I may be overly cautious, but I have never had a broken ring at startup while many others have.
I recently inherited a 1960 Corvette with a 283 that’s been sitting for 25+ years, and since I’m low budget, I’m going to preserve everything I can, including the engine, even if it takes more time.

Look up mustie1 on you tube for some resurrection videos. He is a air cooled VW man but works on all kinds of neglected and abused crap.
His mission is to get them running with no money and little parts.

Enjoy. Its addictive…