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IdahoDoug IdahoDoug is offline
Coeur d'Alene, Idaho
Join Date: Aug 2017
Posts: 461
I'm not there to see, but this sounds precisely like what's going on. I've been seriously wrenching as a hobby for 40 years, and am a former Worldwide Powertrain Planner for General Motors and did not have clarity on this until it happened. So, the valve stem/valve guide interface is super tight and lubricated by the fuel. Old fuel is this spot's absolute worst enemy and you definitely have that going on. You were smart enough to stop and wonder what's happening here.

To fix it, I recommend you remove the cams and the lifters/cam followers, whatever's atop the valve stems. Now without the cams presssing on them, check if one tip is lower into the block than others. I'm confident you will find that. Now take a brass hammer and go from one tip to another giving it a blow that slightly opens it and lets the valve snap shut again. Likely most of them will do this with a pleasing ring sound and one or more will sound dramatically different - a dull thump. Those are the gummed/siezed ones. Spray a fuel varnish cleaner (or Seafoam noted below) of your choice down there and let it soak. Do all of them because you are logical enough to know that the ones still movin also have gummy varnish, but the siezed ones were simply incrementally tighter.. Come back and tap on them periodically to help the cleaner work into the valves. Eventually they will all ring or sound consistent.

So now you've saved the engine from destruction.

The fuel tank has quite a bit of varnish that fresh fuel dissolves into gummy fuel. You need to either remove and clean the tank, or put a borescope in there, find the height of the varnish line (wherever the old fuel line was as it dried and left the solids) and fill the tank above that level with a strong mix of fresh fuel and my favorite - SeaFoam Motor Treatment. I am often bringing older cars back to life, so I buy it by the gallon container and you should for this project. Currently working on a red 1988 Toyota Supra 5 speed Targa that has not run for 12 years.

Take this advice or not, but empty the fuel tank. Then pour pure Seafoam in - maybe a quart with all the injectors out and in bottles. Turn the key on or whatever fires the injectors into the bottles. This will dissolve the sludge in the pump and lines (put a fresh filter on now and have a second on hand) with the full strength. Then fill the tank above the line you found with the borescope and enough Seafoam to have it at LEAST the maximum mixed strength. (I use 25% stronger routinely.

With the car level, several times a day go out and shake the car to agitate the fuel in the tank. After a week of doing this, plus tapping on the valves, you will dissolve the goo into liquid state. Drain off the fuel tank and the dissolved goo in it for use in your lawnmower. Refill it with fresh fuel of 5 gallons or so with the max concentration of the Seafoam. Take the fuel line off before the injectors and pump the pump and lines clear into a bottle so now the lines are clear. Now run the injectors into their bottles to clear the injectors without running the entire goo from the lines and pump/filter through them.

Now reassemble the engine and start it with the max concentration of Seafoam and go for a long drive. Do not let the engine get cold until you have run it for a solid hour. When you fuel up, put in more Seafoam so you are using the max dose for two tanks as insurance the valve stems are getting lubed (Seafoam has lubricants for this) and you ensure any remaining goo stays in dissolved state. Personally, I'd keep using Seafoam for several more tanks but frankly on the first cold morning startup if you experience no noise/issues you are out of the woods.

Sorry so lengthy but this is prefereable in a couple ways - no tank dropping and no head pulling. PM me if you need further input and I'll shoot you my cell.

Heading out to the garage to replace the original radiator in a 1993 Toyota LandCruiser I bought new that has 240k miles on it and has never been touched by anyone by me. Favorite car to work on by far!
84 944, 87 Vanagon, 88 Mitsubishi Van Wagon, 88 Supra Targa, 1990 Audi 90 20V Quattro sedan, 1992 Lexus LS400, 1993 LandCruiser, 1997 LandCruiser, 2017 Subaru Outback.

Last edited by IdahoDoug; 10-06-2019 at 10:16 AM..
Old 10-06-2019, 10:12 AM
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