Cleaning out an engine
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Drifting
Joined: Sep 2010
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From: Oakland CA
Cleaning out an engine
The oil in this 22yr old engine reeks of varnish, fuel and mold. What is the best way to clean out the old. My thought is to drain the oil, refill with cheap oil, drain and repeat before refilling with the good stuff. The TB appears to be Ok for a few miles and the cam gears don't look worn.
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The rotary engine guys use ATF in the intake as well to clean the combustion chamber.
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From: Blacksburg, SC
Race Car
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^^^Yeah, cheap oil. Don't make my mistake. Non-runner for 10+ years. Filled with VR1. Flooded while trying to start. Oil mixed with gas, so changed oil after 100 miles with VR1 again. Then drove it up to Colin for some work including new engine mounts and he suggested a WYAIT oil pan gasket change. Ugggh, so that's 16 qts of good stuff down the drain in less than 500 miles. 
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From: Gig Harbor. WA
Dropping the tank is the only way you'll be able to clean it out effectively. My car's tank sat half the time your's did and the inside was coated with a thick film of old gas. If you don't clean it out I suspect over time the new gas you put in will break that crud down and eventually ruin the fuel pump, clog the fuel filter and probably eventually clog the injectors.
Dropping the tank isn't very difficult, just takes time. Dwayne's write up is what I followed.
You are probably gonna need a new fuel sender as well. Check out what mine looked like when I removed it.
https://rennlist.com/forums/928-foru...l#post13483935
Dropping the tank isn't very difficult, just takes time. Dwayne's write up is what I followed.
You are probably gonna need a new fuel sender as well. Check out what mine looked like when I removed it.
https://rennlist.com/forums/928-foru...l#post13483935
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My oil recommendation:
-- Don't flush with any oil you wouldn't normally use in the car.
-- Some oil passages and galleys may have restrictions caused by crud. Listen carefully for noises.
-- A couple quarts of reasonable ATF in the oil is a good idea for loosening old oil deposits. The ATF is a very high detergent oil equivalent to maybe 5 - 10 wt motor oil in viscosity. So no hard loading on the engine with this mix in it.
---
Were it mine...
Knowing that the TB and water pump are immediate needs, I'd start by cleaning the outside of the engine as one would for the major front of the engine service. While all that stuff is off, put in your favorite blend of engine cleaning chems, and circulate it through using a drill motor powering the oil pump directly. Rotate the crank periodically by hand, ditto the cams. Whatever you put in needs to lubricate the oil pump so probably not a good idea to just put in straight cleaning solvent, but you get the idea. You can drain and refill a few times until the stuff you take out looks OK. Then put in a few quarts of cheap oil, just enough to pump through and get your cleaning brew pushed out. Drain that after you finish the TB/WP service, put in your favorite oil flavor for normal use and you'll be good to go. Following this protocol allows you to be more aggressive with the cleaning steps without worrying about lubrication while you flush. If MM/OPG is in your immediate future, of course you'll have easy access to the bottom end to see your results. Else use a borescope of other inspection cam to look at your results. It's an easy look at the bottom of the sump through the oil pipe port on the front shelf.
-- Don't flush with any oil you wouldn't normally use in the car.
-- Some oil passages and galleys may have restrictions caused by crud. Listen carefully for noises.
-- A couple quarts of reasonable ATF in the oil is a good idea for loosening old oil deposits. The ATF is a very high detergent oil equivalent to maybe 5 - 10 wt motor oil in viscosity. So no hard loading on the engine with this mix in it.
---
Were it mine...
Knowing that the TB and water pump are immediate needs, I'd start by cleaning the outside of the engine as one would for the major front of the engine service. While all that stuff is off, put in your favorite blend of engine cleaning chems, and circulate it through using a drill motor powering the oil pump directly. Rotate the crank periodically by hand, ditto the cams. Whatever you put in needs to lubricate the oil pump so probably not a good idea to just put in straight cleaning solvent, but you get the idea. You can drain and refill a few times until the stuff you take out looks OK. Then put in a few quarts of cheap oil, just enough to pump through and get your cleaning brew pushed out. Drain that after you finish the TB/WP service, put in your favorite oil flavor for normal use and you'll be good to go. Following this protocol allows you to be more aggressive with the cleaning steps without worrying about lubrication while you flush. If MM/OPG is in your immediate future, of course you'll have easy access to the bottom end to see your results. Else use a borescope of other inspection cam to look at your results. It's an easy look at the bottom of the sump through the oil pipe port on the front shelf.