I recently bought a sbc that has been sitting a few decades. The engine will turn over, but I am concerned about 30 years of gunk inside. An idea popped in my head to fill the block with diesel and using a drill on an oil primer for a while to pump it through the engine, change the filter, then fill with good oil and prime until pressure builds. Anybody ever do this? I have heard of people letting an engine run for a bit with kerosene or diesel mixed with the oil to clean it out, but I am wary of ruining the bearings.
The engine is out of the vehicle. Pull all the tin off and clean the crud, clean the pickup, regasket it. I have done the flush with 1/2 50wt and 1/2 naptha. I feel lucky i didnt burn down the shop or wipe out the bearings. Getting all the sludge stirred up, will likely clog your pickup.
I would never flush an engine. Too many ruined that way. Since the engine is out of the car take off the pan and valve covers, inspect and clean. If it is bad take off the intake and clean out the valley too. Really the oil pan and pump screen are the main thing but valve covers are so easy to take off.
Something learned from an engine re-builder on a motor that sat a long time, pull the pan, then with the engine upside down fill the pistons with transmission fluid to get the oil in the wrist pins. (let oil soak in overnight)
Better off to drop the pan & clean out the gunk first. If the pan is fairly clean it's probably OK to run, but if you are worried about it, go ahead with your cleaning project. If the pan is full of crud & gunk, pull the valve covers, de-gunk them, & pull the intake & de-gunk the valley. Cheap insurance, especially if heavily gunked, would be a new oil pump & screen.
3 experience with engine flush. 1 was on a carbureted S10 with a 2.8. When emission testing first started I thought it would be a good idea to “flush all the funk out of my winter beater” Well ran the flush for about 20 minutes, did the oil change. Oil pump was so worn it lost its prime !!! Had to rev the engine to get the oil pump going again!! After that never did flushes on anything ..... ever ! The other two were when I worked at ford , both vehicles less then 10 years old one an F150 the other a 4 cylinder something. Shop wanted you to put the flush in the crankcase and drive the car around the block, both cars came back from there road test knocking badly!! So yeah, it’s out of the car. Pull all the tin, heck for what it’s worth, get a full gasket set and pull the heads so you can see everything and clean it all up replace any old/bad gaskets.
Yeah that was a big mistake. The old timers used to replace a quart or two of oil with kerosene in the crankcase and let it run at a fast idle for 20 minutes or so. Idle only. No load on the bearings that way. Drain and refill with fresh oil.
If you have the engine on a stand, have the fluids out of it, the pan and valve covers off and it’s a used engine, why not go ahead and pull the heads and check for ring ridge/ condition. And do a bearing check. I always hated r and r an engine, likewise overhauling in the car. Rebuilding/ overhauling on an engine stand was pleasant work. While I had it out, I’d check it out! ..... but that’s just me. Bones
Listen to Boneyard51, IMO if bearings look OK (check front main, front connecting rods, SBC oils back to front) always replace oil pump. SBC kits are as very reasonably priced, look for rust/crack damage/water damage. You will get an idea what in fact you bought, a decent core or junk. Imo you might as well make it right, my opinion and $2 buys coffee where I eat breakfast. Good Luck with your project.
If I wanted to mess with it, without taking it apart, I'd just get it running and see what condition it is in. I would not do anything to the oil, besides draining and refilling with fresh modern oil. But a gasket set for that engine is not expensive, and I'm curious, so I'd have to take it at least partly apart. And I would probably change all the gaskets and seals, unless it looked like it had been rebuilt, well, and didn't have many miles on it.
If it is out. I would look at the cooling side too. The block core plugs and if they ran Rad stop leak. Pull the water pump and thermostat. And check for crust or gummy crap.
I've never seen an engine that set for decades that stuff didn't migrate inside. Your SBC has a filter bypass valve if pressure difference across the filter exceeds about 6 to 8 pounds unfiltered oil will get into the oil passages not something I would chance. Do it right not over.
In my gas station days a customer brought in a 65 Galaxie with a 289 that was noisy. Only short trips daily on the car. Orders were to desludge it, don't drop the oil pan though. I pulled the valve covers and intake, literally a massive pile of sludge. Scraped out all that I could by hand. Kerosene brushed over all the surfaces. Drained the oil, filled the pan with Kerosene and pushed it outside for a couple of days. Brought it back in, repeated this twice. Fresh oil, reassemble. Started, no noise. It was about two years later I saw her still driving it so it must have worked.
Engine out. For me, it's a pleasant, therapeutic activity to pull her all apart. Fire in the woodstove, nice stool pulled up. Outlaw country on the satellite. If you find no problems, you don't have to spend much. If you do find a problem, then it's sure time well spent. I like knowing every nut and bolt in the thing.
Well I got around to pulling the drain plug. A bunch of antifreeze came out before the oil... Looks like it's coming apart. I am hoping it was just a leaky intake or head gasket and not a big crack somewhere, but I'll probably have to pull heads to verify. Fwiw, I went ahead and did a compression check and got moderate compression on all cylinders except for #8 which had none, so maybe I will pop that head first to see if the problem is there. Sent from my XT1635-01 using The H.A.M.B. mobile app
The inside looks surprisingly clean considering the slop that drained out after the coolant. Everything has been numbered so it appears to have been rebuilt at one point. I am wondering if this was a rebuild gone wrong which would explain why it was parked 20 years before my friend bought the car out of a field. Sent from my XT1635-01 using The H.A.M.B. mobile app
Most stuff was factory numbered Sitting in a field for a 30 years you are doing it right taking it down did it even have an air cleaner?
So I went and pulled a head off so I could see what was up with #8. I have decided this was a diy rebuild by somebody with more ambition than skills. All cylinder walls had these verticle grooves you could feel with your fingers and the worst hone job I've ever seen. There was one new replacement piston as well so who knows how bad that one was for it to be discarded. Everything looks very clean, in fact the underside of the intake looks brand new, so it is my guess that some body slapped it together and once they realized it didn't run worth a crap they pushed it out to pasture. I am going to take the crank and rods to my machinist and if they are salvageable I will buy pistons and use the rotating assembly in a fresh .030 over block I was saving for my nova. Sent from my XT1635-01 using The H.A.M.B. mobile app
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