71MonteCarloMD Posted July 16, 2021 Share Posted July 16, 2021 I am wondering if you would give me some guidance on burning or loss of oil. It’s a SB 350, no visible oil leaks. After oil change, the oil turns black quite quickly. What should I do as I have to add 1 qt of oil every 1k miles. is this something I should be concerned if I just keep on adding oil? Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 16, 2021 Share Posted July 16, 2021 Assuming it’s the original engine, the oil turning black is usually caused by carbon in the engine. Some people say that you can flush the engine and clean out the carbon. Problem with that is, if the carbon release happens in chunks they end up in the oil pan and block the pickup screen. Not a fan. Change the oil more often and eventually it will get cleaner. You could pull a valve cover and see how clean the top of the head is. The using of oil could be multiple issues. Is it smoking when you start it? If it runs fine I would just change the oil a little more often and keep checking the dipstick and add as necessary. IMO. Quote Link to comment Share on other sites More sharing options...
Brew Posted July 16, 2021 Share Posted July 16, 2021 Might need an Italian Tune up! 😎 Quote Link to comment Share on other sites More sharing options...
Brew Posted July 16, 2021 Share Posted July 16, 2021 But seriously, if it runs good & compression is good I would just change oil more & use the best gas you can. Where I live we have non ethanol & that’s all I use in mine. As Dtret said carbon cleaning is a risky business. I’m sure other posters will chime in & offer some solutions that they used in the past. Quote Link to comment Share on other sites More sharing options...
Rob Peters Posted July 16, 2021 Share Posted July 16, 2021 What do your plugs look like if you pull them? You may have some rings going bad with the oil going through and out the exhaust. If there are no leaks the oil has to be escaping out the exhaust. rob 1 Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted July 16, 2021 Author Share Posted July 16, 2021 Not sure if the engine is original but it runs fine. I will need to pull the plugs to see what it looks like. for changing oil more frequently, do I use conventional oil or high mileage? Do I change oil filter when changing? Quote Link to comment Share on other sites More sharing options...
Leghome Posted July 16, 2021 Share Posted July 16, 2021 I always change my filter when I change oil no matter how many or how few miles it has on it. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 17, 2021 Share Posted July 17, 2021 Try Rotella diesel oil. Has a high zinc content for the cam and lifters and diesel oil has detergent in it. It should eventually clean the carbon out. 1 Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted July 17, 2021 Author Share Posted July 17, 2021 Thanks all, I do not have non ethanol gas near me, is octane 87 ok as it runs fine? Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted July 17, 2021 Author Share Posted July 17, 2021 28 minutes ago, MC1of80 said: Rotella diesel oil. Assuming it’s by Shell and which weight should I get as I usually get 5w-30 as it seems to come in 10w-40 or 15w-40? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 17, 2021 Share Posted July 17, 2021 I run 15w-40. The clearances in the older engines even after a rebuild are bigger than the new vehicles that use 5w-30. 1 Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted July 17, 2021 Share Posted July 17, 2021 10 hours ago, MC1of80 said: Try Rotella diesel oil. Has a high zinc content for the cam and lifters and diesel oil has detergent in it. It should eventually clean the carbon out. Interesting. Never heard this suggestion Quote Link to comment Share on other sites More sharing options...
Leghome Posted July 17, 2021 Share Posted July 17, 2021 Interesting. Never heard this suggestion My son in-law told me the same thing it has the zinc and is of a thicker velocity according to Jamie. I still use Valvoline 10 W 40 which is what my engine builder reccomended Quote Link to comment Share on other sites More sharing options...
bigtankjones Posted July 17, 2021 Share Posted July 17, 2021 Yep. Could be bad rings, worn valve guides and valve seals. Quote Link to comment Share on other sites More sharing options...
Glen Posted July 21, 2021 Share Posted July 21, 2021 Prior to buying my 70 SS, I spoke extensively with the sellers mechanic who had done a ton of mechanical work to the car in the time he owned it. He replaced the cam, timing chain, valves, lifters, push rods, installed roller rockers...etcetera... He used Kendall “Liquid Titanium” 20W50 high zinc formula to break everything in and has used it for every oil change since that time. I wasn’t about to create bad juju so I’ve been using the same for my oil changes. I do however use AC Delco filters. Anywho... six of one, half dozen of the other. Everybody has their own favorites, regulars, usuals. Try different things until you achieve the desired results. Quote Link to comment Share on other sites More sharing options...
72 Monte Carlo Posted July 21, 2021 Share Posted July 21, 2021 You should pull the spark plugs and run a compression test of each cylinder, and write it down as you test each one. If it's not leaking the oil externally, then it's burning it out the exhaust. On piston rings, the top ring is meant to hold your compression above the piston so that the engine will fire on each cylinder as it ignites the spark from the plug. The 2nd (lower ring) is there to wipe the oil off the cylinder wall as the piston moves in its downward stroke so that oil is not being introduced into the combustion chamber. Depending upon how many miles are on the engine, it could be carbon buildup or the piston rings are worn. That's why I would recommend a compression test first to see where each cylinder is currently at, and if the compression of all 8 cylinders is within service limits. Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted July 23, 2021 Author Share Posted July 23, 2021 All, thanks for sharing and I took picture of the spark plug from each side, doesn’t look like oil is coming to them? will try the compression test soon. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 23, 2021 Share Posted July 23, 2021 Are all the spark plugs like the one pictured? That one is not horrible. That one is not your oil consumption. Check all the plugs. If they look like that one you have a leak somewhere. Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted August 1, 2021 Author Share Posted August 1, 2021 All, I pulled all spark plugs except one, they all look the same in the pictures above. I noticed there’s small smoke coming from exhaust on passenger side as it comes and goes away. Is that how the oil burns? If so, what can I do to fix that? Quote Link to comment Share on other sites More sharing options...
Dtret Posted August 1, 2021 Share Posted August 1, 2021 It’s possibly just a valve seal, if it’s only a little bit Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted August 1, 2021 Author Share Posted August 1, 2021 Thanks Dennis, that’s what I suspect after reading some info as will do compression test to confirm that the cylinders are in good shape. Curious what’s the complexity level for a DIYer to replace the valve seals as I never rebuilt an engine but did rebuilt other stuff like carb, brake caliper? Quote Link to comment Share on other sites More sharing options...
Dtret Posted August 2, 2021 Share Posted August 2, 2021 55 minutes ago, 71MonteCarloMD said: Thanks Dennis, that’s what I suspect after reading some info as will do compression test to confirm that the cylinders are in good shape. Curious what’s the complexity level for a DIYer to replace the valve seals as I never rebuilt an engine but did rebuilt other stuff like carb, brake caliper? You should be able to do it with the purchase of a few special tools ( not expensive) or rent a tool from the auto parts store. The hardest part is readjustment of all the rockers. But really if it’s not smoking bad and not using a bunch of oil let it be. Usually when it is time for valve seals it’s probably getting close for a rebuild. Remember the rings could be wearing down also. Valve seals are just an educated guess. Quote Link to comment Share on other sites More sharing options...
jft69z Posted August 2, 2021 Share Posted August 2, 2021 1 hour ago, Dtret said: ...and not using a bunch of oil .... I think he said a quart every 1K miles Rick, You need to be very mindful of making sure the piston is at the top of the cylinder for each valve pair you work on. If not, you run the risk of dropping the valve into the cylinder, past the point in the valve guide that you can't grab part of the stem to pull it back out. I use air thru the spark plug hole to keep the valves closed, but some people shove a rope in the cylinder to keep the valves from dropping. Never had a problem with just the air, but again, more special adapters, etc to get it done. A compression test is a good place to start, maybe a leakdown test too. Quote Link to comment Share on other sites More sharing options...
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