The 430ci possibly burning a quart of oil at about 800-1000 miles is that due to low pressure piston rings design? Thanks.
Is the motor stock, if not please give a good bunch of details for us to chew on because this week my crystal ball is getting worked on and not available for insite.
Yes stock. No problems with motor. Just asking what caused the oil consumption at about 800-1000 miles burning a quart. Was that cause of lower piston ring tension or?
My stock original 1969 430 has almost 80,000 miles and I don't need to add any between oil changes. Compression test and plug examination will give you a clue.
Any smoke at any time? Initial startup would be possible valve seals. During hard acceleration might be valve guides. Check the PVC hose and see if it is full of oil. Do you have adequate fresh air going into the engine via a breather?
Thanks. All not necessary though. These engines doing this kind of oil consumption is normal. My question is what is causing oil consumption in this engine design? I know that some don't use as much oil. But with a 430ci i have always been around a 1000 miles and a quart of oil. Nothing wrong with the engines though. That is not my question here.
Piston rattle due to not enough octane or too much timing will increase oil consumption as will of course sticking rings from carbon. In either case SeaFoam treatment can help.
Yes. I have mentioned this before here and have been told that a quart on 800-1000 miles is normal as long as the plugs don't foul.
I think some are/were better than others especially now that most are 100K+ miles. Mine was using some oil but then I put new valve seals (teflon) in on both intake and exhaust and barely used any oil. Maybe a quart in 4000 miles. So, I don't think it is a "design" issue other than being a carbureted motor with a choke. Most motors back then used some oil....not built as tight as engines today plus fuel injection results in less washing of cylinder walls on cold starts.
I had a 1965 Chevelle SB that used even more oil than yours. What I found; valve seats shot with only 45K miles on the engine. When I was running 60 mph and had to let off the gas for slower traffic, I could see that nice blue smoke coming out of the tail pipe in my rear view mirror. When running without letting off the gas, no smoke. You might want to check your tail pipe for oil residue. This Chevelle when I bought it in 1972 (7 years old= 6,428 miles per year) came from HI and was garaged most of the time. I assumed; the valve seals deteriorated from lack of driving. You could tell the car was garaged because the exterior paint looked new. Had that Teal/Blue color, a very beautiful car. Later on, the Powerglide trans started slipping. This car needed to be run, NOT sitting in a garage for months on end. VET
I have also replaced the valve stem seals in the past (intake only). I did not know installing seals on the exhaust side would help? To me it is no problem. Like i said i was just asking what it could be some engines always seem to burn more oil. I have read here that when these 430's were new some could also easily burn a quart at a 1000 miles while others did not....
Why have you concluded "It's normal". That is false from my experience. As 69Wild said above, the ones I have owned did NOT need oil between normal changes. This includes one that was well over 100k miles.
Well, unless you do a complete tear-down, not sure you will ever know what is causing the burning oil situation. I'm not a Buick engine expert. From what I have read - Please read the following - The 430-cubic-inch (7.0 L) was only produced from 1967 until 1969. This engine had a bore and a stroke of 4.1875 in × 3.9 in (106.36 mm × 99.06 mm). The 430 four-barrel engine was rated at 360 hp (268 kW) and 475 lb⋅ft (644 N⋅m) of torque. This engine was used in large B-, C- and E-body Buicks. Most parts except the pistons interchange with the 400 and 455. My understanding is, is when the 430 clock is bored out, it becomes a 455 ci engine. The reality is, all parts can be swapped between the 430 and 455, with exception of the pistons. If anybody on the forum can add or correct me. The 400, 430 and the 455 is a very old engine design, and I would think, Buick engineers have not changed a lot of engine parts between these engines. Like I said, I'm not an Buick engine expert. VET
I have read here members said they never had great oil mileage, that is why i said it. I am only interested about what my initial question is.
If it's a stock engine, it does not have low-tension rings. Therefore, the tension "pressure" of the rings as installed by GM is not the cause of your oil-consumption problem. It may be that those rings are worn-out, or the cylinder wall has wear/glazing/scoring. Maybe the rod bearings are worn out, and they're throwing excess oil on the cylinder walls that the rings can't scrape away. As said, the PCV system is suspect. There's dozens of potential causes of high oil consumption. Chevrolet used to say that a quart to 700 miles was "normal". That's what the Chevy "Zone Representative" told me in '84. I have no doubt that that sort of nonsense was also parroted at the other GM divisions. It's a lie designed to lower warranty repair claims, and save GM money by screwing the customer. "A quart to a thousand" hasn't been "normal" since long before I was born. WWII era, or maybe into the 1950s. SOMETHING IS WRONG. Even antique engines can have improved oil consumption when overhauled using modern machining techniques to correct the sloppy OEM machine work of the time. Don't confuse "normal" with "common", like that zone rep wanted us to. It was common for engines to burn excess quantities of oil, but it wasn't normal. And since something is wrong, if you find and fix that something (or somethings), your oil consumption should greatly improve. The question is, does it mean enough to you to spend the time, money, effort, and enthusiasm to find and fix the problem(s), or are you satisfied dumping a quart-to-a-thousand, and shutting the hood? "I" would at least verify the easy stuff. PCV. Oil contamination via faulty fuel pump or faulty choke. Misfires. Detonation. Overheating. Cylinder compression and leakdown testing. Maybe pop a valve spring or two and check valve stem-to-guide wear. And don't mistake oil leaks for oil consumption. Is the engine filthy? Oil trails leading from the oil pressure switch/sending unit? Front seal? Rear main leakage? Valve covers?
Just the info i was looking for. Thanks. And yes a stock engine. If the pcv hose is clogged the pcv unit at the back of the intake manifold should be clogged as well? I replaced it ones before it rattles when you shake it which means it works fine.
1. If a PCV hose is "clogged", EVERYTHING is suspect, and nothing is guaranteed. The PCV valve may or may not be damaged/faulty as well. The PCV valve should be examined, maybe replaced, perhaps cleaned with solvent (aerosol carb spray is what I use.) A "clogged" hose indicates excessive oil/carbon/dirt/debris getting into the PCV system, but that could be from either end depending on what is wrong. I've seen more "soft" hoses that suck shut under vacuum, than "clogged" hoses, but there've been a few of them, too. 2. A PCV valve in good condition will "rattle". They can rattle, and STILL BE DEFECTIVE. "Rattling" is not a sufficient test of the valve. 3. A PCV valve can be in perfect condition, but if the valve is drawing excessive oil mist into the PCV system and thus into the intake manifold, you'd have excess oil consumption even though the PCV valve and hose is fine. The PCV valve should be baffled to reduce or eliminate oil mist being drawn into the PCV system. Missing or damaged baffles cause excess oil consumption. 4. Excess blow-by can overwhelm the PCV system, forcing oil mist past the baffle at the PCV valve, and also causing oil mist to be drawn into the air cleaner via what should be the "fresh air inlet", but becomes a crankcase vent due to the large amount of blow-by. If pressure builds-up in the crankcase, oil can be forced past seals and gaskets leading to external leaks. EXCELLENT questions.
Understood. There is no excessive blow-by. No external leaks. The engine has never been apart. Believed to be 63K original miles. Runs strong. No smoke. No plug fouling. No problems at all. 19" of vacuum. I run it mostly like an old lady. But i do add a quart of oil every 800-1000 miles. I run mineral 15w40 by Valvoline.
