Valve cover smoke after switching to synthetic oil
- Thread starter Fred A
- Start date
No, stay with syn oil. How are you seeing oil coming from the valve covers when the breathers are sealed to outside air? With the "in" coming from the air cleaner housing and the "out" going into the carb base via the pcv system?
CBODY67
CBODY67
Coming from valve covers? You'll have to be more specific. Do they leak? That's the usual cause. Try tightening the bolts on the valve covers, but I'll bet the gaskets are shot.
I use synthetic in my drivers and semi-synthetic in my old cars. Even in brand new engines. Never a problem.
bronze turbine
Active Member
Probably your valve cover gaskets are leaking oil on to the manifolds.
RemCharger
Active Member
No synthetics in old engines for this guy.
Hope you put something in to try and save the cam
Hope you put something in to try and save the cam
You should be using a high zinc classic car oil. Castrol GTX Classic. Lucas Hotrod/ Muscle car oil, Brad Penn/ Penn grade. Etc...
Hot Rod & Classic Car Motor Oil | Lucas Oil Products
Lucas Hot Rod & Classic Car Motor Oil is manufactured with the highest quality paraffinic base oils and is fortified with a unique additive package containing high levels of zinc, molybdenum and phosphorus, which provides a tougher, thicker additive film for maximum protection even under the...
High Performance Oils -
penngrade1.com
Knebel
Senior Member
Can I recommend a Liqui Moly brand ceratec or mos2 additive. I ran that with every oilchange in a 4cylinder 7000rpm engine with flat tappet and no hydraulic lifters. Never had any real wear and after a few oilchanges I even noticed a 1 to 2 mpg increase! I think the ceratec is better, smaller partickes.
Can crank case pressure increase slightly when using new / fresh / synthetic oil, resulting in seal and gasket leaks where they weren't happening before? Assuming the crankcase is relatively sealed / close to begin with. Is the PVC valve supposed to prevent crankcase over-pressure? Maybe it needs to be checked here?
commando1
Old Man with a Hat
What's the best oil?
70bigblockdodge
Old Man with a Hat
Synthetic flows easier, or has characteristics of a thinner conventional oil, hence the 0w20 or whatever. How can it be a Zero weight oil? Well it's not, but it acts like one. They work well in modern cars that don't contaminate the oil very quick. Old cars with starting on the choke, or short trips will dirty a oil fast, negating any benefits of synthetic in short order. It will not hurt anything per-say, but expense is more and the life is about the same as conventional oil, so why? Peace of mind? They do lubricate better due to pairing down the good and getting rid of bad in regular oil.
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can I switch back to conventional oil?Car not driven just idle
I think switching back to conventional oil is not a problem. Change the filter also. When I change oil in any car, I like to do it in the morning after it has sat overnight, let it drain for a 1/2 hour at least, and then pour maybe a cup or two of fresh oil into the oil fill hole and let that also drain out.
The idea, or theory, or reports of synthetic oil interacting with seals and gaskets and engines leaking when they never leaked before has been around for a while, but you hear far less of that now because all the old cars with the old gaskets and seals are mostly gone. But 20 years ago this sort of talk was a lot more common.
But as others have stated, unless you have a roller cam, everyone needs to be paying attention to zinc (ZDDP) levels in the oil they're using. There are people in the Bobs-the-oil-guy forums that post oil analysis results and the zinc levels of some modern retail oils are there to see.
But if your valve cover gasket is leaking and that's why the oil is smoking on your exhaust manifold, then you need new gaskets. Since I have a 318 (with only 5 cover bolts) I went searching for a rubber gasket with a steel liner, and was able to get one relatively cheap (about $18) but haven't put it in yet. I assume they're also available for the big blocks.
The idea, or theory, or reports of synthetic oil interacting with seals and gaskets and engines leaking when they never leaked before has been around for a while, but you hear far less of that now because all the old cars with the old gaskets and seals are mostly gone. But 20 years ago this sort of talk was a lot more common.
But as others have stated, unless you have a roller cam, everyone needs to be paying attention to zinc (ZDDP) levels in the oil they're using. There are people in the Bobs-the-oil-guy forums that post oil analysis results and the zinc levels of some modern retail oils are there to see.
But if your valve cover gasket is leaking and that's why the oil is smoking on your exhaust manifold, then you need new gaskets. Since I have a 318 (with only 5 cover bolts) I went searching for a rubber gasket with a steel liner, and was able to get one relatively cheap (about $18) but haven't put it in yet. I assume they're also available for the big blocks.
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Exactly what oil is in the car?
My Brad Penn (now Penn Grade) oil is a semi-synthetic with a high amount of zinc and phosphorus.
IMHO and based on reading a bit on the subject....
First, a lot of the oils aimed at the old car, flat tappet market are synthetic or semi-synthetic. Some are conventional oil too.
Second, most of the damage that occurs from using an oil with lower ZDDP levels are where there's high pressure valve springs. Your Chrysler has lower pressure springs that are 46 years old.
Third, yes you do need some ZDDP with your flat tappet cam, but damage doesn't just happen the second you fire up your engine... It takes a bunch of miles and read my second point.
So... First thing is to fix your leaks. Doesn't matter what oil you put in, it's still gonna leak. Valve covers are easy...
If you feel more comfortable, change the oil. You haven't done any damage and I'd say if you ran the oil until the next change, it will be OK. But... Since you are questioning it, go ahead and change the oil. I run the Brad Penn oil Motor Oil | Brad Penn | PennGrade 1® High Performance Motor Oil There are a lot of other, similar oils and if you ask 10 guys what they run, they will give 10 answers.
But, again, what oil did you use?
If you are willing to use an additive, just dump it in the oil that's in there. Basically, you are doing exactly like you did before, using a low zinc oil only now you are dumping some snake oil in it.
Personally, I don't like oil additives. You don't know if the additive is doing what it's supposed to or not. I think most additives for oil or gas are specially formulated to take money out of your wallet.
Your oil is already at 760 ppm of zinc. 1000 to 1200 is optimal and over 1500 can cause problems. US_Val_AdvancedFullSyn_10W30_MO_EN.pdf - DocuSign CLM Too much zinc, over 1500 ppm, can cause some corrosion problems that are worse than too little.
The thing that started this is your valve covers are leaking... You need to fix that. All the old wives tales about synthetics leaking more is so much nonsense. Chances are your valve covers have been leaking for a while... You are just noticing it now.
Sixpactogo
Well-Known Member
I agree on leaving the oil alone and replacing the valve cover gaskets. I use the better grade neoprene gaskets. I clean the head lip and valve covers real good. (make sure the mounting surface around the holes is flat) My personal way of installing is to smear a thin layer of black High temp RTV on both sides of the gasket. I then install them just finger tight and let them dry over night. then torque them to 40" pounds. (not foot pounds)
Never had one leak after using that method.
PS: with an older engine with lots of miles you may start noticing other leaks such as the pan or timing chain cover. Synthetic oil is thinner and does have a habit of finding those areas. Good luck.
Never had one leak after using that method.
PS: with an older engine with lots of miles you may start noticing other leaks such as the pan or timing chain cover. Synthetic oil is thinner and does have a habit of finding those areas. Good luck.
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