Had my 283 rebult by a local reputable shop. It did sit in a dry garage for 3 years before I got it in a car and running, but now it's out of warranty. It's burning a quart of oil every hundred miles, and fouling a set of plugs every 700 miles. Compression is 125-140 accross the board. Smokes when you start it, smokes when you decelerate, most of the time it smokes at idle. Not like a mosquito fogger, but it ain't cool. Oil pressure is 30 at idle, 60 down the road. I recently changed the oil and added a quart of Rislone (on the advice of another engine builder), and took a 650 mile road trip to "break it in". It's got 2200 miles on it with no improvement. It runs great before the plugs foul. Question: Is it worth throwing away a saturday to throw in a set of umbrella valve seals, or is this a lost cause?
Don't take just my word for it but when G.M. first came out with that engine they had trouble seating the rings because the blocks were so hard. Their cure was to sprinkle Bonami cleanser down the carb. at fast idle. Everything I've read it worked. I had a 265 rebuilt in the '60s. It never quit using oil.
Several things come to mind here. 1. Were the rings installed up-side-down? 2. Yes, put FORD rubber umbrella valve seals on the heads. And I would before I tore her down.... 3. Pour a small bottle of good old MMO in her after squirting some in each sparkplug hole, just in case it's rings need un-sticking. Now if this was onna my "dingle-berry/Krylon spray can" overhauls, I'd run the dog-sh*t outta her and roll on just like I've done before BUT I always checked her oil at every fill-up!! pdq67
Try the umbrella seals first. Lots less headache than pulling the heads. Just remember to carefully put a rope in the cylinder and bring up the piston slowly on the compression stroke to keep the valve from falling into the cylinder. If that happens, you will most likely be inclined to say a bad word or two...
What does a vacuum gauge show? Low and steady, fluctuations, needle jumping around, etc. That will tell you a lot about the condition of the rings, valves, etc. Sounds a bit like a Monte Carlo I bought that had sat in a storage unit for 8 years. Guy sold it cheap because he thought the engine was toast. Smoked at start up, smoked at idle, smoked when you let off and vacuum was low just like bad valve seals. Mine had better compression though and there wasn't more than 5 PSI difference between all 8 even though it had 96,000 miles on it. Check your intake gaskets before you go too crazy. Pull the carb and see if there is a film of oil in the runners. If there is then chances are good the gaskets are leaking along the bottom edge pulling oil from the lifter valley. I put new intake gaskets on mine and oil consumption went from a quart every 50 to 1/2 a Qt. every 2,000.
I did that to an engine once. Dissolved the cleaner and trickled it down the carb. The new rings I put in were'nt sealing properly. Did the trick nicely.
"Is the baffle installed in the lifter valley?" Good point, but it may have a road draft tube on it so it won't be an issue, imho, b/c everything would puke out it straight down to the road... Not smoke out the tailpipes. PCV valve hooked up, RIGHT as are the intake manifold gaskets not sealing right. pdq67
Another vote for bad valve stem seals. The early heads weren't machined for umbrella seals and the "O" rings are marginal at best. Perfect Circle used to sell a tool to machine the guide bosses and install their Teflon seals, worked great and oil usage went to nothing.
more than likely the gasgets that they sell you now are for a 350 and they dont cover the ports on the older smaller heads sounds like it needs a good tear down and re overhaul, a ball hone will put a nice patern on the walls for sealing maybee have someone who dos a lot of SBC do the teardown and re***embly something is not right and a lot of stuff needs to be checked out i built a racing engine with used rings and it did not have all the problems that you are stuck with after rereading this i have a engine that will oil the plugs and drive it all over the country, I am sure it has a guide problem someone must have taken some shortcuts on the work done to your engine
Yeah, that works IF you have an air compressor and the adapter for the spark plug. I didn't for the longest time & the rope always worked.
Three old timers have told me about the bon-ami trick, none of them have heard about anything gettin' hurt by it. That's ***uming it's the rings not seating. There is some oil pooling in the right side, middle two pockets on the intake. However, ALL the plugs foul equally, not just those two. PCV is working properly, and there doesn't seem to be any ring blow-by.
just had the same problem with the rear cylinder of a harley motor I built. Exhaust valve guide seal fixed everything. if not, all you're out is valve cover gaskets and $20 worth of valve guide seals.
Cat tractor also advised using Bon Ami to de-glase cylinders. BUT only use Bon Ami nothing else. And + 1 on intake gasket problems.
They didn't happen to use chrome rings, did they? They can be hard to seat in if the crosshatch isn't just so.
What you're describing right there is typical for bad intake valve guides and/or seals. At start up it will smoke from oil that got past the guides after the engine was shut off. At idle and during decceleration is when manifold vacuum is the highest and it will try to pull oil past the intake guides into the combustion chamber. But if you're going thru a quart every hundred miles I'd think it would be smoking like a train. Make sure you don't have an oil leak somewhere else too. Think it would be worth your time to at least try putting some umbrella seals at least on the intakes. While you've got the valve covers off make sure the oil drain ports in the heads are clear so it's not pooling oil up in the valve covers. See if there's a baffle of any sort in the valve cover where the PCV valve goes in, so it's not pulling in splash oil. Could you maybe have too cold of a spark plug in it? Some engines can be a little picky about having the right PCV valve in them too. If it's an aftermarket valve, maybe try a real ACDelco one in it.
The stock valve guide seals have dried upa cracked from sittin' so long ,,change em to the Ford umbrella style ones ,,BUT ,,you don't need to pull those heads to change em ,,,i've changed seals AND valve springs with out pulling the heads for 30years or more ,,theres a tool to compress the valve springs and a spark plug hole adapter to inject compressed air into the cylinder to keep the valves closed while compressing the springs to change the seals ,,Snap On ,,Craftsman ,,Mac & Matco all sell the tool and adaptor ,, i used to change broken valve springs on my 396 at the drag strip ,,back in the '60's ,,no air adaptor ??? use a piece of nylon rope thru the spark plug hole to keep the valves closed ,,just gotta hand rotate the motor bacwards to bottom dead center ,,snake the rope in,,hand rotate the motor back right way to compress the rope agains the valves ,,compress the springs ,,change the seals ,,rotate the piston down again ,,pull the rope out and go to the next cylinder,,,had to do the rope trick on the side of interstate 80 one day ,,in '70 ,when my '69 SS396 Chevelle broke a spring on my way back to Des Moines from racing all day in Omaha ,, Beats the heck outs pullin' the heads ,,
BUT that would be pulling ATF out of the transmission not the crankcase YES it would be fouling plugs
Oil will wick up the bolt holes if the intake gaskets are leaking, forgot to add my Monte was doing that too. Just because there's no visible oil on the other side doesn't mean that side isn't leaking along the bottom as well. Even if it's only leaking on one side in one spot it can still pull into all 8 cylinders although the cylinders closest to the leak would probably foul soonest and the worst but it wasn't by much on my Monte. The O-ring seals "shouldn't" dry out in 3 years, especially on an engine that has never been run before. Not saying it isn't possible though, never say "never".
I had the same problem with oil usage and everything checked out fine but the PCV valve, so I changed it out for a new NAPA auto parts one and it still ****ed oil. So then I looked on a mustang forum to see what they had to say and everyone told me to get a motorcraft PCV valve from ford that was "for" my mustang. went down to ford and got a PCV valve from them and within 5 min the problem was gone. But I my second question is what rings does it have? If it has chrome rings they are a ***** to seat and if not done right, could end up using alot of oil. Chevys do have ****ty valve seals (the o ring is a joke) so I would definatly reccomend the umbrella seals if you get that far into it.
i had a late 70's truck i rebuilt the 350 in years ago. i used chromoly rings and had a hard time getting the rings to seat.. my dad was a mechanic for gm back in the 60's and early 70's, he told me to put a half quart of diesel fuel in my oil and drive it down the road and back pretty hard.. did it ,they seated, and or unstuck, and i changed the oil and filter
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