Hey guys I’m trying to get the advice about the test I did on my 63 impala. It actually runs good and has plenty of power however it occasionally smokes on the freeway for a few secs then goes away. I just did an oil change recently and when i rechecked it I was shocked that it was low. Thats when I decided to test the compression and these are the results. This car I drive almost everyday just around my neighborhood barely on the freeway. I don’t have a lot of money since I’ve got another classic impala,live in San Diego, blah,blah… What would you guys do if you were in my situation? Thanks
Check to see how loose the valve guides are , if they're within reason ( not sloppy) put some umbrella seals on the stems , see if that helps . Looks like #1 has some oil control issues .
Your results are not alarming, except the first result. The rest of the plugs, well, maybe the type of driving you mentioned is a factor. I had a SBC that would foul #8 plug, rest were okay. I just lived with it. OT car that #8 was a pia to get to.
Is the inlet manifold tight?? Does it have a PCV valve around that area?? And as others have said, could be valve guides or old/hardened seals.
Just from my experience, only “blue-ish” smoke I have had from bad guides and seals was some puffing on start up, and off the pedal-worse with using a gear for a down hill grade under a higher vacuum.
^This. While #1 is a bit lower than the others, its not alarming IMHO. Check the oil more frequently, and as suggested, pull both valve covers and inspect the valve seals as a simple and easy (well, new valve cover gaskets might be needed) first step. If they are hard. brittle, or pieces of some of them are laying on top of the heads in the oil pools, you should replace them.
The one is a bit low, but not alarmingly so. I might remove the valve covers and see if the return holes in the head are open so you don't have any puddling of oil. If you want to save money, just check the oil regularly and drive it as Squirrel has said.
I don’t have oil leaking out of the valve covers. I forgot to mention that left side exhaust tail pipe I found oil residue. It’s weird why it doesn’t smoke at idle or low speeds. I drove on the freeway for 5 mins and it smoked for like 10 seconds then stopped.
If it was mine I’d drive it, maybe run a qt of Rislone or MMO for a few hundred miles if a ring is stuck it may free up. If the problem persist I would run a grade heavier oil say go to 10w40 from 10w30, but I wouldn’t go heavier than 20w50. Dan
The original valve seals on those engines are the O ring that seals the stem to the retainer, and there's a steel cup over the top of the valve spring, which acts as an umbrella. The O rings get hard and leak after time. You can change them with the heads on the engine, but it's kind of a pain, and won't fix the other problems that the engine probably has. But if it's running good enough to drive, and you keep up the oil level, it will run for a long time...and no need to spend the time, money, and effort to "fix" it. It's showing it's age, but it ain't broke yet.
Another thing we used to do when we had one oil fouling cylinder was to run a couple steps hotter plug in that hole to keep the deposits from building up too fast. There are some who claim pouring a few ounces of seafoam into a cylinder and letting it soak overnight helps to "de-coke" the rings, never tried it myself. If you try this MAKE SURE you crank the engine over a few times with no plug in that cylinder to purge it of any remaining liquid seafoam. You don't want to bend a connecting rod trying to compress a liquid. I think getting it out on the highway and running it a few MPH above the speed limit for 50 miles might do the engine some good too. If there are stuck rings in that cylinder (evidence of this is the compression going up when you added oil to the cylinder) a good hard highway run may loosen them up.
That 1'st pic is brutal! Not the death sentence, but something to be made aware of..... Lot's of good info given above ^ For a temp to get you by, screw in a non fouler, and a hotter plug. This is temporary. Id'e go for seals as Jim has suggested first, and see how things change/don't.
Generally , most cylinders ,when you add oil ,the compression reading will , regardless of initial compression results , the reading will go up . Put a step hotter plug in & see if it will stay a bit cleaner .
There’s a reasonable chance your lower compression in 1 is due to the carbon build up. Doesn’t necessarily help your oil consumption but I’d have a go at backyard de-coke job, but that’s probably frowned upon nowadays, I’m sure there’s some modern fuel additives you could try instead.
I had an OT Chevy wagon that supposedly had a bad engine, it had an anti-fouler on the #8 plug and a miss. So I took that off and put in a slightly hotter set of plugs and drove it for another 7-8 years. I don't think that the car was driven hard enough before I got it.
That low one is about a 15% drop, really not terrible. And the wet test brought it back up. Possibly cracked rings? I took apart a strong running yet smoky 327 many years back. That was loaded with broken and cracked rings.
Delco R45S is available from rockauto for a buck a piece, plus postage....that's what I'd use. Of course you could just scrape off the carbon and put it back in and drive it, and when the engine starts running rough, take it out and scrape the carbon off again. I did that with my 55 Chevy years ago.... lately I leave the old spark plugs in the old cars I play with, as long as it's running reasonably smoothly there's no need to replace them.
I’ve done valve stem seals on a SBC without taking the heads off. You can either hook up an air compressor hose with a spark plug fitting or fill the cylinder with a cord and run it up to TDC on each cylinder like I did. TDC is easy to check on each cylinder with the valve cover off. You then can use a lever type tool to compress the valve springs. I installed both a cup and o-ring seal on each valve. It seemed to fix the crusty deposits on the spark plugs.
I had an OT 72 Camaro built to LT1 spec's that had one cylinder that the rings didn't seat. I got good at changing that plug but had better luck with Autolite plugs lasting a lot longer than AC plugs. I'm a GM guy heart and soul but to this day still run Autolite plugs.
Check the PCV system [if it has one] How much $$$$ do you want to throw at that engine??? [You're doing a TH350 swap as well] The cheapest way is to buy a later model runner roller cam 350 and disguise it to look like a 327 Or you can get a bit ruthless and re-ring the engine [but be warned, it will end up being more than just rings when you open it up]
I had always heard that if compression was low and you add oil and it comes up at all that it has to be rings. That's not true. I did a compression test on a big block Buick and one hole had 20 lbs. All the rest were normal. Added oil and it went up to 60. Uh oh. Pressured up the cylinder with air and wouldn't you know, the air was coming out of the exhaust. I had a carboned up valve that was stuck open just slightly. After a valve job all the cylinders have good compression. I'd pressure up the offending cylinder and see if you can hear where air is going. That will tell you what you're dealing with.
The Jalopy Journal
