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Need SBC(350) help quick! My DD is down...

Discussion in 'The Garage' started by BowtieBlazer, Jun 25, 2005.

  1. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Alright folks I could really use some help solving a very mysterious problem. I blew a head gasket and got water in the oil of my old 350 two weeks ago. Luckily I still had the motor from my last blazer project. The history on that motor is that its a nice 350 that ran flawlessly when I parted the truck out. The previous owner of the truck claimed it to be a crate motor and by the way it ran then until now I had no reason to think other wise. I shecked the block # it was manufactured in 98' The motor sat on a roll around motor stand for the past year inside a shop, completely covered minus the exhaust manifolds. I spent a night at the end of last week replacing the valve cover gaskets, oil pan gasket and rear main seal, pulled the performer RPM intake off in favor of a regular performer and sealed everything back up tight. The good news is that the engine has no leaks--really nothing to speak of before but wanted to be sure that it wasnt going to need maint. again soon. Before planting the distributor I bought a manual oil pump tool to prime the motor over before starting it up for the first time.

    I dead timed it at 0 and it fired over first time, GREAT! I adjusted the timing with a timing light and advanced it to 8 degrees and hooked up the vacume advance. The motor purrrrrs but I have light exhaust smoke, looks bluish grey, smells like junk. I drove it around a bit and performance was horrible with all the combusted oil and smoke, so I drove it back home, at certain RPM's it'd almost level out, but still smoke. (we're talking mosquito smogger thick) Knowing I'd get pulled over for smog here I just parked it for the night.

    I next disconnected all unecessary vacume lines from the carb to eliminate the posibility of it coming in from the tranny line of pcv valve -- no change.

    I swapped carbs to the one that came off my running motor -- no change.

    I did a compression test and my results were:
    cylinder 1: 145psi fouled,oiled cylinder 2: 145psi fouled
    cylinder 3: 140psi fouled ____cylinder 4: 150psi fouled,oiled
    cylinder 5: 150psi fouled,oiled cylinder 6: 145psi fouled,oiled
    cylinder 7: 140psi fouled,oiled cylinder 8: 150psi fouled

    Since then I have pulled the valve covers and watched the lifters with the motor running and all seems fine--everything rocking at the same rate. I was told I may have clogged oil passages (this motor has approx 80K on it) and I have maintained it habitually so I doubted it but I figured I'd ram a doubled over coat hanger down them anyway just to make sure all was well.....no problem, no mentionable sludge. Next I ran motor flush through the motor maybe to free any sticking lifters and free up junk....

    I replaced the oil and added some lucas oil stabilizer to maybe lube up the oil ways -- a suggestion from one mechanic at work -- no change

    Now I am still burning oil and not sure where it would be coming from....valve stem seals?? I cant see them smoking the entire time...The motor as you can see above has great compression and that was checked with the block cold. some times at startup I have no smoke and it slowly builds to a smog, other times it starts light right off the bat to much heavier, no matter what its thick when I goose it or drive it. I'm baffled where do I go next????

    Please help its my DD and I need to not bum rides for another week. :dunno:
     
  2. LongIslander26

    LongIslander26 1/2 ton status

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    Mosquito smogger.

    I'd checked to see if the distibutor weights are seized, and double check the intake manifiold gasket seal. (Spray some carb cleaner along the intake and carb base, and see if the rpm picks up) Double check your firing order and plug wires. I assumed you put fresh plugs in it. You've got good compression like you said, but that oil has to be coming from somewhere. Is it blue smoke, white smoke or black smoke? You got a head scratcher on your hands, to be sure.
     
  3. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    its blue smoke, real blue, brand new intake gasket, and carb base seal, I have sprayed both with no change in RPM's..... the smoke turns more grey under throttle, no white or steam from the exhaust my last motor the exhaust was hot enough to burn you from the steam, the cooling system is staying pressurized as well.

    It smells like oil, I have a clear fuel filter on and the gas is clean as could be...

    most of the guys I know that have years of experience with SBC's are baffled....
     
  4. LongIslander26

    LongIslander26 1/2 ton status

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    Mosquito smogger.

    Well, if it ran good before, then sat, and now you've changed some parts, it would have to be in something you changed. I'm wondering if you had some rust get into the cylinders that had their exhaust valves open slightly, and the exhaust not sealed when it sat? Any bubbles in the coolant when it's running with the radiator cap off?
     
  5. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    no bubbles now that the system has purged the air(heater on and drove around the block)
     
  6. LongIslander26

    LongIslander26 1/2 ton status

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    Hmmmmmmmmmm....

    How long, in hours or miles, has this motor been run since you swapped it in?
    How high of an RPM can you get it before it starts blowing smoke?
    Are you ABSOLUTELY SURE the timing pointer on the balancer is accurate?
    (could the distributor be off a tooth and skewing your timing readings?) :confused:
     
  7. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    just wentoutside upon another suggestion and uncapped the valve covers (oil fill and pcv ports and noticed smoking coming from there......

    could I have good compression and bad oil rings?
     
  8. LongIslander26

    LongIslander26 1/2 ton status

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    Maybe??

    Maybe. There are oil control rings on the pistons that don't hold compression, and vice versa. It's tough to tell without being there and seeing it in person.
     
  9. fatbob

    fatbob 1/2 ton status

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    My best guess is a internal vacuum leak. The intake manifold did not seal right and it's sucking oil vapors from the oil valley and fouling your plugs. This makes more sense because your compression is good, it ran well before, and it's fouling all the plugs. Check the pcv system as well. Plug it off and take a spin around the block. Be aware take you might not see immediate results
    because there might still be some oil in your exhaust system, and that will have to burn off. Put a vacuum gauge on it and post what its reading.
    Good luck
     
  10. icer97

    icer97 1/2 ton status

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    You can also find an internal vacume leak by using the methode you used earlier with the carb cleaner. Remove the oil fill cap on the valve cover and give her a snort.
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    If this engine sat for a long period of time without ever being turned over then the rings may have lost some of their tension and it is now burning oil. I would drive it around some more and usually after a while of driving the ring tension should come back and stop burning oil. The other thing that can happen is that a ring can sieze in the piston ring land and no longer able to freely move around as it needs to and this will also cause it to smoke.
     
  12. LongIslander26

    LongIslander26 1/2 ton status

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    Burning oil

    That makes sense to me.
     
  13. readymix

    readymix 3/4 ton status

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    If it is a crate motor it was likely cast in Mexico. Look for the "CE" or "MEXICO" stamped on it. Those blocks are not the best to begin with. From the sounds of it your oiler ring spreader or skirt is broke. Seen it cause teh same thing before.

    I can't remember the years but chevy switched to a different profile rings for a few years before they realised it was a stupid effort to reduce drag on the enging internals. Then they just switched it all to metric sizes. If it turns out to be the rings be sure you get the right ones or it will burn oil within a few thousand miles
     
  14. crawlink5

    crawlink5 1/2 ton status

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    I have to say my comments below are just opinions and as such may be completely wrong. I've been talking to Josh on the phone about this problem and it seems he has exhausted everything I can think of but for the intake/intake gaskets idea. Past that I'd say start pulling apart.

    the siezed oil rings is a good idea. Though, its been a long time since I've had to deal with oil ring problems. Back in the early to mid 80s I was into street racing. I had a 350 that regularly saw 8000 rpms and occaisionally 10,000. Towards the end of it's life, the rings went bad quick and it started smoking. Now, when I tore it down the oil rings fell apart and some of the compression rings were broke. One piston didn't have the groove for the top compression ring anymore. And it didn't smoke as bad as Josh's truck(it was bad though - undrivable but see-through, i could still see a car behind me).

    Do you think it would smoke bad at idle with the oil rings seized or cracked? Would the oil rings on all 8 cyl sieze or crack sitting up for a year? He did say that all 8 cyl had fouled plugs.

    What about pouring some kroil into the cylinders to loosen up the oil rings? get about 4 cans and put in cylinders one at a time and turn over by hand to let the pressure push past rings.
     
  15. diesel4me

    diesel4me 1 ton status Premium Member

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    smokem..

    Sounds like you guys have covered all the possibilities!--it does sound like the rings or cylinders might have gotten rusty while sitting,and didnt like being woken up again--or maybe it could be the intake sucking the oil in internally as suggested...we had a similar experience at the junkyard I worked at--

    We had a GMC truck with a mint 350 motor--it sat about a year before someone wanted to buy it--so we sold them that motor knowing it was a strong runner with no smoke and good oil pressure when we evaluated it earlier.... we put the motor in for the customer,and boy were we embarrassed when it started!--it fogged us right out of the shop!--at first,we blamed the OLD motor--it may have dumped lots of oil or antifreeze into the exhaust system,and it often takes 30 minites or more for all of it to burn off,before you can blame the "new" engine...but after an hour,it was still smoking like a chimmney,and we had to pull it back out again,and find another motor to install..

    Only had 1 other small block chevy motor there--a 305 that had no intake manifold,and was full of acorns and leaves in the valley pan!..we figured it was a lost cause,but since the boss told us too,we pulled it and swapped all the missing parts back onto it,and it DID actually run!--and pretty good too--shocked us! :screwy:

    We pulled that 350 that smoked apart,and other than a bit of surface rust on the cylinders,it looked good!--the rings were badly stuck in their grooves though--looked like black paint holding them in,flush with the piston--we tried to pry the rings out gently,but they broke..and I doubt anything you add to the gas or oil would have budged them either--

    -I've seen Marvel Mystery Oil work miracles on stuck rings and valves,but soaking that motor with it,and adding some to the gas and oil did nothing!..we even soaked one piston in laquer thinner overnight,and the rings were still stuck the next day,and broke off when we tried to pry them out...another customer bought that motor and rebuilt it with new pistons and rings,and it ran great again!--I havent figured out why some motors do this,and others can sit for years and actually seize up,and be persuaded loose with a pry bar and oil in the cylinders ,and run good again with no smoke after they run for awile!... :dunno: :what: :screwy:
     
  16. kgblazerfive

    kgblazerfive keymaster Premium Member GMOTM Winner

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    I'm voting for the intake seal idea. Why would a oil ring seize and not the comp ring. The motor thats in my stock car bought on e-bay as a core and some of the rings were stuck to the piston but it was either all of them or none didn't single out just the oil rings. It wouldn't have the compression if they were seized. Its not seals only would smoke on start up. I would pull the intake. If it was heads gaskets it would not have the comprssion either. How long has it ran could it be just oil in the cylinders from assembly?
     
  17. fatbob

    fatbob 1/2 ton status

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    Dont forget the pcv system. If the valve cover doesnt have baffles, you could be sucking oil straight though the pcv valve. This would also cause ALL the cylinders to be fouled. I just dont believe the odds of the rings sticking or breaking in all the cylinders at the same time. :crazy:
     
  18. 4trolls

    4trolls 1/2 ton status

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    when I have had blue smoke and good compretion, it has allways been valve guides
     
  19. LongIslander26

    LongIslander26 1/2 ton status

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    Blue smoke

    I had blue smoke, and good compression, and everybody and their brother told me it was the valve guide seals, so I busted my ass replacing them ,and it was the intake seals all along. Also the plugs that were in it were too short, so it wasn't lighting off the cylinders properly. 8 plugs and 2 intake gaskets later, problem solved.
     
  20. jhellwig

    jhellwig 1/2 ton status

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    I would say that if you didn't have the right plugs that that would be the biggest source of the problem.
     

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