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#1
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Blow-by 383 rings not seated? (video inside)
Alright guys I finally got around to taking a video of my engine and what it is doing. For those of you who don't already know it is a 383 sbc with approx. 1200-1500km on the engine. The engine still consumes quite a bit of oil but there is no visible smoke out the pipes. As of recently it has also developed a very loud ticking sound that appears to be coming from the passenger side of the engine. There is a lot of blow-by smoke out of the valve cover as well as you can see in the video. This indicates the rings haven't seated I am assuming and the engine will probably need to be taking back down and re-honed with new rings. If anybody could give some suggestions as to what I should do and what that ticking noise is it would be very much appreciated.
http://www.youtube.com/watch?v=GepqitxYWLw Thanks, keith Register now (free) or login to remove ads |
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#2
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sounds like you have to adjust the valves alot of clicking going on.
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#3
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Assuming the valves have been correctly adjusted, could be a collapsed lifter. I wouldn't be driving it like that until you can pull it apart to have a look, should be pretty obvious which one is the offending lifter...a push with a screwdriver on the rockers on the passenger side will tell ya which one it is.
Sounds like one of the center two lifters on the passenger side, pull the valve cover...takes 10 minutes. |
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#4
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Find the noisy lifter, it should cure the blowby if an exhaust valve isn't opening properly which I am betting on the pressure which should go out the exhaust valve will cause blowby. Learned this from experience.
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#5
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I agree with the above, you need to find that noise and take care of that first. Not sure if it will cure that blowby but it may help.
__________________
Artificial Intelligence is no match for Natural Stupidity Chet |
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#6
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I also agree you must locate the collapsed lifter before you can move on. Cole
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#7
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Hey guys thanks for all the suggestions here. Anyways I have one hell of an update for all of you. Today I took the time to start tearing things down and see what I could find. Sure enough the exhaust lifter for cylinder 6 seems to be totally collapsed and the rocker is completely loose. I removed the intake manifold to take a look at the lifters. The only lifter that seems to be sitting very low in its bore was that for cylinder 6 exhaust, so I am assuming this means it is collapsed. Since I was already this far into it I had all intentions of removing the heads so I could take a good look at the cylinder walls to see if I had ring problems where the blow-by could be coming from. I eventually got the driver's side head removed and I am speechless.
One quick look at the piston heads and I think I have found the cause to all the strange noises and engine problems I have been having with this rebuild. I have spent close to $12,000.00 on this project and, to say the least, I am devistated. This was my first and now most likely last attempt at building an engine. All the pics are posted below, feel free to comment and sympathize for me. I hope nobody's first engine build goes as bad as mine did.Driver's side bank- no explanation needed. http://img.photobucket.com/albums/v...ESTROYED001.jpg Cylinder 1- again there is nothing right with this image http://img.photobucket.com/albums/v...ESTROYED002.jpg Cylinder 3- http://img.photobucket.com/albums/v...ESTROYED004.jpg Cylinder 5- http://img.photobucket.com/albums/v...ESTROYED005.jpg Cylinder 7- http://img.photobucket.com/albums/v...ESTROYED006.jpg Cylinders 1&3- http://img.photobucket.com/albums/v...ESTROYED008.jpg The head (AFR aluminum head I bought brand new, probably scrap aluminum now)- http://img.photobucket.com/albums/v...ESTROYED009.jpg Cylinder 1 combustion chamber- http://img.photobucket.com/albums/v...ESTROYED010.jpg Cylinder 3 combustion chamber- http://img.photobucket.com/albums/v...ESTROYED011.jpg Cylinder 5 combustion chamber- http://img.photobucket.com/albums/v...ESTROYED012.jpg cylidner 7 combustion chamber- http://img.photobucket.com/albums/v...ESTROYED015.jpg That's all the pics I have for now, ******* my life!! |
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#8
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The heads are repairable. At least some of the valves are likely now bent.
This engine was assembled wrong (top piston ring end gap) and/or was subjected to severe detonation abuse (excessive spark timing advance, low octane fuel/excessively high compression ratio, severe WOT fuel lean out. (fuel system flow capacity (volume, not pressure) Thats the only way to break multiple piston ring lands. When you disassemble it, Carefully remove the piston rings from the pistons and set them in the cylinder squarely and measure the ring end gap with a feeler gauge. The engine block will need to be magnafluxed to check for cracked cylinder bores. The rods will have to be fully inspected for bent and out of round condition on both ends. Sometimes its not as bad as it looks. What is the part # of the cylinder heads? |
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#10
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Hey F-Bird. A few things. I gapped the rings myself and these are Keith Black hypereutectic pistons that require a much larger ring gap for the top compression ring due to tight piston to cylinder wall clearance. I remember gapping the top rings at 0.028" because this is what I was told to do by the manufacturer or else the tops of the pistons could be history, which they are anyways. With this in mind I do not think it was the ring gaps that caused this but I will do as you suggested and double check all the gaps when I pull the pistons. I believe it was detonation that caused my piston heads to explode. The reason I say this is because on break-in my timing was accidently wayyyyyyyy too far advanced and I remember someone telling me that with these pistons if you get detonation even once the head of the piston WILL break. I have been running 92 octane and my compression ratio is right around 10:1 so I don't think it is an octane issue. I will never use these pistons again and I can't see why anyone would because if ever the distributor started slipping and advanced the timing well there goes the pistons. The heads have quite a bit of scraping and cuts in the flat areas you can see in the photo. Would I be able to get the heads decked enough to remove all the damaged area? By doing this I would raise my compression ratio but I guess I could use a thicker head gasket to counter that. Here is the link to the exact heads I have http://www.jegs.com/i/AFR/033/1036J/10002/-1. Anymore suggestions or input is appreciated.
Keith |
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#11
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You best "CC" the combustion chambers on those heads. It takes a lot of abuse to get the damage shown on those pistons KB hyper or otherwise. If you do not correct the real fault, a forged piston will still be damaged from this abuse. It will either break the ring lands the same or the ring lands will pinch and the piston will scuff the cylinder walls destroying the ring seal quality just the same. It just takes a bit longer.
This did not happen during intial break-in. It happened while running the engine under full or partial load. If the chamber are actually 64cc, or even smaller then the cr is way too high for 92 octane. If the fuel was something othe than actual 92+ octane the engine will be damaged especially if the fuel system causes a leanout or the timing is way off, or combo. The broke pistons are the result, not the fault. With a severe tuning fault like this, a $800 forged piston will get destroyed too. It takes a lot to break these pistons. Last edited by F-BIRD'88 : 05-31-2009 at 08:55 PM. |
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#12
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I tell anyone who askes not to use these pistons, you only have to be bit once to realize the high ring placement isn't all its hyped up to be. Mine looked just like yours even with my .032" gap. Used the gap # in between street nitrous and race nitrous on gas, and never even sprayed it with my little 150hp kit, never got the chance to
. Figured it must have been a momentary lean spot that killed mine. Got three months out of the set, broke three right out the corner of the intake valve pocket. Rebuilt with forged TRW's and it has been together 12+ years now. KB hypers are false economy, they will cost you in the end.You couldn't give me a truck load of them, I would feel like a crook to even give them to others
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#13
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When you rebuild this engine build it with a true measured 9.8:1 cr.
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