Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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This piston was in the 305 HO that i am going to put in my project car. The second pic is of the bore. It had two small place in it.
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1985 TransAm BLK/GLD Stock
1985 TransAm BLK/BLK
305HO (soon as it is put in) 5-speed, 3.27 posi, WS6, power everthing. http://www.geocities.com/bullfrawgs
I've seen similar wear on high mileage engines that have been pushed hard. The rings can be worn very thin, then the pressure from high speed and heavy load cracks the rings in the grooves. The rings begin to fragment and the pieces break through the ring lands, taking the second ring and oil ring rails with it.
The photo of the cylinder wall is difficult to diagnose because of the glare, but is there a noticable grooved pattern in the wall? This would indicte thin rings that broke up as well.
If heard of similar damage (but have never seen it firsthand) of boosted and NOS engines losing piston rings and lands from heavy load in a similar manner, then torching the side of the piston down to the skirt. Was there any trace of ring fragments in the crankcase?
Looks like you might be borng the old 305 if you really want to save it. For what you're going to invest in gmachining and pistons, a 350 is probably looking pretty reasonable right about now....
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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway." Adobe Acrobat Reader
That's detonation. Somebody ran it hard while it was too hot, or on too cheap gas, or with the timing advanced too far. It almost always happens on the side of the piston next to the spark plug.
I'll second Vader's advice; to restore that 305 to usable condition, you're going to have to spend some major $$$; the additional cost of changing to a 350 will be negligible.
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"So many Mustangs, so little time..." ICON Motorsports
There were pieces of rings in the oil pan. It was only that piston that was like that. It still had the top ring intact. The bore has two small nicks that are in that picture. The motor has about 60,000 miles on it. The bore wasn't wore much at all. All the rod and main bearings looked bad(due to the metal fragments). The crank and cam were ok. I can get a replacement piston for this motor and a rering kit. It would be a lot cheaper than a 350 but do yall think them two small nicks will hurt? I will hone it out but i am not sure that the nicks will come out completely.
[This message has been edited by bullfrawg (edited March 19, 2001).]
Im wondering what temp the engine was running at or how much oil pressure you had at the time?
I know that pushing a engine with high mileage and burning crapy gas will do an engine in, but these SBC's are tuff mothers.
So it make me question oil pressure and water temp.
ps in HO rebuilds be very picky with the new piston type some of these flat tops they sell
dont like pump gas with the HO heads and you might see similar damage
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85 Camaro RS 350/350 stealth intake, holley street avenger 670
true dual exhaust. "ButtStang killer"
82 firebird 305 all original - the cat and smog crap."All show No go"
I was planning on using this motor for a few years until can get around to building a 350 or getting a crate motor. I will ask the guy i got it off about the tempature, the oil pressure, and the octane he ran. The motor came out of an 85 Monte Carlo SS. He now has a 350 in it. If he ran the 305 the way he runs it now then it was run pretty hard.
For what it costs to sleeve a 305, you can get a whole truckload of junk blocks. Sleeving a 305 would be about the stupidest possible way of dealing with this situation. If it were me, I wouldn't put it back together as a 305 at all. Think about it: you're going to buy a block, pistons, a crank or at least work, a cam, boring & honing, etc. etc. etc.; a 350 block costs exactly the same as a 305, a 350 crank costs the same, a 350 cam costs the same, etc.; so why spend 350 money but have a 305 at the end? Doesn't make sense.
But if for some reason it absolutely has to be a 305 and not a 350, I would just go to the boneyard and look at all their 305 blocks, and pick out the best one of the appropriate design. You ought to be able to easily get a nice 305 block for under $200 since they're mostly getting melted down.
It sounds to me like you would be wasting your time talking to this person about the particulars of this motor's history. Basically, you have all you need to know sitting right in front of you; namely, the motor you have is garbage. Throw it in the trash and start over. It hardly matters how it got like that unless you're just curious. I doubt he'll tell you the truth about the details of his poor maintenance and driver abuse anyway.
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"So many Mustangs, so little time..." ICON Motorsports
Actually I ain't buying all the **** you named. I ain't planning on spending more than $150 on this motor(the 350 i want is $3000). I am getting the rering kit and 1 piston. It don't need boring. This is just a temprorary motor. The motor ran good with the busted piston. It just smoked every now and then. The guy i got it off of is a good friend and he said that he only put 10,000 on it. The rest came from the guy before him. When he got it he replaced the thermostat, intake gaskets, and reset the timing. He also said it smoked ever since he had it. P.S. I know that building a 350 is cheaper than building a 305. All i wanted to know if them two small places might cause premature failure on new rings.
I think you will have trouble with the gouges in the bore. They're far enough down that they won't leak compression into the crankcase too bad but they may chew up new rings.
Who knows, maybe it was already torched by the time your friend got it... that's the way it is with used cars.
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"So many Mustangs, so little time..." ICON Motorsports
