Broken Piston IN Oil Pan. SIGH. 37 miles on motor
03-21-2009, 11:58 PM
#1
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Join Date: May 2008
Location: Sheboygan, WI
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Broken Piston IN Oil Pan. SIGH. 37 miles on motor
late last season I rebuilt my 350 lt1. I went with a eagle crank, eagle forged i beams, and speedpro slugs. I got LE2 h/c package, and a few other bolt ons to support it all.
I got 37 miles on the motor last year and it started ticking, gettin pregressivly louder. I didnt know what it was so i brought it to a shop that specialises in corvetts (with lt4). they could not tell me the problem after 3 hours of disgnosis time @ $80/hr. I drove the car to the shop and it ran good but with some ticking, then when i went to pick it up they insisted that I trailer it home, they ever offered to do it for free. I never heard it run after they got the paws on it.
So I put it away for the year. now I got it out and I pulled the motor back out to see what it was, and I found a nice little suprise in the oil pan: (some parts are on the ground in this picture)
I kno the shop will not take responsiblity for it, and I dont expect them to, but I know that they know somehting major went wrong, and I would have apreciated if they told me. So, anyway. I spend the day being mad about this all and now im over it. im ready to deal with it.
first step is finding out WHY this happened. I need some help with this part.
I know that I made one mistake when asembling the motor. I torqued the rod bolts to 40ftlbs with moly lube but all in one step, didnt allow for stretch. and this is what I asumed the knocking was. and it does look like thats what the problem was: (this is how unscrewed it was when I opened up the bottom of the motor)
so it was definatly loose. but how could this cause the piston to shatter? from the blows of the crank, enuff to pop the rod up fast enuff to shatter piston?
enuff to do this:
damn, that takes alot to do that.. so as of now, this looks to be what caused the problem. so thats a hard lesson learned. noted...
SO, what can I do now!
the way I see it, I can either get this done cheap, or get it done rite.
so the crank looks amazing (somehow) and the cylinder walls look to be in good shape.. I think I need to get the crank checked to be sure its still true. I need to get all the junk pieces out of there. the rite thing to do would be take it all appart and have the block cleaned. crank checked, and heads looked at.
I dont know the reason for this post, I guess im looking for someone to tell me just clean the junk out, and put a new rod and pistons in and hope for the best.
I got 37 miles on the motor last year and it started ticking, gettin pregressivly louder. I didnt know what it was so i brought it to a shop that specialises in corvetts (with lt4). they could not tell me the problem after 3 hours of disgnosis time @ $80/hr. I drove the car to the shop and it ran good but with some ticking, then when i went to pick it up they insisted that I trailer it home, they ever offered to do it for free. I never heard it run after they got the paws on it.
So I put it away for the year. now I got it out and I pulled the motor back out to see what it was, and I found a nice little suprise in the oil pan: (some parts are on the ground in this picture)
I kno the shop will not take responsiblity for it, and I dont expect them to, but I know that they know somehting major went wrong, and I would have apreciated if they told me. So, anyway. I spend the day being mad about this all and now im over it. im ready to deal with it.
first step is finding out WHY this happened. I need some help with this part.
I know that I made one mistake when asembling the motor. I torqued the rod bolts to 40ftlbs with moly lube but all in one step, didnt allow for stretch. and this is what I asumed the knocking was. and it does look like thats what the problem was: (this is how unscrewed it was when I opened up the bottom of the motor)
so it was definatly loose. but how could this cause the piston to shatter? from the blows of the crank, enuff to pop the rod up fast enuff to shatter piston?
enuff to do this:
damn, that takes alot to do that.. so as of now, this looks to be what caused the problem. so thats a hard lesson learned. noted...
SO, what can I do now!
the way I see it, I can either get this done cheap, or get it done rite.
so the crank looks amazing (somehow) and the cylinder walls look to be in good shape.. I think I need to get the crank checked to be sure its still true. I need to get all the junk pieces out of there. the rite thing to do would be take it all appart and have the block cleaned. crank checked, and heads looked at.
I dont know the reason for this post, I guess im looking for someone to tell me just clean the junk out, and put a new rod and pistons in and hope for the best.
03-22-2009, 01:00 AM
#3
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Join Date: May 2008
Location: Sheboygan, WI
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thanks for the support. man I cant describe the feeling when I pulled that pan off (I did it in the car because I thought I was just looking at re torquing the rod bolts (and maybe new bearings), but once I pulled the pan off and seen a oil scraper ring pop out the side I was pissed, I droped my tools and went for a walk. took me about 20 mins to accept that, then I decided, well I beter pull the motor out now. so I did. I got it out. Its really hard to stay posative when out in the shop, but I cool off when I come home, and realise that I can deal with it. then I go out the next day posative.
anyway. I WILL have that car back on the road in 30 days or less!
anyway. I WILL have that car back on the road in 30 days or less!
03-22-2009, 01:44 AM
#5
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Location: Sheboygan, WI
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Why all new rods and pistons, all the other rods and pistons are fine. I would just need one rod, and one pistons/rings.
New rod = $32.92
New piston = $20.99
Rings= $40 (can only find a full set)
Polish crank = $45
New oil pump = $37.99
Gasket set = $175
Bring to a reputable machine shop have them reassemble the shortblock = Not going to happen. I made a stupid mistake and i paid the price for it. if I throw in the towel and let a shop so it for me then I will lose. I want to do this myself. :-)
well adding up the numbers is making me feel alot better, this should be a bit cheaper than I thought.
New rod = $32.92
New piston = $20.99
Rings= $40 (can only find a full set)
Polish crank = $45
New oil pump = $37.99
Gasket set = $175
Bring to a reputable machine shop have them reassemble the shortblock = Not going to happen. I made a stupid mistake and i paid the price for it. if I throw in the towel and let a shop so it for me then I will lose. I want to do this myself. :-)
well adding up the numbers is making me feel alot better, this should be a bit cheaper than I thought.
03-22-2009, 04:23 AM
#7
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Join Date: Oct 2001
Location: Engineerland
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You can match the rod and piston to the others which should all be the same anyways. I would want to have a close eye on the skirts of the other pistons for imbeded particles and have the machine shop hit the hole the piston failed in with a hone while the torque plate was on to look for shadows or scratches. Have the crank checked for square, stroke, etc. If it looks crappy/damaged either overbore it (cheap mans rigged way) or you can put a sleeve in it.
If the cap was loose on the rod it probably let the gap open up on the rod and let the piston move on up closer to the head. Piston meet Mr aluminum head sorry piston you are brittle and your failure mode is a whole bunch like glass rather than deforming you explode and the wrist pin finishes off pulverizing whatever is left.
Use a stretch gauge on the rod bolts next time. Not a cheap one either the springs arent strong enough to do a good job on the cheap junk. In all actuality though you probalby forgot to torque the thing down. Get one of those stupid bingo markers or a cheap felt tipped pen and dot each one after you torque it this time. Then go back and check each one unless you actually take initiative and get the stretch gauge. Record the stretch of each bolt make a little sheet in excel and print it so you have something neat to put it on.
Seems to me like it was getting looser on your way there, and the shop reved it up heard a loud bang and said OH **** and told you to trailer it home because the loud noises and terribly rough running would have been a dead give away that it was all blowed up good now.
Better luck to you next time.
ps: Dont feel too bad when I was a kid my dad bought a new chevy truck on the 30 mile trip home turning on to our road we hear a VERY loud PING and then we're leaving a trail of oil on the road, wth. One of the outer 4 bolt fasteners had vibrated loose and the crank caught it and threw it right through the side of the oil pan wile coyote style. My dad burned the **** out of his hand picking it up in the road. The dealer gave him a oil pan so he pulled it put the bolt back in and put the new pan on over it
.
If the cap was loose on the rod it probably let the gap open up on the rod and let the piston move on up closer to the head. Piston meet Mr aluminum head sorry piston you are brittle and your failure mode is a whole bunch like glass rather than deforming you explode and the wrist pin finishes off pulverizing whatever is left.
Use a stretch gauge on the rod bolts next time. Not a cheap one either the springs arent strong enough to do a good job on the cheap junk. In all actuality though you probalby forgot to torque the thing down. Get one of those stupid bingo markers or a cheap felt tipped pen and dot each one after you torque it this time. Then go back and check each one unless you actually take initiative and get the stretch gauge. Record the stretch of each bolt make a little sheet in excel and print it so you have something neat to put it on.
Seems to me like it was getting looser on your way there, and the shop reved it up heard a loud bang and said OH **** and told you to trailer it home because the loud noises and terribly rough running would have been a dead give away that it was all blowed up good now.
Better luck to you next time.
ps: Dont feel too bad when I was a kid my dad bought a new chevy truck on the 30 mile trip home turning on to our road we hear a VERY loud PING and then we're leaving a trail of oil on the road, wth. One of the outer 4 bolt fasteners had vibrated loose and the crank caught it and threw it right through the side of the oil pan wile coyote style. My dad burned the **** out of his hand picking it up in the road. The dealer gave him a oil pan so he pulled it put the bolt back in and put the new pan on over it
.
Last edited by WS6T3RROR; 03-22-2009 at 04:26 AM.
03-22-2009, 07:03 AM
#8
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Location: Kantuckee Yo'
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Similar thing happened to me a few years ago. I built my entire motor from the short block up. Motor ran for 5 miles before knocking like crazy and continued to get worse. My two mistakes were making the main bearing clearances toward the tight side of GM spec and assuming that the guy who turned my crank had properly cleaned it out. Upon tear down all found 4 out of 5 main bearings destroyed and the crank scarred.
At that point I pulled the motor out and gave it to a local engine builder and told him to build the short block and I would do the rest.
My advice is to contact a reputable engine builder and give him the short block and allow him to determine if the components are worth saving and whether or not a replacement individual piston and rod are in order. Have him build the short block and PROVIDE a warranty for the motor for x amount of time or miles.
As simple as the short blocks seem to build, its the precision amount of detail that will determine how long they will last and how well they will perform. Things like ring gap, torquing of the rod bolts, main and rod bearing , balancing and most important, cleanliness can be a challenge for a backyard mechanic unless he has the experience and proper tools and equipment.
I applaud your effort in doing it all. But give some thought to having a professional do the short block.
At that point I pulled the motor out and gave it to a local engine builder and told him to build the short block and I would do the rest.
My advice is to contact a reputable engine builder and give him the short block and allow him to determine if the components are worth saving and whether or not a replacement individual piston and rod are in order. Have him build the short block and PROVIDE a warranty for the motor for x amount of time or miles.
As simple as the short blocks seem to build, its the precision amount of detail that will determine how long they will last and how well they will perform. Things like ring gap, torquing of the rod bolts, main and rod bearing , balancing and most important, cleanliness can be a challenge for a backyard mechanic unless he has the experience and proper tools and equipment.
I applaud your effort in doing it all. But give some thought to having a professional do the short block.
Last edited by wrd1972; 03-22-2009 at 07:07 AM.
03-22-2009, 07:04 AM
#9
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Join Date: Sep 2008
Location: NY
Posts: 88
As long has he gets the same rod/piston that came out, then hell be fine with it being balanced. If its really an issue, pop out a good rod/piston and bring the new one to a machine shop, and have them make them the same. But as far as the crank, Thats your call, I would have it sent out and checked to see if its out of round, just from the rod bounceing around in there.
03-22-2009, 08:15 AM
#10
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Join Date: Mar 2008
Posts: 172
As long has he gets the same rod/piston that came out, then hell be fine with it being balanced. If its really an issue, pop out a good rod/piston and bring the new one to a machine shop, and have them make them the same. But as far as the crank, Thats your call, I would have it sent out and checked to see if its out of round, just from the rod bounceing around in there.
Different parts are made in different lot numbers. There is no way you can say they will all be the same but they will all have a margin of error within them. Now if he has his original bobweight card then yes they can make that single one the same as the others, if that is what is being said then I agree. However you cannot buy something from out of the box and place it in the hole and say its fine. If you do you may get another 37 miles out of it. Even in a matched set they still have to be worked to achieve the correct balance and thats from a set of eight, not a lot of thousands.
03-22-2009, 08:55 AM
#11
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Join Date: Feb 2004
Posts: 4,800
Head is likely damaged some too. Piston that loose could have easily hit an open valve.
An aquaintance had CarQuest in Sheboygan redo a shortblock for him.
He had over siliconed everything so much it got into a bearing and began to knock. Bearing had a smooth rounded groove. That piston also ended up cracked up by the wrist pin.
Far as a new piston and rod and balancing. Let the shop inspect everything and they should be able to match the new piston and rod to the others.
Have you looked closely at the bore that broken piston was in? I would have expected damage to the bore if not from the piston from the wrist pin.
An aquaintance had CarQuest in Sheboygan redo a shortblock for him.
He had over siliconed everything so much it got into a bearing and began to knock. Bearing had a smooth rounded groove. That piston also ended up cracked up by the wrist pin.
Far as a new piston and rod and balancing. Let the shop inspect everything and they should be able to match the new piston and rod to the others.
Have you looked closely at the bore that broken piston was in? I would have expected damage to the bore if not from the piston from the wrist pin.
03-22-2009, 12:28 PM
#12
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Join Date: Oct 2004
Location: las vegas
Posts: 1,130
i was going by your statement of "either i can get it done cheap or get it done right"
doing it cheap is replacing what went bad
doing it right would be to check the block, i am almost willing to bet the very bottom of the bore is bad(mine was), heads need to be checked,for the price of new rods with arp bolts is not bad and the pistons can be an option unless the bore is hurt enough to constitute a bore job.
what are your intensions as far as use of this motor,curising,playin etc?
doing it cheap is replacing what went bad
doing it right would be to check the block, i am almost willing to bet the very bottom of the bore is bad(mine was), heads need to be checked,for the price of new rods with arp bolts is not bad and the pistons can be an option unless the bore is hurt enough to constitute a bore job.
what are your intensions as far as use of this motor,curising,playin etc?
03-22-2009, 12:47 PM
#13
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Join Date: Jan 2009
Location: Northwest Corner Ohio, Wauseon
Posts: 404
Similar thing happened to me a few years ago. I built my entire motor from the short block up. Motor ran for 5 miles before knocking like crazy and continued to get worse. My two mistakes were making the main bearing clearances toward the tight side of GM spec and assuming that the guy who turned my crank had properly cleaned it out. Upon tear down all found 4 out of 5 main bearings destroyed and the crank scarred.
At that point I pulled the motor out and gave it to a local engine builder and told him to build the short block and I would do the rest.
My advice is to contact a reputable engine builder and give him the short block and allow him to determine if the components are worth saving and whether or not a replacement individual piston and rod are in order. Have him build the short block and PROVIDE a warranty for the motor for x amount of time or miles.
As simple as the short blocks seem to build, its the precision amount of detail that will determine how long they will last and how well they will perform. Things like ring gap, torquing of the rod bolts, main and rod bearing , balancing and most important, cleanliness can be a challenge for a backyard mechanic unless he has the experience and proper tools and equipment.
I applaud your effort in doing it all. But give some thought to having a professional do the short block.
At that point I pulled the motor out and gave it to a local engine builder and told him to build the short block and I would do the rest.
My advice is to contact a reputable engine builder and give him the short block and allow him to determine if the components are worth saving and whether or not a replacement individual piston and rod are in order. Have him build the short block and PROVIDE a warranty for the motor for x amount of time or miles.
As simple as the short blocks seem to build, its the precision amount of detail that will determine how long they will last and how well they will perform. Things like ring gap, torquing of the rod bolts, main and rod bearing , balancing and most important, cleanliness can be a challenge for a backyard mechanic unless he has the experience and proper tools and equipment.
I applaud your effort in doing it all. But give some thought to having a professional do the short block.
Do it right or youll have to do it again.
03-22-2009, 12:51 PM
#14
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Join Date: May 2008
Location: Sheboygan, WI
Posts: 856
thank everyone for the responses!.
I kno what you mean about lettin a shop asemble it, but I just cant do that. I am a ASE certified mechanic (in steering and suspension, electrical systems, and brakes) and I need to do this. This is the first car engine I have rebuilt and I need to do it myself. If I end up doing it wrong AGAIN, and somehting like this happens again, then I will throw in the towel and let shop take care of it. but I think I will sucessful this time.
I just remembered. I do have the original ballance card, with and one of my other pistons/rods im sure a shop can get my new stuff all set for me to use.
I am on my way out to the shop to remove all the slugs, rods, and crank. im going to send the crank in today for polishing and inspecting.
also, I talked to the company who sold me the parts and he said he can sell me 1 SIR5700BBLW rod, 1 Speed Pro H859CP piston, one set of rings for $120.00. Then im going to get a new set of mains and rod bearings ($40 from the same guy). IM going to hold off on ordering until my crank is inspected because if the crank has to be cut I need to get .010 under crank bearings.
so that should take care of the rotating asembly.
now I need to worry about the block and head. I will take a closer look at both today and post back.
I kno what you mean about lettin a shop asemble it, but I just cant do that. I am a ASE certified mechanic (in steering and suspension, electrical systems, and brakes) and I need to do this. This is the first car engine I have rebuilt and I need to do it myself. If I end up doing it wrong AGAIN, and somehting like this happens again, then I will throw in the towel and let shop take care of it. but I think I will sucessful this time.
I just remembered. I do have the original ballance card, with and one of my other pistons/rods im sure a shop can get my new stuff all set for me to use.
I am on my way out to the shop to remove all the slugs, rods, and crank. im going to send the crank in today for polishing and inspecting.
also, I talked to the company who sold me the parts and he said he can sell me 1 SIR5700BBLW rod, 1 Speed Pro H859CP piston, one set of rings for $120.00. Then im going to get a new set of mains and rod bearings ($40 from the same guy). IM going to hold off on ordering until my crank is inspected because if the crank has to be cut I need to get .010 under crank bearings.
so that should take care of the rotating asembly.
now I need to worry about the block and head. I will take a closer look at both today and post back.
03-22-2009, 01:42 PM
#15
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Join Date: Oct 2001
Location: Engineerland
Posts: 1,517
A very similar response was given earlier and I hate to disagree but I do whole heartedly. Just because you buy the same brand does not mean it is the same. Sorry if you think that it is but talk to a machinist and I will guarantee you they will tell ya the same.
Different parts are made in different lot numbers. There is no way you can say they will all be the same but they will all have a margin of error within them. Now if he has his original bobweight card then yes they can make that single one the same as the others, if that is what is being said then I agree. However you cannot buy something from out of the box and place it in the hole and say its fine. If you do you may get another 37 miles out of it. Even in a matched set they still have to be worked to achieve the correct balance and thats from a set of eight, not a lot of thousands.
Different parts are made in different lot numbers. There is no way you can say they will all be the same but they will all have a margin of error within them. Now if he has his original bobweight card then yes they can make that single one the same as the others, if that is what is being said then I agree. However you cannot buy something from out of the box and place it in the hole and say its fine. If you do you may get another 37 miles out of it. Even in a matched set they still have to be worked to achieve the correct balance and thats from a set of eight, not a lot of thousands.
As long as the little end and big in weight match up to the rods he has and the piston weight matches up (even if it takes a little work) he will be fine.