Removing piston from the bottom?
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From: Still under the hood in O
Removing piston from the bottom?
I have a wrist pin knock on the #8 piston. I'm thinking of dropping the pan again and pull the piston from the bottom to repair it. It sure would save me a LOT of work and time compared to pulling the head or the motor for a rebuild.
For the record; the motor is not very old and the seal is very good as are the bearings, no real need for a rebuild or re-ring job. Just the one wrist pin problem.
Has anyone pulled a piston from the bottom?
For the record; the motor is not very old and the seal is very good as are the bearings, no real need for a rebuild or re-ring job. Just the one wrist pin problem.
Has anyone pulled a piston from the bottom?
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Removing piston from the bottom?
90f150moneypit
How did you come about it was a wrist pin knock? I have never experienced that, I have dealt with a thrown bearing where it would knock at 1500 + rpm is the sound the same/ how does it differ? The more you post the more I understand the moneypit part of your username. j/k. How old is the motor? Looks like the heads and pan are coming off. Good luck
How did you come about it was a wrist pin knock? I have never experienced that, I have dealt with a thrown bearing where it would knock at 1500 + rpm is the sound the same/ how does it differ? The more you post the more I understand the moneypit part of your username. j/k. How old is the motor? Looks like the heads and pan are coming off. Good luck
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From: Still under the hood in O
Removing piston from the bottom?
Well, it starts after it warms up. It doesn't do it when it's cold or at idle. Only when the engine is revved up, not on deceleration.
I thought it may have been a rod bearing but I pulled the pan and checked them.
Then I found a site with a pretty good knock troubleshooting article. It said that if the knock goes away when you pull the spark plug wire from the bad cylinder it's a wrist pin. If it gets worse it's a rod bearing. Well, when I pull the #8 plug wire it goes away.
This makes sense because the compression is good across the board and the oil pressure and water temp are good as well. Plus there is absolutley no metal in the oil or remnants in the pan or around the inside of the block, in fact everything still looks fresh.
The motor only has about 40K miles. I bought it from a new car dealership 10 years ago and I've only driven it daily for 5 years. The motor had a fresh rebuild when purchased.
What really steams me is I paid the going price 10 years ago of over $13K and as it sits it isn't worth $3K! All told, so far I have over $18K in a very nice knockmobile.
At least it runs good.
I thought it may have been a rod bearing but I pulled the pan and checked them.
Then I found a site with a pretty good knock troubleshooting article. It said that if the knock goes away when you pull the spark plug wire from the bad cylinder it's a wrist pin. If it gets worse it's a rod bearing. Well, when I pull the #8 plug wire it goes away.
This makes sense because the compression is good across the board and the oil pressure and water temp are good as well. Plus there is absolutley no metal in the oil or remnants in the pan or around the inside of the block, in fact everything still looks fresh.
The motor only has about 40K miles. I bought it from a new car dealership 10 years ago and I've only driven it daily for 5 years. The motor had a fresh rebuild when purchased.
What really steams me is I paid the going price 10 years ago of over $13K and as it sits it isn't worth $3K! All told, so far I have over $18K in a very nice knockmobile.
At least it runs good.
Tuned
Joined: Feb 2003
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From: Oregon
Removing piston from the bottom?
I had a 2.3 that knocked like that. A piston had actually cracked in the pin boss area and partially collapsed.
Those pins are hardened tool steel and don't usually wear unless it was too loose in the small end of the rod. It probably hammered your piston.
Those pins are hardened tool steel and don't usually wear unless it was too loose in the small end of the rod. It probably hammered your piston.
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Removing piston from the bottom?
90f150moneypit
Well appears you have isolated the cylinder if not the problem, just a matter of repair. I know you have seemed to eliminate the bearings but it sounds similar to when I had a thrown bearing, it came about like clockwork at 1500 rpm it would knock get it under 1500 it went away, and I was pissed the whole time, haha. Good luck, seems you should be able to fix it. later
Well appears you have isolated the cylinder if not the problem, just a matter of repair. I know you have seemed to eliminate the bearings but it sounds similar to when I had a thrown bearing, it came about like clockwork at 1500 rpm it would knock get it under 1500 it went away, and I was pissed the whole time, haha. Good luck, seems you should be able to fix it. later
Tuned
Joined: Jun 2003
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Removing piston from the bottom?
You said you don't want to pull the head? Your going to have to to get the piston in/out right? unless you plan on pulling the crank, and I don't think you can do that with the engine in. I replaced my #8 piston/pin a month ago as it got burnt due to the PCV pumping into the #8 runner. It wasn't too bad really. Pulled the upper/lower intake, jacked the engine up, dropped the pan, pulled the head...and then pulled the piston. I did the rod bearings while I was there because the journals were fine, but he bearings were worn. I just put regular size in. Runs great now.
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From: Still under the hood in O
Removing piston from the bottom?
Hrrm. How long did it take you?
I guess that's what I'll have to do.
I guess that's what I'll have to do.
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From: Indiana
Removing piston from the bottom?
When you replace that make sure you check the cylinder. When they rebuilt that engine they could have just reringed it and not done anything to the block. Which could be why your having problems now. From what your saying it also sounds alot like piston slap.
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Removing piston from the bottom?
Actually, I have taken a SBC piston out the bottom (rerung it and put it back in). It was a PITA, but easier IMO that pulling the motor and head. It lasted about 20000 more miles. Good luck.
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From: Still under the hood in O
Removing piston from the bottom?
I thought about piston slap when I had the pan off as well. I checked what I could of the bore, it was in good shape. Of coarse I couldn't see the upper half either but there was no metal shavings. I wish I had thought of the wrist pin when I was under it, oh well.
I've just about made up my mind to get another block and rebuild another engine as time and money allows. I priced all the parts already needed for a completely new (minus block) motor. With rebuild kit (including Hyper. pistons) plus Eagle crank and rods it would be under $1K plus the machine work to the block.
I went to the local dealer to check on a short block and they quoted me $1900 with a $300 core!
I would rather build it with quality aftermarket parts and my attention to detail for less than that $1600.
I've just about made up my mind to get another block and rebuild another engine as time and money allows. I priced all the parts already needed for a completely new (minus block) motor. With rebuild kit (including Hyper. pistons) plus Eagle crank and rods it would be under $1K plus the machine work to the block.
I went to the local dealer to check on a short block and they quoted me $1900 with a $300 core!
I would rather build it with quality aftermarket parts and my attention to detail for less than that $1600.
Tuned
Joined: Jun 2003
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Removing piston from the bottom?
I pulled and replaced my piston in 2 days. Saved me lots of money and the rest of the engine was fine. Had I the space and time I would have pulled it and rebuilt it the right way...I will some day in the future. I think its a good way to go if you are looking to get the truck back on the road. I agree you really can't do it unless you pull the head off. I would do it again if I had to.
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From: Still under the hood in O
Removing piston from the bottom?
Thanks, I may just do that. For now I'll just drive it easy. It's okay as long as I don't get on it, keep the RPM's down. When I get time I'll either start on a new motor or pull that piston out.