Pullin the engine again!! ugh...answer this plz!
05-23-2009, 06:40 PM
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Pullin the engine again!! ugh...answer this plz! So I'm goin through the basic season prep this spring, made a list of things I want to get done on my car before I get it on the road again..and one of the things to look at was a upper engine tick on the d/s engine bank. I originally thought it was from the head (maybe a sticky valve/lazy spring etc). Well I pull the head off and started to inspect the the springs and glanced at the block and lo and behold out of #5 cylinder..(first time I've uploaded pics so forgive the placement/quality) The ringlance has disappeared on the thrust face of the piston...the 'tick' that I drove on for a long time thinkin it was a valve was actually my piston disentegrating. (stock ls1 pistons btw) so now I'm done with pullin this every spring. I'm movin on to forged pistons. Question(s) are-what type of forged piston would be the best for my application? Its a daily driver/street machine, standard bore with no boost application..yet. ls6 cam and ls1 crank. I'm on a little bit of a budget as this money goin to the pistons was goin to go for a new paint job/rims for my ride.
The other question is -Why does this happen? especially with a mostly stock ls1/ls6 engine? I've seen many pics on this site with the same problem/carnage...is it just detonation? improper seating on the rings?
All comments and questions welcome
Thanks.
The other question is -Why does this happen? especially with a mostly stock ls1/ls6 engine? I've seen many pics on this site with the same problem/carnage...is it just detonation? improper seating on the rings?All comments and questions welcome
Thanks.
05-24-2009, 04:35 AM
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I wouldn't mind keeping the price around 1000 or so. 60000 miles on the motor. About 5000 since it was rebuilt-the block was basically fully rebuilt before being placed back in the car last spring. New bearings (cam/rod/main) and cylinder honed. I can always fully rebuild, I guess, since its completely apart but I dont know if thats necessary since it was serviced last spring. The block is going to a local speed/tech shop just to make sure there are no micro cracks on the block because of the piston takin a dump.
05-24-2009, 12:58 PM
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I sample measured 2 sets, i placed the rings without pistons in the cylinders to make sure they had an adequate gap. I cant remember if I measured them all-I guess some of them could of been tighter than others. Thinking the rings were all the same is me being complacent I guess..oops.
Thanks 'willyfastz', I'll look into those.
Thanks 'willyfastz', I'll look into those.
05-24-2009, 01:08 PM
#7
Yup, lesson learned. Measure each ring pack in the bore it's being installed into, then pop them into a Ziploc bag and number it with a Sharpie.
If you find a ring pack with end gaps too small, try other rings before you start filing. You'd be surprised how much variation there is in off-the-shelf rings.
And whatever you do, make sure the rings are square in the bores before you measure. I use an old piston with the #2 compression ring installed, just set the ring to be measured high in the bore and use the piston crown to push it square, the old #2 ring will ensure alignment by seating against the deck surface of the cylinder.
If you find a ring pack with end gaps too small, try other rings before you start filing. You'd be surprised how much variation there is in off-the-shelf rings.
And whatever you do, make sure the rings are square in the bores before you measure. I use an old piston with the #2 compression ring installed, just set the ring to be measured high in the bore and use the piston crown to push it square, the old #2 ring will ensure alignment by seating against the deck surface of the cylinder.
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05-24-2009, 04:27 PM
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Thanks conan! Nice ride btw. Is there any particular rings that I should use with these pistons? I know if I intend to use nitrous in the future I should put nitrous rings in but I dont know if I will put any shot to this engine ever. I guess I am thinking pro-charger install is a possibillity but I don't know if I need a special kind of ring for that application.
05-24-2009, 05:07 PM
#11
Bear in mind that everything is a compromise. Cost, durability, and noise are the three variables.
With NA and no nitrous, you can focus on cost and noise...go with cast hypereutectic pistons and lots of compression, save $$. They'll be quiet and cheap.
If you're going with a blower, you'll need forged pistons and less compression. The more boost you plan to run, the lower static compression you'll want to plan for. You'll go with more durable forged pistons, which will cost more and be piston-slap noisy when cold.
If a blower is in your plans, but not for now, going with low-compression forged pistons means you'll be giving up a lot of efficiency in the meantime and you'll feel it every time you mash the gas. Low compression and no forced induction to make up for it means you've got a modern version of the late 1970's under your hood. Yuck.
With NA and no nitrous, you can focus on cost and noise...go with cast hypereutectic pistons and lots of compression, save $$. They'll be quiet and cheap.
If you're going with a blower, you'll need forged pistons and less compression. The more boost you plan to run, the lower static compression you'll want to plan for. You'll go with more durable forged pistons, which will cost more and be piston-slap noisy when cold.
If a blower is in your plans, but not for now, going with low-compression forged pistons means you'll be giving up a lot of efficiency in the meantime and you'll feel it every time you mash the gas. Low compression and no forced induction to make up for it means you've got a modern version of the late 1970's under your hood. Yuck.
05-24-2009, 05:55 PM
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The Mahle pistons come with their rings, which are pretty good. Also the Mahle pistons require tight piston to wall clearances, like .001 to .003. So if installed correctly and with a few little tricks (not need'ed but I always do it) they will run quiter than stock.
05-24-2009, 10:13 PM
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Bear in mind that everything is a compromise. Cost, durability, and noise are the three variables.
With NA and no nitrous, you can focus on cost and noise...go with cast hypereutectic pistons and lots of compression, save $$. They'll be quiet and cheap.
If you're going with a blower, you'll need forged pistons and less compression. The more boost you plan to run, the lower static compression you'll want to plan for. You'll go with more durable forged pistons, which will cost more and be piston-slap noisy when cold.
If a blower is in your plans, but not for now, going with low-compression forged pistons means you'll be giving up a lot of efficiency in the meantime and you'll feel it every time you mash the gas. Low compression and no forced induction to make up for it means you've got a modern version of the late 1970's under your hood. Yuck.
With NA and no nitrous, you can focus on cost and noise...go with cast hypereutectic pistons and lots of compression, save $$. They'll be quiet and cheap.
If you're going with a blower, you'll need forged pistons and less compression. The more boost you plan to run, the lower static compression you'll want to plan for. You'll go with more durable forged pistons, which will cost more and be piston-slap noisy when cold.
If a blower is in your plans, but not for now, going with low-compression forged pistons means you'll be giving up a lot of efficiency in the meantime and you'll feel it every time you mash the gas. Low compression and no forced induction to make up for it means you've got a modern version of the late 1970's under your hood. Yuck.
I understand the ratio between boost and compression but the whole idea here is to move on from hypereutectic pistons to forged. I'm going overboard with the piston replacement here and I know that but I'm just doing it for more peace of mind just in case there might be detonation...cause it would just be my luck. With a forged piston in there its more of a safety net than anything else that the ring lance wont take a vacation on me again.Willyfastz-what are the few little tricks that you have up your sleeve that will make them run quieter than stock? Willing to share?
05-25-2009, 12:19 AM
#14
Thanks conan! Nice ride btw. Is there any particular rings that I should use with these pistons? I know if I intend to use nitrous in the future I should put nitrous rings in but I dont know if I will put any shot to this engine ever. I guess I am thinking pro-charger install is a possibillity but I don't know if I need a special kind of ring for that application.
05-25-2009, 02:55 AM
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K. Now I'm confused a little. I understand they're will be a compromise but are you saying that I can't go with normal (stock) compression with forged pistons? I'm new to the forged piston marked so I'm green as go here. I understand the ratio between boost and compression but the whole idea here is to move on from hypereutectic pistons to forged. I'm going overboard with the piston replacement here and I know that but I'm just doing it for more peace of mind just in case there might be detonation...cause it would just be my luck. With a forged piston in there its more of a safety net than anything else that the ring lance wont take a vacation on me again.
Willyfastz-what are the few little tricks that you have up your sleeve that will make them run quieter than stock? Willing to share?
I understand the ratio between boost and compression but the whole idea here is to move on from hypereutectic pistons to forged. I'm going overboard with the piston replacement here and I know that but I'm just doing it for more peace of mind just in case there might be detonation...cause it would just be my luck. With a forged piston in there its more of a safety net than anything else that the ring lance wont take a vacation on me again.Willyfastz-what are the few little tricks that you have up your sleeve that will make them run quieter than stock? Willing to share?
05-25-2009, 07:19 AM
#16
Forged pistons come in whatever dome/dish you want.
My point was that with a blower you won't want stock compression. You could build it, but trying to avoid detonation would be a losing battle.
Not a good way to approach it. If you hose up clearances, something catastrophic will happen whether you're running forged or cast pistons. If the ringland doesn't fail, the ring will likely get to welding temp and seize in the bore...tossing a rod through the block.
Last edited by crainholio; 05-25-2009 at 07:24 AM.