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New rings or replace pistons

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Old 08-08-2018, 06:23 PM
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Default New rings or replace pistons

Did a search but couldnít find exactly what I was looking for. I have a 1998 Formula with 160k miles on it. No mods daily driver. I recently pulled the engine to replace oil pump and give it a once over. Ended up giving the short block to a local machine shop to clean up and check over for me.

They said the cylinders are showing .003-.004Ē wear and I can either re-ring it or bore it out and get new pistons. I donít plan on modding the car and will likely see some daily driver use for a couple more years. Has anyone just ran new rings without issues? If I did decide to bore it out, whatís the next piston size up? My shop is telling me itís a .020 oversize which seems like a lot. The 1998 blocks has the thinner sleeves so not sure if that is a good idea.

Basically looking for some input on what I should do. I donít want to spend more money than I have to considering how much money has gone into replacing suspension parts, AC, cooling etc. Thank you.
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Old 08-08-2018, 06:46 PM
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Default LS-1 Forged Pistons at + .006"

Hi Rocky, I can supply Forged Pistons at +.006" AND use +.005 rings.
DO NOT WASTE money for a Bore job.

Lance
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Old 08-08-2018, 06:58 PM
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How much do you trust what they are telling you? Frankly I have a hard time trusting anyone with my engine but at this point it certainly makes since to re-ring your pistons. Just like it makes since to go back through the cylinder heads with a new valve job, seals, springs and retainers. At 160,000 miles your cam bearings may be showing significant signs of wear and need to be replaced. If your in this far go ahead and install an LS2 timing cover and timing chain and while your at it throw in some new lifters. But if you want to just put a (xx:xx) on it then put it all back together and just run it!
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Old 08-08-2018, 08:03 PM
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Originally Posted by pantera_efi View Post
Hi Rocky, I can supply Forged Pistons at +.006" AND use +.005 rings.
DO NOT WASTE money for a Bore job.

Lance
Thanks for the tip. Will send you a private message.

Originally Posted by 01CamaroSSTx View Post
How much do you trust what they are telling you? Frankly I have a hard time trusting anyone with my engine but at this point it certainly makes since to re-ring your pistons. Just like it makes since to go back through the cylinder heads with a new valve job, seals, springs and retainers. At 160,000 miles your cam bearings may be showing significant signs of wear and need to be replaced. If your in this far go ahead and install an LS2 timing cover and timing chain and while your at it throw in some new lifters. But if you want to just put a (xx:xx) on it then put it all back together and just run it!
I probably should have included a bit more details about what else Iím doing. I got a set of 241 heads locally for free that had about 20k on them. Nice and clean and figured I will give them a light lap job at home and be good. Iím replacing all the wear items while I have the engine apart. Ordered new lifters, new timing chain, oil pump etc. Gave the short block to the shop to deal with the cam/main bearings and pistons/rings. Just wasnít sure at what gap the pistons must be replaced as this is my first time diving into an engine and the shop Iím dealing with really isnít a speed shop. Thanks.
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Old 08-08-2018, 08:25 PM
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A shop need not be a speed shop to know basic engine assembly/machining operations. Speed shops sell performance parts. Any engine shop they have would have the same capabilities as any other engine machine shop. As long as the shop you are using knows how to assemble an engine you should be OK.
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Old 08-08-2018, 10:59 PM
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Reading this excerpt below has got me thinking I should just get new rings and a light hone being that mine is a 1998. And it's got me a little worried the shop is even suggesting a 0.020 oversize piston

The blocks are actually cast in place around these liners (rather than the normal practice of pressing the liners into the block after it has been cast). On the very earliest LS1 blocks produced in 1997 and 1998, the sleeves may not always be positioned 100 percent perpendicular within the block casting, meaning that the final-bore sizing and honing process left one side of the walls thinner than the official engine design specs called for. Therefore, 1997–1998 LS1 5.7L aluminum blocks can only be safely honed (not even bored!) just 0.004-inch over the stock bore diameter. Improved liner positioning in 1999-and later 5.7L LS1 blocks and all LS6 blocks permit boring up to 0.010-inch oversize. Either way, you are SOL at wanting to go 0.020-over for a reliable LS1 aluminum block rebuild.

https://www.hotrod.com/articles/max-...for-ls-blocks/
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Old 08-09-2018, 07:36 AM
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I would be more worried about someone pulling a 160k mile engine apart that doesnt plan on modding the car.
Or am I missing something here? Replacing oil pump??? Just because you wanted to or because it was having issues?
These engines in stock form will go 300,000 miles with nothing more than a lifter tap. With proper oil changes of course
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Old 08-09-2018, 08:22 AM
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The shop may have suggested.020 if it has an older boring bar. It can be hard to center in a worn cylinder to cut .005 of each side all the way down. I do agree with getting the .005-.006 over pistons because you can throw it in a hone and clean it up and know youíre gonna seal new rings.
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Old 08-09-2018, 09:46 AM
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Normally a 3.902” to 3.905” bore size is the next step up. As mentioned, no need to bore it to that size. Just a good torque plate hone should do it.
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Old 08-09-2018, 12:08 PM
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Originally Posted by Ls7colorado View Post
I would be more worried about someone pulling a 160k mile engine apart that doesnt plan on modding the car.
Or am I missing something here? Replacing oil pump??? Just because you wanted to or because it was having issues?
These engines in stock form will go 300,000 miles with nothing more than a lifter tap. With proper oil changes of course
I too wonder why urgency to open up the engine? I daily drive my 332,000 mile TA and the only thing that I have done engine wise is replace the oil pump (it was tired at around 280k and the pressure was under 20 at hot idle.) While there I replaced the timing chain and sprockets. I am using a quart of oil between 3k oil changes, but I still am gonna just drive it.
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Old 08-09-2018, 01:51 PM
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Come on guys, if I was smart Iíd have sold the car a long time ago lol. Most of the what Iím doing is just for my own learning and Iím probably doing stuff that isnít needed. I have a 90 Iroc and 09 vette which will be a proper project car in the future. This is just a learning excercise and an expensive one at that.

The oil pressure had been dropping steadily for about 12 months, and combined with all the oil leaks the car had I figured I would just drop the cradle so I didnít have to work on my back. Had been seeing a little milkiness in my recent oil changes and had a set of newish 241 heads so off my old heads came. Once I saw all the crud I figured a hot tank was in order. At that point itís at the shop so might as well throw in some new bearings and inspect so here we are.

I guess an option I still have is to just leave everything as is and reassemble with some new bearings. I canít find a set of non-forged 3.903 pistons so Iím leaning towards just replacing the rings. I was hoping someone with experience could tell me if this is a really bad idea or I should be ok.

I will be posting more pics later but here are some showing the block. Havenít always been on top of my maintenance and it shows.



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Old 08-09-2018, 02:53 PM
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Ooof. Yeah, she’s gonna need a hot tank. Make sure the shop your using has a torque plate for the LS engine. Believe it or not, 21 years later, some shops still don’t have one.
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Old 08-09-2018, 03:35 PM
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Nice!
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Old 08-10-2018, 04:36 PM
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I don't see why you couldn't you just go through the cylinders with about 7-10 strokes of a FLEX ball hone to get some cross hatching in it and then clean everything up really good and reassemble with new rings and bearings.
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Old 08-10-2018, 04:37 PM
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Originally Posted by 01CamaroSSTx View Post
I don't see why you couldn't you just go through the cylinders with about 7-10 strokes of a FLEX ball hone to get some cross hatching in it and then clean everything up really good and reassemble with new rings and bearings.
Because he secretly wants to have a completely rebuild engine and is trying his best to justify it in his mind.
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Old 08-10-2018, 05:18 PM
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Originally Posted by 01CamaroSSTx View Post
I don't see why you couldn't you just go through the cylinders with about 7-10 strokes of a FLEX ball hone to get some cross hatching in it and then clean everything up really good and reassemble with new rings and bearings.
I guess this is what I was asking for some input on. If I had one of the newer blocks, I think I would just hone it to 3.905 and get new pistons. Mine being a Ď98, Iím thinking of going the route you mentioned. It wonít be any worse off than it was before I dropped it off. A little piston slap and oil consumption letís me know sheís there.

Originally Posted by Ls7colorado View Post
Because he secretly wants to have a completely rebuild engine and is trying his best to justify it in his mind.
I will try and make better life decisions in the future.
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Old 08-10-2018, 07:07 PM
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What are you going to do for a cam?
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Old 08-10-2018, 07:37 PM
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Originally Posted by gesto View Post
What are you going to do for a cam?
Keeping stock cam for now. I have an A4 and was planning on keeping TC for now. Stock TC stock cam. Only things Iíve got lined up are ARH lt headers and LS6 intake mainly cuz I wanted to ditch the EGR/AIR. Nice dd car with a lil punch I hope.
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Old 08-10-2018, 08:50 PM
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I guess i'll do it. Take that aluminum block and put it in your garbage disposal. Aquire an lq4/lq9 and put that in there with your accessories. Get it tuned and you will still have $ left over and a better engine. If the 100 lbs difference is too much go on a diet. At lowe's they have some nice aluminum looking paint if you want to keep the stock look.
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