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LS7 Conversion

 
Old 02-12-2018, 10:11 PM
  #41  
ajrothm
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Bee Jay, that engine had bearing material pumped through EVERYTHING.... so there is going to be scratches/trash EVERYWHERE...

You are going to have to clean the block really well, it needs to be hot tanked for sure to start. Then line bored. All of your main bearings got trashed because of the rod bearings failing and sending trash through the whole oiling system


At a minimum, the block will need to be cleaned, line bored. The two smoked rods will likely need to be replaced, and the replacements needs to be resized. Obviously whatever pistons are damaged will need to be a replaced and a clean up hone on the cylinders..

It shouldn't cost TOO much to fix it but...definitely not a budget repair. Now is a good time to have the valve guides replaced and a good valve job. Along with a good cam and valve springs.


I'm not buying the "lead free" bearings were the initial cause of the failure. Technically, the bearings should never touch the crank anyway... If it starved for oil, it would have killed any kind of bearings. My guess is, the oil was filled up incorrectly on one of the oil changes, if not that, then something else happened to the pump/dry sump system.


LS7s are nasty engines, especially when cammed...its worth fixing it for sure and will be killer in your 79'..
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Old 02-12-2018, 10:57 PM
  #42  
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More carnage! Look at the side of the rods! And here is the #6 bore. Maybe I should get my $150 back.



Last edited by Bee Jay; 02-12-2018 at 10:58 PM.
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Old 02-12-2018, 11:05 PM
  #43  
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Originally Posted by ajrothm View Post
Bee Jay, that engine had bearing material pumped through EVERYTHING.... so there is going to be scratches/trash EVERYWHERE...

You are going to have to clean the block really well, it needs to be hot tanked for sure to start. Then line bored. All of your main bearings got trashed because of the rod bearings failing and sending trash through the whole oiling system


At a minimum, the block will need to be cleaned, line bored. The two smoked rods will likely need to be replaced, and the replacements needs to be resized. Obviously whatever pistons are damaged will need to be a replaced and a clean up hone on the cylinders..

It shouldn't cost TOO much to fix it but...definitely not a budget repair. Now is a good time to have the valve guides replaced and a good valve job. Along with a good cam and valve springs.


I'm not buying the "lead free" bearings were the initial cause of the failure. Technically, the bearings should never touch the crank anyway... If it starved for oil, it would have killed any kind of bearings. My guess is, the oil was filled up incorrectly on one of the oil changes, if not that, then something else happened to the pump/dry sump system.


LS7s are nasty engines, especially when cammed...its worth fixing it for sure and will be killer in your 79'..
Thanks.
My Chevy dealer thinks my aftermarket oil filter caused a loss in oil pressure. They insist that I use the Delco filter on the new engine. I'm beginning to think that all I got for my money were the heads, crank, and the block. Can the oil pump be cleaned out? The oil pan should fit in my 79. This is going to be long and expensive. Where is the best place to get an LS7 aftermarket rods and pistons?
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Old 02-12-2018, 11:18 PM
  #44  
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Has the motor been apart before?
It looks like you have a mix of old style rods and the newer notched ones.
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Old 02-13-2018, 12:56 AM
  #45  
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Originally Posted by MCMLXIX View Post
Has the motor been apart before?
It looks like you have a mix of old style rods and the newer notched ones.
No,the motor only had 7,000 miles on it when I bought it.
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Old 02-13-2018, 04:04 AM
  #46  
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You could just get a set of Callies Compstar rods for about $600 a set new, likely going to need to bore it after seeing that one cylinder, at that point you may as well buy some Wiseco pistons to the tune of $900 with GFX rings. So about $1500 for the rotator, then probably $500 worth of cleaning machining on the block, balancing etc. Absolutely buy a new oil pump, new oil hoses and a new dry sump tank....do not reuse ANYTHING that's internal.... because metal will be trapped in it. Even lifters.

Realistically, I could see it costing about $3k to properly rebuild the bottom end with forged parts and new necessary parts. (oil pump, cam/lifters/trays, timing chain set etc...) plus fixing the heads... Even if you end up at $4k total, that's pretty cheap for a forged LS7 with a good cam and repaired heads... And it will make over 500rwhp in your car... H/C LS7s usually average around 550-560 rwhp, and the engine is light.
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Old 02-13-2018, 04:12 AM
  #47  
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And yes, ALWAYS run Delco filters.... There is a specific procedure to change/refill oil on the dry sump cars, so if you start doing it yourself, read the manual.

Lots of places to buy rods and pistons from. Honestly, I'd have the block checked out first to make sure that cylinder will clean up. There is not much meat in the liners to bore these things... You MAY get away with .010" over, and the pistons will be custom order for sure.


I had to bore an LQ9 block over .005" and ordered custom Wisecos and it took a month to get them.


With as much damage as occurred, you see why GM replaces engines as opposed to "fixing" them and hoping nothing comes back to haunt them in the future.

A crate LS7 is about $13k and still has the valve guide problems. The ONLY fix for the valve guide problems is aftermarket guides/valve job to true up the guide to seat relationship.
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Old 02-13-2018, 07:08 AM
  #48  
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Just for clarity, the 2013 Z06 LS7 only as well as early C7's suffered from bearing failure. I seriously doubt the oil filter caused an oil pressure failure as long as you were using a quality LS7 oil filter. There are many good LS7 filters besides the AC Delco such as amsoil, Mobil 1 EP, Wix Napa Gold, etc. The bearing failures are not from the oil or the filter, but most probably the bearing material itself. Pre-2013 LS7's did not suffer from the bearing failure issue. Read this:

https://www.corvetteforum.com/forums...for-z06-3.html

I have been using the Mobil 1 EP in my LS7 since 2010 with no issues.

Last edited by jb78L-82; 02-13-2018 at 07:09 AM.
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Old 02-13-2018, 09:39 AM
  #49  
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Originally Posted by ajrothm View Post
Bee Jay, that engine had bearing material pumped through EVERYTHING.... so there is going to be scratches/trash EVERYWHERE...

You are going to have to clean the block really well, it needs to be hot tanked for sure to start. Then line bored. All of your main bearings got trashed because of the rod bearings failing and sending trash through the whole oiling system


At a minimum, the block will need to be cleaned, line bored. The two smoked rods will likely need to be replaced, and the replacements needs to be resized. Obviously whatever pistons are damaged will need to be a replaced and a clean up hone on the cylinders..

It shouldn't cost TOO much to fix it but...definitely not a budget repair. Now is a good time to have the valve guides replaced and a good valve job. Along with a good cam and valve springs.


I'm not buying the "lead free" bearings were the initial cause of the failure. Technically, the bearings should never touch the crank anyway... If it starved for oil, it would have killed any kind of bearings. My guess is, the oil was filled up incorrectly on one of the oil changes, if not that, then something else happened to the pump/dry sump system.


LS7s are nasty engines, especially when cammed...its worth fixing it for sure and will be killer in your 79'..

I was thinking a lubrication issue from the start. How could bearings just fail, especially after more than a thousand miles.
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Old 02-13-2018, 10:52 AM
  #50  
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Just quick note.

If the bore doesn't clean up and needs a sleeve I would recommend Race Engine Development. He bored and resleeved a LS2 block for me so I could stroke it to 427 cubes. He uses ductile iron sleeves that are much stronger than the GM sleeves.

A bare LS block can bee shipped in a plastic storage bin at least that's how he sent it to me.
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Old 02-13-2018, 11:55 AM
  #51  
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Originally Posted by Bee Jay View Post
Thanks.
My Chevy dealer thinks my aftermarket oil filter caused a loss in oil pressure. They insist that I use the Delco filter on the new engine. I'm beginning to think that all I got for my money were the heads, crank, and the block. Can the oil pump be cleaned out? The oil pan should fit in my 79. This is going to be long and expensive. Where is the best place to get an LS7 aftermarket rods and pistons?
Bee Jay
I think you got a nice set of low mileage heads for $150.

The rest is trashed. The color of the crank looks like it got so hot, it would scare me too. Rebuild it and miss one detail, it will do it again. (My 2 cents).
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Old 02-13-2018, 12:08 PM
  #52  
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I had a ERL 427 short block shipped to me in one of those plastic boxes. I couldn't believe it when I saw it. I still have the box.

I have a new 2 gallon dry sump tank for sale if your interested Bee Jay. This is a Peterson Z06 tank. $350 plus shipping.
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Old 02-14-2018, 07:55 AM
  #53  
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Originally Posted by jim2527 View Post
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Old 02-14-2018, 04:47 PM
  #54  
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Damn, the crank is bent. 45 thousandths out. Now I know why it was so hard to rotate. They will inspect block, rods, and pistons next. Anyone know of a good LS7 crank for sale? I will probably need the whole reciprocating assembly. Damn.
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Old 02-14-2018, 05:07 PM
  #55  
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Have it straightened, after a good crack check. Machinists do it all the time.
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Old 02-15-2018, 11:35 AM
  #56  
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Originally Posted by L88Plus View Post
Have it straightened, after a good crack check. Machinists do it all the time.
He said it’s too far out. 45 thousandths is a lot.
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Old 02-15-2018, 04:29 PM
  #57  
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Originally Posted by Bee Jay View Post
He said it’s too far out. 45 thousandths is a lot.
Nah. Send it to me. I have a 10 pound sledge. We can bend that sucker .045 easily.

Seriously I'd ditch it also.
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Old 02-15-2018, 08:58 PM
  #58  
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Try LS1 tech for used parts. Or sometimes Pro Touring or Lateral G net has some good stuff.
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Old 02-16-2018, 02:11 AM
  #59  
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You can get a K1 crank and rods reasonably priced, and I feel their quality is better then the Compstar stuff. You can get a whole K1 rotating assembly (pistons, rods, crank) for about $2100.
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Old 02-24-2018, 12:10 AM
  #60  
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The rods are bad. Hopefully a 5 thousandths bore will clean up the one bad cylinder. So I’ll be needing a complete LS7 rotating assembly. Any recommendations? Reasonable recomendstions?


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