Aluminium 5.3 punched to 5.7 - bore to sleeve misalignment
01-06-2015, 09:22 AM
#21
I doubt anyone messed up the block, it's just the way it was cast. Cylinder bores have a blueprint X and Y axis. Regardless of where the cylinder is cast, the machine doing the work will locate the cylinder bore in the correct location. If this were an iron block you would never notice the core shift unless you sonic tested the block.
01-06-2015, 09:59 AM
#22
What height did they deck the block to? Pistons rock in the bore, could that be why you're getting that measurement? Is it an equal .020" on both sides?
Fwiw, I had a 402 LS2 built and it was decked to 9.221", leaving the piston .014" out of the hole. With a .055" gasket that still leaves .041" quench.
Fwiw, I had a 402 LS2 built and it was decked to 9.221", leaving the piston .014" out of the hole. With a .055" gasket that still leaves .041" quench.
01-06-2015, 07:12 PM
#23
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Dam Stan I hate to see stuff like this. Ya know you can try to cover everything but the end result usually involves someone's else's poor judgment or lack of experience.
I can't do my own work anymore and when it comes to simple things like setting up a rear after a repair stresses me out because its dam hard to find someone with what I EXPECT for the end result. I know a couple guys I trust BUT I'm still worried until I see the final result.
With your block I would personally spend a few extra bucks and send it off to someone to check the center line of the crank with bores etc . Seems to me there could be ALOT of things way off. I'm interested , do all the pistons stick out equally? There are so many questions in my mind about this block I wouldn't use it until they were all answered. Plus what didn't I think of? A good engine builder will know the answers to all yer worries. Good Luck.
I can't do my own work anymore and when it comes to simple things like setting up a rear after a repair stresses me out because its dam hard to find someone with what I EXPECT for the end result. I know a couple guys I trust BUT I'm still worried until I see the final result.
With your block I would personally spend a few extra bucks and send it off to someone to check the center line of the crank with bores etc . Seems to me there could be ALOT of things way off. I'm interested , do all the pistons stick out equally? There are so many questions in my mind about this block I wouldn't use it until they were all answered. Plus what didn't I think of? A good engine builder will know the answers to all yer worries. Good Luck.
I just got my bridge in the mail and checked how for the pistons are above the deck. They are all between .021 and .023" above. That's in a cold 45F shop, quick calc the cold temp should change it more than .001 or so but I'm going to try again with some heat.
01-06-2015, 07:14 PM
#24
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What height did they deck the block to? Pistons rock in the bore, could that be why you're getting that measurement? Is it an equal .020" on both sides?
Fwiw, I had a 402 LS2 built and it was decked to 9.221", leaving the piston .014" out of the hole. With a .055" gasket that still leaves .041" quench.
Fwiw, I had a 402 LS2 built and it was decked to 9.221", leaving the piston .014" out of the hole. With a .055" gasket that still leaves .041" quench.
01-08-2015, 10:53 PM
#26
Good it's the 5.3 block and not the ls3 block. The 5.3 block sleeves check a good bit thicker than the ls3 blocks gm likes to offset so bad! You'd be amazed how many ls3/l92 blocks we return to gm for this issue. With the Texas Speed Cnc block digitizing and blueprintung machine we out the bores on factory blueprint but that doesn't mean the bore was cast in place correctly. As a result we use the ole eyeball test and kick out some blocks before they ever get to the Cnc machine!
You guys would be shocked how off a factory block can be machined from gm.
I'll post a block test result sheet for you guys.
Jason
Texas Speed
You guys would be shocked how off a factory block can be machined from gm.
I'll post a block test result sheet for you guys.
Jason
Texas Speed
01-08-2015, 11:01 PM
#27
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Good it's the 5.3 block and not the ls3 block. The 5.3 block sleeves check a good bit thicker than the ls3 blocks gm likes to offset so bad! You'd be amazed how many ls3/l92 blocks we return to gm for this issue. With the Texas Speed Cnc block digitizing and blueprintung machine we out the bores on factory blueprint but that doesn't mean the bore was cast in place correctly. As a result we use the ole eyeball test and kick out some blocks before they ever get to the Cnc machine!
You guys would be shocked how off a factory block can be machined from gm.
I'll post a block test result sheet for you guys.
Jason
Texas Speed
You guys would be shocked how off a factory block can be machined from gm.
I'll post a block test result sheet for you guys.
Jason
Texas Speed
02-21-2016, 01:36 PM
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I've been struggling with this engine. Lots of blow-by when hot, zero when cold. The engine at this point only has maybe 2 hours of street time and a day at the dyno. Engine is hot during the vid.
Some back story...
There was an oil leak coming from the rear main after the first (gentle) test drive last spring. July 4th weekend last year, this became a hellacious gusher that oil coated the whole underneath of the car and headers which created a smoke storm. I did a compression check while the engine was hot and nothing obvious came from it. All cylinders were similar in pressure but at the lower end of what was expected (cant remember actual PSI right now, can't find my notes).
Compression ratio 11.5:1, cam 234/238 @0.050. Dynamic compression ratio is 9-10.1 depending if I use advertised duration or 0.050" lift for int ABDC.
I recently replaced the rear main seal, leak is gone but I have not driven the car. Vid above was taken today. I can't accept that this much blow-by is ok.
Some back story...
There was an oil leak coming from the rear main after the first (gentle) test drive last spring. July 4th weekend last year, this became a hellacious gusher that oil coated the whole underneath of the car and headers which created a smoke storm. I did a compression check while the engine was hot and nothing obvious came from it. All cylinders were similar in pressure but at the lower end of what was expected (cant remember actual PSI right now, can't find my notes).
Compression ratio 11.5:1, cam 234/238 @0.050. Dynamic compression ratio is 9-10.1 depending if I use advertised duration or 0.050" lift for int ABDC.
I recently replaced the rear main seal, leak is gone but I have not driven the car. Vid above was taken today. I can't accept that this much blow-by is ok.
