Brand new 383 built stroker gone bad after 200 miles... need input
07-07-2010, 10:59 PM
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Brand new 383 built stroker gone bad after 200 miles... need input Ok guys I need your input here... I want your insight in to what might have caused my failure... I have my own theories but I want to hear what some of you may say about it
So the story is,
Last winter I decided to rebuild my heads cam Ls1 (swapped into an RX7) into a fully built 383 stroker. Everything was torn down sent to a machine shop. here is the list of the parts put into it
-Promax Performance Bore and Hone to 3.908"
-Promax Performance CNC deck machining
-Full rotating assembly balance
-Acid dip/wash
-Compression ratio 11:1
-Mahle forged pistons 3.908" diameter. compression high is 1.105" .927 Wrist Pin
-Eagle H-Beam forged connecting rods length 6.125"
-ARP L19 connecting rod bolts
-Eagle forged 4" stroker crankshaft
-Clevite 77 hard backed main bearings
-Clevite hard backed camshaft bearings
-Celvite hard backed connecting rod bearings
-Fel-Pro Head Gaskets PermaTorqueMLS, 3.945 in. Bore, .053 in. Compressed Thickness
-Fel-Pro complete engine rebuild gasket set
-Comp Cams ultra Gold Rocker Arms 1.72 ratio
-Comp Cams Pro Magnum haydraulic roller lifters
-ARP chromoly main studs
-ATI Fluidamper Harmonic Balancer
-Improved Racing LSX rear sump trap door racing oil pan baffle
-oil pick-up tube girdle
-PRC 220cc stage 2.5 aluminum 5.3L heads
-COMP cams hardened chromoly pushrods 7.400"
-Rollmaster Double-Roller Adjustable Timing Set, Heat-Treated
-Fully Ported & Shimmed LS6 Oil Pump
-TSP Magic Stick V.3 - 237/242 .603/.609"
-ARP head stud kit
Anyways so we got it all back together, primed the oil through the motor and fired her up. She caught pretty quick and oil pressure jumped up to 60 psi right away. I let it idle up to operating tempurature and dumped the oil (15W40 as per my engine builders advice). put new oil (15w40 again) in and over the next couple weeks I put about 200 miles on the motor to break it in. I never really much much load on the motor because I still had my 36# injectors in from the last setup and on the old tune it was not getting enough fuel so I was taking it pretty easy. Anyway after 200 miles I dropped the oil again and then it was off to the dyno with new 60# injectors... here's where the problems happened
They started with part throttle tuning which went fine. When they got to the full load tuning there was so much pressure inside the block it actually pushed oil out the rear main seal. So to relieve the pressure they took off the oil fill cap (i also have two seperate catch cans for each bank). Anyways they did a pull again with the oil cap off and the motor was just smoking out of the fill tube like a chimney. so they shut her down and gave the car back to me, ran fine on the way home but still would smoke out of the fill tube while idling and lots of oil vapor being caught in the catch cans. I ripped the motor out (not wanting to risk further damage) and pulled it apart. I found that the main bearings were worn and shiny, and also my piston skirts (coated) got pretty chewed up and the cylinder walls got banged up enough that they couldn't be rehoned, scrapped the block...
I've tried to give as much info as I can for you guys, if you have any questions feel free to ask. I just want to know what you guys who may have been in this situation may think the cause(s) are... whether it be oil starvation, maching, bad tuning. I have my own theories but I want to hear some of yours
thanks!
-Jeff Archer
So the story is,
Last winter I decided to rebuild my heads cam Ls1 (swapped into an RX7) into a fully built 383 stroker. Everything was torn down sent to a machine shop. here is the list of the parts put into it
-Promax Performance Bore and Hone to 3.908"
-Promax Performance CNC deck machining
-Full rotating assembly balance
-Acid dip/wash
-Compression ratio 11:1
-Mahle forged pistons 3.908" diameter. compression high is 1.105" .927 Wrist Pin
-Eagle H-Beam forged connecting rods length 6.125"
-ARP L19 connecting rod bolts
-Eagle forged 4" stroker crankshaft
-Clevite 77 hard backed main bearings
-Clevite hard backed camshaft bearings
-Celvite hard backed connecting rod bearings
-Fel-Pro Head Gaskets PermaTorqueMLS, 3.945 in. Bore, .053 in. Compressed Thickness
-Fel-Pro complete engine rebuild gasket set
-Comp Cams ultra Gold Rocker Arms 1.72 ratio
-Comp Cams Pro Magnum haydraulic roller lifters
-ARP chromoly main studs
-ATI Fluidamper Harmonic Balancer
-Improved Racing LSX rear sump trap door racing oil pan baffle
-oil pick-up tube girdle
-PRC 220cc stage 2.5 aluminum 5.3L heads
-COMP cams hardened chromoly pushrods 7.400"
-Rollmaster Double-Roller Adjustable Timing Set, Heat-Treated
-Fully Ported & Shimmed LS6 Oil Pump
-TSP Magic Stick V.3 - 237/242 .603/.609"
-ARP head stud kit
Anyways so we got it all back together, primed the oil through the motor and fired her up. She caught pretty quick and oil pressure jumped up to 60 psi right away. I let it idle up to operating tempurature and dumped the oil (15W40 as per my engine builders advice). put new oil (15w40 again) in and over the next couple weeks I put about 200 miles on the motor to break it in. I never really much much load on the motor because I still had my 36# injectors in from the last setup and on the old tune it was not getting enough fuel so I was taking it pretty easy. Anyway after 200 miles I dropped the oil again and then it was off to the dyno with new 60# injectors... here's where the problems happened
They started with part throttle tuning which went fine. When they got to the full load tuning there was so much pressure inside the block it actually pushed oil out the rear main seal. So to relieve the pressure they took off the oil fill cap (i also have two seperate catch cans for each bank). Anyways they did a pull again with the oil cap off and the motor was just smoking out of the fill tube like a chimney. so they shut her down and gave the car back to me, ran fine on the way home but still would smoke out of the fill tube while idling and lots of oil vapor being caught in the catch cans. I ripped the motor out (not wanting to risk further damage) and pulled it apart. I found that the main bearings were worn and shiny, and also my piston skirts (coated) got pretty chewed up and the cylinder walls got banged up enough that they couldn't be rehoned, scrapped the block...
I've tried to give as much info as I can for you guys, if you have any questions feel free to ask. I just want to know what you guys who may have been in this situation may think the cause(s) are... whether it be oil starvation, maching, bad tuning. I have my own theories but I want to hear some of yours
thanks!
-Jeff Archer
07-07-2010, 11:16 PM
#2
and also my piston skirts (coated) got pretty chewed up and the cylinder walls got banged up enough that they couldn't be rehoned, scrapped the block...
Someone fitted the pistons WAY WRONG...nothing else to consider. Find another engine builder!
This engine must of had some terrible piston noise at start up!
Someone fitted the pistons WAY WRONG...nothing else to consider. Find another engine builder!
This engine must of had some terrible piston noise at start up!
07-08-2010, 12:12 AM
#5
I think I am with choice one and 2 piston slap. thats the only way that your skirts are going to get beat up like that. You know what would help out pics if you have any. Cylinder walls and pistons top and skirts.
What size pistons cause i think i missed them on the list and what rings where u running.
oh and is there any one cylinder that you can get at least a top and bottom measurement.
also with gm engines some have no audible piston slap and some have audible piston slap on only one or two cylinders.
What size pistons cause i think i missed them on the list and what rings where u running.
oh and is there any one cylinder that you can get at least a top and bottom measurement.
also with gm engines some have no audible piston slap and some have audible piston slap on only one or two cylinders.
Last edited by 02*C5; 07-08-2010 at 12:19 AM.
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07-09-2010, 05:20 PM
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