Well I ended up cracking a piston on my 7MGE after going NA-T with 7MGE electronics, most likely due to detonation, I was monitoring with an lm-1 wide band but only got to realtime datalog once to my laptop, during the logging session I saw my AFR at 4k rpms hit 14.1 but then increase immediately to 11:1, I was tuning with an SAFC II...
To combat going lean again I will install a Walbro fuel pump, EGT gauge, aeromotive afpr kit, take out the j-tube restriction and get rid of the fuel pulsation dampener. I was previously running the stock turbo AFPR and 440cc injectors.
I am in the process of getting everything together for a rebuild. At first I was thinking I would just replace the piston that was cracked and have them all balanced but after thinking about it for a bit I might as well do a full rebuild. This engine only has 15k on it since it was fully rebuilt and all the cylinder bores look great, no nicks or scratches that my thumbnail gets caught on, although they will need to be honed.
I already had an 1.2mm HKS MHG and ARP's but will probably go with a 2.0MM Cometic MHG to lower compression a bit. I was just wondering after I get all the machining done, IE the block and head decked, and the cylinders honed how hard is it to assemble the shortblock and check all clearances. I will probably be going with a new set of OEM pistons .020 over, Clevite 77 main and rod bearings(not sure what size since I will have the machine shop check the crank and thrust bearings. I have never assembled an engine before... Any help is appreciated.
Setup Before Cracking Piston
Pulling Engine
Cylinder Bores
Cracked Piston, Hairline Cracks through the ringland and scuffing from detonation
To combat going lean again I will install a Walbro fuel pump, EGT gauge, aeromotive afpr kit, take out the j-tube restriction and get rid of the fuel pulsation dampener. I was previously running the stock turbo AFPR and 440cc injectors.
I am in the process of getting everything together for a rebuild. At first I was thinking I would just replace the piston that was cracked and have them all balanced but after thinking about it for a bit I might as well do a full rebuild. This engine only has 15k on it since it was fully rebuilt and all the cylinder bores look great, no nicks or scratches that my thumbnail gets caught on, although they will need to be honed.
I already had an 1.2mm HKS MHG and ARP's but will probably go with a 2.0MM Cometic MHG to lower compression a bit. I was just wondering after I get all the machining done, IE the block and head decked, and the cylinders honed how hard is it to assemble the shortblock and check all clearances. I will probably be going with a new set of OEM pistons .020 over, Clevite 77 main and rod bearings(not sure what size since I will have the machine shop check the crank and thrust bearings. I have never assembled an engine before... Any help is appreciated.
Setup Before Cracking Piston
Pulling Engine
Cylinder Bores
Cracked Piston, Hairline Cracks through the ringland and scuffing from detonation
