Holes in pistons?
- Thread starter Alligator
- Start date
I would most definately mark the injectors if it's not too late, and not reuse the hurt cyl until you get it tested.
Mine was #4 also. Exact same failure as Tommy's. My injectors were tested and all showed good. I still think it's a heat issue. For some reason the oil can't keep the piston cool enough, IMO. I made sure all my squirters were centered on the inlet hole of the piston when I put them back in. I'm planning on adding an external oil cooler (in addition to the internal one) and an oil temperature gauge.
that may be a problem with lbz and lly's, from what i read the oil squirters stop spraying once down to a certain oil press , maybe they should be made to squirt at all times,
so mainly what im trying to fix is the lb7 stuck injectors that cause the crank case to fill with diesel and extend the life of them
so mainly what im trying to fix is the lb7 stuck injectors that cause the crank case to fill with diesel and extend the life of them
I've been into mine more times than i wish to count
An it sucks for us LB7 boys
Every one of my falure's/problems has always been fuel in the oil with no other issues. Had one with a loose nozzle cap, a return line seep, one injector was spraying from the inlet fitting which i snuged up against the retention pin and stopped it. And ive had 3 of them develop (im guessing, cause i cant see them) Cracks at the inlet fitting, and fuel sprays from the retention pin area and out of the small hole in the end of the body where the inlet is (im guessing its a bore hole passage to intersect the fuel inlet to the inside of the body and the installed inlet fitting blocks the end) All of the cracked injectors had had the small steel ball pressed in the body just at the botom edge of the solinoid cap, was pushed out against the cap and it should be seated in there some. IMO---LB7 injectors are just a crappy design and or made from a poor choice in materials. This is my biggest angst to the LB7, i dunno, why the hell cant Bosch get us a part that works? Maybe these need to be made from forged chrom-moly or somthin? ON TOP OF THAT there a Pain In The ASS to change! I swear, if theres no advances around by the time i rebuild mine...Its getting converted to LLY or newer heads and injection sys. etc, etc. 
we might send mine out to get tested and flowed to see wht they show it just cost some dinero. but may give some insight on whts gioing on
Injectors were definitely marked, pulled them out a couple of weeks ago and put them in individually marked baggies.
I've been into mine more times than i wish to count
LB7 boys
when my injectors went bad in my 02 lb7 i was driving around for like 6 hours and keep smelling diesel fuel and i stoped poped the hood and couldnt find nothing leakin so i kept driving and it was raining i finaly made it home at midnight and the next day when i went to load up the truck to haul a load the whole underside and tailgate was covered with diesel fuel and oil i was so pissed and i had rough idle and no white smoke , so i checked the oil and it was smack full of diesel , so i took it to the dealer and they put in 8 inj and and after they were done and i got the truck back i noticed i lost about 5-10 pounds of oil pressure after the new injectors and new oil and filter and i was pissed , so now im trying to improve the longevity of the injectors . also u can have your injectors bench tested and they might test fine but bring them up to operating temp and things start to change big time
How could this be done?
How many of these failures are due to faulty injectors?
Does anyone know if GM is researching as to why these pistons ae not holding up?
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apperently the oil squirters are regulated they open at 29 psi and seem to stop spraying after a hard run when the oil pressure drops after the hard run and drops below 29 psi from what data logging has shown oil press below 29 psi after a hard run, also from what i gather from guys that have had pistons crack , is they seem to be down on power just before they let go , basicly what im thinkin is that the explosion in the piston bowl is so great that its puttin extreem pressure on the outer edge of the piston bowel and causing the piston to split in half like a coconut .im thinking that when the cool oil hits the two halfs of the pistons it causing it to contract fast and shrink and split in half since the rod and wrist pin is blocking the oil from hitting directly on the middle of the piston, so far i have not seen any piston failers on pistons that have had the piston bowel re worked , with increased fuel and boost after the modded pistons have been installed now im talkin bout stocker lbz pistons that have had the bowels re worked , but i could be wrong
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Keep the pedal to the metal
I thought this was proved that they squirted to lower than 29psi? Something like 13???maybe not
There was a huge thread a while back on DP. Supposedly it was discovered they do indeed squirt way below 29psi... nwpadmax did the test.
ben
ben