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Talked to my engine builder (the guy that built the 5.3 initially back in 2015 for me). Like a couple of you gents had suggested, the head gasket appears to have been compromised. This allowed oxygen to be pulled in during the down strokes on the afflicted cylinders and the resulting effect was somewhat like a blow torch.
Looks like I'll be boring the block (to whatever size it takes to clean up hole # 6), hoping that the Compstar rods and Crank are still good. I'm going to get the PRC Stage 2.5's resurfaced, valve jobs and then sell them. I'm going to a thicker deck aftermarket head. Also, looks like I'll be doing some other switch ups.
Taking off the twins, putting the PT76875 kit back on. This winter, I'll weld up a T6 flanged kit for a BW S475.
I'll be going to the Holley HP system and retiring the HPTuners setup.
Still on the fence about swapping out the Isky Triple 12 cam to a Stage 2 of some type.
Head gasket failure is not gonna allow air /oxygen to be drawn in - only coolant . Intake gasket may allow unmetered air in under vacuum conditions but not under boost . It's probably going to turn out to be be those injectors, if that's the case why change the set up unless the goals have changed?
I'm going by what my engine builder (Coppola Motorsports) said since he'd experienced the same situation on two of his 9 second Corvette engines. The injectors are at Fuel Injector Clinic for cleaning/flowing. They contacted me on Monday night to say they received them and would let me know this week about their findings.
As far as the setup change, I'm a restless soul. The PT7675 single I had before the twins was fine but I'd always wanted to try to build a twin kit. I like the twins a lot. Power comes on early and fast. Traction has been elusive though. I'd also been reading a lot of posts about the BW S475 over the years and want to try that.
Originally Posted by GMCGreg
Head gasket failure is not gonna allow air /oxygen to be drawn in - only coolant . Intake gasket may allow unmetered air in under vacuum conditions but not under boost . It's probably going to turn out to be be those injectors, if that's the case why change the set up unless the goals have changed?
Pulling the engine apart to get the block and heads over to the machinist. I see that #4 piston didn't escape unscathed. Due to the lighting at the time I looked, I didn't even notice that #4 has a piece of piston missing. I find it amazing it drove home with no more than a sensation that I had a burnt plug wire.
Do you still have the knock sensors in place? Wonder if those TR6's overheated and caused some detonation? How long were you running the TR6's? Projected plugs are generally bad for boosted applications. The center electrode can get so hot it fires off the fuel before the spark. What fuel were you running? 93, 93+meth, E85 ?
Well, now that you mention this, I'd been running BR7EF's since 2015 but late last year, a buddy of mine with a ProCharged 416 LS3 (2011 SS Camaro) took his car to a nearby highly regarded tuner for a dyno tune. One of the first things the tuner did was go over Steves car completely making sure it was mechanically sound before strapping it to his dyno. He saw the BR7EF's in his engine and scowled. "Here's your first problem. You need TR6's here. BR7EF's are too cold and should only be used for Nitrous LS engines". When Steve got his car back (dyno'd at 739 rwhp) I was impressed. So I swapped to the TR6'S. I may have shot myself in the foot with that move.
Yes, Knock sensors are in and in the stock locations. Two years ago,I was running E85 all the time, street and strip. Last year and this, just pump 93. Live and learn. I'm have a set of BR7EF's waiting to go into the new heads (just ordered a pair of RPC heads a few minutes ago)
Just got a good look at the cylinder walls of #4 and #6. No deep scratches but there's some distress above the top ring level that will need to be addressed on those two holes.
Originally Posted by white01ss
Do you still have the knock sensors in place? Wonder if those TR6's overheated and caused some detonation? How long were you running the TR6's? Projected plugs are generally bad for boosted applications. The center electrode can get so hot it fires off the fuel before the spark. What fuel were you running? 93, 93+meth, E85 ?
Took the engine apart down to the last nut, bolt and seal.
1. Rod journals /bearing shells looked good over all but one 'almost' had some copper showing.
2. Main journals, overall, looked good but there was one very thin (the width equal to the thickness of a razor blade) line of copper in the middle of the last main bearing.
3. Thrust bearing saddle looks good but it's pure copper showing on the thrust surfaces. Seems I'd read somewhere that that was common/more common on cars that used Transbrakes.
4. Cam bearings look great.
5. Some of the piston tops look like they're barely used.
6. Piston #6, the most afflicted, had pinched down on the top ring enough that it was immobile but other than that, I didn't have any difficulty getting it out of the cylinder.
7. Piston #4, the other affected one, didn't have the same condition, just the piece of piston crown missing.
8. The cam, Isky Triple 12 looks to be in great shape.
Measured the bores to make sure they were stock/standard (3.780") and they were. So probably can get it cleaned up with just going .010 over.
Been looking at the SUM-8706 (Summit stage 2 turbo Cam) and it looks like I'm going with that one.
Heading over to meet a gent from whom I purchased some new RPC heads. I'm told it has thicker decks so that's the reason I'm switching from the PRC Stage 2.5's.The RPC heads come with dual springs and titanium retainers.
I'll be cleaning up the deck surface of the PRC heads and getting the unaffected one surfaced to the same level to keep the chambers equal.
I wasn't able to log the run. I fired up my laptop in the staging lanes when I was a few cars from the starting line but then that guy blew his trans or engine and it shut down the track. They made it seem like it was going to be few minutes to clean up but it was over an hour. I didn't have the presence of mind to shut off the laptop and the battery expired
Fuel Injector clinic notified me they were shipping back my injectors but did not convey in the email what they found. I hope there's some kind of before/after representation on a document when I pick them up and not just 'cleaned'.
I keep meaning to take a picture of the manifolds ports so you can see that 6 ports are dark/sooty and #4 and #6 are like chalk white.
Some slight variances but nothing as agregious or as glaring as i would have expected. I guess this just means it was a compromised head gasket and the TR6 plugs. Heres the crank thrust bearing.
Got ya on the laptop. I’ve seen me do the same.....
Im surprised at the variation on the FIC injectors. I thought they were better than that?
What brand on the thrust bearing?
My Clevite failed the same. There is a simple mod that can be done to the bearing that will supply pressurized oil to that surface.
I did it and switched to King, but don’t have enough runs to say it fixed it.
Bummer on the melt down. 416 at 7psi (e85 and bigger cam?) is much different than 5.3. at 20+psi, 93 and triple 12 cam. Cylinder pressure drastically different. IAT? Takeaway - always best to know the "why" behind the "what" to use for a given combo. The injectors having almost 5% difference is surprising. Another bummer if you can't adjust fuel per cylinder. As Ron mentioned, thrust mod to improve oiling to rear thrust surface https://www.enginelabs.com/engine-te...shaft-endplay/
It is a transbraked TH350. I've had an order in for a PTC but they're behind due to lots of us wanting Converters. That latest 10.3 pass, I let off a little early, I had two burnt , broken pistons, a leaking head gasket and a cheap Boss Hog TC that was staying at 6,700 rpm for each shift (Blowing thru the converter).
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