I obviously have to rebuild now and I want to get some info from the crowd.
I just did a compression test all the cylinders were making around 170-185 psi except 7 which made 100. I didn't have a chance to pull it yet to see how much wear there is and if I need to bore the engine out.

1) Does anyone know the cause of why everyone has problems with the #7?

2) Where is the best place to find parts and what are the best parts to get. (pistons, springs, rods, etc.)

When I think of more questions I'll ask.

Thanks in advance.

 

I see this all the time.The stock pistons are ok but sometimes you get A little detonation and the first one to go is always #7.When you tear the engine down,you will most probably see broken ring lands on that piston.The corvette engines do the same thing.

 

Intake design and #7 getting more air than the rest is what I've read.

 

I have seen this too many times as well... in vette's... and apparantly trucks are not immune either. Results definitely show the #7 is being hammered to destruction due to detonation. However, we are talking about 2 completely different intake manifolds. Unless someone can post hard data (such as flow characteristics of each intake / port) I still think some other sinister thing is happening... or perhaps the combination of 2 completely different perhaps poorly designed intake manifolds coupled with coolant flow issues. One thing is for certain... the coolant flow between a truck engine and a vette engine is the same... including the fact that the back 2 coolant vent ports are blocked off. Earlier vette's (97-00) had a common "manifold" that tied all 4 vent ports together. I don't recall earlier year (99-03 timeframe) trucks ever having this from the factory. As for vette's I speculate GM cut off the back 2 ports when the (LS1/LS6) redesigned intake manifold, with its lower floor, hit the streets in 01. How this effects coolant flow around #7 i don't know... but I think coolant flow or lack thereof is a possible culprit or contributor...

... just speculating here...

(edit) Hmm... just thought of something... I have one of those older vette style 4 vent port "manifolds"... may have to see if it fits under the truck intake manifold

Bill

 

I would like to see a injector balance test performed on these damaged vehicles. I found a lot of clogged #7 injectors back in my dealership days and these were stock vehicles . just an idea. If you were local , I'd test em just to see the results. Goodluck with your repairs

 

So with people running the Victor intake to help this situation out....is it helping? If so wouldn't it point to the stock intake? Or is the Victor not really helping #7?

 

Yet another possibility...

Do you remember if it was a mix of GenIII based vehicles you saw this problem with? More trucks? More vettes? Trucks and vette's do have completely different fuel rails as well... with one common thing... fuel entrance is on the drivers side. Both vette's and trucks also share(d) timeframes in which both had return style and returnless fuel supply. I 100% agree that the injectors should be checked...

Bill

 

I think those are very valid questions. Unfortunately I think when most #7 failures happen... its chalked up to a lean condition and blamed on the truck intake. How many guys are putting Victor Jr intakes on stock engines? I don't think the vette guys can do this... not without the elbow sticking through the stock hood. The tuning absolutely must be changed when intake manifolds are swapped... hence making it extremely difficult to compare and contrast. Is the common scenario a motor gets burned up, the intake manifold gets blamed, and then the Victor Jr goes on top of a new forged motor? Are their enough engines out there with Victor Jr's to make a compelling argument that they are truely solving the dreaded #7 burn up? I certainly think there is an argument that carburator style intakes DO indeed flow more favorably... hence horsepower gains over the stock composites... at least up top.

more speculation of course

Bill

 

So what we need to know is how many stock internal engines are running the Victor intake and have still blown up #7.

 

Damn did I call that one or what

IF you are looking into a forged motor give me a call, we can work something out for you.