402CI lq9 machining issues
Thread Starter
Staging Lane
Joined: Jan 2014
Posts: 80
Likes: 0
402CI lq9 machining issues Hi guys. ive got a built engine consisting of:
lq9 block
cp Bullet flat top pistons
lunati rods & crank
engine is twin turbo, making around 1200rwhp @ 24psi boost
around 3-5000 miles street driving and a few race weekends. (no odometer)
anyways. i have had a injector go bad, lifting and torching a head in the process. when i lifted the heads i found that all 8 holes the hone marks were worn off the bores at top and bottom sides of each cylinder, sides look perfect. this engine has no blow by and ran 100% perfect untill the injector issue. have included a couple of pics, each bore is the same. any score marks you see look much worse than they are. you cannot catch a finger nail in them. also included my measurements of the bores taken with a inside micrometer NOT a bore guage.
lq9 block
cp Bullet flat top pistons
lunati rods & crank
engine is twin turbo, making around 1200rwhp @ 24psi boost
around 3-5000 miles street driving and a few race weekends. (no odometer)
anyways. i have had a injector go bad, lifting and torching a head in the process. when i lifted the heads i found that all 8 holes the hone marks were worn off the bores at top and bottom sides of each cylinder, sides look perfect. this engine has no blow by and ran 100% perfect untill the injector issue. have included a couple of pics, each bore is the same. any score marks you see look much worse than they are. you cannot catch a finger nail in them. also included my measurements of the bores taken with a inside micrometer NOT a bore guage.
Thread Starter
Staging Lane
Joined: Jan 2014
Posts: 80
Likes: 0
thanks mate. what about the deck heights. its in the measurements pit but ill add the measurements here for the bank im worried about:
1. -0.009 3. -0.004 5. 0.000 7. +0.003
this IS the bank which had 2 lean injectors, cyl 1 15% blockage torched the head and cyl 5 was also 10% blocked and the gasket blew out here also but no head damage
Ideas?
1. -0.009 3. -0.004 5. 0.000 7. +0.003
this IS the bank which had 2 lean injectors, cyl 1 15% blockage torched the head and cyl 5 was also 10% blocked and the gasket blew out here also but no head damage
Ideas?
thanks mate. what about the deck heights. its in the measurements pit but ill add the measurements here for the bank im worried about:
1. -0.009 3. -0.004 5. 0.000 7. +0.003
this IS the bank which had 2 lean injectors, cyl 1 15% blockage torched the head and cyl 5 was also 10% blocked and the gasket blew out here also but no head damage
Ideas?
1. -0.009 3. -0.004 5. 0.000 7. +0.003
this IS the bank which had 2 lean injectors, cyl 1 15% blockage torched the head and cyl 5 was also 10% blocked and the gasket blew out here also but no head damage
Ideas?
FWIW, my pistons were "out of the block" by different amounts:
1: +0.0035 / 2: +0.0007
3: +0.0025 / 4: +0.0010
5: +0.0020 / 6: +0.0025
7: +0.0045 / 8: +0.0035
On a fresh build, too. The right bank has a "lean" to it, but the left bank seems just...uneven.
1: +0.0035 / 2: +0.0007
3: +0.0025 / 4: +0.0010
5: +0.0020 / 6: +0.0025
7: +0.0045 / 8: +0.0035
On a fresh build, too. The right bank has a "lean" to it, but the left bank seems just...uneven.
Were you taking these measurements just above the wrist pin? If not, piston rock in the bore will lie to you.
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Those numbers came solely from "piston rock". At TDC, I loaded one side of the piston, took a deck (dial) indicator measurement, repeated this on the opposite side of the piston, and averaged the two against the deck "0". I prolly should have used a mic to measure from the wrist pin hole to the deck, but aren't these, in fact, "real world" numbers?
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