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7 Bolt Failure and Teardown

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BlackDSMthingy

Proven Member
96
17
Aug 16, 2014
Leominster, Massachusetts
A Friend of mine recently purchased a 98 GSX from a younger kid with expectations of modifying it with his son, but the "freshly rebuilt" 7 Bolt started making a "ticking" noise. When I finally got a chance to see the car in person, it became evident that this thing was not just sticking lifters. It basically sounded like rocks in a garbage disposal.
Well out it came and the teardown was begun.
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A lot of E-Bizzle and aisle 5 from Autozone on this one...
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Maaaaaaybe a little boost leak...
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Not a good sign. Something definitely made the oil pressure not get here. This is babbit material embedded in the cam lobe. Loud noises, 5lbs oil pressure, and still running 10W (?) break-in oil with less than 500 miles on this performance build. No idea who machined or assembled it. Should be interesting...
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I actually chipped my thumbnail on the cylinder walls.
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Three different balancer bolts. Vibration? Come at me, bro....
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That! That right there! What could it be in the piston skirt?
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Looks familiar, but I thought it went....
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Oh, waaaaaaait a tick. That's not right... Looks like the balance shaft behind the oil pump snapped and the bearing played tonsil hockey with the reciprocating assembly. You see kids? This is why we can't have nice things...
Upon further inspection though, and a little thought, I am now wondering if when they installed the front case they caught the edge of the rear balance shaft bearing with the shaft itself and pushed it out of the bore. Without the support of the bearing, the shaft snapped. From the way it ate into the block I'm assuming it ran a few miles before it finally gave up the ghost.
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As far as the loss in oil pressure, the balance shaft being broken absolutely destroyed the oil pump by making the oil pump drive gear eat right into the front case. This thing had more scoring than Ron Jeremy...
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This was the best rod bearing of them all...
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And the pistons had almost all the teflon sanded off the skirts.
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A shot of the number 2 piston and rod. Reminds me of my old Chinese friend, Sum Ting Wong....
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They also reused the original timing components and just threw a kevlar main belt at it. Looks like the original balance belt was put back on, but there's not much left to tell.
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This engine had me quite vexed. Why would someone blow $800 on the reciprocating assembly and reuse the timing components? I mean, there's some really good stuff in this car, but it's literally mixed with used, Chinese and Ebay stuff. It's all sideways. It had a cracked Chinese flywheel with an Exedy six puck sprung hub clutch kit (cracks due to there only being five out of six pressure plate bolts, and the five that were there didn't match, and none of this helped the engine) and a bolt for the rear carrier bearing JB Welded into the crossmember. Also, it was running stock 450cc injectors, non-recirculated BOV with the stock MAF, stock ECU with no tune or fuel controller at all, no wideband, a Mitsu TD05H cold side with a 20G wheel, Injen snorkel with the BOV hole duct taped over, and catless exhaust big enough to pass a grapefruit through. People say our cars are princesses, but I've never seen a car like this run at all. Says something about the malleability of the DSM. I'm still in awe... If anyone can chime in with some ideas as to what may have happened, feel free. I'm thinking my theory is right or at least was a part of it, but just seeing if anyone has run across this before. I already told my buddy the entire engine is a write off and he's on the fence as to do a 6-bolt swap or rebuild my 7-bolt from my Talon, but I always try to learn as much as I can from a failure such as this so when I build my engines it is less likely to happen. This post also serves to remind us all of the importance of not only quality part sourcing, but quality machine work from a reputable shop and proper, clean component installation and integration to achieve a complete, well-rounded package that works together as a whole to better our cars' performance and reliability. Don't take short cuts, and take your time. Plan the car as a system, not as a big turbo with wheels. It's like an ecosystem all its own. And whatever you think it will cost? Double it. Looking forward to hearing from you guys and thanks for taking the time to read this post. Hope it answers some cool questions for all involved....
 
I'll be honest; that was a really fun post to read. I'm always intrigued with trying to figure out why things have failed, and for the exact same reason as you. It looks like you hit the nail on the head as far as cause of failure. If you're careless enough to throw random bolts in random places, there's nothing that tells me that the front case wasn't installed correctly. I'm really surprised the bs belt is even still there. Why did the guy waste his time and effort building that engine instead of just throwing his money in the trash. The down side is that the previous owner is now probably one of those people who think dsms are junk.
 
That's sad as it looked like a nice shortblock. If the pistons aren't to scored up, I'd clean them up and have them recoated, probably by swaintech. Hopefully you can clean the crank up and reuse it, and all you'll really need is a new oilpump to fix up the shortblock.
 
OMG Wow! and I'm here complaining about my car previous owner and his crappy hid installation.
 
Apparently it was a young kid that my buddy bought this from. I have no idea what he paid for it, but it was too much. It's a shame because it's a rust free 60k car, but it has a Terminator wing, cheap ground effects bondo-d on, triangle vents in the bump and both front fenders, and, get this......flip flop paint INSIDE AND OUT. E-Bizzle and Autozone were his family I guess. But the foundation is there. It's literally like putting a pig mask on Angelina Jolie. Seriously, 2003 called and they want their car back. Let's not even talk about the Got Boost stickers and the sponsor stickers up the front of the door. "Oh noes!...."
 
That's sad as it looked like a nice shortblock. If the pistons aren't to scored up, I'd clean them up and have them recoated, probably by swaintech. Hopefully you can clean the crank up and reuse it, and all you'll really need is a new oilpump to fix up the shortblock.
I'm thinking the block is borderline. I could reuse it with a shaft eliminator kit and boring the cylinders over, but I have to check with my dial bore indicator to see if these are still 84mm or not. I would get it magged and hot tanked too.... He's on the fence as to whether he buys my 7-bolt stocker from me, a 6-bolt from my other buddy with ECM V3 or just gets a crate. Like I said, the car itself is worth it after all the previous mistakes are corrected and he takes the makeup off....
 
I'll be honest; that was a really fun post to read. I'm always intrigued with trying to figure out why things have failed, and for the exact same reason as you. It looks like you hit the nail on the head as far as cause of failure. If you're careless enough to throw random bolts in random places, there's nothing that tells me that the front case wasn't installed correctly. I'm really surprised the bs belt is even still there. Why did the guy waste his time and effort building that engine instead of just throwing his money in the trash. The down side is that the previous owner is now probably one of those people who think dsms are junk.
I feels ya brah. I've met so many people who just don't understand these things and think they're all that until it blows up. Then it's the car's fault and they go buy a Civic. Reading an issue of Super Street does NOT make you a DSM mechanic, and what's worse is some of the shops around that promote this way of thinking (at least in MA where I am). Good, knowledgeable DSM people are hard to find, and most I've spoken with have agreed they feel adrift amidst a sea of idiots. Thankfully, if you do find a good shop or person who does quality work on these cars, they are almost always eager to bench race and pass the "tip & trick" torch to fellow enthusiasts. We really do have a great community and great support. And we're ALL still learning.....
 
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