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99 GSX Rod Knock

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15+ Year Contributor
499
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Dec 22, 2007
San Antonio, Texas
Hello. On this fateful day my car developed what I believe to be rod knock. Yesterday I made a boost leak tester, and fixed MANY leaks that I have been driving around with for about a month.

I took it out for a drive this morning, after everything warmed up. I give it a some gas, and hit fuel cut. The boost had gone up more than planned, because my fixed boost leaks caused the boost to go up. I stop at a store and turn down the boost from 14lbs to 10.5 (I only have a fuel pump & s16g). I then proceed to drive back home. I made sure the boost was set to 10.5 lbs, and then roll into full throttle. The car went no where, like I had more boost leaks! I thought perhaps my (auto) tranny was slipping. To further investigate, I went down another road, and went from a 40 roll and gunned it. It pulled pretty good. No hesitation or bogging. Weird.

Almost at my apartment, I give it some more gas for one more pull. I heard this clicking sound, and thought my bumper or tire caught something. I tap the gas, and sure enough, the sound corresponded with throttle. :(

I park it, and find the idle to be very smooth and have no abnormal sound. But, when I rev in neutral, about 2k rpms and above, it gets a knocking sound. Very loud, and from the middle of the engine. I panic, and go research. I come back, and one by one pull the spark plug boots to see if it goes away. Sure enough, when cylinder 2's spark plug boot is pulled, it sounds completely normal.

I believe this is rod knock! :( It does sound like the youtube rod knock vids. Except most of the engines on youtube have a pulsating knock, and the knock is at idle as well. Mine doesn't pulsate, and it only knocks at 2k and above.


I do have 2 exhaust leaks, and have been driving around with it until I can get my stripped turbo flange holes re tapped. One is at the turbo/manifold, the other is manifold/head (dunno how that happened). My car is about 1200 miles over due on an oil change. It also had low oil for about a day. (It was on the low oil mark.) It was low about a quart. The oil is really black and dirty.

I have researched and my next thing to do is pull the oil pan, and check for shavings. I will also look for any bearings that I can see and check if anything looks amiss.

I love my car, but it is getting expensive! 200 for payment 200 for insurance. 200 for premiums gas, 150 for fix its a month.

Should I sell my 99 gsx, or fix it. I have little money right now.
My friend is willing to sell me his used 7 bolt for $1000, but its been abused by a 50 trim.

Am I dreaming, or could that exhaust leak be the culprit? refer to this post #11
http://www.dsmtuners.com/forums/newbie-forum/201182-fixing-rod-knock-possible.html#post1674631

Any advice on what I should do.
 
Hey, first off, sorry to hear the bad news. I can't help you as far as the diagnosis goes, but I would rebuild it. For $1k you could build the bottom end, there happens to be a pretty big bottom end sale that ends tonight (check your local listings). Or you could do a stock rebuild for close to nothing.

Some of us local guys would be more than willing to help out!! All you have to do is get ahold of a daily driver...
 
If the crank is good, you could easily have it built between $1500 and $2000 by shopping around for specials on quality parts. You could then throw whatever you want at it as long as your tune is good. That would be my route.
You could do a 6bolt swap and be done with it.

I guess it really depends on your goals. You do need to tear it down and see what failed and try to diagnose why.
 
I just wanna tear richard & frank a new asshole. Make it look like they stuck it in reverse.

I am going to drop the pan and post pics. If nothing is conclusive, I will then tear it down. Then go from there. That $800 high hp package is kickass, I just don't wanna buy shit right now when I don't have any definite answers. I pm'd him.
 
Why because the 6bolt doesn't get the rod knockWTF........Anyways what i would do is check the compression accross all pistons, btw the exhaust leak would not make the same noise as a rod knock. Take the car to a shop that you trust and have them check it and that way you can have a better second opinion. As far as rebuilding goes, if you want a strong engine for cheap just throw some 6bolt rods and 2g pistons together, otherwise everything else is up to you.
 
What you're talking about is IDENTICAL to what mine sounded/acted like when I spun my rod bearing. Also on my number 2 while I think about it. It wasn't until I pulled my my rod caps that I saw any signs of failure, and this is what I found.
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Wow, three 99 gsx's with spun rod bearings. I take care of my car, not like I abused it. Perhaps this is a new problem that is now arising because 99's are finally getting up there in miles?
 
I don't know... I'd just bought mine and had done alot of stuff done to it. It had 128k miles on it, but only 70 (not 70k) of those were mine. I bought it not running, needing a clutch. It spent about 7 months in my garage. It still don't even have the clutch and flywheel broken in. But right now it's having a g4cs built for it.
 
You may not have been hard on it, but you sure weren't nice to it by letting the oil get they way you described.

Hopefully the crank is good and will only need to be polished, just build the 7bolt if so. I did that back when and beat the snot of it daily before it gave up 3 years and some 60000 miles later, when it welded the #2 rod bearing to my pretty Crower rod.

Any questions, you know I'm the gulf coast section or you can pm/email me. If I can find time, I'd be willing to cruise down and help you out.
 
I'd suggest not buying your friend's 7-bolt, unless it is a 99 also.

The '99 blocks used the newer split thrust bearing design that has been claimed to significantly reduce the chance of crankwalk. Keep yours and rebuild it. The stock rods are the weakest point in a 7-bolt. Replace the pistons if they fail inspection, maybe consider Eagle or Scat and a set of good rod bearings, I recommend ACL Race series. Like boostedt28 said, you can have a very solid engine for $1500-2000.
 
Thanks for the advice and help.

The oil problems are not a reflection of how I treat my car. It only happened because I was just finalizing the install of my s16g. I mentioned it because perhaps it will help with diagnoses/advice. I talked to Fast Track and they were nice enough to extend their bottom end sale until I tear down my car.
http://www.dsmtuners.com/forums/ven...ast-track-bottom-end-package-800-shipped.html
 
Justin,

You would be much better off just upgrading your bottom end now, if you decide to keep the car. Here is what you are looking at for a "stock" rebuild with 1g big rods.

Mitsu OEM pistons: $199.99
Slowboy Racing :: Engine :: DSM Engine :: Pistons :: Mitsubishi OEM 7 Bolt Pistons

1g "big rods": These usually sell for around $100 for a set of 4

Labor to install pistons on rods: FFWD was going to charge me $250 to do this

Main & Rod bearing: $85
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Clevite 77

ARP Main studs: $59
EXTREME PSI : Your #1 Source for In Stock Performance Parts - ARP Main Studs

So for a 2g piston 1g rod combo, your looking at around $694.
_____________________

Look at how much a "built" short block will cost you:

Wiseco Pistons: $420 shipped (Buschur Racing special)
Buschur Racing - Your source for Mitsubishi racing parts and accessories

Eagle Rods: $310
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Eagle H-Beam Connecting Rods: Mitsubishi Eclipse 7-Bolt 92-99

Main & Rod bearing: $85
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Clevite 77

ARP Main studs: $59
EXTREME PSI : Your #1 Source for In Stock Performance Parts - ARP Main Studs

$874 for a bad ass built bottom end, price difference of $180.
 
Sorry to hear that i myself have been through 3 engines and all spun bearings on cyclinder 3 so i feel your pain. I myself would rebuild just so you know that you have a fresh start on a motor that wasn't abused.
 
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