School me on the LS1 cars 98-02, Cobra owner want's to learn.

**fatboyq** · 03-20-2006, 10:06 AM

Hi guys,

I currently own a 1999 cobra I like it allot and have about 4k worth of mods, 4.10s, exhaust, ported manifold etc. I love the way it rides with the IRS in the back. Anyway I'm selling the car now and have a best offer of $13,500 I need to payoff some bills equivalnt to $5500. That would leave me with around $8k cash, I wanted to find an older 98-00 LS1 equipped car with higher miles on it.

I want to know if a LS1 with 120k miles is something I should be worried about? I found a 00 Z28 in pewter which I like allot 6m new clutch and thats about it for $7k cash, is this a good deal? how long will these motors go for? and if they break how much will a rebuild cost?

I dont want a car that I will have to sink allot of money into. with a budget of 7-8k is it possible to find a decent LS1? I dont like the look's of the 93-97 model and I don't want to step down to LT1.

what are some common problems with the LS1? I hear springs and oil pumps suck anything else?

what do you think about an older vette 92? I know they have an LT1 but all the vette owners told me there is nothing like one. I found a few for $8500 with about 12ok on them.

thanks!

**third_shift|studios** · 03-20-2006, 10:44 AM

never heard of a spring or oil pump problem. the biggest problems with them are clutches, and if you really pour on the power adders-you'll destroy the stock differential. They are all aluminum engines rated for 320 @ the fly and with a lid and exhaust you can get 320 to the wheel no problem. The 98-00 synchronizers are shitty [made from carbon, not brass] so drive the car and monitor the smoothness of the shift.

My engine is 100k miles. Major problems:
•stock clutch gone at 83k miles
•overheated the engine b/c i removed the heads but didn't torque them down correctly again-casued a $1500 repair, really coulda been worse for a self-inflected, idiot accident.

these engines are supposed to take a lot of shit though. Obviously, an m6 driver prolly beat the shit out of that car, it may have had more owners b4 him and he's trying to get rid of a bad egg. Just don't dive into it. good luck.

**snaggeltooth** · 03-20-2006, 11:33 AM

here is the thing. To get you a good 98+ you need to be in the $10k plus range. I would not trust a f-body with over 100k miles, esp around the Chicago area. And if this guy tells you about the clutch there is prabably other things he didnt. And to burn out a clutch he was driveing it hard and you dont want another persons mistakes. I would stay away from a high millage C4 Vette also. but thats just me...

**Motrv8d Steve** · 03-20-2006, 11:33 AM

The stock F-body LS1 engines have been rated at various HP thru out the 98-02 model years (305-320) but from what I've learned about them the number is more like 350 at the flywheel. Once you open up the restrictive stock intake and exhaust, the number should be more like 360-365 and more depending on what you do to those two.

Known issues with these cars as far as I know:
ROTORS: the stock ones are a POS and I had to have mine turned at 8K, way too soon.

PASSENGER SIDE POWER WINDOW MOTOR: Notoriously slooooow and they burn up way too soon as well. It's good to know how to lube them with silicone so you can avoid this.

REAR END: this was already mentioned.

M6 TRANSMISSION: Some guys, including me, have had to have their Tremec M6 rebuilt way too soon. I had to rebuild mine at 41K, again, way too soon. I never mistreated it the way some guys do, I just drive it the way it should be driven. Never been to the track and maybe I've had 5 street races since 1998, so I'm not really abusing it, ever. But the clutch had fried as well so it cost about $2500 for a rebuild.

T-Tops: Some guys have complained that they leak but mine have been perfect since new and have never leaked. Silicone lubricant is good.

SHIFTER (M6): You'll need an aftermarket one, the stock is a POS.

That's all the known LS1 issues I can think of for now but I know there are more.

Also know that the sparkplugs are really, really, really hard to replace. Well not all of 'em, just the one of the last ones deep in the engine bay and you have to be a contortionist with a lot of patience to pull it off.

But other than the rotors and the rebuild, my 98 Z28 has been pretty bulletproof and has hauled major ass since day one. I still like it it lot.

I have about 55K on mine which isn't a lot for it's age. I have a very short commute.

**fatboyq** · 03-20-2006, 11:44 AM

Thanks for the info, the one I'm thinking about is on ebay 2000 M6 z28 buy it now for $7000. He is a local guy who buys and flips F body cars, it needs a window motor. car looks really clean for 7k.

**snaggeltooth** · 03-20-2006, 12:10 PM

before I bought anything ,esp off ebay, do a carfax. you can do a one-time for $20 or as many as you want for $39 , I think. Sometimes guys who already have an accouton here will do one for you. but 120k miles for a 00 is a lot of miles . And $7k is very low. I would definatly take it to a garage or dealership and have someone go over it real close..

**norm43a** · 03-20-2006, 12:22 PM

My 98 (bought new) hasw 162K. Never a plug out of it, replaced the clutch at 90K. Same story on the window motors. Need to replace the shifter, but that's about it. Still runs like a scalded dog.

**third_shift|studios** · 03-20-2006, 12:38 PM

i hate ebay...definatly talk face to face w/the guy. everything looks good on paper [web page, whatever]

**BillyT** · 03-20-2006, 12:45 PM

Piston Slap?
Bent Pushrods?

**Shpoone** · 03-20-2006, 12:46 PM

OK, I just gotta know how any of you guys answering this thread got so many miles out of your stock clutches?

90K, 83K, 41K?

I've owned a 2000 Camaro SS, and now my 10th Anny Hawk. Had to replace the clutch at only 22,000 miles on the SS, and just did the clutch on the Hawk at 42,000....and it was WAY overdue (should have been done at about 30K). I don't consider myself to be hard on my cars either

.

$7,000 sounds good up front, but do like these other guys suggested and get the car checked out before finalizing anything. Motrv8d Steve gave you some indication of how expensive things get when they go bad....

**Motrv8d Steve** · 03-20-2006, 02:27 PM

oh yeah Billy mentioned the dreaded piston slap.

Mine has it but it hasn't been an issue at least not yet. A lot of the LS1's have audible (sometimes pretty loud) piston slap. Mine is kinda weird in that when I'm idling, I hear it but as soon as I push in the clutch, it goes silent. If i put the car in neutral and let out the clutch again, the thing sounds actually pretty bad but it doesn't affect performance. I don't burn measurable oil and it doesn't smoke at all.
Good luck to me if I ever go to sell it, it will prolly be an issue to a would-be buyer. Some have it worse than others so ask your seller about this. Mine did it since it was new. Some LS1's don't have it all. You can do some research on LS1 piston slap I'm sure.

Not sure about the bent pushrods.

**FasstChevys** · 03-20-2006, 02:36 PM

Originally Posted by fatboyq

what do you think about an older vette 92? I know they have an LT1 but all the vette owners told me there is nothing like one. I found a few for $8500 with about 12ok on them.

thanks!

IMO, stay away from those '92 era Vettes...they're basically no faster than the '93-'97 LT1's and aren't worth squat. I think you're better off with the '98+ LS1. Throw a 125 hp nitrous kit on there and be deep in the 12's. Good luck!

**FasstChevys** · 03-20-2006, 02:38 PM

Originally Posted by Motrv8d Steve

M6 TRANSMISSION: Some guys, including me, have had to have their Tremec M6 rebuilt way too soon.

Aren't they a T-56? (Borg-Warner)

**91Z28** · 03-20-2006, 05:17 PM

Originally Posted by FasstChevys

Aren't they a T-56? (Borg-Warner)

At some point Tremec started building them. I think unless you like to powershift you'll be fine even with a decent amount of mods.

**91Z28** · 03-20-2006, 05:17 PM

Originally Posted by FasstChevys

Aren't they a T-56? (Borg-Warner)

At some point Tremec started building them. I think unless you like to powershift you'll be fine even with a decent amount of mods.

**ss~zoso~ss** · 03-20-2006, 05:37 PM

nice to see a mustang guy going CHEVY!

**fatboyq** · 03-20-2006, 06:16 PM

Thanks for the advice I might try to bargin down to 6500 and see what he says. I like all cars no matter what badge is on the grill. Mustang cobras are nice cars and the driving position seats, trunk and irs make for a good daily driver, weekend toy. I love the F bodys for the same reason fast cheap car that your average guy can buy and get his cheap thrills.

Life is short there are so many nice cars out there why just limit yourself to one manufacturar or one specific model.
Mitsu evo
subaru sti
supras
eclipse
vette
porsches
350z
S2000
z28s
firebirds
mustangs
M3
M5
S4
audi rs6
are all nice in my book and I would love to one one of each in my lifetime!!

but being recently married and expecting our first child, it makes no sense to drop 25k on a depreciating asset. that is why the 98-00 LS1 are appealing as they have depreciated to a point you can buy one without a loan.

**LS1 Eddie** · 03-20-2006, 06:24 PM

LT1's are a little less expensive and can be monsters as well...as I'm awaiting my heads to come back from being ported. Hoping it will be a Viper killer.

**pecha** · 03-20-2006, 06:25 PM

I traded in my 98Z a year ago for around $7K
I was willing to sell it for roughly same price
It had 42K miles
Search for a lower mileage car, man.

**jking** · 03-20-2006, 07:27 PM

Originally Posted by Motrv8d Steve

oh yeah Billy mentioned the dreaded piston slap.

Mine has it but it hasn't been an issue at least not yet. A lot of the LS1's have audible (sometimes pretty loud) piston slap. Mine is kinda weird in that when I'm idling, I hear it but as soon as I push in the clutch, it goes silent. If i put the car in neutral and let out the clutch again, the thing sounds actually pretty bad but it doesn't affect performance. I don't burn measurable oil and it doesn't smoke at all.
Good luck to me if I ever go to sell it, it will prolly be an issue to a would-be buyer. Some have it worse than others so ask your seller about this. Mine did it since it was new. Some LS1's don't have it all. You can do some research on LS1 piston slap I'm sure.

Not sure about the bent pushrods.

IMO, your noise sounds more like a throwout bearing from your description.

I had an engine rebuilt under warranty for piston slap. When the engine is cold, is sounds like a midget is under the hood beating on a piece of wood with an aluminum bat. A hollow sounding knock that speeds up with the RPMS, and pretty much goes away when the engine is warmed up. You could still hear it a little when you rev it.

They replaced all 8 pistons and that fixed it.

The car came out feeling stronger, and trapped 2-3 mph higher on average at the track.