mvvette97

I'm going to start looking for one. I have a C5 but I just always liked the ZR1. What are the problem areas I should look for when shopping for one? Also I have heard something about the LT5 that's they are oil burners. Is this true? Some people make it out to sound so bad but the 00-01 LS1 is known to burn oil also. Anyway if you guys could give me a little info on what to look for that would be great, thanks

94ZR1

Most of the problems with a Z would be the same as with any C4
The LT5 engine is extremely durable and it is not an oil burner
Tranny rear diff etc are the same as on other C4s

Good luck in your search

The sound at 7000 rpm is addictive

win1876

Do a search on this site or go to www.zr1netregistry.com

WydGlydJim

Transmission is a little different from a dimensions standpoint; it is not a direct bolt in; but yes ZF internals could be had. '90s do not have valve guide seals, so they are certainly going to burn a little oil, but it is not an issue on a good engine. I have a '90, and I like to think it makes it more like a race engine! The LT5 is one of/the most durable engines in automotive history. As stated above, the net registry is a wealth of info!

95ZR1

Problems with a ZR1?

-Speeding tickets
-Lighter wallet whether its modification addiction
or cleaning product habits.
-most people don't know about the ZR1.
It will be your job to educate them.
-most mechanics don't know about the LT5.
Be prepared for scraped knuckles.
- Did I mention speeding tickets?

Ted

kmoudy

The problems associated with the Zr1 are not much
different from those of a normal C4 except.
You will find yourself becoming addicted to
Seat time.
neglecting your wife and children, forgetting to feed the dog, etc...
my 90 is not an "oil burner" maybe your friend was
talking about the 9 quarts it takes to fill the engine.
yes, 9 quarts.
with the information on this web site and the
zr1netregistry's site, many of the smaller problems, you can learn to fix yourself. Even if you are a novice
mechanic like me.

mvvette97

Thanks for the replies. Just wondering is there any way to install valve seals on the heads?

Crabs

Yes..... A good machine shop can do it for you quite readily.
However it's going to require removing the heads, and that isn't a job for an amateur. Getting them off isn't so bad, it's the getting them back on and the cams timed that is a beoch. I've heard that it's easier to do that with the entire motor out of the car.
There's a small handful of ZR1 guru's out there who are quite capable of doing the job; from East to West are:
Corey Henderson, http://www.hendersonperformance.com/index.html
Mike Ebert, http://www.acsvette.com/
Jim VanDorn, http://www.automastersofbg.com/
Marc Haibeck, http://zr1specialist.com/
Doug Rippie, http://www.dougrippie.com/
Jeff Flint. http://www.pnwzr1.net/

But really, not having the valve seals are *no big deal*, my '90 doesn't burn hardly any oil at all.
It's all a matter of perception. If you perceive it to be a problem the simple answer is buy a later year.

Good luck!

mvvette97

ok, how many miles would you think the engine could get before the valve guides would become worn enough to make it start to use alot of oil? I mean it's really no big deal just as long as it doesn't drink oil. My 97 C5 doesn't burn any but my 2000 trans am will use about a QT. in 3000 miles. Same engine in both cars and about the same milage. But a little oil isn't a problem to me as long as it doesn't use like a quart in 500 miles.

Crabs

From my own observations and from what I've read here, if a ZR1/LT5 is loved by someone who takes care of it and treats it with the dignity and respect that is due the King Of The Hill, it can go a lifetime, i.e., a couple of hundred thousand miles with no excessive oil consumption.
If a hack owns the car and does not love it or treat it right, all bets are off.

cv67

Valve guides rarely wear out, I wouldnt worry about it.

DRM500RUBYZR-1

You will more likely need a double knee replacement before a VIN "J", motor needs valve guides.
It simply is not a common failure.
Come to think of it, I cannot think of any significant common failure on these damn near indestructable motors, short of some bonehead hitting 1st when going for 5th at full tilt, or over-zealous nitrous use.
Buy it!
Drive it!
Enjoy it!!!
Marty

mvvette97

Cool, I will not worry about that then. Thanks for the info guys

Jagdpanzer

Welcome to the world of DOHC engine design. The overhead cams of the LT5 act directly against "bucket" style cam followers located above each intake and exhaust valve. This valve actuating arrangement does not impart wear causing side forces on the valve stems like rocker arms do on push rod engines. Also, because of the lower reciprocating mass of this design you do not need as high spring pressures to achieve high engine rpms which also makes for an easier life for the valve train. This is one of the reasons many of these engines easily achieve 100k + miles with just regular maintenance and the use of recommended oil and coolant brands.

Michael McCrea

I am looking at a 1995 ZR1 with 135,000. km on the OD. It looks like it has been very well looked after just from looking at Photos of the Car, his Garage is 100% in the #OCD Man Corvette Cave. He also restores and sells C3's as well. He has owned the Z for 15 Years. The Car is about 4 hours away from me. Just doing research on the Car as I was looking at C5 Z06 and C6 but when this turned up I got very interested. New Paint (Black) a year ago, New Leather Seats, Door Panels and Various Interior Pieces in the Console, etc.

DRM500RUBYZR-1

Certainly sounds like an owner that did not treat the car like a washing machine, but rather as a treasure,
Maintenance on these cars means everything.
With 135k miles it should be nearing the END.............of the break -in period.
Advice then is simple.
Buy it, Drive it, ENJOY IT!
Good luck!!!

Marty

cv67

Youll never have to worry about worn anything even with a 90 they are simply that durable.
I had a chit ton of miles on mine they dont use oil like the ls do. Youll never have to dig into the engine
They can go to 7k but dont make any power up there...unique sounding engine
Most aftermarket catbacks/mufflers they sound similar to a BBC.

Make sure the trans shifts perfect. They are way better than a T56 but you dont wanna have to rebuild one.
Too many sellers who if youre lucky mention "an occasional grind just needs fluid probably". Nope
Friend here runs 9s with his stock ZF never had it cracked open

rosssober

Having bought a very needy ZR1 with 75000 miles last year, I can chime in. The bulk of the problems with a C4 ZR1 stem from it being a C4 Corvette. You will encounter problems in most everything except the engine. The LT5, once working correctly is very robust. After failing to find my intake leak that was causing numerous running problems, I sent my car to Marc Haibeck for repairs and improvements. Best money you can spend. The car is much faster, fully reliable and now finally handles the way I had hoped. I would recommend that any car this age will need all of its suspension bushings replaced, along with the shocks. Unless the car was stored in a climate and humidity controlled environment, the rubber will be shot. Mine does use a quart of oil every few thousand miles. But, my car has had a rough history. And I run it out to 7000 RPM at every chance I get. Here's a short list of things I have had to touch that wouldn't be considered maintenance:
Secondary vacuum pump
Clutch Master, Slave and Hose
All the suspension bushings and shocks
The Selective ride control
The Starter
Targa top adjustment
Engine cooling fan motors
Air conditioner-minor repairs
Pinion seal on the Diff
Console lid latch
There are others that I am forgetting at the moment. But it's largely typical old Corvette stuff and not endemic to the LT5. Parts are largely available and the support from the community is unbelievably great. You will never meet nicer people than in the ZR1 community. I love my cruddy ZR1. But, if I had spent $20-$30K up front, versus the $7500 I spent, I likely would not have had so many repair issues.
I want to buy another ZR1 that has had a better life to have in addition to my current car. And I wouldn't hesitate to recommend ownership. Happy hunting!!

If you want to read up on the ZR1's particular technical concerns, spend some time reading Haibeck's articles posted on his website. Highly informative!
http://www.zr1specialist.com/

1985 Corvette

If I remember correctly, the owner’s manual for the ZR-1 (1991 anyway) states that use of up to a quart of oil in between scheduled changes is normal. If you couple this with higher mileage LT5s developing oil leaks and it’s easy to think the engine is drinking oil. And the LT5 has a lot of places to develop oil leaks where gaskets or sealant fails.

Off the top of my head leaks that I have found, fixed and some potential future issues:

Cylinder head sight holes (mine were leaking)
Crank position sensor seal (mine was leaking)
PVC grommets (mine were leaking)
PVC breather box (mine was leaking)
oil pan from loose bolts (were leaking)
Spark plug O ring seals (not leaking yet)
Cam covers (passenger side is leaking)
Cam cover bolts (48 w/ rubber washer,some leaking)
oil pressure regulator cover (was leaking)
oil filter housing (not leaking yet)
oil cooler lines (slow leak, cooler weather project)
Front engine cover (was leaking)
Low oil sensor (was leaking)

That’s 13 leak points…technically 61, if you count every cam cover bolt and it’s individual washer seal that are 30+ years old. Imagine my surprise when checking the oil after a fresh change and just a few short drives over a few weekends when first getting the car before fixing any of these leaks.

Paul Workman

Yes. I had seals installed on mine when I had the heads off for porting. The "bugaboo" is the cams have to come off and consequently reinstalled to machine the valve guides to accept the seals. This means the engine has to come out to facilitate the cam phasing once they are reinstalled.

Seals. It is worth doing "while your in there", but oil consumption is not so much of an issue (AT ALL) to warrant pulling the heads just to do seals: combine it with porting, if you want to.