1991 corvette ZR1

[Rainer S.]

I am looking at a 1991 ZR1, which is for sale locally. Would anybody know, what the approx value for a low mileage (40,000) car would be, and what options I should be looking for.

[Mike M.]

Re: 1991 corvette ZR1

91 zr1 with 450 k miles ought to go between 20-26k unless its immaculate. far as i know, you got all options(except maybe the smoke top) as part of the ZR1 option. good luck, mike

[Craig S.]

Re: 1991 corvette ZR1

Mike - was that 45K or 450K Craig

[Clem Z.]

Re: 1991 corvette ZR1

if you think buying parts for a 57 FI is expensive try buying parts for ZR-1 engine. one thing to check for on a ZR-1 engine is that the proper oil filter is installed. because the filter mounts with the input/output on the bottom you MUST use a filter with a anti drain back valve. if you do not every time you start the engine it runs without oil pressure till the filter is refilled and you hear the death rattle of the engine bearings.

[John P.]

Re: 1991 corvette ZR1

The only option you really had a choice on when ordering the ZR-1 is the tops you either get the fiberglass or the glass top or both

About the oil filter if you use a oil filter without a check valve the noise you (MAY) hear is from the cam chains rattling not the engine bearings...
it really doesn't mater what oil filter you use its up to you many people have there own preference.
also check out the www.zr1.net for more information

oh and I have a 90 ZR-1 so im not shooting from the hip

johnny

[Clem Z.]

Re: 1991 corvette ZR1

if the ZR-1 uses a oil pressure controled cam chain tensioner and if there is no oil pressure to it there is also no oil pressure to the bearings. the noise may be the chains but the bearings are also taking a beating with no oil pressure.

[John P.]

Re: 1991 corvette ZR1

Ok what you are referring to the "noise" is the cam chains rattling at initial start up my car doesn't make this noise some cars always make the noise, as far as these being oil pressure controlled they have a cam chain tensioners that keeps them tight and they get there oil flow from the heads, but I cant describe the oil galleys for the LT5 take a look at the web site and it may have a diagram, It sounds to me like you are questioning the design of the LT5's oil pump and filter placement?? I didn't design it.....

As for the oil filter with the check valve all it does is when you turn the motor over it sends that oil to the chains that's the only thing it is accomplishing, you have oil pressure when you are starting the car the LT5 turns over for about 10 seconds while it is checking the crank position before the coil packs start sparking and all that time the oil pump is priming in the engine..

The only thing that the oil filter with the check valve is for is to alleviate that cam chain noise that is it, it has nothing to do the engine bearings the motor has 10 quarts of oil in it so im sure the bearings are fine this filter is also not the GM replacement or the original these are after market items the gm filter doesn't have a check valve.

some owners complain about this noise and id be glad to take the car from them because of this noise
go to the zr1.net and read up on the LT5 lots of info there is a great educational web site about the ZR1

[Clem Z.]

Re: 1991 corvette ZR1

i may not be explaining myself clearly but if the oil pump is making no oil pressure to the bearings the 10 quarts in the pan is doing nothing for the engine bearings but letting them run dry till the oil filter refills and pressurizes the oil gallerys.

[John P.]

Re: 1991 corvette ZR1

Ok like I said I cant explain what and how the internals of the motor run I cant remember If I had my book I could I do know that the oil runs through the
center f the crank shaft to the bearings but beyond that I cant help you,
but I believe this problem is just like every car ever manufactured they all have
some damage at the first start up of the day.. that's normal

but for A "fact" when Gm sent these cars from the factory they had a standard
oil filter with no check valve in them, that is an after market oil filter
and the LT5 is nothing like any standard Chevrolet motor like I said read up on it and you will understand it
I am just trying to keep bum scoop from getting out there about the motor and the car..

That is all im not saying anything else here because we both think we are right if I had my book with me I would be happy to but I didn't bring it with me out on this deployment and its been almost 9 months since I left so I cant remember everything from it..

johnny