Hi Guys
I've owned my Z28 here in the UK for two years now. I only run it in the spring/summer and it sits on my driveway over autumn(fall) and winter-it's too big for standard UK single garages!!
Anyway, since I've owned the car(low miles 48,000-genuine) it has made a whine from the engine(305cid 4bbl). I've disconnected the power steering pump,alternator and AIR unit(all of which are driven off the front belts) and the noise continues. It's very loud and is similar to a high pitched supercharger in tone. The last thing to check would be the water pump- the temp on the gauge never goes past 120F (and has never done so). The pump does not leak but I think it may be the pump as a last resort. Can I run the engine for a brief 10 seconds or so when cold with the drive belt disconnected to check for bearing whine?
Also, I'm trying to change the spark plugs and they are proving to be a real PITA as I've got Edlebrock manifolds and they are tight to the plugs and actually hide the plugs on the left bank near the firewall.
Would I have to take the manifolds off to get to them or is there another way(tips). The plugs were very badly sooted up as I only do 1500-2000 miles a year in the car-I'm suprised he runs!!
The car also pulls to the left under braking-could this be down to a sticking caliper? Also, the front wheels scrub when doing tight reverse or forward manouvering in car parks-is this normal or is there a problem with the rear diff? The car does have a very slight scuffing sound coming from the rear when coasting.The car was restored in the states and is my pride and joy-I want to get him running perfect.
Cheers
Daf(Cammy85)

 

you can run the engine for several min. with the water
pump inop-that is most likely the cause of the noise
as i can't think of anything else that would cause the
noise
i'd check that temp gauge to make sure it is reading
right-120* is way too cold,should run around 195*
too-cold running will cause gas-washing of the cylinders
,oil contamnation,etc.
i have eldebrock headers on mine(forget which model)
had to use "shorty"plugs(most bosch plugs and mid80s
or earler AC plugs are "shorty"length.
brake pulling might be air in the brake lines.
my car does scrub the tires some in tight turns,but
drives perfect,so that might be a thirdgen
characteristic.
the scuffing from the rear might only be brakes rubbing
a little.

 

Yes, you're fine running for a while with the water pump disconnected.

Should be reading higher than 120* on the temp. Stock 195 thermostat will stabilize just below the half way point on the gague. 180* almost down to he hash mark between the 100 and 210 lines. 160* a little below that hash mark.

Plugs you get to however you can. An open end wrench on the hex-nut at the end of a regular spark plug socket works in most cases. Or just putting a box wrench directly over the plug.

Tires rubbing on the inner fender wells at full steering lock.... normal, unfortunately. Possibly worse if the wheels/tires are non-stock and different sizes/ wrong wheel offset.

If the pull under braking is constant that's almost always a bad front caliper. 3rd gens use full-floating single-piston calipers so there's plenty of places they can get sticky and not work as well as the other side, causing a pull. A partially obstructed front brake flex line (from the frame to the caliper) and also cause a similar problem. Best to replace everything, even if it's just with stock components, on an older vehicle with some miles on it.

Don't overlook worn out suspension components in this process, either. Ball joints and all the steering components (9 joints total in the front suspension system, not counting the bearings at the top of the struts). Worn out idler arms are VERY common on many GM vehicle of that vintage (goes from passenger side frame to centerlink and allows the centerlink to move up and down on that side if it's shot), but everything can go bad if not maintained properly.

 

Since you said it has always made the noise, is it possible a previous owner replaced the timing chain with a noisy gear drive? Those are loud and sound like a supercharger. There isn't an easy way to check though..

 

Thanks for the info guys!
The thermostat was replaced last year as the housing was leaking(one of those chrome units with rubber O-rings). Replaced with iron housing and fibre gasket. It still ran cool though. Coolant is never contaminated and the car never boils over even when I was stuck in heavy tailbacks for ten miles in the height of summer!
I will check the rear shoes for scuffing and the tyre scrubbing is normal?
It seems that the rear end wants to push/pull the car in a straight line and the tyres get scuffed slightly under hard lock-is this normal??
I will check the front caliper for pulling under braking.
Where's the best place to get a replacement water pump for my block(LG4) if I wanted to replace it?
Also-The car is running the LG4 motor(155 bhp standard) but has been de-smogged. It runs a new quadrjet Rochester and has Edlebrock inlet and exhaust manifolds with a 3inch Flowmaster Turbo system(twin pipes). I was told that the car made 247bhp and 311lbs/ft of torque on this new set up(also has high discharge coil, piggyback on the distributor and a full set of Splitfire leads-A/C has been disconnected)). Is this a reasonable amount or is this an over exaggerated reading(I do have dyno printout from previous owner)?
Any info would be appreciated.
Dafydd

 

Thank God Bill Porter went with the design for the 3rd Gen-it's one hell of a beautiful car. The lines are superb and take very little to enhance!!!