I mentioned in a previous post that the Corvette had been sitting around for at least 9 years before I got my hands on it. What’s amazing is it actually started and ran on the ancient fuel that was in the tank.
Unfortunately, although it ran, it didn’t run well. It would stall and splutter. Backfire through the exhuast when cold. It was a real mess.
It was not a good idea to be running it on such old fuel, so i siphoned the 25 or so litres that were in the tank and replaced it with new fuel.
I went to start it up and after cranking it a few times it came to life. It even started idling better once the old fuel in the lines got pushed through. It now starts on the first crank even on a cold morning.
Servicing – Motor Oil
Of course it wasn’t just the fuel that was ancient. The oil also has been sitting there just as long, so I bought a filter and 5L of oil and did an oil change. Interestingly when researching the type / grade of oil to use, Chevrolet recommended a 5W-30 oil and many online forums are recommending that or 10W-40. However on the Penrite Oil website they recommend a 20W-60. A much thicker grade of oil.
According to Penrite, Chevrolet used the thinner oil in the 80’s to help them get through emissions. They recommend their 20W-60 as our climate is much warmer than in the USA and it also has extra zinc added for protection. They say they have been recommending this oil for Small Block Chev engines for decades and not had any issues. Given the outstanding reputation Penrite has in Australia, I was happy to follow this advice. It’s certainly been running great in my Mercedes.
Oxygen Sensor
With the engine running fresh oil and fuel, there was really nothing preventing me trying to get rego. At the very least I would have a definitive list of outstanding issues that need to be immediately resolved. I pulled out of my driveway and headed for my mechanic – but disaster struck in the first 300 metres from home!
I was driving off when I heard a loud pop, followed by a hissing / decompression sound then my engine started sounding rough – really rough like it dropped a valve or something. But interestingly, there was no smoke, no puddles of fluid of any type on the road, oil pressure was great andcoolant temp was great. It was difficult to explain.
I decided to drive it home and put it up on the hoist. I remembered the 380SEC making a similarly horrible sound when I was tuning it. I had removed the bung for the O2 sensor, and not fitted the sensor – effectively leaving a gaping hole in my exhaust.
Looking under the Corvette, I found it. The O2 sensor had snapped in 2 and effectively caused the same issue.
A quick online search found that the GM part number for the O2 sensor was 19211437 – the same part number as used in a VN Commodore V8. As luck would have it, Repco had one on clearance for $38. I picked it up and had it fitted in about 5 minutes. Smooth running again.
Brake Fluid
I also discovered on my brief test drive, that the brakes were horrible. I had to smash my foot into the firewall to slow down even from 20km/h. Before trying for rego again, it definitely needed a brake system flush.
I opened the brake fluid reservoir and what I found was shocking. Brake fluid isn’t supposed to be this colour. I siphoned it out using a brake fluid bleed kit / siphon and got to work bleeding the brakes.
I started at the back of the car – jacking up both sides and removing the wheels. From there I had access to the bleed nipples and started sucking the old fluid out. I found that I wasn’t just getting old fluid, I was also getting some solids coming out. It was the worst I’ve ever seen (not that I’ve seen many).
All in, I topped up 1 litre of fluid, but interestingly only a little over 600ml came out. The system was full of air and who know what else, but it wasn’t brake fluid.
That was on the back of the car. I will continue with bleeding the front of the car in the morning.
The difference in the fluid in the before and after pics is like night and day. It will definitely stop better after this.
Tyres
Tyres are proving to be a real hassle for classic car owners. With even boring family SUV’s running 19, 20 & 21 inch wheels, 14, 15 & 16 inch wheels are proving to be difficult to find.
The Corvette runs 255/50r16 tyres and these are practically impossible to find today. I seem to have 2 options:
- Toyo Proxes R888R – A road legal semi-slick tyres that retails at around $360+
- Michelin Pilot Sport – A high performance tyre for people with deep pockets at around $770+ each
I’m not particularly pleased with either of these options. I definitely can’t afford the Michelins and the Toyo’s are still over budget and may not be too good in the wet, although being a convertible and a classic, I don’t plan on much wet weather driving.
I’ve reached out to AGR Tyres in Sefton to see if they can help. I know Ramy from AGR quite well, and if he can’t find me something, no one can.
Some Corvette owners are running 245/50r16 tyres, but seeing as mine was optioned with the 9.5″ wide rims, I’m not sure this will work. Most early C4 corvettes run 8.5″ rims.
