Revision Corvette ZR-1 model year 1990 #125

[Thomas ZR-1]

The radiators for cooling water and engine oil were fitted back into the shroud housing as well as the AC condenser.

[Thomas ZR-1]

The cooling water system was connected with a new set of black silicone hoses.

At the end the air filter case was equipped with a new K&N filter element and the AC pipe system was installed with adapters for the modern R134a refrigerant. A custom calibration chip from Marc Haibeck (Haibeck Automotive) for an OEM engine was installed into the engine control module to make the engine run perfectly and smoothly.

[Thomas ZR-1]

What a shame, nobody cares...regardless: the story goes on....

[Thomas ZR-1]

14. Wheel alignment, test drive, technical check and car dyno

The engine installation was followed by the wheel alignment to adjust the overhauled front and rear axle. The following data was adjusted:

Front axle: Caster angle 4??6?
Camber angle -0.15??-0.25-?
Toe angle 0.15?
Rear axle: Camber angle -0.5?
Toe angle 0.15?

The following under car view was without complaint.

[Thomas ZR-1]

With the new and adjusted suspension I did a 1000 km test drive on the German Autobahn (Highway) to find and solve possible hidden problems and mistakes?but there was nothing. The engine was run in (new bearings) at once. The 1000 km were divided in 3 thirds while driving 2000, 2500 and 3000 RPM engine speed. At the end I changed the oil to have the engine full load qualified. This check was successful as well.

[Thomas ZR-1]

After the test drive it was time for the official technical check at the German T?V. The ZR-1 passed the required tests including the special check for getting registered as a classic vehicle in Germany.

Based on the porting of the injector housings and the plenum the engine seemed to be really powerful. So I checked the engine power on a car dyno in Cologne with 406.5 PS (401 HP) as result. This was over 25 PS (24.7 HP) more than stock. It?s justified on the better air flow into the engine by the ported intake.

[Thomas ZR-1]

15. Operating liquids

Engine oil: Mobil Delvac MX 15W40 9,0L (incl. filter PF 970C)
Transmission oil: Castrol Edge 10W60 2,1L
Differential: Castrol Limited Slip 75W140 1,25L
Power steering: AC-Delco 105074 0,7L
Air conditioning: R134a 820g refrigerant + 20g comp. oil
Brake fluid: ATE DOT 3 0,7L
Clutch fluid: ATE DOT 3 0,15L
Anti-freeze coolant: C11 14L (incl. 50% water)

[Thomas ZR-1]

That`s all folks! 1000 hours of work in 10 month and much money for a brand new car.

[dredgeguy]

Thomas you have done an incredible job bringing your Z back to like new condition. Congratulations! One day we should get a group over to Germany and drive the Autobahn all together...on my bucket list but that is for another thread. Thanks for sharing.

[DRM500RUBYZR-1]

Originally Posted by Thomas ZR-1

What a shame, nobody cares...regardless: the story goes on....

Thomas,
While it may seem like nobody cares, I doubt this to be the case.

Heretofore, the majority of "restorative efforts, concerned hoses, radios, starters, wheels, exhausts and paint correction.
While there are a number of examples of those who do a "deep-dive" into mechanical upgrades, improvements, repairs, and full blown restorations, they are comparatively few.

This not only holds true for ZR-1's, but C-4's in general.

Using Corvette Forum as an example, If you review the C1, C2 and even the C-3 sections, you will find the bulk of the posts lean towards restoration.
Many of these cars have gone beyond simple repairs and upgrades and now focus more and more on restoration.

You can still find, and always will find, low mileage survivor cars from 53-82. Their numbers dwindle however, and the economics of bringing well-used one back to day one condition are breakeven to favorable.

As C-4's age, and with ZR-1's as a subset, this evolution will likely continue and also continue to grow. The economics have not supported restoration but that is changing slowly as well.

You, and a handful or two of those before you, mostly on this Registry, are essentially the pioneers of these all out restorative efforts with ZR-1's.

Your efforts and results are outstanding!
As an example, I too likely have 1000 hours invested in my ZR-1.
The difference being my 1000 hours consisted mostly of cleaning and waxing.
Big difference between keeping a near new car new ( which many of us do ) versus a restoration.

Perhaps a final round of pictures of your completed project, as well as the before condition might be a more graphic statement of your results.

Regardless, your results are indeed outstanding. Even more so when done away from the source of most parts!

Maybe we should create a new sub forum for Extensive Restorations.

I found your summaries of each step fascinating!

Well Done!


Marty