The GMMG Registry Forum

....work in progress..........

HOW DO YOU MAINTAIN YOUR CARS?

HOW DO THE LARGE COLLECTORS MAINTAIN THEIR CARS?

There is always ongoing conversation about how to maintain your cars.

GAS, ENGINE, INJECTORS, BATTERY, OIL, PAINT, INTERIOR, TIRES, STORAGE/GARAGE

How do you do it?

Misc information from the web & my lifelong experiences……..

GAS:

If cars have not been started or driven there is a high probability the fuel pumps will be bad.

Here is what a bad GMMG fuel pump looks like. (Hard plastic that falls apart when touched & corrosion on parts)

Fuel pump from Bobby Labonte Blackbird #38
What is the shelf life of gasoline?

The shelf life of gasoline varies based on storage conditions and whether additives are used:
• Regular gasoline: Typically lasts 3 to 6 months without stabilizers.
• Premium gasoline: Can last up to 9 months.
• With fuel stabilizers: Gasoline can be stored for up to 3 years.
• Proper storage in an airtight and light proof container can also help prolong its shelf life.
• For best results, consider using a fuel stabilizer and store gasoline in a cool, dry place.

AIR FILTERS: Matt insisted on paper (factory) air filters & hated FRAM or other reusable filters.

Some use higher octane AV Gas.

The shelf life of Aviation Gas (AVGAS) can vary based on storage conditions, but generally:
• AVGAS can last 8-10 years if stored properly and uncontaminated.
• It is engineered for greater stability and can last up to 12 months without significant degradation under optimal conditions.
• Factors such as temperature, humidity, and exposure to light can significantly affect its quality and usability.
• Proper storage in a cool, dry place, away from direct sunlight and moisture, is essential to maintain its shelf life.
Overall, AVGAS is designed to be a long-lasting fuel, but proper handling and storage are crucial for maintaining its quality.

• What is the cost of AVGAS? $4 to $7 per gallon
• The cost of AVGAS (Aviation Gasoline) can vary significantly based on location and other factors. Generally, in the United States, AVGAS prices range from $4 to $7 per gallon. However, prices can be higher at smaller airports and may vary due to supply and demand conditions.

MAINTAIN GOOD FUEL / INJECTOR ADDITIVES:

Products like Sea Foam, Stabil, fuel stabilizers & injector cleaners are often used.

For discussion………

What does this mean?

Fuel life may be 3 to 12 months. If the cars are not driven enough the fuel goes bad.
One option is to drain the tank every year if using Premium Non ethanol gas.
With AVGAS maybe drain every 3 years.
What should I do?

ENGINE PERFORMANCE:

If you have an old tune on your GMMG you can wake it up with new software programming & a dyno tune.
Companies like Hawk’s, NicKey & Vengeance can wake up your GMMG.

OIL: Matt Murphy informed me to use Synthetic oil with Zinc for larger GMMG motors.
I use oil with zinc in all my GMMG’s.

BATTERIES: Do you use battery tenders? Why or why not?

PAINT: A good detail shop can do paint correction & professional ceramic coat seal.
There are new ceramic coat wax products for those that want to do it @ home.

INTERIOR: Keep the leather soft with leather cleaner & conditioner.
Do NOT use Armor All. WHY? Armor All tends to dry out leather & marine vinyl & eventually it cracked.
Armor All plastic cleaner is OK under the hood.

TIRES: What do you inflate to for winter storage?

TEMPERATURE & HUMIDITY: High humidity is about the worst thing for cars.
Some put carpet under the cars. Not good if the floors sweat & humidity level is not controlled. The carpet will hold a lot of humidity under the car.
Running a dehumidifier & fans help.

COVERING CARS: Here is a cool cover…… Nyle Wing – Dick Harell #2
OTHER: What are your thoughts & ideas?

Jim Smith January 29, 2026[/b]

I am not suggesting this is right but here is how I do it. I have been tweaking this my entire life.

I have owned over 130 cars in my 81 years, about 45 4th Gens & about 30 were GMMG’s.

I currently have 13 cars, boats & other toys. Seven GMMG’s

WINTER STORAGE & SHOWROOM - TEMPERATURE & HUMIDITY

My showroom is 100% climate controlled like a museum.
Very little air moves in the showroom & this minimizes dust.
Air conditioned, heated (I keep @ 50+ in winter), dehumidified, floor heat, 100% finished floors.
I always have a piece of rubber membrane roofing material between the tire & floor.

FUEL:
Years ago with metal gas tanks – I kept them full.
When plastic tanks came along I kept the gas level low. (see thread above for photos)
I have replaced 4 fuel pumps in 4th Gens. Everyone was corroded, dry & the lines hard, rotted & cracked.

Why?
GM Service techs say it is because the tanks are not full & air & fuel cause corrosion & hardening of anything rubber or plastic. OK, that makes sense to me.

What is the fix?
Keep tanks full?
I drive all the cars a few miles in spring & fall if they are not the 2 or I drive often in the summer.
I use Sea Foam in everything. I have not drained the tanks & will start this process this summer.

OIL:
I change oil & filter every 2 years whether I drive the cars or not.
I use synthetic with ZINC in all the GMMG’s & Mobil One in the driver cars, boats & everything else.
.

Yes, Valvoline racing oil contains zinc. Specifically, Valvoline VR1 Racing Oil has a high zinc content, which is designed to provide extreme wear protection for high-performance engines. The zinc is part of a compound called Zinc Dialkyldithiophosphate (ZDDP), which helps reduce wear on engine components under high-pressure conditions. This high zinc formula is particularly beneficial for older engines and high-performance cars, ensuring better protection against engine wear.

BATTERIES:
I have battery tenders plugged in to anything that will not be driven withing the week.
In the winter I have over 20 battery tenders plugged in to everything.

PAINT: I have hand detailed & ceramic coated most of the cars myself.

CAR COVERS:
I cover cars with painters’ plastic & DO NOT use ca covers.
Why? I can kind of see the cars & painters’ plastic has fewer small scratches & swirls in the paint.[/b]
. I learned about Marine Vinal & Leather years ago when I was National Sales Manager for Premier Pontoons. My 1st fun project after I retired.

INTERIOR: I use leather cleaner on seats & dash. NOT ArmorAl

WHY? ArmorAl tends to dry out leather & marine vinyl & eventually it cracked.
Leather conditioner keeps things soft.

I will use ArmorAl under the hood on plastic parts & other outside plastic parts (or rubber restore)

I also crack the windows just a touch to take pressure off the window gasket.

TIRES:
I inflate to 45 psi for winter storage & I always have rubber membrane roofing rubber between the tires & the floor.
35 psi for summer driving.

OTHER:

What changes do I need to make?

I will drain the tanks every couple of years & continue with Sea Foam.

I will drive the cars more.

What other suggestions do you have?

Jim Smith
January 19, 2026