Rebuilds based on time?

Our local F club had a workshop tour day last weekend and interestingly the main gist of the managers chat with us was that leaving cars sitting is the worst thing you can do - condensation of vapour coming out of the oil inside the engine (especially if the car has been started but not run up to temp); deterioration of flexible bits such as hoses and tyres that get 'conditioned' during use; modern fuels that gum up or even go to jelly if left too long etc etc; also interior leathers etc dry out. His opinion was regular maintenance was a far better indicator of a car's health than mileage.

 

many aircraft components are overhauled on time in service, and not actual engine / flight time. i would rather have a car with some miles on it, driven weekly , than one that sits.

 

I have taken apart two engines that sat for many years before I started pulling them apart. It was amazing that stuff was still oily and rust free. One engine had been outside and had a cylinder full of water and rust, but the other 7 cylinders looked good, the crank looked good, etc. I think the engine on a car that sat in reasonable storage would be fine. BUT everything else wouldn't be fine. Coolant gets acidic after a few years and starts eating everything from the inside out. This is a bigger deal with an aluminum everything car like a Ferrari than a small block Chevy. Brake fluid gets water in it over time. I read recently that brake fluid will pull water from the atmosphere through metal brake lines. Yikes. Then those rust from the inside out. Rubber seals gets hard and brittle from not getting lubed. I bought an old Ducati that hadn't been run in 10 years and the valve seals shattered as if made from glass when I tried to remove them.

I don't think the car would need an engine rebuild, necessarily, but it might need virtually everything else rebuilt/replaced. Storage is hard on a car.

 

When an engine stops, some valves are open, some are closed and some in-between. The open valves have springs that are at the limit of their compression. This is okay for normal use but if the car sits dormant for years these springs can lose their elasticity (I've seen it). The result is some of the valves won't have sufficient spring tension and will "float" before they should.

Combine this with the broken springs that I've seen on a couple 328's and you might want to plan on replacing all the valve springs.

 

This is a great question. Not all low milege cars just sit for 10 years. What about the cars that are started and run several times a year. How do belts and hoses hold up in a consutant 45 dergree garage? What kind of neglect is really required for brake lines to rust from the inside out. I have a friend with a 1964 Ferrari with 3k miles on it. Everything works great. Thats a long time with the original brake fluid in the car. Is inside storege the answer?

 

There is no wear on the steel parts that do not do any thing, gaskets and rubber parts have a "shelf life" and will need to be replaced. So these people who do not drive their cars are saving them for the future owners who will. And I thank them.

 

Well thats over 100 miles a year. That could be starting and running to operating temperature once a month.

 

Take a bit of wisdom from the aircraft engine manufacturers. Lycoming deducts 40 hours per month from TBO for an engine that sits idle over 30 days continuous. I have a ring gear out of my other 308 that has some rust pits on the one side from where it sat motionless for years. But its not just a Ferrari, any car will do that. Cams can rust from sitting dry. Like 2NA eluded, valves sitting open fatigue the valve springs, the the cylinders can oxidise. Even a slight film of iron oxide on the cylinders will be imediately swept into the ring grooves and foul them up permanantly.

On the other hand, provided the car does not rust or rot away, the big parts arent really getting worn out while it sits. If I were going to restore an old car, one with low miles and needing a major going through would probably have many more useable parts than a car with 200K miles that was driven regularly. Miles also flex and weaken the chassis, so high mileage cars are more squeaky sometimes, its all a trade off.

But I think more to the point of the OP, low mileage on a 20 or 30 year old car is not really anything that a real mechanic or gearhead would want unless the motor has been torn down recently, or at least been opened up, heads and pan off, and thoroughly inspected. IMHO I would say any engine between 15 and 20 years of age should be opened up. Thats not saying it needs to be overhauled, but at least inspected and re-gasketed, new oil seals, maybe a valve grind, etc., etc.. Low mileage AND a recent verifiable engine/gearbox/clutch freshening would be about as good a machine as money could buy provided the rest of the car is on par.

 

This is a great question. I have wondered this my self. I did design machines for a living but not automobiles so I have some data but not alot.

I have a good freind who designed the oils and their additive packages for Exxon. He told me the fuel today does not have stabilzer like it did a decade ago. The length of service varies but he said fuel will begin to get gooey at about 6 months with some lasting about 1 year. He always used stabil in his vehicles. The additive packages used in oil tend to disapate with time. The petroluem based oil degrade, additive packages for protection disappear and the oil absorbs some water. The synthtics do not absorb water at least to the amount of the natural oils. This is why you are beginning to see cars with synethtics recommending longer oil change cycles. The new Porsche 911 (997 variant) has an oil change frequency of 20,000 miles or every two year whichever comes first as an example.

I quoted Brian because i think this is correct. I know that time efffects gaskets and they dry out if not used and you will get oil leakage. There are seals we use in industry but I do not think that are used in cars because of the cost.

The valve springs being under pressure is a great point. I had never frankly thougth of that. The materials in the newer springs do not take a set. Gun people always tell the owner to not load the clip with bullets for to long because the spring will not feed well because it has lost elasticity. This is not true today at least with modern guns. It surely was a problem with guns in the middle of the last century. Cars i suspect changed in the 70's but I do not really know.

If the car is run every other month or so even idling will help gaskets and such.

I could go on but where does this leave us?

Assuming the car was put up and not run for 5 years. In my view the gaskets would need to all be replaced. The gas would have turned to Jelly, even with Stabil added, so the fuel tank, the lines and the carb/ Injector would all have to be cleaned. Brakes and all other fluids including transmission should be replaced. The antrifreeze if it is a modern type should last 5 years some even goes 10 now. i would still flush the radiator and put in fresh antifreeze. The early aluminum radiators would oxidize and leak badly. The new ones are okay.

As Brian suggests I think the engine would be okay, Syn oil probably no rust, natural oils, probably some but not enough to rebuild the engine.

If the car sat dead for 19 years then I think it would be prudant to repack or replace all of the wheel bearings and I suspect an automatic transmission would not give service very long.

Brian did a great summary in my view.

Lee

oh on airplanes, Private planes and their engine have a TBO. This is Time Before Overhaul. Normally 1500 to 2000 hours depending on the engine.

The airframe must be inspected every year and signed off by a mechanic even if the plane only flys 1 hour. If the plane is part 135 or commercial it is every 100 hours of operation or 1 year which ever comes first.

 

I recently brought two Daytona Spyders back from 18 years of non-use. You recore the radiators, get new a/c condensors, clean out the dry sump tank (it was scary in there), rebuild the brake calipers, booster, master cylinder, new brake lines, rebuild or replace fuel pumps, replace/rebuild exhausts, new wheel bearings, turn or replace rotors, curve distributors, free clutch (it will be rusted shut), replace clutch if necessary, replace gearbox seals, blah, blah, blah.

For the engine, dump the oil, put in thin oil (I started with 10 - 30 GTX, I normally use SWEPCO 15-40W) with Marvel Msytery oil and let it soak a bit. (You do this with what engine builders call the "oil pig" (pumps oil into the motor).) Then, see if you can hand crank the motor over. If so, you're probably in luck. Do everything mentioned above, put new gaskets in the motor, adjust valves, time the cams, curve the distributors, new ignition wires, rebuild the carbs, dump new oil in and fire it up. I got lucky, the bottom end in both motors were fine and the engines purred. I drove the car around for about 100 miles, came back and dumped all the fluids to see what we had. Everything looked good. After about 1000 miles, one car that we didn't initially touch the gearbox on started leaking at the shift shaft seal. So, we pulled the gearbox and replaced all the gaskets and seals since we opened it up. The original shift shaft seal literally crumbled in my hands. I have no idea how it lasted the first 1000 miles before it leaked.

Another car of mine, a 59 250, had seen very, very little use over the past ten years. Starting it up for the first time looked like some mosquito abatement program. After putting in new oil with a quart of Marvel Mystery oil, one side came back right away, smoke gone. The other side was still smoking. At this point, it's looking like either a stuck ring or cracked ring. So, another dump of oil, checked to see what the oil coming out looked like, then new oil with another quart of Marvel Mystery Oil and then take it out for a drive. Thirty miles later, the 1959 250 is blowing no smoke. I've been using it as a "daily" driver the past month. No smoke, great compression, embarrasses 4cams and Datyonas on acceleration, and hasn't left me stranded. Of course, this now means the motor or gearbox will probably blow up tomorrow.....

Oh, don't ask me how or why Marvel Mystery oil seems to work. I have no clue. I thought the mechanics that told me to try it had spent too much time sniffing brake/carb cleaners. I'm a believer now.

So, just because a car has been sitting doesn't mean it necessarily needs an engine rebuild. I'm four for four (I did the same thing with a C/4) in not needing to rebuild a motor for cars that have sat for a period of time. One thing I always rebuild on these cars is the brakes. If there is one thing a car must do, it must stop. I just don't take chances with the brake systems.

Steve

 

MMO is weird amazing stuff isn't it. I think it must have some kerosine in it. No advertising and it has been around for decades and still sells!

 

I bought a Cooper Monaco with a TRACO-built aluminum Buick v8. It had been stored on a trailer in a concrete warehouse for about two years. The master cylinder was frozen, so replaced it. Pushed clean brake fluid through it to all four wheel cylinders. The ignition points were rust balls, so replaced them. Replaced the battery and spark plugs, took the pan off and found a nice clean oily shiny crank and cylinder walls, put fresh oil and gas in it, turned the engine over my hand a few times, hit the starter button and it fired right away and ran like a champ. I ran it on the race track several times, no smoke, no misfires, nothing bad happened, amazing.
Ed