Cylinder Rust Quandry

[BLstangin]

This is just from the race gas. It's so dry the cylinders rust. Big issue on dirt track cars, they race them throw them in the trailer and pull the plugs a couple days later and they will be rusty. If using race gas it has to be fogged if it sits at all or it will flash rust the cylinders. Probably nothing wrong with the cylinders and if you had started it up you would have never known the difference.

[Old School]

All you have is the results of an engine being stored in a high humidity area. Chances are the cylinders that are affected had the valves open or the spark plugs removed letting the damp air inside. The white on the piston is from the gas residue/moisture reaction.

The rust is more prevalent at the top of the cylinders where the rings haven't "glazed" the bores. The top of the cylinders always rusts first. The glazing seems to reduce the rust.

Clean everything up with steel wool/kerosene, 400 sandpaper and auto trans fluid, or whatever. I doubt that you will see any difference in the engine once its running.

The only way I have found to prevent rusting is to fog the engine with auto trans fluid, tape off all opening, leave spark plugs in and wrap with clear stretch wrap. Keep a dehumidifier on.

[BlitzA64]

This is just from the race gas. It's so dry the cylinders rust. Big issue on dirt track cars, they race them throw them in the trailer and pull the plugs a couple days later and they will be rusty. If using race gas it has to be fogged if it sits at all or it will flash rust the cylinders. Probably nothing wrong with the cylinders and if you had started it up you would have never known the difference.

Suppose you ran the engine with some 2 stroke oil in the fuel after the event rather than fog? I hate making the smoke screen.....

[n2omike]

As for my engine... I'm about to call the guy who did the block work. Probably going to pull it the rest of the way apart and have him hone those cylinders and get new rings. It's on the engine stand right now with the heads off. The rusted area is in the worst possible spot... right at the top where the rings are sealing maximum pressure. I've been acquiring parts and building this 'bucket' engine since 2008. No sense in cutting any corners at this point.

There's probably a saying out there... If you're wondering if you should do something the 'right' way... the answer is almost always 'yes'. lol

Thanks for all the input! It has been educational and appreciated!

Moral of the story to everyone out there... OIL YOUR CYLINDERS! NOW!!!

[TheNovaMan]

Hone minimally, coat pistons, and install new rings, or go to the next oversize and probably have to re-balance? How much mass does coating add? To what tolerance was the crank balanced? Did they add any mass to the bobweight for oil?

I know it would cost a set of head gaskets, but I'd be curious to know how the TDC leakdown numbers compare with BDC.

[n2omike]

Right after making that last post, I called the machinist who did the bore/hone job and emailed him the pictures... expecting to tear the thing apart. He is 74 years old, is a one man band, is completely honest and incredibly talented. He does the block work for a local Super Stock record holder and can fix pretty much anything. Anyway, he said the same thing some others have. It drew moisture and rusted a little at the top where there isn't as much oil. If I had never taken it apart, after a little run time, I'd never known it had ever rusted. lol He said he would hone it if I truly wanted him to, but there is zero need... so, I guess it gets to stay together. lol

I appreciate everyone's input. Hopefully, others as well as me have learned something. This stuff can be nerve racking... but I still plan on oiling/fogging the cylinders any time this thing is going to sit for a while!

[David Redszus]

Race gas does not form rust, unless it contains alcohol.

But the combustion by-product of combustion of any fuel is large amount of water.
If the hot, moist air is allowed to cool, it will condense to form water droplets...and rust.
Rust requires water and oxygen in order to form.

The probable cause of rust in the upper cylinder is due to rust in the exhaust system.

Remove the exhaust system, sand blast to white metal, and the rust will be gone...until
it rusts again. There is a good reason why stainless exhaust pipes are used.

If the lower cylinder shows rust, it is due to acid formation in the oil, caused by
exhaust gas blowby. Combustion gas based acid in the crankcase also eats bearings.

[fabr]

Race gas does not form rust, unless it contains alcohol.

But the combustion by-product of combustion of any fuel is large amount of water.
If the hot, moist air is allowed to cool, it will condense to form water droplets...and rust.
Rust requires water and oxygen in order to form.

The probable cause of rust in the upper cylinder is due to rust in the exhaust system.

Remove the exhaust system, sand blast to white metal, and the rust will be gone...until
it rusts again. There is a good reason why stainless exhaust pipes are used.

If the lower cylinder shows rust, it is due to acid formation in the oil, caused by
exhaust gas blowby. Combustion gas based acid in the crankcase also eats bearings.

I think I understand the why that would be so but would you please expand on this?

[David Redszus]

A cast iron header, or steel tube pipe will rust internally with use.

Rust particles will break free from the surface and exit from the tailpipe.

But when operated at partial throttle, the chamber pressure can be lower than the pipe pressure
which causes a reversionary air flow...along with rust particles entering the chamber from the exhaust.

The trick is to keep the exhaust pipe clean and free of rust or to use stainless tubing.

[BILL-C]

Rust in the exhaust does not cause the rust in the bores and combustion chambers. A more accurate statement is the rust in the pipes and in the cylinders are both caused by the same exhaust gasses. Most of my customers use stainless headers and still have rust issues in chambers and bores when they get lazy and don't fog the engine after running on race gas. Pump gas engines do not seem to suffer from this issue nearly as bad or not at all.The type of fuel you use has alot to do with the severity of this issue. For example Q-16 is waaay worse than pump gas.

[BLstangin]

I know for a fact as soon as you go to race gas it becomes a problem. Maybe a better way of saying it is that race gas doesn't have the additives in it that pump fuel does to combat rust in the cylinders after its been shut off. I wonder if adding some 2 stroke oil to race gas would actually cure this issue or not. In the dirt track world we can't add anything to the fuel and all it takes is a couple seconds with fogging oil at an idle and shut it down and its done. On a street car with race gas this could be pain, since my new engine will be on race gas I'm kind of curious what could be added to the fuel that would stop the rusting but not affect the fuel itself?

[David Redszus]

I know for a fact as soon as you go to race gas it becomes a problem.

That statement is absolutely untrue.

All that is necessary is to review the components contained in race gas to see the impossibility.

Rust in the exhaust does not cause the rust in the bores and combustion chambers.

Also absolutely not true.

Please review the following YouTube video.
Engine Performance Expo Day 3 - Episode 28 : Tool Hacks, Tips & Tricks with Jon Kaase

Or... call Jon Kaase and ask him to please explain this issue to you.
(770) 307-0241

[rebelyell]

A cast iron header, or steel tube pipe will rust internally with use.

Rust particles will break free from the surface and exit from the tailpipe.

But when operated at partial throttle, the chamber pressure can be lower than the pipe pressure
which causes a reversionary air flow...along with rust particles entering the chamber from the exhaust.

The trick is to keep the exhaust pipe clean and free of rust or to use stainless tubing.

Yup ... and (for some 30 years) Federal emissions regs mandates Generous & Lengthy warranties on all OE emissions components; including (but not limited to) exhaust manifold, catalytic convertor and anything in-between the two. Hence, OEs' wise choice of stainless.

[BILL-C]

I know for a fact as soon as you go to race gas it becomes a problem.

That statement is absolutely untrue.

All that is necessary is to review the components contained in race gas to see the impossibility.

Rust in the exhaust does not cause the rust in the bores and combustion chambers.

Also absolutely not true.

Please review the following YouTube video.
Engine Performance Expo Day 3 - Episode 28 : Tool Hacks, Tips & Tricks with Jon Kaase

Or... call Jon Kaase and ask him to please explain this issue to you.
(770) 307-0241

Kaase is talking about dry rust flakes from headers migrating upstream into combustion chamber and intake ports when engine starts. I am referring to the rusting that happens in the chambers and on cylinder walls.Rusty headers and cylinder walls are both caused by the same exhaust smoke (that includes water vapors) that originates in the chambers , goes through headers and out tailpipes.

[David Redszus]

I know for a fact as soon as you go to race gas it becomes a problem.

That statement is absolutely untrue.

All that is necessary is to review the components contained in race gas to see the impossibility.

Rust in the exhaust does not cause the rust in the bores and combustion chambers.

Also absolutely not true.

Please review the following YouTube video.
Engine Performance Expo Day 3 - Episode 28 : Tool Hacks, Tips & Tricks with Jon Kaase

Or... call Jon Kaase and ask him to please explain this issue to you.
(770) 307-0241

Kaase is talking about dry rust flakes from headers migrating upstream into combustion chamber and intake ports when engine starts. I am referring to the rusting that happens in the chambers and on cylinder walls.Rusty headers and cylinder walls are both caused by the same exhaust smoke (that includes water vapors) that originates in the chambers , goes through headers and out tailpipes.

While Kaase showed large rust flakes for effect, much smaller rust particles will infect the combustion chamber during
normal engine operation; it is a continuous process. Often the rust is found under a layer of carbon, even with aluminum heads. Clearly, the aluminum heads did not rust; it came from elsewhere.