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I plan on rebuilding my 1600 sprint GT engine next year and was wondering if anyone has come up with a way of coating the block interior against corrosion, particularly the area at the base of the liners.
Tim
 

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Probably not a good idea to use paint in that area. That area is a machined surface ... adding any paint will alter the cylinder height. Using antifreeze and distilled water is about the best thing. Good luck
 

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There is more. First, as pointed out above, a correct and changed antifreeze for aluminum block / radiator vehicles is necessary for it's anti-electrolytic properties, and these do wear out. Most water jacket corrosion is electrolytic. If there is corrosion, as mach oxidation as possible should be removed as it insulates against heat transfer, as do most paints. For race engine builds, some glue liners in and seal (ONLY) the bottom of the water jacket with epoxy, not much is needed. This can be problematic to the uninitiated for disassembly, but there is a trick. DON'T do this unless you know what you are doing! The big issue here is dissimilar alloys in a water based, likely electrolytically conductive mix. Just like a battery or electroplating device. Best and most effective is good antifreeze changed as recommended. This is only my opinion from my own experience as usual.
 
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i could be wrong but i think he is talking about the INSIDE of the block..below the liners above the pan, i do know that painting the internals of a block where oil is concerned it helps oil get back to the pan faster so it can get back in the system faster, i also belive there was a similar reason to do it to water jackets but ive never bothered on the water side
 

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Oil side Alfa blocks paint is a waste of material and effort. The aluminum is SMOOTH as compared to cast iron surfaces of engines where epoxy paint is used. I did paint one, once. Some idiot had sand blasted the inside of the block. It was a sand cast 750 Veloce block that needed to be saved. After multiple power washes and an ultrasonic clean up, it was tediously masked inside and spray painted with an epoxy used on iron race engines to (hopefully) encapsulate errant media that might come loose. It worked. I don't want to do it again.
Opinion again from my experiences over time.
 

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On the Nord engines I opened up that always had proper coolant in them, I never really encountered any corrosion. Maybe a tiny bit on the headstuds but nothing that limited the removal of the head.
As said above, any contact surfaces where the liners sit in the block should be clean and not painted. Also any surface where an important bolt/nut sits on should stay clear of paint.

Besides, I don't think many paints will really hold up well to the hot and oily environment on the inside of an engine. If paint starts to flake and get in the oil system you can cause far more damage
 

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If you have the piston sleeves out why not coat the the head studs up to where the
threads start with this stuff?.
Corrosion between the studs and the head drillings is why it is so hard to get the head off..
 

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It's electrolytic stud corrosion. It can happen under paint. If you want to really eliminate head stud corrosion, there is a way, discovered by accident. We had a soft stud in a race engine that did not want to hold torque. With the engine apart the stud was pulling out the threads in the block. Removed, the hole in the bottom of the water jacket was repaired with a stainless steel TimeSert. The same stud was reinstalled and the engine went back racing. YEARS later the engine reappeared again as a street engine and was disassembled. All the studs had even corrosion except the one with the TimeSert under it. The stainless steel insert acted as a dielectric between the aluminum and steel. Since then, whenever a block needs this repair SS inserts are used. One sand cast 750 1300 block rescued had all new studs installed, all with SS TimeSerts underneath. Good dielectric antifreeze is the everyday solution. As always, just my opinion from my own experiences.
 

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If you use a sacrificial magnesium anode you will have next to no corrosion of your aluminum parts. McMaster Carr has them. I run straight water in my race motor and since using the anode have no corrosion. You can see it work as it dissolves into the coolant.
 

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I disagree with the electrode. Sacrificial anodes are used in situations where you can't do anything about the the electrolyte, such as the water in your water heater. Or the lake your boat is sitting in. Or the ocean.

If you put an active metal in your coolant, you will rapidly exhaust the corrosion inhibitors. Then you're left with a fairly aggressive reaction between the anode and the rest of the engine metals.

Just keep fresh coolant in your engine and run it occasionally to avoid any isolated stagnant volumes.

Sacrificial anodes are for marine engines.
 

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I disagree with the electrode. Sacrificial anodes are used in situations where you can't do anything about the the electrolyte, such as the water in your water heater. Or the lake your boat is sitting in. Or the ocean.

If you put an active metal in your coolant, you will rapidly exhaust the corrosion inhibitors. Then you're left with a fairly aggressive reaction between the anode and the rest of the engine metals.

Just keep fresh coolant in your engine and run it occasionally to avoid any isolated stagnant volumes.

Sacrificial anodes are for marine engines.
I ran without an Anode and had corrosion at the liner block interface. Then used the magnesium Anode and the blocks look like new when torn down. Back in the day there were vendors selling these. I have 12 years of experience over about 6 different Alfa engines. It works.
 

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This has been covered before on the BB. Part of the issue is what is in the water. Years ago racing, we were not allowed anti-freeze in engines on the track as spilled on the track it was slippery. Running both Alfa and Ferrari race engines, plain water as a coolant was a problem, even when drained after a race session. We started using the small container of "Bars-Leak" as it had two important functions. It had a water pump seal lubricant and if we used distilled water, it had an anti-electrolytic so there was no electrolytic corrosion. Todays anti-freeze has the same additives. However, with non-pre-mix 50/50 anti-freeze, you are wise not to trust local water as a mix agent as there may (or may not) be dissolved minerals that the mix must neutralize. Mix non-pre mix with distilled water. Factory 50/50 pre mix uses distilled water in most cases.
To many, this apparently does not matter, as plenty of vintage Alfa engines when disassembled are found to have lots of electrolytic corrosion in blocks, heads, intake manifolds and water pumps.
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