Engine Paint -- Inside

[CarlG]

Since I have my engine disassembled to the bare block, I figured that this would be the perfect time to renew the paint in the valve chamber and the crank chamber. Haven't a clue as to what was on there, but it was a "mineral red" color. Some of the paint came off when the machine shop cleaned it prior to doing some machine work on it, and I'd like to do that now rather than have it go back together unpainted.

So, after that long explanation, I'm open for suggestions as to what to use. After having worked in an aircraft shop, the term "Glyptol" comes to mind, just not sure if that is appropriate for this application.

[Fullraceflathead]

Red Glyptol is what I use on modern Racing engines. The iron surfaces must be spotless to be sure the paint won't later come off.

[MikeK]

Just the fact that it is presently wearing away in your engine should raise a big flag.

I've torn down lots of engines that have been 'improved' with glyptal. The red oxide is a fine abrasive (think crocus cloth) and the oil pump gears get prematurely worn as the stuff slowly dissolves away from the oil additive package. The red oxide fines, released as the oil package deteriorates the coating binder, go on to trash your bearings. In a model A, even with a filter, the rod bearings are dipper fed and will get the stuff in them.

The glyptal paint binder is exactly the type of organic material modern oil additive packages are designed to remove! It is not a catalytically cross-linked coating! Even if it were, why would you want to add a thermal barrier between the metal and the oil?

I'll take a pass on any block that has been adulterated with glyptal or any other type of coating/sealant.

[J and M Machine]

I wouldn't recommend doing so.
You'll never get it factory fresh for the paint to truly adhere.
When the paint flakes off the first place it will go is the pump screen.
Just look at the enclosed picture. someone had a better idea.

[Mitch//pa]

yep thats what i was thinking also NIX that painting idea...
its a 40 hp model A

[Big hammer]

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Proofs in the pudding or oil pump screen :-(

[Vic in E-TN]

WOW
This is a very important point to make. We need to get the word out to some of the engine builders.

Vic

[Dave in MN]

I was a big fan of using Glyptol inside the engine until I had the opportunity to open an engine overheated by running low on coolant. The enamel was coming off the hottest areas of the block in sheets. I have not used it since.
Good Day!

Update after reading later postings:
Well, the insides sure look nice when they are painted that deep rich color don't they? It sure gives the impression that someone really cares about their work. For some, it may be about better oil movement but for me it was about the "Look". But indulge me...read on. My original post was short, I should have further explained my reason for eliminating the use of interior sealers. It was not just because an engine may overheat and then the seal would peel. In the engine I describe above, the operating temps were hot enough that the new Snyder's 5.5:1 head cracked and the pistons scuffed so I know it was very hot. As I was repairing the heat damage, and removing every bit of loose and remaining well-bonded Glyptol, it became crystal clear to me that I was possibly inviting future problems. Should any sealer peel from the valve chamber surface, for any reason...overheating or not, it would likely end up in the main bearings or blocking oil from flowing through the supply tubes to the main bearings. I just made a risk to benefit judgment and decided to eliminate any further use of interior sealers. Right or wrong...educated or knee-jerk reaction...it really doesn't matter because it's JMO.
My Rebuilds, My reputation, My opinion...My call!

ps: I fell off a roof once because I was so accustomed to walking near the edge that I let my guard down. It wasn't a high roof but I had time to decide before I even hit the ground that it was not going to happen again. Painting the insides of engines seems to me to be like walking near the edge for no real important reason and not paying attention to the perils.

[colin1928]

Originally Posted by J and M Machine

I wouldn't recommend doing so.
You'll never get it factory fresh for the paint to truly adhere.
When the paint flakes off the first place it will go is the pump screen.
Just look at the enclosed picture. someone had a better idea.

Yea seen this way to often
No paint for me

[plind]

Hi..

But why paint it inside..?? when the valvecover is on place , all is the same..
So the same here , No paint for me

[BRENT in 10-uh-C]

Ok, can we step back on some of these reasons for not using it;

Someone mentioned it was coming off in an engine that needed to come apart because it was overheated. Isn't this like saying in the future I'm not using cast iron rings because they will fail and lose tension when the engine is severely overheated?

Yes, race engine builders use this because it is a more time-efficient way to control oil. Our 410" race engine block was just retired for a new block and the Gyptol that was in it has seen run time with 240 degree temps and lots of abuse over the years. Many similar race engines have experienced the same and we find it does not peel off. The benefit for a Model-A engine is to seal the pores and gets the oil back to the pan where the oil's suspended particles can collect there. With regard to being a thermal barrier, 'one can make a valid argument that promoting heat in the areas that do get coated is a good thing as most Model-A engine temps are cooler than what the oil companies want their oil temps to be to keep their additives working.

Now, here's a thought. Not sure I would want my cast iron cylinder case being factory fresh. When the Rouge cast a block, how long did it set between the time it left the foundry until it was in que to go thru the engine shop? I have removed blocks from my hot caustic tank and within 2-3 days there will be a slight flash of rust present. That is why most reputable builders have a rotor-blaster to (re)clean the block. If the inside of the block is truly cleaned, then Gyptol peeling is not an issue. Now I totally agree that if it isn't, then there will likely be issues ...but it is kinda like saying all babbitt bearings are bad because it will crumble or fail in a Model-A engine with compression ratios higher than stock. Maybe we shouldn't be blasting our engine cases because tiny particles of media/shot will embed within the pores and dislodge later and go thru the oil pump.

One final thought, a good quality detergent oil that is changed with frequency should remove most contaminants that are in the engine. Now don't forget contaminants include anything from minor deterioration of this paint, ....but also includes items such as the cast iron material as it wears and falls into the oil, the timing gear material as it wears ( think about how the crank gear rusts when engine sets) or the rust that develops on distributor shafts /etc. and falls into the oil. So is minute particles of paint going thru the pump worse than the particles of cast iron off the rings or the rust particles? Sometimes us as rebuilders try to 'over-think' things on our beloved Model-As where we can justify or nix anything we want by logic or opinions that seems believable to us.

[Jim Brierley]

Glyptol is more important on modern engines because their casting are rough, and it is needed to return the oil to the crancase quickly. Our engines have smoother castings. I don't use it because if it isn't in there, it won't cause any problems.

[d.j. moordigian]

Originally Posted by BRENT in 10-uh-C

Ok, can we step back on some of these reasons for not using it;

Someone mentioned it was coming off in an engine that needed to come apart because it was overheated. Isn't this like saying in the future I'm not using cast iron rings because they will fail and lose tension when the engine is severely overheated?

Yes, race engine builders use this because it is a more time-efficient way to control oil. Our 410" race engine block was just retired for a new block and the Gyptol that was in it has seen run time with 240 degree temps and lots of abuse over the years. Many similar race engines have experienced the same and we find it does not peel off. The benefit for a Model-A engine is to seal the pores and gets the oil back to the pan where the oil's suspended particles can collect there. With regard to being a thermal barrier, 'one can make a valid argument that promoting heat in the areas that do get coated is a good thing as most Model-A engine temps are cooler than what the oil companies want their oil temps to be to keep their additives working.

Now, here's a thought. Not sure I would want my cast iron cylinder case being factory fresh. When the Rouge cast a block, how long did it set between the time it left the foundry until it was in que to go thru the engine shop? I have removed blocks from my hot caustic tank and within 2-3 days there will be a slight flash of rust present. That is why most reputable builders have a rotor-blaster to (re)clean the block. If the inside of the block is truly cleaned, then Gyptol peeling is not an issue. Now I totally agree that if it isn't, then there will likely be issues ...but it is kinda like saying all babbitt bearings are bad because it will crumble or fail in a Model-A engine with compression ratios higher than stock. Maybe we shouldn't be blasting our engine cases because tiny particles of media/shot will embed within the pores and dislodge later and go thru the oil pump.

I've painted the insides of engines for 45 years with Rustoleum.
The only thing that takes it off is the "hot tank" or Nitro. Yes, it
has to be clean and oil free before it's done. I've look in engines
that I did 30 years ago and it still looks perfect! The engines clean
up easily with soap and water,...oil the cylinders and it can sit for
a long time.....and won't rust! The people that have the paint come
off is due to the wrong paint or poor prep work !!

[H. L. Chauvin]

The POR 15 Company, when asked, reported that they did not have test results from coating engine interiors, so they did not recommend using it to coat engine interiors.

While always experimenting & trying different things, I cleaned interiors of engine, transmission, & differential with POR Marine Clean, treated with POR Prep & Ready, & applied one coat of POR 15 which made the interior cast iron surfaces "feel" smooth.

Maybe in a few years if anything explodes, I will have a report for everybody to read ........ until then, everything appears to be working ....... engine oil stays very clean with an oil filter & air filter.

[Kohnke Rebabbitting]

I have never painted anything on the inside of any engine, what for.

Two Model A engines built the same with one painted inside, and the other not.

Who could tell me with facts, that the painted one will be the best engine out of the two, and for what reason, and if a man running for his life would notice it!

All I have ever seen in the past is opinion!

I remember when this fairy tail started on here a few years ago, and it has been past around like a truth.

Just like when I first posted on the barn, an idea was being past around that you couldn't grind a crank past .020, or the babbitt wouldn,t hold up because it was thicker.

So the fact is if you have a crank ground to .040, or .050, and the babbitt falls out at .020 thousandths wall thickness difference, it would have also fell out at standard also by the guy who done the work.

All babbitt will stay, if it is done right!

[H. L. Chauvin]

Also heard years ago if one drives by a pasture after a rain & the cows are standing in the water ............. this means the fish are biting; but maybe still not as costly or as informative as ........... you can keep your doctor & keep your insurance !!!

[BRENT in 10-uh-C]

Originally Posted by Kohnke Rebabbitting

I have never painted anything on the inside of any engine, what for.

Two Model A engines built the same with one painted inside, and the other not.

Who could tell me with facts, that the painted one will be the best engine out of the two, and for what reason, and if a man running for his life would notice it!

All I have ever seen in the past is opinion!

I remember when this fairy tail started on here a few years ago, and it has been past around like a truth.

Herm, your thoughts have merit. Painting the inside of a block is much akin to some believing a 3-angle valve grind is superior to a 45° angle cut in a Model-A block. Others will suggest the valve should be cut at 44° while the seat should be 45°. Some builders feel non-detergent oil is better yet some feel detergent oil is better in the 'A' engine. Each Model-A engine builder chooses a method that they feel makes them successful, ...and just like cooks in the kitchen may have a different recipe for cooking meatloaf than what someone else does, --in the end it is still meatloaf. Stick a fork in this debate, ...it's done!

[BlueSunoco]

Great thread. When we have the motor rebuilt in the '30, no way do I want it painted on the inside now. I feel that the oil splashing around in a driven engine is just fine for protection.