Does Glyptal coating really help oil flow in engines?

wickedmach1 · Aug 12, 2007

Is coating the areas where oil flows in the engine block with Glyptal really worth the extra work? I know some engine builders use it and some don't. I will for sure blueprint the block and grind away and smooth any areas where the casting is rough. I will chamfer all oil and water passages for better flow. Any opinions on the Glyptal?

ultrastang · Aug 13, 2007

Glyptal is an electrical motor insulative varnish with a very tough finish once it's dried.

Used in automotive applications, Glyptal is good for two reasones: It speeds up the return of oil back to where it gets picked up, and it also seals the surfaces of the casting. Cast iron has lots of pores where small particles of dirt can lodge, then turn loose later and get circulated through the oiling system. If they are covered over with the Glyptal, then they are trapped.

...actually, it's good for three reasons; It's about the same color as the factory red oxide primer that was used on the Ford 8- & 9-inch 3rd members. This is an N-case 3rd member I have that I sprayed with Glyptal inside and out.

http://img339.imageshack.us/img339/5616/monarch9inchncase003ak8.jpg

mikethebike · Aug 13, 2007

If you are going to work all the oil passages and you do it correctly why would you want to go back and coat the block with something that might come off and ruin everything? I just don't see the advantage.

rbohm · Aug 13, 2007

well you got two good and opposing view points there. now for mine.

when properly applied, gyptal adheres very well, and doesnt flake off like many coatings can. it has also been proven to allow oil to flow back to the pan better than leaving the block as cast. that said, it has also been proven that just smoothing the interior surfaces of the block gets you about 95% of the same gains that the gyptal will, without the expense of preparing the block for coating.

for me, i wont add any coatings to the interior of the block that might flake off and cause problems.

69gmachine · Aug 14, 2007

rbohm said:
well you got two good and opposing view points there. now for mine.

when properly applied, gyptal adheres very well, and doesnt flake off like many coatings can. it has also been proven to allow oil to flow back to the pan better than leaving the block as cast. that said, it has also been proven that just smoothing the interior surfaces of the block gets you about 95% of the same gains that the gyptal will, without the expense of preparing the block for coating.

for me, i wont add any coatings to the interior of the block that might flake off and cause problems.

I don't know what source you refer to that has "proven" that glyptal allows oil to flow back "better", but I'll tell you why I don't believe it: once the cast iron is coated with oil, the oil is running off of oil, with only the viscocity of the oil affecting how fast it flows. Only after it has sat for extremely long periods will it make a measureable difference, and then only for a few minutes until oil is sloshed everywhere. Same goes for smoothing the interior surfaces (which is a ton of tedious work).

If anyone has some real scientific data from an SAE paper or other publication, please provide your source. My money says it's an old wive's tail, perpetuated by car magazines. Might be a good science project for my son though...

ForceFed70 · Aug 14, 2007

OK, silly question here but what's the point?

So the oil flows back to the pan quicker... big deal. You'll never empty the pan (unless you are low on oil) so why does it matter how quickly it returns?

1320stang · Aug 14, 2007

Well, in an FE, if you don't do the oil mods, and have a factory non CJ passenger car pan, you can fill the valve covers up rather quickly and starve the pan.

There was a recent post about this same subject on the FordFE.com site and the conclusion wasm that when you pay a big time engine builder a bunch of $$ for a engine build, it seems like your getting more for your money when it's gyptal'd, ie. it sells well.

My opinion, just smooth the valley and knock down the cast flashing everywhere and call it good.

mikethebike · Aug 16, 2007

1320stang said:
Well, in an FE, if you don't do the oil mods, and have a factory non CJ passenger car pan, you can fill the valve covers up rather quickly and starve the pan.

There was a recent post about this same subject on the FordFE.com site and the conclusion wasm that when you pay a big time engine builder a bunch of $$ for a engine build, it seems like your getting more for your money when it's gyptal'd, ie. it sells well.

My opinion, just smooth the valley and knock down the cast flashing everywhere and call it good.

Back before the side-oiler Ford ran external oil return lines from the valve cover directly to the pan.
I still think a well preped block does not need a coating...especially in a street car.... maybe in a 10,000+ rpm race motor...but not in a street car. Waste of time and money IMHO. And Soarings.

1320stang · Aug 17, 2007

That was the SOHC motors that they ran the return oil lines externally. With the new mods you don't need to.

mikethebike · Aug 17, 2007

1320stang said:
That was the SOHC motors that they ran the return oil lines externally. With the new mods you don't need to.

They also did it on the pre-side-oilers that came before the 1965 427 medium-riser engines that came in the 427 S/C Cobra...427 cid Holeman-Moody 14.5/1 compression ratio 550 H/P NASCAR engines. It is my undeerstanding these preceded the SOHC.

ultrastang · Aug 17, 2007

There are quite a number of professional (read, expensive) engine builders that use glyptal in their engine builds for engines that they are building for both street and track use.

I've never heard of an instance where the coating has come loose and damged an engine in any way.

I guess when it gets down to it, it's up to you the owner, to do as you wish with what's yours.

Does Glyptal coating really help oil flow in engines?

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