Ceramc coating and thin film lubricant

[Isaac Zackary]

No. No emissions requirements, testing or other. Not that I'm trying to make a polluting hog out of it. I'd like to try a really lean burn. Lean enough to reduce NOx.

[serialk11r]

Originally Posted by Isaac Zackary

Sadly no. This car doesn't have any sort of temperature gauge. Well, now that I'm rebuilding the engine I'll install an oil temperature and a cylinder head temperature gauges. So I won't be able to compare. All I'll have to go by is that the normal operating temperature should be between 300° F and 350° F CHT. So if it's lower that would be a sign the thermal barrier ceramic coating is working.

As far as the thin film lubricating coating goes, I'm skeptical that it really helps too. But I though, why not.

Aww, that's too bad. How close to the combustion chamber is the temperature sensor?

I've always wanted to do a thermal barrier coat on the valves and head, but I'm still waiting on "the one" car to go all out on with modifications and upgrades. Everyone swears the coatings work, but it would be good to see some direct evidence. The only numbers I can find is some website that put an engine on a dyno after coatings and the engine appeared to gain a few horsepower, but more direct evidence would be better.

One reason it would be super interesting to see how much the temperature drops is that direct injection gains most of its power/anti-knock ability from the fact that fuel can enter the cylinder at a colder temperature since it's not being cooked by the valve. If a ceramic barrier can drop the intake valve temperature and in cylinder temperature, you might be able to bump the compression ratio up like with a DI engine. I don't know if it's possible but if the intake tract can be coated too then it would help even more.

As far as the lubricant goes, the one interesting place where that could be useful is the piston skirt. Bearings are almost always under hydrodynamic lubrication but the piston skirts are not, and OEMs use a myriad of coatings on the skirts. Which coating did you get? Oh yea, if it's possible you might want to ask to get the piston wrist pins coated, apparently those experience some wear as well.

[Isaac Zackary]

I'm putting the cylinder head temp sensor on the spark plug gasket. It's a 3/4" reach spark plug. Also this won't be a good example to follow for direct injection. This engine is carbureted. The goal in this engine will be to "cook" as much fuel as possible to get it to vaporize before entering the combustion chamber. On this engine with its raised intake manifold this is done by means of heat risers that conduct exhaust along the intake manifold. Also preheated air that is used to enter the carburetor controlled by a vacuum operated thermostatic valve. I'm going up with the compression ratio but not by much.

Another thing about the Temp Sensor. Sadly it's a thermocouple type that's not ambient temperature compensated. I'm trying to figure out some sort of box to keep the cold junction the same temperature.

As for reducing or increasing NOx, the thermal barrier coat should reflect more heat back into the combustion chamber. But it should also keep hot parts from dissipating more heat into the combustion chamber. Also I'm cheating the exhaust ports so overall head temps sound be lower for that reason too. Who knows how much heat will contribute to or discourage the production of NOx.

So far I'm having problems with the rod bearings. I'm not sure yet if it's from the ceramic coatings. The problem is that a couple of the rods feel tight. Yet when I stick a Plastigauge on them they read fine. I'm suspecting that the rods are out-of-round. I'm going to have them resized and then see if that fixes the problem. I've already found that the wrist pin bushings are out of spec so I'll need to have them thoroughly checked anyway.

I did have the piston skirts coated too with the lubricant coating. As well as the valve stems.

[freebeard]

I had an engine in my old panel van that had oil and cylinder head temp gauges. The cylinder head temp gauge had two pickups, on #1 and #3 cylinders, on a toggle switch.

I never saw any difference. Probably due to the dog-house oil cooler.

[spdfrk]

Can remember where I read it but I saw somewhere the Northstar engines had their skirts done with ws2 because of carbon problems to get them through warranty.

[Isaac Zackary]

Originally Posted by freebeard

I had an engine in my old panel van that had oil and cylinder head temp gauges. The cylinder head temp gauge had two pickups, on #1 and #3 cylinders, on a toggle switch.

I never saw any difference. Probably due to the dog-house oil cooler.

Did you have a dual port with the OEM cylinder tins with the vanes? The single port engines with the non-doghouse shroud had hotter #3 cylinders because 1) the oil cooler made the #3 and #4 cylinders get hotter cooling air, 2) because the #3 and #2 cylinders were offset from the fan shroud and 3) because the way the single port draws in the #4 and #2 cylinders before the #3 and #1 cylinders the #3 and #1 cylinders receive more air and fuel and run hotter. So the #3 cylinder gets everything that would make it run hotter.

With the dual port with the doghouse shroud and cylinder tin vanes all of those problems are dealt with making all the cylinders run about the same.

[freebeard]

My experience confirms the conclusion.

Stock 1600 dual port with the kool tin. 009, extractor and dual Solexes. It also had an oil temp sensor that lived in the dipstick hole so it could read the sump temperature.

I've still got that extractor exhaust. I think it's going to go on the weekly driver. A new stock muffler, tips, clamps and gaskets is about $150. A ceramic coated or stainless steel version of the stock muffler is $250. Compared to 'in hand'. It will probably sound a little ratty, but not as bad as the car does now.

My recollection is that the price of an extractor exhaust stayed at $49 for something like 25 years. It had some anti-inflationary affect that was noticeable.

[kafer65]

Here is one lifter I modified out of my Beetle.

I noticed #4 was always a little hotter with a doghouse shroud with all of the stock tin installed. The shroud heater ducts are also welded shut. I ran 312*F head temps with an Engle W130 cam and CB turbo EFI. I did have oil light flicker at hot idle and a Melling 30mm oil pump. I don't know if that mod had anything to do with it. That was with Mobil 1 turbo diesel truck oil or Bradd Penn oil. Seemed to run better at 9:1 compression over 8:1. I wanted to try the coating on the pistons but some DIYs had some flaking if I remember correctly.

[Isaac Zackary]

I've also got the HVX oiling mods. I did mine a little different and slotted the lifter bores instead of the lifters and got single grooved lifters.

As for flaking the ceramic coating in the Gunnison chambers seems to scratch off easily. I'm really not that impressed by it so far. But I need to run the engine before I make my final comment on it.

[freebeard]

Once it's assembled, hopefully you won't have scratchy chunks of stuff passing through the combustion chambers.