Building an engine for mileage..

[mjo]

My thoughts on the copper: IMHO too much oxygen and water would pass through the intake manifold and rust the copper.

If you had access to a custom cam design and can add a turbo - I would try redesigning the engine for the Miller cycle. You'd have FE gains and achieve more power than the Atkinson Cycle.

[fumesucker]

New camshafts and such are beyond what I intend to spend but I do appreciate the comments, the atkinson cycle in particular is an interesting concept.

As for the copper plating, it seems to me that just plating the intake valves would get you a good bit of the benefit without all the trouble of plating the entire head..

As I mentioned I used to work in a plating shop, getting the intake ports to plate is going to be a chore and you're going to have a hard time finding a shop that will put a raw cylinder head in their copper tank, they won't want to risk the possible contamination to their expensive tank chemistry.

Plating ions don't much like to turn corners, the outside portions of the head are going to get a thick layer of plating while the ports are going to get very little.. One possible tactic might be to get a little plating solution yourself and fill each intake port with solution, place an electrode in the port and run the current through that way.

Getting the ports clean enough to accept plating is going to be another problem, you'll probably have to grind the entire inner surface to the point where you have clean metal..

[GasSavers_RoadWarrior]

Actually, you have to get quite a bit of heat on bare copper to oxidise it significantly, this is the reddish or blackish film you might see while soldering copper with a torch. It is more likely to form a passivating film of copper carbonate and or acetate (verdigris) which retains the catalytic activity. Decomposition of this and significant formations of oxides happen around 200C I think so as long as the port doesn't get that hot, it should work for quite a while. If the port is getting much hotter than about 150*, it won't work too well anyway, because the copper begins to catalyse a different reaction, favouring acetic acid and formaldehyde over H2 and ketones.


Edit:

Something that was just bugging me was why they use copper stills for distilling spirits... As far as I can figure this out, it's because significant amounts of water deactivate the dehydrogenisation phenomena, so this won't work in conjunction with water injection and it won't work in conjunction with an HHO system if it's output is excessively "wet". Aside from that, the 78* temp they use for distillation is at the low end of the temp range, so even when they're getting it really pure it's just barely beginning to happen, and the purest alcohol will touch relatively cold copper. Also the actual acidity and sulphur content of the mash appears to put different kinds of coatings on the copper, and copper actually helps by pulling some of this crap out of the distillate. So the chemistry there is subtly different. The few ppm of ketones that end up in the spirit probably give it a rounded fruity flavor (Don't let this keep you from your favourite traditional copper stilled spirit, ketones occur naturally in fruit, so are what makes even fruit taste fruity.) Even with the attack of acidity and sulphates a still made with relatively thinwall copper tubing is expected to last 8-10 years. Copper hot water pipes in homes last many years too of course. Therefore I'd expect intake port plating to last at least 2 years.

Another thing I discovered from a different source is that a small amount of methanol, of around 5% of the volume of ethanol accelerates the ethanolic/copper reactions. So in a 10 gallon tank of E10, with 1 gallon ethanol, just about 6 and a half ounces of methanol (Fondue fuel) would significantly improve the reaction. Actually, it might even be worth trying methanol on it's own without the copper plating, since other metals weakly catalyse this reaction, giving it a kick with 5% methanol to the ethanol content MIGHT make this happen without having to do anything to your motor.

Another really, really, (yes really) weird thing, you won't believe this... copper plus ethanol plus paraffinic hydrocarbons (there's at least a small percentage in a typical gasoline "soup") plus silicon/silica/silicates plus heat = trialkoxysilanes...... this could mean that any silica dust that gets past your air filter is turned into synthetic lubricant or semi-solid surface lubricant/coating...... this might only happen in tiny tiny amounts... but it sure sounds better than having silica dust "grinding paste" enter the motor.... no, I doubt this will let you run filterless, it won't do anything for .1mm sized "rocks".

[GasSavers_RoadWarrior]

Originally Posted by fumesucker

Plating ions don't much like to turn corners, the outside portions of the head are going to get a thick layer of plating while the ports are going to get very little.. One possible tactic might be to get a little plating solution yourself and fill each intake port with solution, place an electrode in the port and run the current through that way.

That's the way I was gonna tackle it. Copper sulphate if I can find it, or copper pipe and battery acid.

[samandw]

Hey, I just ran across this website today and it made me think of this thread.

http://www.polydyn.com/performance_coatings.htm

[GasSavers_RoadWarrior]

I saw the "PolyDyn Performance Oil-Shedding Coatings" there and it got me thinking of a DIYable take on the idea... so I've been looking out lipophilic coatings (oil repellants) and discovered the whole field is a bit high tech still apart from the old favorite PTFE or Teflon... which is still a bugger to apply... remember you're trying to get a non-stick coating to stick to something.

However... a method has presented itself... it appears that using a powder form, one can polish/smear or partially abrade it onto a surface to give a fairly functional film. This can be apparently be done with a polishing wheel. I'm guessing also that if you got a block of PTFE and rubbed it hard all over what you wanted it on, given a surface that wasn't mirror finished, then following that with hard application of the polishing wheel and repeating may also have the desired effect....

Now PTFE in motors has been frowned on as an oil additive because it's claimed benefit is reducing piston and bearing friction, where it's thought that the temperatures and pressure there are too much for PTFE to withstand for long... but using it on the crank throws, con rods, and parts that need to shed oil rather than keep it, would appear to be a good idea, because these parts should not be getting near as hot. I wouldn't recommend it for the piston skirts though, pistons get quite hot.

Anyhoo, seems like a straightforward method of potentially reducing windage which is a parasitic loss.

[samandw]

What I found most interesting about those coatings was this:

"PolyDyn Performance Ceramic Coatings are the most notable of the coatings. PolyDyn Ceramic Coatings are polymer composites with insulating ceramics designed to significantly reduce heat transfer and saturation. PolyDyn Ceramics are effective on cylinder heads, valve faces, intake mainiolfd, piston, headers and exhaust."

This could potentially allow higher compression ratios without detonation, if it kept the head temp and valve temps lower than uncoated.

I know Dick Miller uses these coatings on his Oldsmobile V8 builds.

[fumesucker]

Good idea on the oil shedding coatings for crank throws/rods, etc..

Does anyone know of a cheap source for suitable PTFE ?

One trick I have seen to help keep pistons cooler is to drill small holes in the big end of the con rods on either side of the center of the I beam web that go through into the bearing surface.. The result of this is a jet of oil which shoots out the hole which you have aimed at the piston crown/skirt, the oil carries away heat from the piston.



11:1 compression on 87 octane unleaded

If you can make it work though, it should boost efficiency considerably.

[fumesucker]

I found some prices on piston coatings..

$192 for anti friction coating on the skirts and thermal barrier on the dome on a set of eight pistons..

http://www.f-p-s.com/services.html

[philp100]

Fumesucker, have you considered a diesel engine swap for your ranger? Check out www.4btswaps.com. Quite a bit more work but guys are claiming some pretty impressive mpg numbers.
If you are gonna dump money into an engine I think it bears at least exploring the option.

Phil