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#15
by
vanbcguy
on 25 Feb, 2013 09:20
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I did not have the pistons coated. It's not something that I know a lot about, and decided to keep things a little more on the simple side. I am prepared to learn and spend more if it will help, though.
What can you guys tell me about piston coatings? (cost, who does them, dimensional changes, special precautions, etc)?
The coatings act as a thermal barrier, keeping the heat from combustion in the cylinder where it belongs and where it can actually do work, rather than letting it absorb in to the piston. You coat only the piston top, as that is the only area that comes in contact with the flame front.
Heat = expansion = force pushing down on the piston. Some of the heat is absorbed by the cylinder head, the cylinder walls and the piston itself - that heat is "lost" to the cooling system / oil and doesn't do any useful work. Coating the cylinder walls isn't practical, but the piston top is an easy win and helps with engine longevity as well. Less heat absorbed by the piston means more work done in the cylinder.
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#16
by
RabbitJockey
on 25 Feb, 2013 11:48
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i'd love to try an idi with ceramic coated pistons, exhaust ports, valve faces, head combustion surface, and also to ceramic coat the inside of a prechamber but only the top head part not the inconel insert. i believe the inconel needs to still be able to get hot, who knows. but u maybe just as far ahead to run a tdi since the finnish are revving them to 5500+ and making big power up there... my post became some what unrelated.
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#17
by
Jetmugg
on 25 Feb, 2013 12:17
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I know what you are talking about. The hi-tech options for engine building are all out there. For my application, I want to give myself the best shot at being competitive against the record, without getting so complex that something gets screwed up.
If I am successful with this 1.5L record attempt, my next goal would be to go after the 2.0L engine record, probably by putting a TDI or M-TDI in the same vehicle. The record in the 2.0L class is 129.xxx, a pretty far cry from the 106 mph in the 1.5L engine division.
Steve.
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#18
by
Jetmugg
on 25 Feb, 2013 12:58
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#19
by
UnderPSI
on 25 Feb, 2013 13:33
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Please do come after the record, the current record holder has a 1.5 tdi that I would love to see run but he won't bring it out until his record had been broken.
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#20
by
Jetmugg
on 25 Feb, 2013 14:31
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Fascinating. Do you know what they did to build the 1.5 TDI? I understand if you are not at liberty to discuss the details, but that would be a very interesting engine to learn about.
There's virtually no information on the web about their race vehicles, as I have never seen mention of the build details of the truck or the streamliner.
Somebody from Ohio ran against the H/DT record last year, but they must have had mechanical problems. I don't think they ever put together a run over 85 mph or so, and then there were some turnout runs.
I seriously hope that I can be competitive against their existing record. I plan to be at WOS in September, and will put my best foot forward.
Steve.
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#21
by
theman53
on 25 Feb, 2013 15:14
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I researched the friction coatings and dispite what Swaintech says the skirt film is NOT to be used as a wall clearance builder. It is to be thought of as lubrication and nothing more. The ceramic or whatever it is they put on the tops is fine and that is the coating I was thinking of. Make sure you mark the bottoms with a scratch or something as you will not be able to read the tops when you get them back.
Audi Technologies or Air Cooled Engines Plus in Tiffin Ohio does the coatings as well, but he still has my head from last April, so don't go to him until I get my head back. BTW he was around 20.00 per piston cheaper than Swaintech.
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#22
by
UnderPSI
on 25 Feb, 2013 15:16
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I can say it was put together with a mix of factory vw tdi and idi parts. The current holder only runs with the Utah salt crew.
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#23
by
theman53
on 25 Feb, 2013 15:24
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i'd love to try an idi with ceramic coated pistons, exhaust ports, valve faces, head combustion surface, and also to ceramic coat the inside of a prechamber but only the top head part not the inconel insert. i believe the inconel needs to still be able to get hot, who knows. but u maybe just as far ahead to run a tdi since the finnish are revving them to 5500+ and making big power up there... my post became some what unrelated.
The Malone engine I bumped here a few weeks ago stated that he did the inside of the precup and wouldn't do it again. He said it acted like it never warmed up and blew a bit of white smoke, LIGHTLY at idle even warm.
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#24
by
rabbid79
on 25 Feb, 2013 19:38
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My thoughts exactly - the only parts that I'm really worried about are the pre-cups. I have heard of people "peening" them in place, but don't know if that's a good idea or not.
Steve.
Please don't "peen" them. If anything, you might research "friction stir welding" in a couple of spots to see if they can be secured better that way. I know dissimilar metals can be welded this way, but not specifically inconel and aluminum.
Anyway, really cool project. I would really like to go out to Bonneville and watch you run.
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#25
by
Jetmugg
on 25 Feb, 2013 20:17
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The only friction stir welder I have ever laid eyes on is in a metallurgical research lab at the University of Missouri - Rolla. I don't know of any in common commercial use.
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#26
by
rabbid79
on 25 Feb, 2013 20:28
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I've wondered if you could put a friction stir welding bit in the chuck of a large drill press, and just stir the edge of a swirl chamber and the head together. Just thinking outside the box here.
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#27
by
alex17young
on 25 Feb, 2013 20:33
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looks like a fun build!
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#28
by
R.O.R-2.0
on 26 Feb, 2013 11:24
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Looks good but I bet they could have ported your head quite a bit more around the guides. Let us know if you dyno it. I would love to see what it makes for power.
head should have been heavily ported..
that barely looks like they did anything..
did they even blend the bowls to the valve seats?
there is LOTS to be gained from a good port job, especially on the exhaust side, and your exhaust ports look untouched..
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#29
by
theman53
on 26 Feb, 2013 13:32
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Looks good but I bet they could have ported your head quite a bit more around the guides. Let us know if you dyno it. I would love to see what it makes for power.
Especially on the intake side. The exhaust side flows pretty well stock.
head should have been heavily ported..
that barely looks like they did anything..
did they even blend the bowls to the valve seats?
there is LOTS to be gained from a good port job, especially on the exhaust side, and your exhaust ports look untouched..
