anyone running ceramic coated pistons?
ceramic coated pistons?
- Thread starter sodafeld1
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I used cerakote brand heat reflective coating on the piston crowns and cerakote brand antifriction cote on the skirts/sides of the pistons in my turbocharged 3B. They sell 4 oz sample bottles for about $35. It's enough to do at least 20 pistons. I brushed it on and baked it the pistons in the oven to cure. I cannot remember if I sandblasted the surface of the pistons or not.
My 3B is turbocharged and has been overheated more than once by previous owner and is on it's 3rd(at least) cylinder head. Old pistons finally gave out running it a bit hot last summer(cracked rings). I did a "in frame rebuild" (remove head and oil pan, hone with electric drill and flex hone and replace pistons, rings, rod bearings only). Piston to bore clearance much as .006" due to heavy use of flex hone required to remove light scoring. Piston ring end clearance increased to 2/3's of the way between minimum and maximum acceptable in 3B manual in order to allow for high heat expansion due to non-factory turbo.(upon recomendation from another Mud member that too tight ring end gap causes them to crack when too hot). Cheap from China $140 piston set off ebay was coated with cerakote at home.
About 8000 miles on the engine so far and just got back from a 800 mile road trip going accross mountains with speeds mostly 65-72mph and EGT's peaking on hills at over 720C(I back off if I can't crest the hill before 735). It's still running fine.
Tests on Youtube show if you hold a blow torch to the piston crown of a uncoated and coated piston for the same length of time while measuring temp on the bottom of the piston the coated piston will be 20-30 degrees cooler..............Not much difference, but when you know you do have a problem with high combustion chamber heat a few small improvements(coatings and extra clearance for heat expansion) can give you a little buffer that prevents damage from those occassions you aren't paying attention to EGT's on your diesel with increased fueling.........................The difference is not much and it is no miracle shield for your pistons. You can't reliably say: "I can run 50 degree hotter EGT's for extended periods with no consequence because my pistons are coated". At $35+- for a sample bottle and brushing it on/curing it yourself it's cheap insurance. I couldn't justify paying $100+ to have it the pistons proffessionaly coated for my purpose and I have no reason to believe it would be any better in effectiveness than brush on(what difference other than cosmetic?)
My 3B is turbocharged and has been overheated more than once by previous owner and is on it's 3rd(at least) cylinder head. Old pistons finally gave out running it a bit hot last summer(cracked rings). I did a "in frame rebuild" (remove head and oil pan, hone with electric drill and flex hone and replace pistons, rings, rod bearings only). Piston to bore clearance much as .006" due to heavy use of flex hone required to remove light scoring. Piston ring end clearance increased to 2/3's of the way between minimum and maximum acceptable in 3B manual in order to allow for high heat expansion due to non-factory turbo.(upon recomendation from another Mud member that too tight ring end gap causes them to crack when too hot). Cheap from China $140 piston set off ebay was coated with cerakote at home.
About 8000 miles on the engine so far and just got back from a 800 mile road trip going accross mountains with speeds mostly 65-72mph and EGT's peaking on hills at over 720C(I back off if I can't crest the hill before 735). It's still running fine.
Tests on Youtube show if you hold a blow torch to the piston crown of a uncoated and coated piston for the same length of time while measuring temp on the bottom of the piston the coated piston will be 20-30 degrees cooler..............Not much difference, but when you know you do have a problem with high combustion chamber heat a few small improvements(coatings and extra clearance for heat expansion) can give you a little buffer that prevents damage from those occassions you aren't paying attention to EGT's on your diesel with increased fueling.........................The difference is not much and it is no miracle shield for your pistons. You can't reliably say: "I can run 50 degree hotter EGT's for extended periods with no consequence because my pistons are coated". At $35+- for a sample bottle and brushing it on/curing it yourself it's cheap insurance. I couldn't justify paying $100+ to have it the pistons proffessionaly coated for my purpose and I have no reason to believe it would be any better in effectiveness than brush on(what difference other than cosmetic?)
I had some 3B pistons coated, but I haven't had the chance to run them yet. I did extensive research and they are commonly used in very high performance applications. I have a colleague that swears by doing it. I don't think they are specifically needed or will protect from abusive over heats, but I do think it is a reasonable thing to do to help things run better and last longer.
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- Thread starter
- #4
Really Thanks very much for the replies. I see a future in ceramic components in engines, but, it still is in early development I think. 8000 miles is not bad. And intrepidly brave, like an astronaut. I would be using an endoscope to monitor the wear on the piston surface through the precombustion chamber periodically. can get a bluetooth 5mm endo on amaz for $50aud.
Personally not interested in putting a turbo on my 2h, I just chug along. Most interested in engine longevity. It is common for a stock 2h well maintained to live a life between 600-800000km. This is without ceramic coating. Alfin pistons have been around for awhile and looks fairly unanimous that they are long lasting.
I have a bit of a background in ceramic tec, I like the stuff. Such as Zirconium is really hard stuff which can handle thermal heat transfer very well. I think the weak spot in all ceramic coatings is the adhesive or bonding mechanism. The adhesive certainly is not prooven for 600-800000kms.
Glass can be baked to steel by enamelling, hard but brittle. Ceramic bonding to aluminium alloys have very different expansion ranges.
One can get ceramic coated pistons ready to go in Oz for an extra $35aud per piston. I am very tempted, there is much research being done. The nature of thermal ceramic has great potential for the action spot of the top of a cylinder. But I am yet to see a bonding mechanism which is long lasting. I think eventually a castable semi rigid but flexible ceramic composite which is baked shall be developed. That way the thermal qualities are maintained throughout the whole piston, one piece.
Ceramic coatings are used on manifolds and exhaust systems, it looks great and smooth, works brilliantly, but I have only seen them abrade off in time..
It is really interesting stuff and part of the future for better thermal qualities, hard wearing components.
Thanks guys.
Personally not interested in putting a turbo on my 2h, I just chug along. Most interested in engine longevity. It is common for a stock 2h well maintained to live a life between 600-800000km. This is without ceramic coating. Alfin pistons have been around for awhile and looks fairly unanimous that they are long lasting.
I have a bit of a background in ceramic tec, I like the stuff. Such as Zirconium is really hard stuff which can handle thermal heat transfer very well. I think the weak spot in all ceramic coatings is the adhesive or bonding mechanism. The adhesive certainly is not prooven for 600-800000kms.
Glass can be baked to steel by enamelling, hard but brittle. Ceramic bonding to aluminium alloys have very different expansion ranges.
One can get ceramic coated pistons ready to go in Oz for an extra $35aud per piston. I am very tempted, there is much research being done. The nature of thermal ceramic has great potential for the action spot of the top of a cylinder. But I am yet to see a bonding mechanism which is long lasting. I think eventually a castable semi rigid but flexible ceramic composite which is baked shall be developed. That way the thermal qualities are maintained throughout the whole piston, one piece.
Ceramic coatings are used on manifolds and exhaust systems, it looks great and smooth, works brilliantly, but I have only seen them abrade off in time..
It is really interesting stuff and part of the future for better thermal qualities, hard wearing components.
Thanks guys.
Consider this point, the coating helps a little bit, but is rather expensive compared to the material cost of the component if you are a factory building the engines. The manufacturer only needs to make engines that last reasonably well as expected. They do need to sell new vehicles new parts and service through their dealerships when things break and wear out....,...... The coatings are desirable in the hopes that they help people obtain reasonable longevity from engines that are abused and pushed beyond their designed limits. At this point not cost-effective for an oem.
- Thread starter
- #6
yeah your right. manufacturers well realise that it is not in their best interest to build something which shall lasts longer than 7 years.
