Lots of people have been seeing my progress with Sumebore testing and development on Facebook. If you want to follow along, I make frequent posts on the Raby's Aircooled Technology FB page.

Porsche first used SUMEbore with the 918 Spyder, providing added durability over Alusil and Lokasil. The SUMEbore coating is applied only .004” thick, just like Nikasil. However, it is applied using a high temperature spray on process that fuses the coating to the aluminum bore in a process that is much more environmentally friendly than plating.

These coatings has excellent heat transfer, avoiding the pitfalls of iron sleeves, and offers reduced drag, improving efficiency. Iron is alloyed with other compounds, including ceramics, providing excellent durability over traditional steel liners. Another big difference is that SUMEbore coated cylinders do not receive a crosshatch during honing. They are honed to a mirror finish. Crosshatch is not required for oil retention as the coating has microscopic pores that hold oil.

Other manufacturers similarly have used SUMEbore and other APS and PTWA cylinder bore coatings on their aluminum engine blocks for high performance engines, like those found in the Nissan GT-R and Ford Shelby GT500, in place of Nikasil coatings, so we figured why not try it on an Aircooled engine?

We currently have a 1999 Boxster with a 3.2 engine built to 3.8 using SUMEbore on the road and are excited to be testing SUMEbore coated Nickies the current engine I have pictured here, which is ready for the dyno for round 1 of testing.

If you want to learn more about this family of cylinder coatings, check out this article from the AERA on mirror bore coatings:

http://www.engineprofessional.com/articles..._Tvvo_vpims_jjs

How we are using the T4 to advance this development:
I re- purposed an old 914 2.0 SCCA engine that we’ve had laying around to use as the test bed for the first “Sumebore” cylinder test engine.

In these tests we are comparing proven Nikisil cylinder plating to that of Sumebore to compare directly back to back. In round one I have built the test engine 1/2 Sumebore and 1/2 Nikisil and have optimized piston ring packs, ring gaps, and ring tensions. In round 2 and 3 we will compare output, data log blowby, log CHT and perform used oil analysis for wear metals, fuel intrusion, and viscosity loss.

This is a joint effort between Raby’s Aircooled Technology, LN Engineering, and Total Seal Piston rings to advance cylinder technology well into the future without fear of environmental challenges limiting engine longevity and power output. Nikisil is well proven, but requires acids and other hazardous materials to be performed correctly. In the future we believe this will make a big impact on all aircooled Porsche engines, including those that had factory Nikisil cylinders. We are performing this work at least a decade before we “have” to... Put simply, using Sumebore with this old 914 engine is a way that we’ve made some history.

We already have water cooled Porsche M9X engines using Sumebore, so using the simplicity of the aircooled engine made sense for this direct comparison. The T4 allows changes to be made in a fraction of time that the watercooled engine requires. Between components being made, and some practices being put in place, we can perform a cylinder change on the dyno in less than 45 minutes. Note there’s no sealant on the cylinders, and that the engine uses a Teflon buttons instead of piston pin clips.

All of this makes things happen fast, for one factor at a time practical application testing to be done. This has been a huge endeavor, with a budget that is shocking. It’s nice to have the support of the Oak Ridge National Laboratories as another tool in the toolbox making this happen.

Everything with this is about consistency, and being able to make fast changes to the cylinders, or even a fast internal repair should something fail during endurance testing. The choice of sealant, specs and etc are all major considerations. We even used the same bore size with this T4 as we have the water-cooled Sumebore engine, and also retained the same ring tensions and ring packs. The test engine ends up as a 71x101.6 just over 2.3L, and will make a solid 190HP over a period of weeks while being punished. All the parts here are used, except the cylinders, position rings and etc. This is a true "Mule motor" that will have the snot beat out of it.

The choice of cooling system is also for ease and speed when changing cylinders. I can remove one strap on the OTT and leave the fan in place. The drive can also stay in place, and the upper plenums popped off.. I can have the cylinder head off in less than 7 minutes, cylinder off in 3 minutes, and parts swapped and back together in less than 30 minutes.

When people ask me "are you still building, and developing 914 engines?" I just have to laugh.. Hell, the biggest developments to hit the Porsche aftermarket in the last 20 years are being tested right now, and I am using a 914 engine to do it! We have already learned a ton!
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Here's a few more pics

Jake, you should include pictures of the engine you are using for this test. AL woops you beat me to it!

Will you be comparing the frictional losses?

Yes, but that comes later. Right now it's all about development of a ring package, skirt clearance, and break in oil/ regimen. The first test will only be 1 hour, then we will pull it apart to read the rings and cylinders.

We have nothing to start with. Its a perfectly clean piece of paper.. We also have no one to really ask... Oak Ridge gave us something to start from, but that's about it.

That's amazing and I appreciate that you are constantly pushing the boundaries to keep our P-cars running and running stronger than ever. Keep up the excellent, leading-edge work.

Thanks for sharing Jake, I might have to go back toa Type IV if the price of these cars keeps going up.

By the way I know we have at least one ORNL employee on the board here and a few that work at sister laboratories.

In this case, the T4 is being used to advance other Porsche engines, primarily. The T4 will end up benefiting from this, but due to cost it likely will be the last engine that sees this mainstream.

I'll have to proprietary on this for a while, and we'll be the only ones that know how the hell to make it work. Development has it's benefits :-)

I just think it's cool to be using a 50+ year old engine design to work out the development for engines that are generations newer, and having cylinder failures left and right due to Lokasil, and Alusil factory cylinders.

This is really cool, and I can't wait to read as the testing progresses. wow.

As always, respect Mr. Jake Raby! Watching this with great interest!

Ian Stott
Moncton
Canada

Sweet ! Makes me happy that old school tech is able to be used for the base of forward advances.

thanks for sharing this with us Jake!. hopefully this will be in production use by the time i get around to rebuilding my stock 2.0 motor which i think will have to happen in the next 2 years or so .

Please keep us posted with update on this going forward.

Phil

Its hard to say.. We have a long way to go. If this works, the tooling to perform the work at LN will be insanely expensive.

This is being done for a time way in the future, when Nikisil will go away due to environmental issues.

I have already achieved some insane milestones from this testing, and comparison... Even before the engine has ever fired up.

I worked for sulzer/metco many years ago when SUME coating was first being developed and implemented in industry. I can tell you with certainty it is about the best plasma spray tungsten carbide coating available.

What makes it so good isn't that it's so revolutionary, but is engineered to the Nth degree from metallurgical application to technique to temperature and flow control.

It also wasn't cheeep or fast, but maybe they've improved on that since I was dealing with it.

Where do you get the teflon wrist pin buttons for the T4?

We had to machine them for the testing. This may lead to a new product to accompany Nickies. I am definitely going to be using them on all my future builds, and LN may want to catalog them.

@getoffmylawn
What I have noted already is pretty amazing.
The process still isn't cheap, but it can be done in house at LN, once we get this all developed.