Apparently a very dirty laboratory. :)

--Ian

Well they do testing for coal samples for the mining industry, this is one of their dirtier scales. It gets calibrated every year so I don't see that implies that it works any differently than a "clean" scale. ;)

I've used the Dart DC2 coating and it still remained perfect after 7k of serious abuse.

And as for the machining burrs - I've got 3 sets of Supertechs here and none of them look like yours.

Although I doubt this - but I'm curious as to weather or not they tried to clean out some of the coating that might have made it's way into places it shouldn't have been?

Bump from the dead,

I hate threads with "incomplete endings" so I'll try not to do the same here.

Everything has been buttoned up on the engine, been doing break-in for the past week or so. Unfortunately my oil pressure sensor kept leaking and I was pulling my hair out why, turns out BSPP threads need to bottom out to seal (doh!).

Did a bit of street tuning, so far I've pulled to 5000rpm. Still need to break it in a little longer to be safe before I raise the RPM limit. "Off" boost response is really good with the higher CR this year. I say "OFF" because I'm Rotrex'd and as such I'm boosting so long as I'm on throttle.

Hot oil pressure at idle is about 30psi, no piston slap during cold idle. Engine has a bit of a rumble to it now with the built head.

I'll be updating with some videos as it gets closer to dyno tune time.


FAB, if your last comment is related to the burrs there, they definitely weren't there as a result of any sort of "cleanup". The material looked the same as the base material of the underside of the pistons so its been fairly uniform. These are cheap pistons though so I'm not really complaining, just a little surprised something so basic would slip past QA/QC.

If that comment wasn't related to the burrs; I doubt they do any cleanup or need to. Looks like a fairly uniform masked line for where they've sprayed the ceramic coating on. Theres nothing in the path of of the rings or anything that would contact the cylinder walls.

Where did you get that supertech pistons smooth down?

What did you use for piston to wall clearance on your setup?

Using oil squirters or no?

Do you burn any oil? If so how much?

Sorry for so many questions, but I'm going to start my build soon and I'm trying to get as much info as possible to get it dialed in correctly.

The oil pressure sensor threads are bspt, not bspp. You have to use a sealant on the threads and the sensor should not bottom out.

Did you guys removed oil squirters or jets with coated pistons ? I'm thinking sending mine for coating too and getting rid of the squirters on the NB track car since the engine is in parts right now.

^^^ What are the benefits of removing the oil squirters?
Seems to me like you're eliminating some of the protective piston cooling by doing that.

Power and less cylinder wash. I don't need piston cooling on N/A track car. I think Bob removed them on his 300+ WHP turbo toy too...

Bob said his oil ran cooler without them. I say, of course it did. But the pistons are hotter because the oil isn't cooling them. If the oil was carrying the heat away from the pistons and out to the oil cooler, then the oil would be a little hotter.

The engine makes more power because the extra little bit of weight of oil on the underside of the pistons and being splattered on the cylinder walls creates a little bit more drag and resistance to movement.

Correct - I think a common misunderstanding is that most people think oil has one job, lubrication. It's actually responsible for +/- 40% of engine cooling.

Lubrication, cooling and cleaning. True race oil that's changed after every weekend doesn't include detergents so more of its volume can be used for the other two jobs.

As long as it doesn't get too hot, higher combustion temps will increase power. Doubt it's from oil weight on the bottom of the piston and "drag" from a slippery substance used for lubricant.

Crank scrapers make horsepower
by removing excess oil from the crank.

Different concept and only effective on motors where the crank counterweights touch the oil-unlike the BP.

For the burrs I used a a dremel tool and some sand paper, not much to it just making sure not to take off any excess material.

I am running 0.0023" PTW measured after coating, coating is at a maximum thickness of 0.0005"-0.001".

No oil burnt, car does not consume any oil.


I'm going to have to argue this one... The threads are definitely BSPP if you look at the OEM oil pressure sender the threads do not taper.

I have my oil squirters removed, the theory was that oil pressure should be more stable without them. This seems to be true so far with the datalogs from 3 track events so far.

If you look at the piston design, it does not utilize the oil squirters. Bob Bundy has a thread somewhere on here that discusses this. I actually took some photos of the OEM pistons which shows how the oil squirters work. Will need to dig around for them.

Less likely to do with "power and cylinder wash, more to do with "its not needed". As mentioned above the oil squirters do not work with Supertech's piston design.

Possibly true. Oil squirters would still spray oil in the general direction of the bottom of the piston, however with ceramic coating hard to say how effective this is as there is already a thermal resistance between the piston material and the area of combustion.

Raisin, I was actually talking about top of pistons. Around edge of the intake valves. Did you smooth them out yourself or did you get that done else where?

Are you planning on staying n/a?

No pressure lubricated automotive engines are designed to have the counterweights touch the oil in the sump. A Briggs and Stratton lawnmower engine is splash lubricated but that doesn't have an oil pump. The purpose of a crank scraper is to remove excess oil from the rotating crankshaft, both from the counterweights and the rod ends. Excess oil causes drag, increases rotating mass, and can disturb the balance of the engine.


What is a crank scraper

Nothing is touched except cleaning the burrs. Supertechs came and were shipped out as is to Calico shortly after.

To answer your question earlier that I missed: I'm not running oil squirters.

Car is currently running a Rotrex since day one.

Thanks for answering my questions, I'm starting a build soon and I just wanted to get info from people that already completed successful ones.

I was talking about this but supertech design must be different depending on the CR.
https://www.miataturbo.net/attachmen...s-piston-1-jpg