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Well, the oil I would have sent would have been full of bearing material, lol. Also I had no idea what it was.

The miata is getting a replacement motor and I was just trying to figure out what kind of oil I wanted to run in it.



Thanks for the info there, I drained the transmission fluid also, so I needed to replace it with something and will look at getting one of those.

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2017 Autocross Chief of Tech

2000 E Street Miata
2015 Focus SE EcoBoost 6 speed
2015 Fiesta ST (Wife's ride)
2012 Yamaha FZ1 sorta crotch rocket? All I know is 150HP and 487 lbs is fun!

We used to have a lot of oil-related failures in the Duff car. After about 6-7 hours the bottom end would come apart. That happened several times. I was talking to Chuck Hawks about it at an event at CMP, and he asked what my oil temps were, so I told him I had no idea. He told me that I really needed to know that, and that above about 250 degrees, oil degrades much more quickly than it does below 250. I put a gauge in the car and we hit 250 in less than 20 minutes of driving and it was still climbing. I backed off so it stayed below 250, and then basically took a cooldown lap for every 4-5 regular laps. Since then we have switched to Amsoil Dominator 15W-50 Pure Unicorn Oil and put the biggest oil cooler that we can fit on the car. Now our oil temps don't exceed 230, even on a hot day, and are generally lower. It's $9.60/quart, which is a little more than non-unicorn based oils, but probably costs us about $5/day more than regular oil, which I can live with. Our last race motor lasted for 19 events, including two 24-hour events, and the eventual failure was not oil-related.

For a track-day car, I'd say put oil temp/pressure gauges in it and keep it under 250 degrees, then use something decent. We like the Amsoil, and have not had an oil-related failure since using it, but I think that the most important thing is temperature.

For transmissions, we use the 5W-30 Amsoil Manual Synchromesh oil. I've been using that stuff for over ten years and my transmissions have worked very well.

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"Every ship is a minesweeper, once."

Considering the failure of 3 of 4 rod bearings in the motor that came out of my Miata, I honestly wouldn't put it past oil breakdown being an issue.

The Camaro would hit 280 by the end of a session, it only had a oil warmer/heat exchanger setup which i'm sure helped a little bit, but not much. I'll likely put an oil cooler on the Miata at some point as well, I just can't imagine with only 4 quarts that oil is staying very cool. Installing an oil cooler really isn't that much trouble and it will only be extra insurance against oil degradation.

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2017 Autocross Chief of Tech

2000 E Street Miata
2015 Focus SE EcoBoost 6 speed
2015 Fiesta ST (Wife's ride)
2012 Yamaha FZ1 sorta crotch rocket? All I know is 150HP and 487 lbs is fun!

Rod bearings are what always failed in the Duff car. The bearing journals on a Honda single-cam crank are small though, smaller than on a dual-cam Honda motor, so I think that there is a lot of stress on a relatively small surface area in a single-cam motor that makes it particularly vulnerable.

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"Every ship is a minesweeper, once."

I'm still amazed at how many people race cars without basic telemetry. Anyone who's ever tracked a car knows the stock gauges are useless. On my Z-24 I found that when the OE water temp gauge read just a tick over 195, the actual temp was over 230. On our race car we have gauges for water temp, oil temp, oil pressure, and voltage.

Regarding oil temps, we ran three races last year and are consistently in the 260-280 range. We have thought about adding an oil cooler, but it's adding another point of failure. Also the hoses will have to be 6 feet long to get from a sandwich plate, around the engine, to the front opening and back.

We have been told that Rotella T-Syn is good to 300 degrees, but I'm not sure how good that information is because I'm not aware of that figure actually being published by Shell Oil. We do change the oil every race, and the transmission fluid (we run Pennzoil Synchromesh) every other race.

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Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

We now have oil temp, oil pressure, and water temp gauges. I'd consider that a minimum. This year we're going to all electronic stepper-motor gauges with separate programmable warning strobes, and adding a wideband gauge after our piston failure last year.

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"Every ship is a minesweeper, once."

Another thing for your endurance guys to look at is a water pressure sensor. It's a really good way to prevent overheating a motor due to something breaking in the cooling system. All you really need is an idiot light for when the pressure gets too low.

I was actually thinking about using the coolant air bubble sensor from an FD in an inline housing like the one that I use for the aftermarket water temp sensor. That would tell me if I was losing coolant.

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"Every ship is a minesweeper, once."

Already have one, same for low oil pressure light. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S