Jump to content

Rotary oil choices


bbaker480
 Share

Recommended Posts

Friday at WGI was our first weekend running an oil temp gauge on the 13B.  The engine came out of @wvumtnbkr's race winning #556 and has run its entire life on whatever name brand dinosaur squeezings were cheap at the time.  Now that we're able to see temps in the new car we're concerned that it might be prudent to run something better.  I think we want to stay away from synthetic because this engine has been run on conventional for likely it's entire life.  

Link to comment
Share on other sites

What temps are you running? Are you running a factory RX oil cooler? Has it been bypassed to prevent it from not cooling?!

 

The bearings are so big in the rotors i believe there isn't the same concern. Oil is used primarily for cooling.

 

When I raced Bridge Ported 12As I used a national brand race oil and good filters. I focused more on cooling. Only used factory coolers from RX2/3/4 cars not the poor excuse factory heat exchanger oil filter base plate type. 

Link to comment
Share on other sites

51 minutes ago, cagedruss said:

What temps are you running? Are you running a factory RX oil cooler? Has it been bypassed to prevent it from not cooling?!

 

The bearings are so big in the rotors i believe there isn't the same concern. Oil is used primarily for cooling.

 

When I raced Bridge Ported 12As I used a national brand race oil and good filters. I focused more on cooling. Only used factory coolers from RX2/3/4 cars not the poor excuse factory heat exchanger oil filter base plate type. 

Stock oil cooler from the 12a that came with the car (I believe this is the same one you are talking about that also came in the RX2/3/4).  Early in the test session we opened up the air dam to bring the water temp down from 245 to 190.  Oil temps when I was out for 40 minutes hovered right around 240 and when our faster drivers went out they saw 270 which I think is still in the acceptable range.  

Link to comment
Share on other sites

Ok, Google how to by pass RX2 oil cooler and then check yours to see if it has been done. I can't remember how to do it. Where the hoses go in to the cooler the is a spring. Something about the spring or something. Been a long time so I'm not gonna guess. 

 

270 way to high. Oil should be no more that 20 degrees more. 

 

Sounds like either cooler is plugged or it's bypassing. 

Edited by cagedruss
Link to comment
Share on other sites

As a suggestion, maybe try to build some ducting to force more air to the cooler as well as checking for plugged or bypassed oil cooler.  Lots of the folks using the rotary say try to keep oil temp below 225 F.

 

I had oil temps getting up to 220 on my non chump car, and I added a small piece of aluminum to deflect more air through the cooler.  The temps dropped to about 200-205.   A bit of ducting goes a long way.

Link to comment
Share on other sites

1 hour ago, Al36rx7 said:

As a suggestion, maybe try to build some ducting to force more air to the cooler as well as checking for plugged or bypassed oil cooler.  Lots of the folks using the rotary say try to keep oil temp below 225 F.

 

I had oil temps getting up to 220 on my non chump car, and I added a small piece of aluminum to deflect more air through the cooler.  The temps dropped to about 200-205.   A bit of ducting goes a long way.

The "undertray" we made at WGI in the pits helped dramatically with water temps and was installed along with making the air dam opening bigger.  I did some digging over the weekend and did not find any clear instructions to check the bypass in the cooler to make sure it's not stuck open.  I do have the option of swapping coolers, the spare parts package that came with the car was pretty robust (thanks @wvumtnbkr) so that may be an option as well but we wouldn't be able to test until Friday practice at Nelson Ledges.  I'd much prefer to fix a potential issue permanently than swap in what may be another faulty cooler.  

  • Like 1
Link to comment
Share on other sites

We can easily check the bypass device on the oil cooler.  While we are in there, lets flush it and see whats going on.  We still need to develop a better undertray for your car as well.   lets make sure the oil cooler is getting good airflow.

 

I would LOVE to have had past data regarding the oil temps in the engine over the last 5 years.... 

Link to comment
Share on other sites

  • 2 weeks later...

There is an RX7 technical race manual that recommends how to mount the oil coolers for racing applications. Depending on what type of front end you are running - it can be counter-intuitive. 

 

We run 2 in series (we had a lot of debate over series vs parallel etc) and our oil temps stay right in the normal operating range. 270 is cooking if its real. 

Link to comment
Share on other sites

This is the undertray I have built to close off the area between the air dam and the radiator/oil cooler. I'm considering putting a divider in above the oil cooler to force more airflow through the cooler. We're going to take a look at the bypass this weekend while we fix a leak in one of the cooler lines.  I also switched from dinosaur squeezings to Royal Purple 40wt. 

 

Don't worry about the self tap screws, they were just for mock up, I'll be riveting everything tonight. 

20180606_205907.thumb.jpg.0cc8fe18d2a47cf1947a9ec469bec585.jpg

Link to comment
Share on other sites

All the things about good airflow and cooler placement apply, but if you start making power you will have no choice but to add a second oil cooler, all of the faster 13B cars like E Prod run 2 coolers. I couldn’t get my oil temps down below 250 until I added the second one, if you do add a second oil cooler make sure you add it in parallel.

 

I always remove the bypass thermostat from my oil coolers, it is located under the big plug that you see on the top of the front cooler in my pic. Once you remove the thermostat assembly you will see an 8mm hole in the divider between the inlet and outlet half of the side tanks. What I do is to use a short M8 button head screw, copper crush washers on both sides, and a mechanical locknut to close up that hole and never have to worry about the thermostat failing again.

 

I use Mobil1 15W50 in my car. It seems to work well, is relatively cheap, and available at every Walmart in the country.

IMG_20161005_202552~01.jpg

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...