full groove main/roadrace

[BILL-C]

Bill I have no business telling a veteran engine builder like your self how to build engines. Looking at your web sight and pictures of cars you build engines for your shop and clientele far exceeds any shop I ever had. I am sure you are aware and use accusump, dry sump oil systems and any parts and means available to keep oil at the oil pump pick up. But there are always maniacs who will defy the odds and tear stuff up.
Keep up the good work and keep looking for solutions.

Dry sump systems and accusumps are not legal in spec Miata. In many other classes a dry sump system will cost you enough "points" to tempt the customers to stay with the stock oil pan with all the tricks inside. These are the ones that wear us out.

[jed]

So are you saying your having bearing issues with the SCCA spec Miata engines??

[BILL-C]

So are you saying your having bearing issues with the SCCA spec Miata engines??

One of my customers has a few of them that he assembles ,maintains.and rents out. He and his drivers are fast and have issues sometimes.

[pamotorman]

take a look at a chevy race block and you will see a groove in the bearing saddle in the block. it has 4 more holes in the bearing insert fed by this block groove

[jed]

Bill I to had a customer that maintained and transported cars to the race track. He stored and maintained 15 to 25 cars at one time. He had a large enclosed transporter that he could put 6 cars in with tires and all the other stuff. Several of his cars/drivers were serious
About qualifying for the SCCA nationals held at a Road Atlanta once a year. I said that to say that the cars were driven hard but not abused.
From my perespective and experience with Miata engines if you are Delivering the short blocks that have been “blue printed” meaning
With the all clearances checked and are having bearing problems you need to look at the assembler. What could he be doing wrong I
Have no idea. Miata lower ends are pretty simple and basic. I just looked at the oil pan it has good baffling to keep oil at the pickup. It has a good windage tray, pick up an oil pump. The oil pump does have powered metal gears. I have only see 2 pumps with broken gears.
Steel gears are availed. Wish I could help. Look hard at the assembler he is over looking something.

[dannobee]

It is my understanding from the autocross people is that the stock pan lacks baffling to combat oil movement when braking. The oil pressure light will come on when braking hard during cornering. A trap door in the pan minimizes the oil slosh going forward.

[jed]

Miata factory oil pans are as good as they get. Google 1800 Miata oil pans and you can see lots of pictures of Miata oil pans, windage trays and pick ups. If your autocross people were talking about stock oil pans they aren’t talking about 1800 Miata. https://www.atkinsrotary.com/store/imag ... etail1.jpg

[hoffman900]

It is my understanding from the autocross people is that the stock pan lacks baffling to combat oil movement when braking. The oil pressure light will come on when braking hard during cornering. A trap door in the pan minimizes the oil slosh going forward.

Autocrossing is way more violent in terms of direction change than road racing... though a curb happy driver (which you need to be to be fast) will bump things around.

[engineguyBill]

Fully grooved main bearings are not a good choice for any performance engine application. Best design is the long-time proven 180 degree oil groove, which facilitates the formation of a wedge of oil between the crank journal and bearing shell ID.

[tuffxf]

Blanket statements like this send people down the wrong path
Some types of engines require a fully grooved bearing to survive in a performance application due to other design limitations.
And have have a look at say a Kawasaki zx14 or Suzuki hayabusa,
More hp/cube than most engines out there and fully grooved from the factory
Cheers

[dannobee]

1800 Miatas are exactly what they were talking about. If you look closely, there's no baffling to keep the oil from sloshing forward on braking. There are a couple of bolt-in baffle kits available that help fix this issue. True about autocross probably being more violent than "regular" road racing, but I doubt the average g-forces are much different.

I seriously doubt that they were all lying when they said that the oil pressure light would come on on hard braking though.

[BILL-C]

Miata factory oil pans are as good as they get. Google 1800 Miata oil pans and you can see lots of pictures of Miata oil pans, windage trays and pick ups. If your autocross people were talking about stock oil pans they aren’t talking about 1800 Miata. https://www.atkinsrotary.com/store/imag ... etail1.jpg

Notice that none of the baffles are sealed like you would see on an aftermarket race pan with trap doors. The stock Miata pan is very far from as good as it gets. Those factory vanes on bottom of pan are just a slight roadblock to the oil trying to get away from pickup. Many of our customers run endurance events and many times the fastest driver does the last stint. If you have leaked or consumed even the slightest bit of oil after 12 hrs of racing that adds to problem.

[jed]

Come on guys if the pan is the problem “fix” it. If there are kits available put one in. The pans are aluminum, mill out the problem areas and add all the trap doors necessary to fix the problem. Don’t worry about modifying the inside of the pan. SCCA doesn’t tear down winners on regional races and I don’t think at divisional races either. Only national races.
Who holds or puts on these 12 hour endurance races and I guess you can’t modify the oil pans. Are the winners torn down?? Where are they held and when?
I’ll have to make some phone calls and catch up.
It nice to here that Miata’s are popular again. Their popularity was going away back about 2010ish. Don’t remember why.
It was hard for me to drive them at 6.2” and size 14 shoe.