When I swapped in a crate motor two seasons ago (i think it was a 1999 or perhaps 2001) I noticed that it didn't have the same pan/windage tray as the 2004 motor that I took out. The later model tray seemed to have more structure to it. I figured it was to help saddle the mains, so I swapped the late model pan/tray into the 2001.

I am now in the process of refreshing the two motors. My goal is to have 2 completed longblocks. I am unsure I need to look for a second late model pan/tray to complete my spare motor.

Is there any consensus as to if these later model pans/trays are needed in a moderate boost /track application?

 

Edit: I apparently have no idea what I'm talking about. Carry on.

 

The MBSP (main bearing support plate) appears to be designed to help support the mains, but there's at least one case of someone (Savington) blowing out a main cap while using the stock bolts and the MBSP. So there's probably a case to be made for running it *and* ARP studs (which requires modifying the MBSP to fit), but it's not a substitute for the studs.

I didn't bother on my motor.

Note that the oil pan is different to accommodate the MBSP, so you need to source one of those too if you want to add it.

--Ian

 

Great. I'll just run with the old style tray/pan. It sounds that it would work easier with the ARP studs. Thx for the tip.

 

not worth the hassle
better to get arp mains like Ian said

 

I run both. Not that I know if the tray actually makes any difference. The tray will require some grinding for the studs.

 

MBSP did me no favors. I much prefer the 99 pan since it takes no work to make the ARP studs fit. ARP mains are just as important as forged rods in a built BP, IMO.

It's important that you run a matching pan/windage tray, since the pans are machined differently. The front/rear seals are also slightly different between the two pans, a detail that few aftermarket seal companies have picked up on.

 

I went the late windage and oil pan with arp hardware route on my current motor and spare motor, modified the windage tray to clear the studs and taller nuts, no problems so far
Drilled holes on the windage tray to clear the studs and taller nuts

 

Are there different part numbers from Mazda? Now I need to check which I ordered.

 

Answered my own question

1997 (no MBSP):
B6F410427
B6F410428

2002 (MBSP):
B54110427
B54110428

 

B6F4 is 94-00, B541 is 01-05. Ain't nobody got time for 90-93

 

at what point would you say that main studs are needed?

 

IMO, if you open the motor, they should go in. I broke my OEM main bolt rapidly at 300whp, which means you should install them at 250. IOW, if you are buying rods, you should be buying main studs.

The motor in Rover right now is a bare-bones build, what I would call a "stage 1" shortblock. OEM oil pump and pistons, but rods and ARP mains.

 

Pretty sure the MBSP/oilpan combo require a different dipstick. The full mark is in a different spot on the stick.

 

Ah crap. Can anyone confirm this? I had 2 motors, one MBSP and non MBSP, and I only have one dip stick in the garage...

 

Are you the one dipstick in your garage?

 

Easy enough. Assemble the motor on the stand, put 3.8 quarts (or whatever the spec is) in it through the dipstick hole, insert dipstick, mark level.

(edit, you can probably do that with the pan sitting on the ground, actually)

--Ian

 

I thought as long as the dipstick matches the tube to which it belongs it's otherwise interchangeable between pans.

 

Miatamecca shows both the tube and stick as 99-05. I haven't searched part numbers.

99-00 dip stick: BP4W-10-450
01-05 dip stick: BP4W-10-450

According to the Priority Mazda Parts store.

 

AFAIK this is correct. The pan height change is miniscule (we're talking the thickness of the windage tray, so ~.040" or so), not nearly enough to require a change to the dipstick. AFAIK the only unique dipstick is from the 99 CA-spec cars, which got a different dipstick and matching tube.