GtoRx7

iTrader: (5)

This is not going to be the most comprehensive write-up ever, but it should make things alot clearer for most. Information on how to do the Rotary drysump conversion is surprisingly next to zero. This is how we do it. Its what I have learned from trial and error, and talking with some very knowledgeable race rotary builders such as Carlos Lopez.


First off. The basics. How does a drysump even work??

Well, here is my okay picture that shows the path of oil in a rotary drysump.



A) It all starts with the rotary engine
B) Oil that flows out from the engine, gets sucked up from the two scavenge tubes.
C) The scavenge pump (backside pump) pumps the oil at low pressure, out to a drysump tank.
D) This is the drysump tank. They can be anywhere from 1-5 gallons in capacity. Here the oil is stored, and air separation occurs.
E) The oil then is GRAVITY fed to the high pressure pump. It MUST be a gravity feed, and they are very very picky about how perfect this is.
F) The high pressure pump takes the oil up to 115+ psi, pushing it through the oil coolers.
G) Then, it will pass through the oil filter, and into the engine. Nice, cool, clean high pressure oil.
H) Any vapors, and pressure changes are taken in by the breather tank.

Now that we understand the system, lets start seeing how its installed. Locate your drysump front cover





Put the cover on your dummy engine. If the engine is assembled, the modifications cannot be done.



First you will need to cut out all the leg supports on the exhaust side of the engine. The scavenge tube will need this room to fit in. The picture shows where they will need to be cut out.



For the 3-rotor guys only. Mazdaspeed DOES NOT sell the 20b scavenge tubes. You must cut, and lengthen each tube by 6" with the proper stainless tube size. This pic shows where it was cut and rewelded for 20b use.



Once you do those modifications to the engine block, lay the tubes back in. You will see the short side scavenge tube will lay perfectly flat on the casting. Use a center punch to mark the dead center. Then drill and tap to a M6x 1.0



Now on the long tube, slide the bracket down, and mark a spot on the aluminum housing with a center punch. Drill and tap to a M6x1.0

Once these mods are completed, clean everything perfectly. Once the short block is assembled, install the drysump front cover.



Then place the super crazy expensive oil o-ring ($34.00 each) on the scavenge tube.
Make sure to use alot of lube, and slide it in carefully, making sure not to tear it.



Once the tubes are in and bolted down, slide the screens on the ends of the scavenge tubes. Then secure with mechanics wire, to make sure they will stay in place.



The tubes should look something like this. Then add your RTV on the engine.

GtoRx7

iTrader: (5)

Make SURE you are using the mazdaspeed drysump rear oil pressure reg. Its much larger, and is made to handle the extra load a drysump puts out.



Then slap on your oil plate. And the engine is complete!


For the turbo guys, here is a good spot to put your return fitting from the turbo.

Sorry, the Oil Metering system cannot be used with a drysump anymore.



Here is my Drysump tank. I custom built it to fit where the ABS was. This is a much harder route, rather than to just purchase a drysump tank.

And that is all there is to it!!

t04tii

Very nice. By doing dry sump you are doing more than 99.9% of most people do, but why not plumb the feed to go to each main bearing instead of just going to the back of the block and use the stock oil passages? The stock passages are small and have lots of turns, decreasing pressure/flow, and increasing friction (making heat).

Stylemon had his engine built by Turblown, and they did this mod. I believe there is some info on it here http://www.87rx7.blogspot.com/.

Looking great man! I think you have a future in graphics...that diagram is ms-paint pimpin!

2Fierce

iTrader: (7)

You win. Great info!

GtoRx7

iTrader: (5)

Yeah, on the engines we have and build are setup with double and triple feeds. Just in the writeup I kept it simple in the picture just to get the concept

Scrub

iTrader: (25)

very nice writeup. I've been wondering about the mazdaspeed dry sump for a long time now. What price am I looking at for the pressure reg and dry sump?

-Dan

zayrx7

sure

zayrx7

sure you do

shm21284

I've personally seen it, and it seems like you're trying to pick a fight. Go back to kindergarden, where Rx7store is.

shm21284

Here's a pick I took from his "team track car" thread

zayrx7

I don't start fights, If you read the thread topic, he say's (How to--- install a Drysump. (finally, I know). But now he has done it another way on customer car, after someone else give advise one the forum.

teddyrx2

iTrader: (33)

nice setup nice write up

shm21284

He did this long before someone suggested it on the forum. Stop trolling his section.

justturbo2

iTrader: (4)

very nice write up

GtoRx7

iTrader: (5)

Thanks!

skir2222

Just a quick question I am sure everyone including me would like to know, what are the advantages to doing a drysump system? Are there any disadvantages? Could this be used on a street car?

charlies7

iTrader: (4)

Funny, I just tore apart an engine that you guys built and TUNED that had low compression on the front rotor. Low and behold the side seals were stuck into the corners and wasnt making compression.

BTW, Logan I love your car and the setup. I cant wait to see those staged TB's in action.

GtoRx7

iTrader: (5)

The two disadvantages are- increased cost, and increased weight needing more space.
Advantages are a constant supply of oil with no air and lots of pressure at high rpms. Mostly it would be used on a road race car, but it seems to be stable on a street car too. We have been only driving ours only on the street so far. Just make sure to warm the engine before driving as cold oil pressures can get over 9-10 bar.

to_slow

iTrader: (3)

Here is some info for those that will want to buy the dry sump kits for the 13b or 20b. The difference is
The 2-rotor version uses 2, 13mm wide scavenge pumps and a 16mm wide pressure pump. The 3-rotor uses 2, 14mm wide scavenge pumps and an 18mm wide pressure pump. The pumps are gear-driven, eliminating the chain drive that is used on the Mazda wet sump system.
Prepare to spend about 1k more for the 20b dry sump kit.

fc3s91

iTrader: (23)

Great write up!!!!

zayrx7

Let's see could be from excess carbon build up or lack of oil supply.

Trjackson

I am sure Logan and Peter aprieciate you backing them up against Zavier, however this is not the thread to be doing it in. My suggestion is contact Jason or Zavier via phone, email, or pm. If they do not respond, then create a thread. Good luck with your motor.

Zavier, stay on topic. If you need Logan to teach you how to install a Drysump, I am sure he will show you. You read too much into the title. "how to install a drysump(finally I know)" refers to logon not posting the write-up in a timely manner. If you look in Defined vender forum, somebody(can't remember off of the top of my head), posted a thread and asked logon to post some kind of informative write up on his drysump. He said he would, however it took him quite some time to do so, hence the "(finaly, I know)". Understand?

Jackson

auricomXL

great write up! has anyone tried fitting a "generic" dry-sump system to a rotary?
i just purchased a partial kit that came from some piston engine. i obviously will have to make my own oil pan (aka plate). i purchased all these parts for a pretty good price, and if it turns out it can't be adapted to the 13b i'll find another use for it. it will be Gilmer drive so i plan on replacing my other pulleys with gilmers (with new parts this will cost an additional $350 or so). ayone have any suggestions?

GtoRx7

iTrader: (5)

Pettit I think made a kit, or was working on one that uses a external drysump system. You can use a external setup with gilmer drive, and make a pan ect. Make sure you get the large drysump rear oil regulator.

auricomXL

i made my plate yesterday using my spare 13b oil pan as a template for the shape and the bolt holes. its made of 1/8" mild steel. i have not drilled holes for my scavenge outlets YET.

however, i have another question regarding the rear regulator:
can the rear regulator be blocked completely by replacing it with a bolt? i would think having oil returning into the pan in this location would make scavenging a bit difficult. having a plate on the bottom of the block will make it difficult for the oil coming from the rear regulator (spark-side) to make it's way back to the port-side of the engine (where my 2 scavenge lines will be located). maybe this is a non-issue. if i scavenge from directly under the two rotor housings at the far port-side of the block, will the oil from the rear regulator be able to make its way over there easily? maybe not much oil flows out of the dry-sump-regulator and i am over-thiking it...

by the way, my oil filter will be relocated, so there is no explicit reason why i should need to flow oil to the rear regulator.

does that make sence-maybe i didn't explain it well?