rotary powered kit car project - help needed!

[GO.]

Hi Guys,

I\'m complete novice with rotary engines, but I\'ve been learning what I can - think I\'ve grasped the theory but now need to put it into practical terms on my 13b...

The story is this, I\'m building myself a lotus seven kit car, using a 13b. All going well so far, until I trial mounted the engine last weekend. Nothing too drastic, it fits in the engine bay, just, but it sticks up a bloody mile! Gonna need the biggest bonnet bulge you ever saw at this point!

My 13b is from an 86 2nd gen, injection, non-turbo. My ideas for shortening it are:
1. shorten sump, sit engine lower in chassis - problem with oil pump being in the way, can the sump be shortened at all, even by an inch or so?? :confused:
2. fitting shorter thermostat housing?? :confused:
3. shorter distributer cap/rotor arm?? :confused:

Do any other series engines have different thermostat housings and dist caps that I could use?

I\'ve read all the discussion on rx7club.com about premixing 2 stroke oil in the petrol tank which would allow me to remove the oil pump - would that mean I could then have a flat sump?? Can anyone tell me how I figure out if I\'ve got a mechanical or electrical oil pump? I\'m a little bit reluctant to go this route as I have no experience with these engines yet!

I\'ve removed the air pump and all the other emissions stuff, I\'m not going to be running cats either so I can move the alternator down to where the air pump used to be to get that out of the way.

Any info/ideas greatly appreciated!

Cheers,

Graham

[MikeLMR]

you can\'t remove the oil pump ... that provides oil for the eccentric shaft bearings among other things. You can however remove the oil metering pump which suplies the combustion chamber with oil to be injected for tip lubrication.

Bill on this forum has a rotary powered Westie but i think he has a dry sump system and is not running the standard intake manifold (probably save a lot of height by scrapping that.

Mike

[GO.]

Cheers Mike.

So oil pump and oil metering pump are separate things, assumed there was only one! Still got lots to learn!

Do both pumps live in the sump?

[MikeLMR]

the oil metering pump is high up on the engine on the LHS , just below the water pump If I recall correctly ... if its anything like the one on my 12a it will have a linkage that moves with the throttle.

are you running the standard injection or going with a replacement carb ?

[GO.]

Ok, cheers for that. So its the normal oil pump that sits in the sump that I can\'t doing anyhting about. Bummer I\'ll have to whip the sump off and see what kind of space is in there.

Was hoping to stick with the injection for now, which I know sticks up a lot but I\'m looking at simplicity for getting it running initially. The main problem is the height of the stuff at the front of the engine - the thermostat being the biggest problem!

[bill shurvinton]

Hi,

Up to my neck in it at the moment, but will get back to you as soon as possible with the full low down on the joys of rotary installation in se7ens.

Feel free to email me on bill@ shurvinton.fsworld.co.uk with any detailed questions.

Car is off the road at the moment. I fitted the wrong clutch plate, so had to pull the engine again at the last minute and now have got a job after being unemployed all summer. however I am near fleet in Hampshire so you can always come down and take a look

Bill

[JayDee]

What about dry sumping it? To get the engine lower.

Jason

[Glenn Butcher]

Hi Graham,

I\'ll give you a few pointers...

The Oil Metering Pump is on the right-hand front side of the engine (i.e. if you are looking in the engine bay it will be on the left front side of the engine).

This pump provides oil to lubricate the Apex seals in the engine, it can be blocked off for sure - and replaced by running pre-mix 2 stroke oil.  This is a preferred option on all circuit racing Rotaries - it is as simple as putting a blanking plate where the OMP sits.

As for the Oil Pump itself - it is contained within the cover of the engine (not in the sump), this shouldn\'t cause you a problem - you can get uprated race ones however.

For the sump, you will still need to run one unless you go the dry-sump route (which is very expensive).  You can actually reverse the sump around or make a custom one etc. as long as it holds a similar amount of oil to the factory one.

**You should also run a baffle plate in the sump to stop the oil from moving around whilst cornering/braking etc.

What you then have to do inside the sump is re-position the oil pick-up pipe to the lowest part of the sump.  The oil in the sump is pumped around through the eccentric shaft and the rotor bearings etc.

There is also an Oil Relief valve in the sump which can be upgraded to a racing one (higher pressure).

I have attached a pic. here of the oil system (actually from a Turbo car - but the principal is the same for non-turbo).

Lots of good technical pics./info can be found on //www.iluvmyrx7.com (all the Mazda factory manuals).  Check these PDF files out:

http://www.iluvmyrx7.com/2ndgen/manuals/89-92%20Manual/01_engine.pdf

http://www.iluvmyrx7.com/2ndgen/manuals/89-92%20Manual/02_lubrication_system.pdf

[GO.]

Cheers lads, great advice.

You\'ve cleared up the oil pump confusion I was having.

Dry sumping would be nice but almost certainly out of the budget unforunately

gbutcher - found that site last night, printed off the relevant pdfs and was studying them last night. Was finding it difficult working out where the oil pump lived, not completely clear on the exploded view. If its not in the sump thats great (contrary to advice given by an RX-7 specialist rebuilders who said it was in the sump and therefore I wouldn\'t be able to shorten it, shall remain nameless).

Next step is going to be to get the sump off and have a nose around to see whats possible. I\'ll have a look this weekend.

I\'ve been told that if I swap the front cover for a 12a, it\'ll give me a much more conventient mount point, and it\'ll make a new sump easier to fabricate. I know the covers swap no problem, is that true about the mount point though? I can\'t see how it would support the weight of the engine effectively.

Thanks again.

[Glenn Butcher]

GO.

Here is the oil pump here in another exploded view (under the front cover of course)...

[Glenn Butcher]

Actual Oil Pump...

[Glenn Butcher]

As for mounting your engine...

Yes - I have done this myself a few times, but a different application.  It was putting a 1989 13B turbo engine into an older model Rotary.

To do this:

1. You need the 12A turbo front cover (which has the engine mounts on the front of the engine 4 bolts for the engine and 2 for the bracket to the chassis one on either side)...
2. You throw away the standard sump, purchase a 12A Turbo sump, which happens to line up in all the bolt holes perfectly in the reversed postition (I don\'t know if Mazda did this on purpose but it is amazing this happens!)...
3. You need to modify the Oil Pick-up pipe, turning it 180 degress and possibly angling it differently...
4. You may as well do the sump baffle at the same time.
Pretty sure that\'s it.


As for mounting the engine - the 4 bolts on the front cover will be perfect, here is an example (bit hard to see - but you should get the jist)...

[GO.]

Glenn,

Thats great. Thanks a lot for your help!

Much appreciated.

So in theory all I have to do is shorten the pick-up pipe and the sump itself, much as with a piston engine.

Do you know if thats true about the front cover of the 12a? If so it would mean I could have a flat sump which will make it easier to keep the same volume.

Graham

[bill shurvinton]

Dry sumping is good, but stick with a centre mount engine if you want to go that route long term.  I didn\'t and have lost much sleep getting it all to fit.

[Glenn Butcher]

Graham,

It is a little difficult to say exactly without seeing your car/engine (got a digital camera??).

But essentially with the 12A sump into an older model rotary it fits perfectly with the main crossmember on the car.

I am pretty sure the sump on your engine has a bulge front and rear of the sump.

The 12A sump still has a bulge in it, maybe about 10cms deep but only at one end - which is normally at the front but is reversed for putting into older Mazdas).

Hard to explain without a pic. (been looking for one - couldn\'t find so I drew it).  See attached, lines in red would be the outline of the 12A sump.