Bonjo

I have the Locost Seven (like the old Lotus Seven) chassis and am about to fit the 12A Drivetrain. 12A with 45mm Webber, 5 sp, and lsd rear. Target weight 1100lbs Target Bhp 140.


OIL>
1. How to retro fit the oil injection to Weber side draft.

2. Can the secondary oil pump be removed and blocked off in favor of pre-mixing fuel with 2 stroke oil?

3. Which facet style fuel pump and how much pressure. I have pressure regulator, 5/16 lines and filter, but can't decide on which pump to buy. 30, 45 or 65 gal/hour. Motor is stock with long tube open exhaust and long runner open intake, no fan, accessories or emissions. My guess is the 45 with pressure set between 4 and 4.5?




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peejay

I've seen 45 DCOE carbs with tubes in them for the oil injection... if you don't want to spend the money for a genuine rotary Weber kit then just pre-mix. Some people say 1 oz per gallon but I always went a little richer than that, better safe than sorry.

General wisdom is the Facet pumps are too small, and you're better off getting a Holley pump and regulator. Holley performance pumps come with the regulator so it's one-stop shopping.

BTW ... on another note, I've heard of the locost before, and funny enough I re-visited the link today because I wanted to see it again. Here's where I found it:

http://www.geocities.com/geo_42_99/ron7/ron7.htm

http://www.angelfire.com/ar/dw42/ is his main page... there is a ton of fascinating info on his site. Pay close attention to "Tyrannosaurus RX". Funny enough, I found this site while I was researching old Ford engines!

MIKE-P-28

iTrader: (1)

Just a dumm question but wont the gas dilute the oil concentration? The carb injects the gas at time of need, seems like the oil would be richer then? In EVERYONE of my rotary's I always retained the OMP and added oil. And I added a lot more than that, Id rather it smoke than drop an apex.

peejay

Dilute what?

The spec for oil use is roughly 1 quart in 1000 miles, right? At 20mpg average highway/city that's 50 gallons of gasoline, or a 1:200 ratio of oil to gas. The actual mix at full throttle is 1:150 or so. Mixing 1oz to 1gal is 1:160.

The oil isn't "dripped in when needed", it just drools out of the tubes in the carb and runs down to the throttle plate, where it gets stuck (at idle) or drools down further to the intake manifold. Eventually it either gets atomized from the air flowing past it, or it drools its way into the engine, where it has a chance of making it into the MIDDLE of the chamber - not the surface of the rotor housing where it's needed - and also has a chance of just getting pushed against the side housing between the rotor's side seals and oil seals.

Pre-mixing ensures that the oil is, in fact, going to the insides of the engine. Not all of it will be used, but as you see not all of it is used when using an OMP, either. 2-cycle oil is also designed to lubricate well when mixed with gasoline, and burn cleanly, while motor oil isn't. Also, motor oil is 99.99% of the time dirty, why would you want to put that junk in your engine?

One downside to eliminating the OMP is that the engine no longer uses oil. Rotaries tend to blow-by a lot of combustion gases when run hard. I had an engine that would gain 1 quart between oil changes, all of that and more (it leaked too) was combustion by-product contamination. This doesn't mean you need to change your oil more often without an OMP vs. with, because this happens on cars with OMP too, except they inject the cruddy, diluted oil back in to the engine so this contamination is harder to notice just by looking at the level on the dipstick.

Bonjo

..removal of the omp affect the main oil pump and oil distro in the rotary, or will it simply cut flow up and out to the carb?

And, what kind of flow rate should I be looking for? Some of the VWs use the facet style running 2 webbers. Most of the Holley pumps are quite expensive and flow somewhere in the range of 110 gph at 6 -10lbs.

With a new baby my project is on hold, so I'll use my time and this board for research.

Thanks for the help.

REVHED

Removing the OMP will have no effect on oil distribution in the engine. As for the fuel pump I'd just go for a Holley Red combined with a Holley 4.5-14psi regulator. This pump will flow more than enough for any 12A.