I have no prior experience with rotary engines and just bought a Lotus 7 replica that has a 13B in it. The car was mostly used for autocrossing. Oil was supplied by adding it to the gasoline. The oil metering system was removed. I want to put the oii metering system back on the car because I don't want to mess with mixing the oil and gas and I am using the car about 90% for the street. Any advice on this? Should I leave it the way it is?

Here's details on this engine.

It was built by a professional RX7 ITA car builder around 2006. Engine has been street ported, balanced with light weight rotors. Engine was new in 1990 (not a junkyard pickup). It has a Weber 48IDA carb that has 50mm bore that has been opened up additionally Dyno checked at 255hp flywheel. MSD ignition with rev limiter, RPM limited to 8600. It has a fan assisted oil cooler and custom C&R aluminum crossflow radiator and a 4.10 Toyota Supra rear end with a Toyota Racing Limited Slip.

 

The mechanical oil metering system could be adapted from an S4 engine ('86-'88). It sounds like in your case this would require an S4 front cover, S4 OMP and some sort of cable setup to allow throttle movement to control the amount of oil delivered.

 

Would the engine be in less danger by just leaving it alone and continuing adding the oil? I am afraid that throttle based systems will not work under engine braking when the accelerator is not depressed.

 

This is a system that has worked just fine for 25+ years. There is a minimum injected amount, which will be delivered at idle and under closed throttle conditions. It is never 0. You'll be using more oil with the premix method, but for typical street driving, either will be more than adequate for lubrication. If seeing track time, some additional premixed oil is good for insurance.

 

I would keep it on premix. It's not that hard to do... Just get the ratio you need and go from there. Remember to use high quality two stroke oil and not engine oil. (Two stroke oil mixes with gasoline and is actually designed to burn)

 

I'd love to see pics of this car's engine bay.

You can buy rotary specific Idemetsu pre-mix oil from http://rx7.com/index.html

or from Pettit Racing
http://pettitracing.com/faq/faq_protek-r.htm

 

do 1987 NA 13b's have this oil metering system and where would it be located? sorry to thread jack, but since we are talking about premixing i wanted to know. thanks..

 

All RX-7s had metering oil pumps. Read through the '86-'88 FSM and '86 training manual for information on it: http://mazdarx7.iougs.com/fsm.shtml, http://mazdarx7.iougs.com/training.shtml.

Premix becomes necessary when someone removes it. Prior to 1989, mechanical systems were used. From 1989 on, electric pumps were used. The electric pumps deliver oil in a more efficient manner, but are also less reliable.

 

Here's a pic of the engine bay I am dealing with.