1972vsonic

Greetings,

I am John from the Chicago suburbs and I admit I am powerless over my recent rotary addiction.



In early 1978 I drove my friend, Mark, to Dixon Illinois from his suburban home to pick up his new RX-7.



It all started early that year when the RX-7 was announced, and we were anticipating it's arrival. Mark had considered buying an RX-3, but thought it wasn't sporty enough. Mark had been calling dealers around the area for months trying to secure one on the first day, (but he would have settled for the first week) they were available to the public. He was unable to score one even after offering a deposit to the dealers to hold one for him. It seems the cars were so hot that the first ones were promised to people with a connection to Mazda beyond their wallet, and Mark didn't have the juice to get one. We called all around the state (Illinois) trying to find one. Mark finally located a dealer in the farming town of Dixon Illinois, about 90 miles West of Chicago who was getting one in and agreed to make Mark the owner (out there they probably had a John Deere tractor that was just as hot as the RX-7). On the day it was delivered to the dealer I drove Mark out there in my 78 Pinto and picked it up. It was a beautiful red one.



Mark found that the car had a serious flaw, it loved to crash into things! Mark used the body and bumpers to navigate around town for about 5 years, meeting most of the local body shop owners in the process, until he had a very bad crash and was seriously injured when a Cutlass ran a red light and struck it in the drivers door. After the crash the car was half it's original width. I don't know how Mark managed not to become part of the car, but he made it through. Everyone who rode in the car loved it, and it had no significant problems other than a clutch replacement.



I have loved the rotary engines ever since, and have followed them in aircraft and boat use, but have never owned one until recently. I am in the process of installing a supercharged marinized 13B in a 15' Mark Twain runabout. The engine was made by Rotary Power Marine, a company that went out of business about 7 years ago after completing very few examples. The engine has been sitting for about 8 years and I have decided to send the keg into a local rotary shop, A-Spec Tuning, and have them disassemble it, inspect it and install any parts that may not have survived the long storage period. In addition I will have them install a new Microtech EMS to replace the Alpha system that came on it. As long as it is apart I may as well have it street ported for a little extra muscle, not that a 15' boat needs more (it came with 90HP). I have seen that there is a company that offers a conversion for the oil metering pump that allows it to operate independently of the engine oil, injecting 2 stroke oil from a tank. Does anyone here have any experience with these. Any suggestions on my project would be appreciated. I have include a couple of photos for your entertainment.

One day I would love to have an RX of my own.



Thanks for listening to my dribble.

thatpoorguy

I think I just got off lol amazing find and welcome to nopistons! Most people just eliminate the oil injectors and add 2 stroke oil to the gas in the tank

1972vsonic

I know that is an option, but the boat has a 25 gallon permanent tank and I have two daughters, and wife who also use it. I want to eliminate the possibility of someone mis-calculating the oil ratio and regretting it. I am also a little worried about the oil mixing properly in the tank. The marina sells premium gasoline and 50:1 premix, which I use in my antique boats, but I don't believe that would be the correct mixture for the rotary. It would be easy to look at an oil tank and know if it needs oil added to it. I hope it is not too much for them to handle after the swap, it went pretty fast with the 120, and it is shedding about 300 pounds as well.

thatpoorguy

I was told by the shop that built mine to do one ounce per gallon to keep it simple but there are different opinions on what the ratio should be

1972vsonic

I was told by one shop to add 1/2 ounce per gallon (256:1), and another to add 1 ounce per gallon (128:1). I am sure that the 50:1 available at the marinas (2 1/2 oz per gallon) is way too fat. If a stock RX-7 used one ounce per gallon of fuel it would exhaust the entire 5.5 quart supply of oil in 2880 miles at a burn rate of 523 miles per quart of oil, at 50:1 it would get only 256 miles per quart of oil. It has been a long time but I don't remember the RX using that much oil.



Here is a nice RX-7 I saw on a recent trip to Victoria Canada, it brought back memories of my friend Mark's original RX-7

thatpoorguy

Yeah, well the engine they told me to run an ounce a gallon is the one in my avatar that's in my fd, which runs a little hotter and has a lot more stress on it than the stock engine.



I love fb's most out of all the rx7's due to their simplicity lol really wish I still had mine :/

RotorDad

Interesting boat, that intake manifold is pretty crazy. It reminds me of the manifolds people use with the bigger 6-71 blowers.

1972vsonic

That is an Eaton MP62 supercharger. If you think the intake is different, you should see the exhaust manifold! II would be interested in any input the experts on this site can provide. I am interested in how much boost any of you are running on non intercooled 13b engines. I am also planning to run it at about 6,200 rpm. is that adequate? I am limited by the prop speed, I don't want to exceed about 3200 rpm and the Mercruiser Alpha stern drive is a 1.98:1 model.

GreyGT-C

i run an ounce per gallon in the race car. If i'm not sure about it... i go a lil heavy on the oil. Worst case, you might foul the plugs out.



VERY Cool project

RotorDad

I was running 10psi on my Camden roots blower before I added a water to air aftercooler on a S5 13B 4 port, with a large street port & 9.4:1 rotors. It's not that you mani looks all that different, usually see the long runner designs with the blower mounted above the engine used with larger blowers.