I have had my '87 RX-7 for 8 years and have always used Castrol Syntec (Full Synthetic) 5W-50. Today I have been told by the dealer that they no longer recommend using full synthetic for rotary engines. Does anyone have any input, comments, etc. regarding this issue. The dealer said that carbon will build up in the engine and the engine will lock up. I have always known that the full synthetic will build up in the engine, but I have also heard that if you run the engine a little harder than normal (about 4000 rpm between gears about once a month), the build up will burn out. I have never had a problem and would just like to query everyone regarding this issue. This morning, I actually had to sign a waiver at the dealer to let them use the full synthetic in my RX-7 (first time that the dealer has ever made me sign a waiver and informed me of this issue). Any advice would be great and if you do not mind, could you email me at jsc1976@prodigy.net



Thanks in Advance, I look forward to the many discussions on this site.

Well... you're really not suppose to be using full synethetic on our cars - it's not good (that i've been told). You're suppose to be using Non-Syn....



I do know that the carbon build up in our cars is gonna be normal whether or not you're using Non-syn. or Syn. oil. That's why it is suggested to redline her every now and then to flush out the carbon build up.



I know it's probably not much help - but if I'm wrong.. anyone, please correct me.

there is going to be carbon build up either way, the difference is not as great as the diff between running your omp and running 2 stroke in your gas. GLHS has over 300,000 on his rotary and he is running 2 stroke.



Justin

Justin -



"billy" off the other forum and I were talking about that last night with a few other RX-7 guys. He mentioned that if you go 2-stroke... it doesn't feed oil... ah, and something else. I thought it was pretty interesting.

Go to www.FC3s-PRO.com read ted's writeup on pre-mix. I personaly ditch the OMP system completely. I run Royal-Purple Synthetic in the Crankcase and use Bombadier Synthetic 2 Stroke for my premix.

I also don't recomend synthetic, I blew an engine once, alot of carbon builded up because of the OMP. It doesn't burn well. If you do disable the OMP you can use synthetic with good results. You will get some oil sipping between the housing over time with synthetic. Synthetic tends not to wet the oil seals and o rings like regular oil does.



C

like everyone else said! If you're still using your OMP, don't use synthetic. I've always used Castrol GTX 20W50. If you don't know what an OMP is, it's an external oil pump on the front of your engine next to the main pulley below the water pump and alternator. It has clear tubes running from it up to the intake manifold.



Welcome to the forum...

I'm disabling the OMP on my new motor, I've been thinking about running synthetic in the engine as a result, but I've read mixed opinions on doing so still... apparently you will have more oil leaking past the oil control rings into the combustion chamber if you run synthetic.



How many miles do you have on one of these motors you have been running synthetic on? Any smoke at startup ever? I'm very curious... motors almost ready to go in the car, hopefully I have a good solution when it comes time to fill up the sump https://www.nopistons.com/forums/pub...IR#>/smile.png

Just run normal oil and change it every 2-3K miles and you shouldnt have ANY problems.

i plan on running premix for my new motor, i just ordered the block off plates for it