I rebuilt and ported my 1990 JDM Turbo engine and I am having issues getting it started up. The front rotor had 3 spikes to 30-35 psi on the compression gauge and maxed out to 120 psi. The rear rotor had 2 spikes to 30 psi and one to 10 psi and maxed out at 110 psi. The plugs are very wet and I am getting a ton of gas and oil in the engine. I took the intake and exhaust off last night and was expecting to find pieces of the side seal in the rear rotor but all I found was oil. Also, the oil port on the turbo was full, my understanding of a turbo is that there should not be oil sitting in the turbo, it should go down the oil drain and basically just spray oil onto the bearing. My theory is that somehow oil was leaking into the exhaust port from the turbo which was fouling the plugs and preventing the engine from being able to start. As I was taking the turbo and exhaust manifold off, I was literally dumping the oil out of the pieces.

Also, there was smoke coming from my oil vent on the filler tube while I was trying to start the car. So, smoke is somehow making it's way from the engine to the oil pan.

I am going to pull the turbo apart tonight and see if there is anything obviously wrong with it that could explain all the issues I have been having, like a cracked housing or something like that. I never saw any leaks externally.

My questions are,

1. Is it possible for the turbo to push that much oil into the engine or is it more likely that this is an issue with the oil o-rings? The one thing that is really making me worry I did not install the o-rings correctly is that smoke is getting into the oil system.

2. With only getting 10 psi on one face of the rotor, does this mean a side seal was damaged or incorrectly installed and I need to replace that seal? I can feel the seals through the intake ports and from what I can feel they are all fine, is it possible that I just need to get the engine started up and this seal just needs to work it's way in and after break-in will be fine? I am going to leakdown test to figure out exactly which face it is and maybe I will be able to check things out a bit easier.

 

id think it would be kind of difficult for oil to go into the engine from the turbo, through the exhaust ports... oil is usually seen in intake pipes.

smoke from the breather on the filler neck is not a bad thing, you may want a catch can or just run a tube down to the ground.

what mods, if any, besides the port job? emissions removed?

 

This is in a 1982 RX7, so lots of modifications to things like exhaust, intake, etc. But relevant mods would be Holley fuel pump (67 gph free flow and 80 psi max), custom turbo oil drain to front cover, stock fuel rails and regulator, stock ignition, stock ECU. By stock I mean 1990 JDM stock not 1982 stock.

I checked the fuel pressure and it goes to 40 psi and sits there, very steady. Also, the port done was a medium street port using templates from Pineapple Racing. I believe that the stock ECU should work fine to start the car with this port. I was going to take it easy and work out any bugs with the engine before I switched over to a different ECU.

After the rebuild, the car started up and ran for a few seconds than died. I had done this 2-3 times, but the engine didn't have coolant in it, so I didn't think about it to much when it died after a few seconds since I didn't want to run it for longer than that anyway. Once I added the coolant, I wasn't able to get it started back up. My biggest fear was that I had a coolant leak but I have not seen or smelled any coolant in the engine. I have pressured up the coolant system and it does drop from 15 psi to 0 but it takes well over an hour for this to happen, so if there is a coolant leak it is minor and should not be preventing the engine from starting.

I figured I flooded the engine from it only running for a few seconds, so I have been working on deflooding the engine. After a few days of different deflooding techniques I got the idea to pull the plugs out and spin the engine backwards to see if I can get any fluid to come out. Thought I might be able to confirm or deny if coolant was getting in to the engine. After a few attempts at starting it and sitting a day or two about 3/4 cup of fluid came out of each rotor. It seemed to be pretty close to the same amount of fluid in each rotor. Didn't see or smell any coolant in that, pretty sure it was all gas and oil.

The engine started up when I first got it, but one rotor was not firing and in a compression test I figured out that one rotor was blown, so this is why I rebuilt it in the first place. The more I think about it, I did not touch the turbo so if the turbo is leaking that bad now it should of been leaking that bad before and the engine was able to start without one rotor. I am thinking that I did not install the oil o-rings properly, it would explain all of my issues and how that much oil is getting into my engine.

 

AFM hooked up/working? pull the EGI fuse and crank to deflood. try some fresh plugs. does the tach needle bounce while cranking?

 

The AFM is connected I assume it works but never tested it. I made sure the flap was opening but not sure if the sensor is giving the right voltage. I have deflooded it lots and the spark plugs are sparking but I could probably use new ones. The tach does bounce when starting.

 

Your compression numbers are weird. Did you take out the valve in the compression tester, or are you numbers only showing compression on one side?

 

If I held the button on the side of the compression tester I saw the needle jump to 30 psi than back down to 0 very steady as each rotor face passed by. If I let go of the button the gauge got up to 120 psi. That was for the front rotor, on the rear rotor one face only jumped the pin on the compression tester to 10 psi. The other two faces of the rotor went to 30 psi. If I let go of the button on the side this rotor made 110 psi.

 

30 PSI is no bueno. You need more then that. Make sure you remove the shrader valve from the tester and check it. If your still only getting 30 psi per face, your too low of compression if your sure the tester is good

 

Not according to these guys... Compression Check

In the section on using a Piston Compression Test, step 8 it talks about only seeing 30-35 psi per face while holding the side button down on the compression tester. I am very positive that 5 of the 6 faces of the rotors are making very good compression. What I am not sure about is if the last face that is only making 10 psi means that a side seal is bad or just needs to go through the break-in period on the engine and will settle itself into place somehow.

But I am going to take the engine apart this weekend since I am thinking my oil rings are leaking which is causing all the oil in the engine and potently the smoke in the oil pan.

 

Its a common myth in the rotary world. 30 PSI is no good on a rotary compression tester, but ok on a regular piston engine compression tester. The confusion comes from reading the spec in the FSM and applying it to the piston comp. tester. But one of those faces are def not sealing.

Take it apart. Just to settle your doubts. You have the FSM, right? Make sure all seals are free and bounce right up after pressing on them. Double check side to corner seal gap. Did u remember the big rubber o-ring oil seals in the oil control rings?

 

Yes I have the FSM for both the first and second gen RX7s. During the build I was very concerned with not making the side seals to short that I may have made it to long so it might not move around freely. This is my assumption of what I did anyway. I know during the build I took my time on these side seals but with this being my first build they are not perfect.

I did install the rubber o-rings but I was not sure how hard to push them in to get them in place. So, it is very possible that I did not push them in all the way. I re-watched some rebuild videos and some of those rings you really need to lean into to get them installed properly, I am guessing this was my issue. Hopefully this weekend I get get the engine apart and it will answer all of my questions.