Back into the wonderful world of the rotary after buying this car (http://www.mazdarotaryclub.com/forums/showthread.php?t=66019) from Freddy, 24 hours in and I\'m wondering why a little plume of smoke came up through a bonnet vent as I pulled up on the drive... :(
The car has a pretty unique "twin single" turbo setup (a non-sequential custom affair from Apexi using two of their turbos) and the engine is currently being run-in (max. 3k revs), so I\'m not hitting boost at all. When I lifted the bonnet, I could see that some oily smoke was coming up from the lower turbo pipe. Being rather hot, I couldn\'t get much of a look at the time, but some peering around when cold has shown what looks like burnt-on oil on the clamp around the turbo housing and possibly an oily (but dry) residue on the heatshield above. I suspect it is the "upper" turbo leaking and the smoke was the drip hitting the hot pipe below, but it\'s difficult to tell without taking things apart.
You can see some pics below, hopefully you can see how the turbos are set up. There are some other engine bay pics on Freddy\'s thread linked at the start of the post.
(http://ianlockwood.net/images/rx-7/turbo_close-up.jpg)
(http://ianlockwood.net/images/rx-7/turbo_clamp.jpg)
(http://ianlockwood.net/images/rx-7/turbo_across.jpg)
(http://ianlockwood.net/images/rx-7/turbo_context.jpg)
My question is (a) can anyone take a guess at what\'s going on and (b) could it just be that clamp with the burnt-on oil not being tight enough? I\'m loathe to tighten it further in case I damage anything (it\'s certainly not finger-loose). Apologies for the lack of correct terminology for the parts of the turbo, I\'ve never had to deal with them before!
Its poss that theres some left over oil residue from where the car has sat for a while? Have you checked the catch can in the corner isnt filling up and flowing oil out anywhere? Pretty sure the turbos where inspected when the engine was out and any issues would have been noticed?
That\'s a good point about the catch can mate, will take a look. Seems a bit far away from the burning zone to get oil over there though. As you say, I\'m sure the turbos would have been checked by Era and I did ask Freddy this (any play in them etc.)
Can\'t see it being residue from being sat around, we did a decent test drive and I didn\'t notice anything - you can smell it in the cabin as well as see the smoke.
Have you got much knowledge of the car? Did you see it when it was being rebuilt? :)
Era rebuilt the block but AFAIK, wouldnt have seen the turbos. Jason at super7 did that and there wasnt any problem with them from what I remember. The smell in the cabin definitely sounds like the catch can. I did see it down at Jasons a few times when I was down.
Cheers mate, Freddy got in touch to confirm all the above. However, further investigation shows the smoke is coming from down below the "upper" turbo. I had another look today with the car running and it seems it\'s coming off the pipe circled, which is attached to the bottom of the upper turbo:
(http://ianlockwood.net/images/rx-7/turbo_pipe_context.jpg)
Close-up - the pipe has an oily residue on it, although you can\'t see anything actually running down it.
(http://ianlockwood.net/images/rx-7/turbo_pipe.jpg)
I\'m guessing this is an oil feed, but I really don\'t know. Can anyone shed any light on what it is? Doesn\'t feel loose or anything.
The smoke didn\'t start to occur until the car had been running a little while, obviously when it got quite hot (only on idle or with the occasional blip of the throttle, no more than 3k RPM and neutral boost/vacuum). It may be coming from even further down than that pipe fitting, it\'s hard to see as it gets very dark, but there doesn\'t look to be much else down there other than the manifold running to the lower turbo (I presume).