Hey everyone. Bought what I thought was going to be a solid deal. Almost never seems to work out that way though, huh?
Bought the car and drove it home (approximately 30 miles away) only to have it no longer start. Self diagnosed that to be an electrical drain issue that I couldnt figure out, so decided to take it to a [rotary] shop to figure that out and do a general wellness check on the car overall.
My car has now been sitting at the shop for the past 4 months (that's a whole other story that I wont get into right now), but it has boiled down to this:
TL;DR: Bought what was supposed to be a fresh rebuild, but a compression test is now showing right about 50psi on a cold start. Shop says that'll mean a blown seal, so it's going to need a rebuild for the fresh rebuild. Lol. Now the question becomes what options do I have for a trusted/reliable shop somewhere close to me? I'm in Las Vegas, NV. Willing to trailer the car to the surrounding states (Arizona, [southern] California, etc) to get the work done properly. Also, am I correct to want to add dowels as all of the protection I will need, or is there a negative to adding dowels if not making increased power levels?
I'm attaching pictures of the information from the for sale thread when purchasing the car, as well as a video of the compression test I was sent by the shop. Any insight is appreciated!




Compression test video link. (sorry, wasn't sure how to embed it in the thread).

https://imgur.com/a/QxHDOA0


Sorry for any ignorance, but I'm not insanely versed in the rotary world just yet. Started out in the Honda game. Lol.
But yeah... Suggestions for a shop for the rebuild, and a tuner would be greatly appreciated!
Oh, and... since it's going to get opened up (and, to my knowledge, the current mods should be able to support it) should I be looking at a street/bridge port? Pros/cons to either, outside of the obvious increased power?

Feel free to ask me any questions and I will address them to the best of my knowledge. I can post pics of the engine bay and whatnot too if anyone wants to see what it looks like under the hood.


Thanks!

 

Low even pulses is indicative of sealing surface wear, not a seal. Also using a standard piston compression tester can work, but it can also be garbage readings depending on how it was modified to relieve pressure.

 

Even pulses. Just put some miles on it and hopefully it’ll come up.
get a 2kw starter motor and a good battery.

 

The video does not show max compression. It shows that the rotor faces are roughly even, which is good.

I would not seek a rebuild based on the attached video.

Put the schrader valve back in the tester and/or don't hold the relief button open. Crank for several seconds and see what the max pressure is.

 

So is the car cranking but not starting at this point?

Using a piston compression tester is good to see the overall pulses of the engine to diagnose a broken apex seal, but it's not great for determining the PSI and quality of compression, a rotary specific tester is really needed for that.

The seller stated the car idled smoothly and had good vacuum at idle, that is really a good gauge of how "tight" an engine is. If you can get it to start will it hold an idle and have decent vacuum?

All that said the RA seals are known to be hard on rotor housings, that could be part of the problem, it could have scored the rotor housings resulting in a compression loss. But, this is me half-remembering info from someone else, not first-hand experience.

Dale

 

Is the car not starting due to the electrical issue or the low compression because those are two very different things. If the car starts and runs fine when the battery is healthy then find the electrical gremlin and call it a day. Or install a battery kill switch until you do.

Also why is a [rotary] shop using a piston compression tester? Like everyone said it's good for comparing even pulses but the numbers itself don't mean anything at all.

 

From the invoices and pricing it looks like a lot of internal seals might have been reused. A proper build will have all new seals, springs, bearings, and gaskets. Looks like you have a nice car with some decent parts but they skimped on the rebuild (probably because they were selling the car). I would recommend doing another compression test with a rotary specific tester for piece of mind. Your closest reputable options in my opinion are PRT or Reliable Performance in Texas. Some also recommend Lucky 7 in California but I have no experience with them. Free free to reach out to me if you need help.I have cars from all over the country here.

 

i would get the car started and running nicely, and then re-do the compression test. we had an Rx8 come in once, in 2005. and it was running on one rotor, compression on the dead rotor was really low. we called Mazda and they had us replace the ignition system, which we did.

car started, it then ran on both rotors, warmed it up, blast it around the block, and viola it then passed the compression test.

that being said, skip the rebuild, and buy a new engine from Mazda, its cheaper, and its all new parts

 

My questions:
1) why use a piston tester?
2) why test the cold engine (as opposed to when fully warm)
3) what rpm was the test done at?
4) how many miles are currently on the rebuilt engine? Has it been fully broken in?

I would be wondering if that shop isn't just looking to get a quick rebuild from a new owner..

 

Also I would not add dowels at that power level, but it you were rebuilding it I would recommend a set of 1 piece replacement dowels with an oil pass-through(to avoid running external oiling) and a set of Turblown engine studs if the motor isn't already studded.

 

Thank you all for the insight so far!
If it makes a difference, car is a JDM import. 1992.

After buying the car, it was a highway cruise to my brother's house, so I kept it at about 65mph and minimal boost.
The battery was drained the next day, but it started with a jump, and I drove it around the block 4-5 times hitting moderate levels of boost every so often. It had an inconsistent sputter in second gear sometimes, but would come out of it. I assumed that's from a lack of it being tuned.
The engine has less than 1000 miles on it, and [as far as I know] it was babied. Though I'm sure there was an occasional WOT pull here and there. I definitely floored it, which is how I saw the stutter.

Got a battery charger and hooked it up to the battery to keep it from draining all the way. ((The XS Power S680 battery (370CCA and 24min reserve) would literally drain to zero after a few hours of sitting. I hooked up a multimeter and went through that whole process and could not find the drain at all, which is what prompted me to take it to the shop later.)) Was able to start it the next day, and drove it home (10 miles away). Car failed to start after that. Cranks, but doesn't start. Tried the deflooding process by pulling fuse and all that.
Got a full sized Interstate battery with much higher CCA and reserve time, and that didn't start it either.

Got NGK BR10EG spark plugs, as that was going to be my next move. I'm still in the process of moving into my house though, and had no tools, which meant no thin walled socket, so I never got around to doing it. I figured since I planned on sending it to a shop to try to find the electrical drain, I would have them do the spark plugs at the same time.

The car idle'd fine when it did start the few times I started it.

*UPDATE*
Unless my rotary knowledge is really bad, I think the guy looking at the car at the shop is not versed in this area at all. He sent me a picture of the spark plug saying that it's overtightened (because he cant get to it, I'm assuming with a regular thickness socket), and that's causing spark issue. Am I crazy, or is he trippin? Lol.

 

hahah. Go and take your car back ASAP.
buy a 2kw starter motor you can buy a Chinese one for cheap cheap or buy a used rx8 one and swap the nose on it.
Your car is just flooded.
Get some miles on it and a decent base tune and the compression will go up.
Its not a rotary size plug is all. You’ll have to grind a socket down to a very thin wall to get it out.
Hook up a multimeter and start pulling fuses one at a time when it stops drawing current you have narrowed down the culprit.

 

Yep grind down a socket or get something like this. https://www.atkinsrotary.com/store/T...et-ARE905.html

If you're genuinely worried about the motor, get a rotary compression tester. You can do it yourself very easily and if I recall they are around $300 from the vendor here that makes them.

 

Yeah, that's the weird plugs that require the thin wall socket. Those are WAY overkill for a motor that's still breaking in and will foul easily on a new motor.

I would either make or buy a thin-wall socket and put plain BUR9EQP NGK plugs in all around. These will install with a regular spark plug socket and won't foul out while you're getting the engine sorted and broken in.

Looks like the big thing that needs to be addressed is the battery drain. There are a number of Youtube videos on how to do it. It's not super hard but it can be time consuming. Most likely it's something with aftermarket electronics on the car - a rewired fuel pump, stereo system, etc. that was wired hot instead of switched. Also is the battery relocated? Bad relocation jobs can cause a LOT of weirdness.

Dale

 

My initial thought was fouled plugs, as well. I'll throw in some 9's until it's broken in and ready for a tune, at which point I'll throw in the 10s.

As far as the drain goes, I went through all of the fuses twice and nothing was showing a drain that was out of spec. It was a few months ago that I did it myself, but I think I only had one fuse that showed any sort of draw, and it was minimal. The fuse that runs the clock/accessories or something like that if I remember correctly. I'll try going through it all again when I get the car back though.
I tested the battery after a night with everything connected as normal vs. recharging it to full and testing again with the negative disconnected from the battery. Battery didn't drain with the terminal disconnected, so I know there is a drain for sure.
Speaking of battery, I searched and saw a lot of people running miata batteries, or the turbo jeff battery tray (which is a smaller group size than stock), and nobody seems to have starting issues. Is it likely the XS Power battery I have with it's fairly low CCA and reserve time is still sufficient for this car, and it just wasn't starting due to fouled plugs? Or is the Haltech and aftermarket stereo head unit too demanding and I need to up it? Also, is it possible that the Haltech is somehow staying 'on' and that could be causing the drain?

Battery is currently not relocated, but if I switch to the Interstate (which is stock group size), I will have to relocate it. No room under the hood for stock sizing.

Thank you all again. I really appreciate it.

 

Jesus, dude. What a mess...

If the car isn't tuned it should not see any boost. Definitely not WOT! You and the previous owner have possibly caused damage to the engine by doing this. The fact that it runs poorly under boost is a sign that you should stop doing that.

I have the exact same battery with an original 25 y/o starter and have no starting issues. I just have to keep it on a trickle charger if sitting more than a few weeks. Check the amp drain when the car is off.

Get a tune.

 

A smaller battery should do fine. I have a Miata battery on my car - it will drain down if I let the car sit for about 3 weeks, I think I have a small current drain but I haven't got around to looking for it. The 51R battery that the Turbojeff tray uses also will do just fine.

Some of the super mini batteries like the Odyssey can be a problem.

I don't see a need to go back to a big stock-size battery. Small batteries also can't crank the car for a long time as well, like when you have a flooded engine or a car that's having starting problems.

Battery size is mainly for reserve to run things with the car off and cranking the car. Once the car is running the alternator takes care of electrical load. When running multiple fuel pumps, IGN-1A ignitions, big stereo, HID lights, etc., you may need a higher capacity alternator if you have voltage drops at large loads.

Dale

 

Haltech, not sure about the newer ones, but the older ones need a much higher voltage than the stock ecu to run, so if you have a small/weak battery, and the cranking volts drops the ecu will shut off.

 

What is your ECU seeing as far as power during crank? I don't mean what does a volt meter say hooked up to the battery but the actual pin on the ECU. Also, I don't know if I would trust whichever shop you're currently going to for engine diagnostics.

 

Gotcha. You mean older than the platinum sport 1000, or is there an "old" and "new" version of the platinum sport 1000?

No clue on the pin reading. And yeah, car is getting pulled from there ASAP.

Of course. I didn't think an aftermarket head unit and HIDs would be enough to warrant having to go back to large battery, or be things that the stock alternator couldn't handle, but the crank was my concern.
I do have a trickle charger.
Perhaps I should have clarified a bit more. There is a base tune (on the rich side) on it. And I wasn't smashing WOT through five gears around the entire block. It was once through 2 and a half gears, to see how it would react, and so I could see where the AFR was sitting on this base tune. Perhaps I shouldn't have done it even the once. But what's done is done. I'm just giving you guys the facts as I have them to help give me as accurate of a diagnosis as possible. Many of you are much more knowledgable than I am in this field, and I'm not afraid to say that, so the worst thing I could do is ask for help while not being truthful as to what I have/haven't done. All the help is much appreciated.


Proper break in is gradually increased load every 500 miles, with oil changes at each stage? New plugs at each stage too, or is that overkill? And typical break in mileage on a rotary? Last thing... suggestions for a proper dyno tune in my [surrounding] area? Southern California is my closest option as far as I know, but I'm not familiar with the shops/tuners out there. There is no one in Vegas that I know of that does it.
Normally I'd search for all of these answers before asking, but since I got ya here.... Lol.

 

i would check voltage at the ecu pin, or plug in the lap top and you can see it when you're cranking

 

Personally, I think "proper" break in varies from build to build and goal to goal based on how tight the tolerances are and what was replaced during the rebuild. An engine with super tight clearances and new bearings/seals will have a much stricter break-in procedure than a motor that was broken apart simply to replace the soft seals.

On the extreme end with new bearings and VERY tight clearances I would personally start the motor and let it idle for about an hour, then shut it down for the day and change the oil. This gives time to ensure the most basic operating environment functions, you don't have leaks, your oil pressure is good, your vacuum is stable and your first heat cycle sees zero load. Imo heat cycles are just as important to a break-in as mileage. Following that, I would avoid positive boost pressure in all situations possible during the break-in!!

For the first several hundred miles I'd try to keep it at or below 3krpms, gentle acceleration up to the peak and allow engine breaking downward through the rev range. Steady-state cruising miles at the same constant rpm (cruise control on a 100 mile highway trip) don't add value similar to the equivalent miles of driving with various speeds and rpm conditions. At about 500 miles I think you're right to give the second oil change and start working them in going forward. From there I'd start bumping the rpm cap up by 1krpms every 100 or 200 miles depending on your self control (4k @ 600 or 700mi, 5k @ 700 or 900 mi, 6k @ 800 or 1,100mi, 7k @ 900 or 1,300mi, 8k @ 1,000 or 1,500mi) while still maintaining the ZERO boost and only gentle/minimum load to accelerate mindset!!

Once you've worked up to max rpm then, and only then, would I schedule your full power tune. Give your tuner several hours on the dyno (I'm currently expecting 4-6 hours when I get mine tuned, most try to get EVERYTHING done in like 2 hours though) to get everything dialed in then go romp that bitch!

This is the super conservative way to break the motor in, and it'll likely reward you with better compression in the long run. Also, don't forget your premix!! Unless you're running soft seals you'll benefit from adding ashless 2-stroke oil to your fuel.

On the other hand, if you're just reusing bearing and oil control rings while running loose clearances you could probably get away with an accelerated break-in of that initial warm up to check for leaks/pressure, then do everything in fast forward. I'd expect blow-by and less than optimal compression and engine performance/longevity this way though..

Hell, I've heard of people breaking in race motors by literally stacking them up, idling to temp, changing the oil, and throwing on the full power tune! I'm pretty sure there is some PR island voodoo going on there though!!

Ultimately, if you ask 5 different "experts" you'll probably get 4 very different answers. I'm not an expert. I have rebuilt my own motor though, and I personally prefer to practice self-control and restraint in an overabundance of caution.

That will depend on what ecu you're running and how picky you are. Your best bet is to ask people in SoCal, instead of hoping that somebody on the East Coast will be able to recommend a tuner local to you. I'm in Virginia, but I towed my car out to Escondido for work, and the guy I'll get to tune mine lives in LA. I'm just going to get him to remote in for my final tune since I can't afford his travel fees

 

There's a wide variety of methods for break-in. The method I've always used is -

- Start fresh engine, idle with a few revs, get the car up to temperature and check for leaks. Let it run about 20 minutes or so. Shut down and change oil/filter.
- Drive under 4000 RPM and no boost for 500 miles.
- Next 500 miles increase RPM slightly and light boost.
- Change oil and filter at 1000 miles
- Drive normally, full boost full RPM.

That's always worked for me.

Big thing to start with is just getting the car where it will start, run, and drive reliably. Don't get into boost since it's un-tuned. Once you get to that point and get some mileage down (500-1000 miles) I'd look into getting it tuned.

Dale

 

Thank you both for the suggestions, fenda & Dale!

Yeah, I wasn't sure how well remote tunes do with FD's since it seems every motor can be drastically different. Lol.
I know it has seen roughly 700 miles since the rebuild already, so not too much more to go.
I should be getting it back within the next couple of days, and then the electrical drain search begins again

I appreciate everyone's input!