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Autopsy and resurrection of my FD
Let's see, where to start...
How 'bout here! https://cimg9.ibsrv.net/gimg/www.rx7...b37b307e15.jpg Last known whereabouts -A little background- That's my FD, had it for over 2 years now. Bought it through the forums and have been thrilled to have it since day 1. I've put a few shiny parts and extra goodies on it, but I'll get to that later. For now, the matter at hand. I was driving through my local tunnels and decided to really rev it out. Brought it up to redline without any drama but when I put the clutch in to shift, the revs dropped faster than normal. I left the clutch in and put the trans in neutral, when to my surprise, the car just died. Still gliding along I tried the key... nothing. So I put on the hazard-lights-of-shame and coasted out of the tunnel and onto the shoulder of the I-90. Not a bad place to break down, at least the view was great. Got a tow home and noticed immediately (now that I was away from the highway roar) that when I tried the key, the engine would turn over, but way slower than normal. I tried to rotate the engine by wrenching on the front pulley bolt, and found it a lot more difficult than it should be. So, at this point my suspicion was a spun or stuck bearing. Nothing left to do, but take the whole thing apart to try to assess the damage, so here goes. |
First step, hood off
https://cimg6.ibsrv.net/gimg/www.rx7...0340a6d614.jpg Intercooler and intake piping -gone- https://cimg4.ibsrv.net/gimg/www.rx7...c71ed692be.jpg Bumper, outta here! https://cimg9.ibsrv.net/gimg/www.rx7...8d2b279abc.jpg |
Big time gap here. I used Rotary Resurrection's engine removal guide to assist me in disconnecting everything needed to move on. I recommend giving it a read, it was a big help.
https://www.rotaryresurrection.com/3...eng_remov.html Anyways, engine is disconnected, time to pull! This was a really cool process. It was like watching a child being born :lol: https://cimg6.ibsrv.net/gimg/www.rx7...b8e5d54739.jpg https://cimg5.ibsrv.net/gimg/www.rx7...132b8130ed.jpg https://cimg7.ibsrv.net/gimg/www.rx7...3878c7426f.jpg https://cimg4.ibsrv.net/gimg/www.rx7...8d73aa006e.jpg https://cimg6.ibsrv.net/gimg/www.rx7...862d0e90f1.jpg Neato! |
Time to start unbolting stuff from the block. I can't say enough how nice it is to work on an engine in open-air, out of a cramped engine bay.
Anyhoo, Transmission off https://cimg0.ibsrv.net/gimg/www.rx7...64f3d5a53a.jpg Downpipe and turbos gone https://cimg0.ibsrv.net/gimg/www.rx7...53c21030c3.jpg Thanks to the magic of time we have Before ^ and After: https://cimg7.ibsrv.net/gimg/www.rx7...866fe493d4.jpg |
Finally ready to tear open the block, lets really dig in here.
Oil pan off. https://cimg7.ibsrv.net/gimg/www.rx7...e96af9352a.jpg Can't see anything blocking the oil pickup, that's a good start. Remember, what I'm really on the hunt for is anything that looks like the cause of any oil starvation. The theory of a ruined bearing being the demise of my engine is still just a hunch, but its the best I've got so far. And an oiling problem would be the most probable cause. Inside the oil pan, the plot thickens. Lots of shiny sparkles. Another sign of bearing failure. https://cimg5.ibsrv.net/gimg/www.rx7...8fca85417f.jpg |
Well well well. Front cover removed and our first piece of hard evidence presents itself!
https://cimg0.ibsrv.net/gimg/www.rx7...6d33200141.jpg See a problem? It's easy to miss... Where's the nut that's supposed to hold down the oil pump gear?! It's in the picture believe it or not. You can see it hiding out under the drive chain on the left, juuuuust above the gear itself. So, according to the Mazdatrix Rotary Rebuild DVD which I'm working off of (highly recommended!!) the washer under the nut is supposed to be 'staked' or have one side folded up to prevent the nut from coming loose (I guess? not really sure how that's supposed to work or if I'm off base as to why they stake it from the factory). Anyways, my washer was just flat, no locking mechanism. Could this have caused the nut to work loose over time? And am I just lucky enough that it didn't get caught in the chain or fall through into the oil pan? |
AHA! Well there's yer problem!
https://cimg9.ibsrv.net/gimg/www.rx7...ec434a61d6.jpg A little blurry in the photo, but look at that Woodruff key! It's totally sheared! With the key in that state I could put the gear on the oil pump and free-spin it without the shaft moving. So there we go! Engine's turning, but no oil is being pumped! Here's some remnants of the key in the gear itself too. https://cimg8.ibsrv.net/gimg/www.rx7...ab600c76e4.jpg Okay! So there's the cause of the damage. Feels good to have found it at least, not have it remain a mystery. Still unclear though exactly what went on though. Did the nut come off first, allowing the gear to slide back and forth, wearing away at the key until it snapped? Or did the key go first, allowing the gear to rotate while the shaft was stationary, thus unscrewing the nut? This I don't think I'll ever really know. |
-Further dissection-
We've found the cause of the damage, but haven't yet found the damage it caused. Uhh, yeah. So let's keep digging. Rear iron removed https://cimg5.ibsrv.net/gimg/www.rx7...7d52e9bf90.jpg Gratuitous shot https://cimg5.ibsrv.net/gimg/www.rx7...34287d632f.jpg And rear rotor extracted https://cimg9.ibsrv.net/gimg/www.rx7...5f1e30e2af.jpg All of that came out real easy so far, I'm guessing the damage must in that case be in the front rotor. |
Phew. Wish I had more pictures to describe this, but what is supposed to happen at this point, is that I should be able to lift the center iron up, and the eccentric shaft should lift up as well just slightly so that I can get enough room to tilt the center iron and get the eccentric shaft through the center hole of the iron (clear as mud?).
What happened instead, is that I lifted up on the center iron, and it lifted the eccentric shaft and the front rotor with it. This meant that I couldn't tilt the center iron enough to clear the eccentric shaft because it would come into contact with the front rotor. So what I'm left with is this three-piece unit: https://cimg6.ibsrv.net/gimg/www.rx7...7b3f4e8e3b.jpg Seems like we've found the damage then, that the oil starvation caused. The rotor bearing is fused to the E-shaft! I for the life of me couldn't pull the rotor off. I was going to have my transmission rebuilt (what better time then when it's out right?) and decided to take this thing over there too, and see if they could pry it off with a gear puller. They chuckled and said they'd give it a shot! |
Got the trans and engine parts back from the shop, they separated the rotor from the shaft with no problems. Looking at them in the light tells the whole story.
You can see the discoloration on the front lobe of the shaft. https://cimg9.ibsrv.net/gimg/www.rx7...06c0f2af99.jpg And here's the rotor bearing that bore the brunt of the damage https://cimg5.ibsrv.net/gimg/www.rx7...7065d3ccfa.jpg There we go, mystery solved autopsy complete. My plan for this engine is to take a closer look at all the parts and determine what's usable and if its worth a rebuild, or part-out. Until then, I've bought a new 13B block and am eagerly awaiting its arrival! |
What's in the box?
https://cimg0.ibsrv.net/gimg/www.rx7...37277b83ec.jpg BAM! Oooooh yeah. https://cimg1.ibsrv.net/gimg/www.rx7...69ec034c53.jpg |
Glad you found the issue and got a new engine. This is a good car. I remember Jacob putting it together.
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Great work!
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Originally Posted by Johnny Kommavongsa
(Post 12387162)
Glad you found the issue and got a new engine. This is a good car. I remember Jacob putting it together.
Folks who want to see Jacob's work and where the car came from can check it out here: https://www.rx7club.com/build-thread...o-one-1106118/ |
Wow. Small world. That was originally my BB roller that he used to transplant the other parts into. Man, if the body of that car could talk. Tough luck on the engine failure. Awesome that you're going for a new engine to breathe new life into it. Sub'd for updates.
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I've torn down some motors like that that ate a bearing. That stinks!
You may be able to re-sell some of the parts from that motor to help recoup some cost. I would strongly advise having the oil cooler (or coolers) professionally flushed and cleaned. When you chew a bearing up that will get all EVERYWHERE in the oiling system. You don't want to start the new engine and have it immediately eat a ton of metal debris from the oil cooler. Search on the forum, people have found some good shops that do a good job of flushing and refurbing oil coolers. The gear on the oil pump is held on with a washer that has a small tang that fits down in the hole where the key goes. Once the nut is tighened onto the washer the side of the washer is flattened up against the nut to keep it from working its way loose. It looks like in this case this is exactly what happened - that washer wasn't crimped and it eventually spun loose. Things like this suck but it's also a good opportunity to go through there and get everything tip top. Dale |
Hey, thanks for the encouragement, all. It's been a while and progress has been made.
https://cimg9.ibsrv.net/gimg/www.rx7...d7beb33a87.jpg Motor unboxed! https://cimg3.ibsrv.net/gimg/www.rx7...557641d732.jpg And onto the stand. I had read that Mazda tests the coolant passages with plain water which will rust somewhat. When I tipped the engine forward a bunch came out of the front coolant inlet, which is the brown you see on the main pulley. Going to flush it with distilled water a few times once its in the car to wash the gunk out before finally filling it with coolant. |
Alright, first up, attaching the IRP oil pan brace and FFE mounts.
https://cimg8.ibsrv.net/gimg/www.rx7...979f96d51c.jpg |
Time then for a tough decision. I've always had an inkling to go single turbo, and no better time than now. This was a hard choice because I really didn't have any issues with the twins. They're good '99s that spool very quickly and add a lot of character to the driving feel IMO. I didn't even really have a problem with the control system. Granted it was simplified, but it was still running sequentially and I never found troubleshooting it overly difficult. However, I guess I just had too much time to think about it, because eventually a box arrived.
https://cimg8.ibsrv.net/gimg/www.rx7...a2a4d8e69c.jpg Borg Warner EFR 8374 IWG |
Nice! That is the turbo the car would've gotten if I'd kept it. New REW and EFR. Love the direction you're going.
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I had bought a Rotary Performance fuel rail and Bosch 2200's ages ago but never got around to installing it. No time like the present. Looks good, I say.
https://cimg3.ibsrv.net/gimg/www.rx7...522f699d8e.jpg |
Originally Posted by aplscrambles
(Post 12395329)
Nice! That is the turbo the car would've gotten if I'd kept it. New REW and EFR. Love the direction you're going.
Also, I almost missed it, this was your roller long ago? Dang, that's cool! That's one of the things I like best about this forum and the RX7 community, it's so tight-knit that you can track the lineage of your car from owner to owner! :lol: |
Originally Posted by XanderCage
(Post 12395334)
Thanks! Again, it was just too hard to think that after all the work is said and done, I'd still be roughly at the power level I was before (if I had just stuck the twins back on). It's hard to say no to the 8374 when it has so much praise behind it.
Also, I almost missed it, this was your roller long ago? Dang, that's cool! That's one of the things I like best about this forum and the RX7 community, it's so tight-knit that you can track the lineage of your car from owner to owner! :lol: |
Here's something I don't hear much about but am super glad exists; Himni Racing's nut & bolt kits.
http://www.himni-racing.com/index.ph...th=229_187_190 Just the right size shiny nuts and bolts to install various parts. I got the kits to reinstall the water pump, LIM, pulleys, and alternator. I just really like the fact that I didn't have to hunt down specific size hardware, then be forced to order things in packs of 20 from McMaster or re-use my old rusty bolts from the prior engine. Here's the water pump kit installed. It definitely wouldn't hurt if I got the housing cleaned, but the super zoom-up shot doesn't do it any favors and it doesn't look quite so bad in person. I'll probably at least hit it with a soft wire brush later. https://cimg2.ibsrv.net/gimg/www.rx7...e278bcac68.jpg And here's just some of the crusty bolts I don't have to re-use. https://cimg2.ibsrv.net/gimg/www.rx7...bf30fed280.jpg |
The turbo has been test-mounted and I can't look at it without grinning.
https://cimg9.ibsrv.net/gimg/www.rx7...d42c37a3fe.jpg |
Very nice! 8374 is a great turbo!
I love mine! |
Originally Posted by estevan62274
(Post 12396045)
Very nice! 8374 is a great turbo!
I love mine! |
MMMkay. As per usual, lots of things to catch up on. Firstly, I had the old primaries I was planning on reusing flow and spray-pattern checked and they actually came back bad (they functioned, but short of spec). Glad I checked, but it got me to thinking about my fuel system choices as a whole. My initial plan was to re-use the stock primaries, FPR, and get a new FPD. I had bought the RP fuel rail a while back to tie those parts together. However, after seeing the poor showing from the injectors I figured it was also time for a new FPR, and if I'm going to do that, I figure I'll just go with the fuel system I lusted after from the start - FFE's full kit with the mini FPR and ID injectors all around.
https://cimg9.ibsrv.net/gimg/www.rx7...19dfbf0ae9.jpg Beauty! |
Here's the system all plumbed-up, I'm happy with it. looks for the most part, nice and tidy! As I understand it, the kit intends you to discard the upper hardlines and run the lengths of tube right to the firewall hardlines. I preferred to use the upper ones, I think it looks nicer, not that anyone will see it...
https://cimg2.ibsrv.net/gimg/www.rx7...9a02b612fd.jpg One problem with this routing though is the hose going from the FPR to the upper hardline. It's kinked and I'm not cool with that. https://cimg2.ibsrv.net/gimg/www.rx7...bedc939742.jpg |
Bought a 45* fitting to replace the 90* and rearranged things so the hose doesn't kink. Doesn't look nearly as good but I'll take it.
https://cimg5.ibsrv.net/gimg/www.rx7...a3e45142b3.jpg |
ACT clutch came in! And it has that Monoloc thingy. I actually didn't realize that comes with the clutch. Not bad! I went with the fairly popular HD/SS combo, and am hoping it doesn't increase clutch pedal force too much, as I'd like a stock feel. I figure if it's too heavy, I could always get the FEED "Big Release" slave cylinder or something along those lines but again, hoping its not necessary.
https://cimg9.ibsrv.net/gimg/www.rx7...4ce538a9d2.jpg Nice n' yellow. Shame it's got to be hidden in a bellhousing. https://cimg0.ibsrv.net/gimg/www.rx7...218cc93b73.jpg |
Installed the new throwout bearing and also as a precautionary measure, replaced the fork with the newer one that is supposed to be of higher strength. Don't really know if the old fork was that hi-strength version as they look identical, but I'd hate to have the thing break at a stoplight which has happened to a friend of mine!
https://cimg0.ibsrv.net/gimg/www.rx7...a449ae48e6.jpg |
Braided SS clutch line just to tie the whole thing together.
https://cimg2.ibsrv.net/gimg/www.rx7...3049290e17.jpg |
Amazing progress! keep going
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In the picture it looks like the vacuum line that is destined to be for the MAP sensor has a plastic T on it. Word to the wise, you want 1 vacuum line from the MAP sensor to the manifold with just the black filter in that line and that's it. Plastic T's can break and fail with heat and that's an easy way to lose an engine - I have had friends in the past who have lost engines to plastic T's.
You should have extra nipples on the back of the UIM if you removed emissions that you can use instead of the T. Looking good! Dale |
Thanks Dale, its those kind of tips that are why I wanted to document everything I could here. If something looks fishy I want to know about it! That T will soon be outta there.
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Alright! Finished product right here.
https://cimg7.ibsrv.net/gimg/www.rx7...1997b33a26.jpg Only not great part is the wiring harness looks pretty ugly now that it's exposed under the UIM. https://cimg4.ibsrv.net/gimg/www.rx7...c731a05ece.jpg |
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Little crooked at first-
https://cimg6.ibsrv.net/gimg/www.rx7...eaed582204.jpg But I shoved it around a bit and now it sits pretty straight. Not perfect, but I think its acceptable. https://cimg3.ibsrv.net/gimg/www.rx7...9717507fe5.jpg |
Using Neo this go 'round. I had Redline before and it wasn't bad, but I did still experience some grinding when cold which I'm hoping might be decreased with NEO. Bearings and syncros had also been replaced, so I'm hoping for a buttery smooth shifting experience.
https://cimg1.ibsrv.net/gimg/www.rx7...715afb5934.jpg |
Okay! Excitement time! Rolled out into the drive to button things up and try to start it!
https://cimg0.ibsrv.net/gimg/www.rx7...d0c340657c.jpg |
Sweet! Congrats on getting her in and ready!
Thanks for sharing... I always love checking out others build threads. I just finished putting mine back together... I need to update my thread too. Steve |
OOOkay. Lack of pictures at the moment, I just got too excited. So, I filled all the fluids, cranked it over a few times without the injectors just to build oil pressure, then enabled the injectors and YEAH! Haha! started right up no prob! Man, the exhaust note is way different. Louder for sure, but it also sounds just more like a rotary. Much more of that classic 'brap' sound. I reaaaaally love it.
Now on to the bad news... My ISC isn't functioning. So I couldn't take my foot off the pedal or the engine would choke out and die. Did some testing and found that it wasn't getting any voltage. I looked at the wiring diagram and it SHOULD be dead simple. Constant battery voltage is supposed to come in thru the EGI relay, and we don't have it. I tested the voltage at the OMP, turbo control, and purge control (the only other things left on that line now that the emissions and twin control system is gone) and they do have battery voltage. Well that doesn't bode well as I can only imagine it means a break where the ISC's wire meets the main voltage line. I tried flexing the harness all around just to see if there was an intermittent break in the wire, but I just got nothing. ARRRRRGH I WAS SO CLOSE!! Man am I frustrated. Oh well, deep breaths. I really think the only thing to do at this point is roll it back into the garage, extract the wiring harness, and open it up to try and find the source of the break. I could bodge a +12v wire to that spot, but dang that's just not the route I want to go regardless of how tempting it is. https://cimg0.ibsrv.net/gimg/www.rx7...39aeb0a11f.png |
Originally Posted by estevan62274
(Post 12399257)
Sweet! Congrats on getting her in and ready!
Thanks for sharing... I always love checking out others build threads. I just finished putting mine back together... I need to update my thread too. Steve |
Originally Posted by XanderCage
(Post 12399259)
Now on to the bad news... My ISC isn't functioning. So I couldn't take my foot off the pedal or the engine would choke out and die. Did some testing and found that it wasn't getting any voltage. I looked at the wiring diagram and it SHOULD be dead simple. Constant battery voltage is supposed to come in thru the EGI relay, and we don't have it. I tested the voltage at the OMP, turbo control, and purge control (the only other things left on that line now that the emissions and twin control system is gone) and they do have battery voltage. Well that doesn't bode well as I can only imagine it means a break where the ISC's wire meets the main voltage line. I tried flexing the harness all around just to see if there was an intermittent break in the wire, but I just got nothing. ARRRRRGH I WAS SO CLOSE!! Man am I frustrated. Oh well, deep breaths. I really think the only thing to do at this point is roll it back into the garage, extract the wiring harness, and open it up to try and find the source of the break. I could bodge a +12v wire to that spot, but dang that's just not the route I want to go regardless of how tempting it is. I did not see any details in here about the wiring harness you used. I will assume you used an OEM harness and modified it for single turbo by cutting off the twin turbo / emissions connectors. The ISC receives power from the main B/W wire that feeds all those connectors. Although the wiring diagram makes it look like all the solenoids are in parallel, the ISC is actually wired in series so cutting those connectors off also cuts off power to the ISC. |
Hah, holy nuts! Well you hit the nail on the head there I reused the old harness and lopped off the solenoid wires. Dang that diagram makes it look like that would work. Plan for today is to take out the harness and open it up (if only I had done that in the first place). I actually had a feeling something like that might be up, thanks for confirming!
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Nice progress man.
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Okay, here's a super scientific drawing of how I broke the ISC connection. As JhnRx7 pointed out, things aren't exactly as they seem in the wiring diagram. The way they are connected, is more like below:
https://cimg6.ibsrv.net/gimg/www.rx7...03ecbb0560.png The rats nest solenoids have their own "branch" off of the wiring harness that looks like you can just cut the whole thing off, insulate the ends of the wires, tuck them away, and move on with your life. However, the wire that provides the constant battery voltage for those solenoids as well as for the ISC is routed from the beginning of the harness, up and SLIGHTLY INTO that rats nest branch before its power is distributed to the ISC. So if you cut the branch off, you're also cutting power to the ISC. Hope this saves someone else from making the same mistake! |
Okay. Now that I understand the ISC problem, I performed some minor surgery on the harness and got a healthy voltage at the connector. Rolled it outside again and this time it idles beautifully! That means I was finally able to get out of the drivers seat and look for leaks, check sensors, and also snap some engine running pictures! It's such a treat to see this thing purring away after so long.
https://cimg6.ibsrv.net/gimg/www.rx7...dbd0272b3a.jpg |
Nice CNC what kinda stuff are you making
Nice build. |
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