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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections. |
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06-30-2014, 08:24 AM | #1 |
Lifetime Rotorhead
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Crank pulley issues
Just when you think life is good and everything is working perfectly on your rotary rocket, the rotary gods smite you with a real WTF problem... Behold:
After taking the car out for a spin yesterday, I pull into the garage and notice this loud regular knocking sound coming from the area of the belts. I'm thinking a loose belt or failing bearings on the water pump, alternator, PS, AC or the idler pulleys. First I removed the PS belt, then the AC belt and let the car idle to see if the sound would change. It didn't, so then I removed the alternator belts (have a dual pulley because no air pump), and manually inspect the alternator & water pump. Spin both and both bearings spin nice & free with no excessive play. Then I remove the fan to see if perhaps it's loose; no issues there. Then I pull the under tray out to get a closer look at the main pulleys, and two very rusty and broken M6 studs drop out... As seen in the pictures, 3 of the 4 M6 bolts snapped within the crank boss, and backed themselves out, so I only had 1 M6 bolt holding all the pulleys to the crank, hence the noise. The 4th bolt snapped during removal. So now the problem is how to get the pulley boss off the crank with the engine in the car, so I can get the remains of those studs out and re-tap the holes as needed for new bolts. Any good ideas? I know that main crank bolt is on there good, and probably has permanent thread lock on it from when the short block was built. Figured I'll pick up the flywheel locker tool, and then get the bolt loose with a big ass breaker bar or a rented impact wrench. I know that for the FC, you're also supposed to keep the clutch depressed with something when you crack the main pulley bolt loose to prevent the Torrington bearings to fall loose when you do this. Sound like a plan? |
06-30-2014, 11:52 AM | #2 |
RCC Addict
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Sounds like a plan, but...
I'd still worry on WHY you ended up with this problem in the first place??? Over-tension the belts? Misalignment? Even if you fix it this time, will it happen again? -Ted |
06-30-2014, 12:35 PM | #3 | |
Lifetime Rotorhead
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Quote:
BTW, I just killed a 1/2 breaker bar (aided by a 3' length of iron pipe) trying to get that effin bolt off! First time I've ever broken a breaker bar, but not too surprising since it was a Horror Freight tool... |
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06-30-2014, 02:23 PM | #4 |
Sigh.....
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Sounds like a good plan. Other option is do you think you can get a drill in there and then easy-out the broken bolts?
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1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles Community Service Manual RotorWiki "Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present." |
06-30-2014, 04:18 PM | #5 |
Rotating Assembly
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I was thinking the same thing. Pull the rad to get clearance and a nice straight shot in. Pulling that front main has such potential to ruin your day (month/year) and Mr Murphy has already given you fair warning that he hates you!
Good luck!
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90 S5 Vert. JDM Tii with BNR Stage1 turbo. Pineapple Racing street port. Bonez cat-forward. Corksport cat-back with Vibrant UltraQuiet resonator. RTek 2 wZeitronix w/b. HKS EBC. Vis CF Tii hood. 3000GT wing. Ground Control coilover kit with KYB AGX shocks. Red and Black leather RX8 seats. Corksport Odura lip & bumper caps, OEM Tii skirts |
06-30-2014, 04:28 PM | #6 |
Lifetime Rotorhead
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For using the drill & easy out, I'd probably need to remove the radiator AND the A/C condenser which I don't want to do (A/C works). Removing the radiator is easy, and will be necessary to get an impact wrench in there, but the condenser can stay put for that (drill & bit is much longer than impact wrench), which is why I'm trying to muscle it off with the breaker bar first... That, plus I don't own a compressor and an impact gun; which may change soon if this thing pisses me off any more.
The good news is that I didn't need to buy that MT flywheel lock tool. A piece of stout angle iron wedged into the flywheel gear teeth, locked against the bell housing & garage floor is holding the flywheel put just fine One other thing to add... So far I've tried to crack loose the pulley bolt with nothing other than a soaking of PB blaster penetrating lube with no luck. How hot would I need to get that bolt with a torch to loosen up whatever thread locking compound is in there, and would a regular propane blowtorch be sufficient heat? Last edited by Pete_89T2; 06-30-2014 at 04:37 PM.. |
06-30-2014, 06:11 PM | #7 |
RCC Addict
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I was going to say...
Get it HOT! You will almost never get it TOO hot with propane. It might turn a dull red. I've used MAPP gas with better success. Heat until stuff starts to smoke. Then try and loosen... The downside is that you NEED to change out that front oil seal on the front oil cover - $5 part, I think. -Ted |
06-30-2014, 06:27 PM | #8 |
The Newbie
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Mazda used some no-shit threadlocker on that bolt and that's why the breaker bar broke. My 350 foot pound MATCO impact wouldn't even budge the last one I did till it was heated. A propane torch will eventually get it hot enough but I'd go with a MAPP, it gets hotter quicker and you can use a propane torch on a MAPP cylinder.
You will need to replace the front cover seal for sure and I'd replace the thermal pellet and the O ring on the bolt too. The copper washer will be okay, smear a little silicone or Loctite 518 on the face of it when you reinstall. Push the clutch pedal all the way to the floor and wedge it there before removing the bolt, I have used a chunk of 2x4 or similar in the past. That will push the E shaft forward and make it much less likely the thrust bearing will fall out. |
06-30-2014, 07:21 PM | #9 |
Lifetime Rotorhead
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Thanks guys, pretty much figured all that heat would trash the front cover oil seal & O-ring and plan to replace those. As for the thermal pellet, I'll soon find out if the shop that rebuilt this engine (Hayes) years ago replaced it with the pellet bypass plug like they were supposed to.
I rigged up a length of 2X4 cut to the right length (just under 30" BTW) to floor the clutch by jamming it against the steering wheel. Put a 1-1/4" half-round notch on one end of the 2X4 so it fits nice & snug against the wheel with a piece of rag in there to protect the steering wheel leather from splinters Good tip on the MAPP gas, I didn't know that MAPP cylinders can be used with a standard propane blow torch valve. Since I'm out of propane anyway, a full tank of MAPP it is! |
06-30-2014, 07:42 PM | #10 | |
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Do you even lift bro?
Mapp is now lpg with p or liquefied petroleum gas with propylene. So propane at around 3450 and new Map-P is around 3600 not the old 5300. You will still get around 10% more BTU out of the Map-p
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06-30-2014, 11:11 PM | #11 | |
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Also if you want to destroy the pulley mount I have a few extra I can send ya one. I also think I have a set of thermal pellet washers too.
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07-01-2014, 06:07 AM | #12 |
destroy, rebuild, repeat
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have you tried the starter trick? breaker bar on the front bolt, tie up against teh frame, then bump the starter with the key. pull the egi fuse so engine wont start, and dont burn up the starter if engine wont turn
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07-01-2014, 07:24 AM | #13 |
Lifetime Rotorhead
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Removal Success -- just got that PITA bolt off! Last night I heated the bolt a bit with a propane blow torch, but I didn't think it would matter - tank ran out in less than 10 minutes of heating, so I called it a night, and figured I'd pick up a fresh tank of MAPP gas this morning. Before I went out to the store to do that, I figured I'd just give it one more shot with the breaker bar + 3' pipe extension, and BAM it cracked loose
Next questions: Given the very limited heating, should I bother to replace the front cover oil seal? What about the O-ring & copper washer on the bolt? I'm figuring I should on both, but don't really want to wait for parts to arrive. Pictures below show condition, all seem clean & undamaged by heat. The FSM says that you're supposed to apply a sealer to the flange side of the bolt, but doesn't specify what kind. Anyone know? I assume this would be a standard Permatex grey or similar that you can buy anywhere? |
07-01-2014, 09:50 AM | #14 |
Lifetime Rotorhead
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Hey Chibs, shoot me a PM to let me know how much you want for the pulley boss shipped to 21921. Probably will cost less in the end than buying the right easy-outs or paying a shop to extract the broken studs
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07-01-2014, 12:46 PM | #15 | |||
RCC Addict
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Quote:
The seal is minimal cost. If it leaks, it's a PITA to remove and replace from scratch. Quote:
The tip of the bolt doesn't get hot, unless you're using acetylene... Also, the o-ring doesn't do that much sealing - the threadlocker + copper washer do more than an adequate job of keeping the oil from seeping outside the engine. Copper washers...I just reanneal and reuse. Quote:
Needless to state that the bolt flange needs to be clean and inspected to be free of damage? Else, any RTV would work... I usually have copper or red hi-temp stuff, so that's what I'll use. Gray will work. (I don't like the blue stuff.) -Ted |
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