Dragonfly Posted March 20, 2008 Share Posted March 20, 2008 I had an issue with a bolt backing out of my Fidanza flywheel again... even though I had red loctite on them I had two come out and one that made a projectile of itself causing the destruction seen in the pictures below. I forgot to take a picture of the "damaged" bolt but lets just say it is not any better than the rest of the parts. Needless to say none of the parts shown are salvagable. Dragonfly Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted March 20, 2008 Share Posted March 20, 2008 Daumm.... which bolts? flywheel to crank bolts, or pressure plate to flywheel? Quote Link to comment Share on other sites More sharing options...
datsun40146 Posted March 20, 2008 Share Posted March 20, 2008 The frist thing I though when I saw the title was "man he broke that tranmisson already?" At least the flywheel didn't comeapart and leave you with more damage than it did. Sorry to have this happen to you, but I'm sure you'll have it up and running in no time. I dunno what I was thinking, I thought you were RB26 J.solxxxxx guy who sawpped in that RB26DETT, thats why my comment is a bit funny... Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 20, 2008 Share Posted March 20, 2008 http://forums.hybridz.org/showthread.php?t=124421&highlight=flywheel http://forums.hybridz.org/showthread.php?t=123299 Post#5 I am going to need to get to the bottom of this issue. I have a Fidanza on my tool bench that needs to go in with the Z32 trans in a few weeks. Locktite RED will let go at high temperatures. Maybe that's the issue here. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted March 20, 2008 Author Share Posted March 20, 2008 Daumm.... which bolts? flywheel to crank bolts, or pressure plate to flywheel? Pressure plate to flywheel. Dragonfly Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 20, 2008 Share Posted March 20, 2008 http://www.acehardwareoutlet.com/(2wes5r55u1spqlqxb0ncbd3q)/ProductDetails.aspx?SKU=1000003803 Max Temp 300F. The lightweight flywheel is going to heat up MUCH quicker than a heavy steel unit so the temp cycles are going to be higher in frequency and amplitude. This could cause bolt loosening AND locktite failure. This is a HIGH TEMP red locktite good for 450F http://www.gizmosindustrial.com/servlet/the-34496/Detail Here is another claim of High Temp thread locker: http://www.solomotoparts.com/product.php?productid=25419&showfull=Y Might want to go with safety wire on those bolts. Quote Link to comment Share on other sites More sharing options...
woldson Posted March 20, 2008 Share Posted March 20, 2008 Now that would make me very angry!!!!!! Sorry about that. Maby a small tack weld that can be grounded off later? With that much damage that is what I would do. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted March 20, 2008 Share Posted March 20, 2008 I think there is something wrong. Aluminum expands more than steel when heated. I'm wondering if your holes were alittle worn or otherwise too big? Are there helicoils in the holes? How much thread engagement did you have? What bolts? What torque on the bolts? Reason I ask that is that I've run GM aluminum flywheels for circle track and on the street in a z with a 327/muncie 4 speed and never seen such a problem. Quote Link to comment Share on other sites More sharing options...
woldson Posted March 20, 2008 Share Posted March 20, 2008 Opps, guess you can't tack it, sorry. Was not thinking about that appently. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted March 20, 2008 Share Posted March 20, 2008 I would be safety wiring all the pressure plate bolts together. At least do 3 groups or 3. best way is to torque all your bolts down and then break out the punch and drill and drill a whole though the outer left corner of the bolt. and then take a long piece of safety wire and make a loop through the first one and then take some safety wire pliers and spin it to the next bolt and lace it through that one and then keep going to the next one. Then your done!! or use this method to drill the heads of your bolts http://www.ekartingnews.com/NewToKarting/safetywire.html Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted March 21, 2008 Author Share Posted March 21, 2008 I definately think it has to do with the differing rate of expansion between the aluminum flywheel and the steel bolts. The bolts were a metric grade that was aproximately an ASE grade 5 each bolt had an allen head with a built in washer and shoulder, I attached each bolt using red loktite and a lock (split type) washer, I used my torque wrench and tightened them in a criss cross pattern in 3 ft/lb incriments to a total of 12 ft/lbs. I was very careful in doing this because I had a bolt come out before but that was because the bolts were to long and bottomed out. I did not think about the fact that the flywheel might exceed the breakdown temp for the red loktite and I am not sure if that was the case as the two bolts that were still fully attached were also still "locked" with the loktite. I am thinking at this point that it was probably a combination of many things all combined to create a freak accident. I will also agree with the comments about using safety wire in the future and make a personal recomendation to anyone who is going to applying heavy shock loads to a light weight aluminum flywheel - be safe and use lock wire on all the pressure plate bolts to insure they will not back out - the other thing I am going to start doing on a regular basis is remove the starter and use a telescoping mirror to visualy inspect the bolts (I will put a dab of "torque seal" on each bolt after assembly) at least monthly or prior to a race. Dragonfly Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted March 21, 2008 Share Posted March 21, 2008 FYI any steel bolt should stretch .004 to .006 inches to hold. 12 lb-ft isn't going to achieve any measureable stretch unless it's really small diameter. I'm assuming that these are approximately 8mm bolts??? If so the torque should have been almost double that figure at around 21 lb-ft. I think that could certainly be part of your problem. In aluminum it is desirable to have two bolt diameters of thread engagement when tightened IMO. In cast iron 1.5 bolt diameters usually gives sufficient holding strength that is equal to the bolt, depending on grade of course. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 21, 2008 Share Posted March 21, 2008 Locktite softens with heat and then sets up again when cooled if, it didn't get excessively hot. Bolts that were still locktited are not indicators that the locktite did not fail. Safety wire sounds like the end-all. Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted March 21, 2008 Share Posted March 21, 2008 Are you going to be able to replace the bell housing,or in other words is your trans ok? Any way around definitely get yourself some wire and one of thesehttp://www.aircraftspruce.com/catalog/topages/nutsaftblok.php,even if the problem lies elsewhere-cant have that happen twice. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 21, 2008 Administrators Share Posted March 21, 2008 I used my torque wrench and tightened them in a criss cross pattern in 3 ft/lb incriments to a total of 12 ft/lbs. S30 Haynes says 17lbs S130 Haynes says 14lbs '78 FSM says 12-15lbs Last weekend I installed a clutch for a friend with an S130. I don't recall exactly what the min/max was, but 20 was 'nominal'. Sorry to hear about your troubles. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 21, 2008 Share Posted March 21, 2008 Another job for JB WELD! juussst playin. This is crazy! Good thing your ok and the explosion didnt cause any further damage! (ie. YOU!) Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted March 21, 2008 Author Share Posted March 21, 2008 I am certainly learning a few things here and I hope others are as well. The reason I used 12 ft/lbs for the bolts is because of the fact I was using steel bolts in aluminum threads, I also felt that the loktite and lock washer would take care of keeping the bolts in place. The bellhousing is history but the transmission is fine (B.W. T-5), I think I may have a line on a replacement bellhousing already. Dragonfly Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted March 21, 2008 Share Posted March 21, 2008 Did you clean the bolts and bolt holes before you put the locktite on? A tiny bit of grease will negate loctite's effectiveness. The discussion of the differing rates of expansion interests me. I doubt it was a factor. If Al expands at a greater rate than steel (~2X http://en.wikipedia.org/wiki/Coefficient_of_thermal_expansion), the bolt hole would get larger relative to the bolt. I'm not sure that this difference would be enough to have much of an effect on the clearance between the threads. Regardless, the locking of the bolt in the threaded hole is effected by the "stretch" or springiness of the bolt as the thread engagement pulls the end of the bolt away from the head. (everyone needs this book: http://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069/ref=pd_ys_iyr25) The expansion ofthe Al in the orthagonal direction would actually add tension to the bolt. It looks like you had insufficient torque. 12ft/lbs is not very tight. A mis-calibrated torque wrench could exacerbate the problem. Sam Quote Link to comment Share on other sites More sharing options...
johnc Posted March 21, 2008 Share Posted March 21, 2008 Some of the things I learned about thread locking: 1. Thread locking liquids do not work well with plated fasteners. Plain steel or black oxide coatings work best with thread lockers. 2. Safety wire just keeps the fasterner from flalling out and it will not hold torque because the wire stretches. The part will eventually fail due to the loss of fastener torque. For those lazy fabricators/racers, safety wire is dangerous: due to the hassel of removing and replacing safety wire, fasteners are not checked for proper torque during a routine "nut and bolt" on the car. 3. Vibration is the the number one cause of fasteners losing torque (other then improper tightening). Reducing the vibration a fastener is exposed to will increase its ablility to hold torque. Suprisingly, hardened washers are an effective tool in reducing the vibration a fastener "sees". 4. There are many mechanical thread locking washers. One of the most effective ones is called the Nord Lock or Wedge Lock washer. It uses tension instead of friction and is effective in high vibration environments. I've used these on my old 240Z after I solidly mounted the engine, trans, and differential. They stopped parts from falling off the car after Loctite failed. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 21, 2008 Share Posted March 21, 2008 If Al expands at a greater rate than steel (~2X http://en.wikipedia.org/wiki/Coeffic...rmal_expansion), the bolt hole would get smaller relative to the bolt. I'm not sure that this difference would be enough to have much of an effect on the clearance between the threads. If it did, it would indicate that the bolt would be held tighter, not looser. Nope, holes also grow in size with thermal expansion. So then the hole will end up growing at twice the pace of the bolt, making it easier to loose torque. Since you said originally the bolts were bottoming out, did you just get shorter ones? I wonder if that had anything to do with it. Wasn't there talk of some people drilling the holes out so that wouldn't happen? Mario Quote Link to comment Share on other sites More sharing options...
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