UR-GHENT MESS-Z-G..My Z's hurting worse than this spelling!

[Guest jjohart]

Beware if you've not heard from me on this board in a while, as my mechanical abilities need again be defined as not suited to self-service repair of anything underhood, and my Z has had its Mass inspection done by my garage, and I paid, got in the car and noticed a brake warning light, even w. handbrake down, and I started in 1st moving fwd. a few feet, sensing no brake resistance, i.e rolling back in neutral as well (5 speed).

My mechanic came out and saw that the fuel and engine temp gauges were reading 100% (digital dash...funny, I had 1/4 tank when I first started it 4 feet and 30 seconds earlier). He popped the hood and saw the coolant res. nearly empty, the belt nearest the fan completely off, warned me to shut off the car immediately "overheating"..and noted that the bolt had come off the harmonic balance shaft.."not good".

He theorized that the bolt had somehow been coming loose for some time (he had in fact seen this happen 2 years ago, and tightened it, telling me if he hadn't caught it then, it could have resulted in catastrophic engine failure). He looked w. flashlight for bolt around underpan, but this was at close, so until tomorrow AM, the Z is sitting there for them to push onto a lift...I sure as hell wasn't even going to start it to back it into an O/N park space, not w. the possibility that the crank could have siezed...but his cursory examination suggested-his commentary before leaving-that the shaft seemed to be intact, so the bolt likely may have tossed off a while back.

I have had this car in the body shop for almost a month (new spoiler/side skirts/fender 2.5K respray, etc), and used it 2-3 days, 3 hours/80 miles total in the last month. I had no driveability issues of note, which is not to say I was using a lot of boost, just warmupability country cruising on B roads in moderate temperatures..no weird readings or noises either.

I have confidence in this mechanic and his shop tech, a former Nissan mechanic, so I don't think they'd tell me the engine's fried to get me to buy a LT1 or an engine swap...they've had quite enough of me with all minor cons I asked them to make a 2005 out of my 83 with (intercooler plumbing interference w. local maintenance items, xenon lights, boost controller wiring, custom stereo fuse issues, lean-itis-cured by unplugging the damn oxy sensor!).

The help I am earnestly requesting from those that might be familiar w. my year and model Z, and the mods (again NPR I/C, custom plumbing, DSM BOV, modified POV, 3 inch exhaust, CAI, 19lb slight lightened stock/OEM material flywheel, 420lb rated Spec clutch, 67K miles, 5 speed, new brake pads/rotors, springs/shocks, clutch brake booster-whatever the hell it's called, etc, etc) IS:

1. Does anyone know the Nissan Part # for the bolt for this whole damn balancer shaft/Watson clip...forgot the name..etc, etc. My mechanic looked like it might take weeks to order one, so if Nissan N.A no longer carries it, or stocks it only out of Myanmar w. 33 week backorder, who might stock it and ship/sell w. what for a price to expect?

2. Since the mechanic seems mystified fairly in that the said missing bolt was found loosening 2 years ago, what tightening specs should he use for the new one..he said "with regular cars, we just adjust to factory specs", suggested he might add a bit of lug/bolt holding grease (again, I forget the exact additive he mentioned, but I would be open to forwarding suggestions for what product might keep this buggery bolt from flying off, assuming the rest of the engine isn't trashed).

3. Following last comment, why in whoever's name (some Japanese/German engineer liking straight six multiple belt designs for mucho service costs..Audi? BMW?) does this bolt seem to want to fly off? I don't think there's a machine shop east of that Dr. Seuss town that did everything twice to assure they had one of everything nice (oops, I think that was Jaguar w. having two XKE's so one could possibly always be running!)..but is there a bolt or bit I could fit for bolting this bolt to the bolt that oft will bolt?!!?

How about a lead anchor trailing from it to the ground...that would seem a way of at least finding it when it pops off!!! Sense my sardonic frustration, and pompous prose...I apologize...again, my attitude of wanting a 350Z out of my 22 year old car, low miles, all rep'l parts and gentle driving habits...IF I had driven out of his shop tonight, I've NO DOUBT I would have driven UPHILL om route 9 west's ski hill-like (medium difficulty/double blue square ski sign icon equivalent, i.e 7% grade+/-?) roadway in Natick, not reaching my house a mile away before my engine was completely trashed.

I'm so glad I know an idiot light when I see one (might need to be on my head for keeping this car)...but I guess I am worried this harmonic balancer shaft bolt blow off issue is like a cork placed on the slave deck filled with winos on a large ship they've been put on blindfolded into and told if they find the plug and pull it, they'll have a lifetime supply of fine wine....a recipe of life's little last luxuries turned slightly excessive, but as Dicken's said might well "reduce the surplus population". Hey it ain't my fault my car is functionally illiterate..but why the heck is it doing it repetitively? Where's the stressor...or is it just self-destruction by design tolerance sloppiness...is this why Nissan still ain't no Toyota?

What the phuuck...maybe I should use that bolt for hockey!

Wish me luck...death by Z scenarios appreciated..preferably w. person or force of darkness responsible for bolt-projectile events (poor old Japanese car thinks its a Jaguar...with all I've spent on it, no wonder!).

Bye

John

Natick, MA

P.S Smartarse bonus question/#4: So, if the optimum bolt tightness is reaffixed/reattained, and all crankery and other belts and drive components are luckily left undamaged...is it possible said unknown force of physics, idiots unknown or some other dark matter would then likely go down the line, so I might see the bolt totally affixed if the NEXT TIME I'm NOT SO LUCKY/SMART to catch THE NEXT PART somewhere on the OTHER SIDE (of the crank driveline) before I do the usual drive down the road blow engine thing I seem destined to....................what is the next most likely part to take the role of engine boomerang toss bit..so I can proactively duck, cover and try to catch it?

Seems to me it might very well be something I was warned about, that my flywheel could cut right through the trans hump and cut my manhood even more apart than Judiaica Nissanica would have originally devised (any bets? gentlemen, start your mechanical recircumcisions!).

In a word: Ouch

P.P.S Query #5: Since the helpful first reply below suggests a two part balancer design could cause bolt failure over time "making it one bitch to set timing on" (SIC), can anyone tell me/thereby my mechanic, what the timing stock settings might realistically be, if in fact they replace this entire shaft (which probably is economic second moon lunacy in labor cost as well)..and if those timing settings should be any different for the modifications I have on my car as well (forgot to mention there's an adjustable Bosch FPR set currently to 7psi over stock, all other mods mentioned above).

Cut to the quick end: isn't bad timing on an engine kind of like having the woman you lust after finally say she wants you and then the bolt pops and you lose your nerve/libido cuz' her giving into your every whim popped your subconcious nerve center, leaving you with nothing left to go for her with (or anything else?)..

or is it like having a good heart but a pacemaker which got thrown off by freak circumstances like standing near a microwave oven (freak occurence producing untoward heart damage...aka the bolt that flies off my h.balancer and the engine in turn in all directions?)

Neither metaphorical choice is more than one single word: Ouch (repeated ad infinitum).....

Thank you, magic power of entropy, which kills all things on earth except the rocks, sand and inner mantle and core (journey to the centre of my Z...soon to be a major roadside automotive disaster worthy of the greatest evolutionary discovery...ZX's to ZX's, dust to dust). Ouch X Infinity (actually kinda like the old QX4's!)...

I'm going slightly mad/losing my religion..bye!

[MusPuppis]

I cant answer with any direct certainty but I've seen one crank bolt come off in my lifetime and what a site that was. It came off a 302 a friend had dropped into his 67 Mustang. It popped off at about 5k RPM and the pulley came off with it.

 

Thankfully no one was killed - but god damn.. The carnage was extensive.

 

The culprit? The bolt was improperly tightened. Its possible your bolt was improperly tightened at some point and when put back on originally, was somehow or another improperly put on again.. and thus failed.

 

Other possible options: (these are just hypothetical.. others more knowledgeable than myself would confirm their validity or point at me whisper "moron").

 

1. Over tightened? Is it possible this could stress the threads on the bolt or shaft, there-by loosening the bolt enough so that it doest really tighten down like it should.

 

2. The balancer is bad. On 302's the balancer is a two part design that can fail over time, causing the balancer to slip a little. Throws the balance off and makes it one bitch bastard of a job to time the engine, heh. I've not taken a look at the l28et's crank pulley, so I dont know if its designed that way or not. If it was bad its possible (maybe, heh) that added vibration worked the bolt loose over time?

 

3. Cross threaded in some way?

 

4. Really weird bad luck?

 

Sorry I cant be more exact.. thats just what comes to mind. I'm sure those far more knowledgable than myself can shed some more light on your problem.

 

recipie of life's little last luxuries turned slightly excessive,

 

If my last breath is taken in the presence of excess eden-esque existence, consider this life well lived.

[Cruez]

That is one heluva read....

 

 

To the quick... I have never heard of one coming off....

[johnc]

They do come off and balancers do self-destruct. Proper torque and chemical locking are important. If you install a new crank bolt, re-check the torque after a few hours of engine running.

[mario_82_ZXT]

If it was already loose, and just retightened, that might be a problem.

 

Jeff P and Tony D have commented on this before I believe.....

 

The FSM states that you shouldn't reuse the bolt and washer, but others have stated that it is fine unless the washer has been damaged or overtightened.

 

I believe one of the best ways to fix this is to get the bolt from NISMO and the washer from a certain model Volvo and machine it down, or something to that extent.

 

It might be outlined on Jeff P's website, or maybe you could send him a PM, but I know I've read about it before.

 

I've alse read story about the balancer coming off and going through the radiator or sometimes through the hood.

 

Mario

[Guest jjohart]

Mr. Jeff has been kind enough to inform me further of the dire likely circumstances of my bolt's impact on said damper...he will hopefully not kill me as well for lifting/repro here (for the benefit of all), FWIW (I ask members who kindly read to consider a reply here as to whether its really likely killed my whole motor, and what advantages this Volvo/weird Euro Nimso part replacement has on durability..I simply don't understand (!):

TEXT BELOW REPRO'D W.O AUTHOR'S PERMISSION for non-commercial purposes only..with gratitude from J.Hart, replicator!

Well sorry to hear about your problem. Generally if the engine is run that

way for a time the damper will end up eating the crank shaft, and possibly

shearing the woodruff key.

Most of the time the crank can be repaired, I have even heard of cutting a

slot in the opposite side of the crank snout to fix the damage to the crank,

but that is extreme cases.

You will want a Volvo damper washer that you find on the B200 and B230

engines, which is just about every Volvo until 1990. You will have to

machine the washer to size on the washer OD to get it to fit the Nissan

damper. I haven't verified the bolt yet, but I do believe the Nismo bolt for

the Euro damper is what you want. I have to call them and order one, I tried

ordering a stock LD28 damper bolt from Nissan but it was only 35mm so I am

still not totally sure what application the bolt came off of. I do know it

is a Nissan part, I just need to find the part number.

I found a long bolt (45mmlong) when I was pulling an LD crank one time the

bolt looked exactly like the stock bolt except it was 45mm long in stead of

the 35mm standard length. I had to shorten the bolt to 40mm to use with the

Volvo washer and it worked out perfectly. I have torqued the bolt to 160

foot pounds, but have changed the torque to 140 foot pounds with RED

locktight and that has turned out well. Anyway, if you go that route with

the damper bolt and washer you will not have any further problems.

One thing though, don't go for the impact wrench, or anything like that.

Pull the starter and wedge a good screwdriver in the flywheel teeth to

torque the bolt. NO put it in gear, apply the brake, or anything like that

to try to tighten up the bolt, it will not work. You need a good positive

torque, and to do that you need to hold the crank fixed to tighten down the

bolt and get accurate readings.

hope that helps, and you can repair your engine.