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Timecode

l28et Damper bolt different than others???

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I ordered the BHJ damper for my 1983 l28et.   The damper bolt from the common Z vendors say for model years 80 and below. Some even have a spicific washer for 280zx vs other year Z's.  I was under the impression they all shared the same bolt size/type and washer. Is a different setup needed for the later 280zx model?

 

Also,  I was planning on getting the Kameari bolt or Nismo but the stepped washer, possibly creating clamping issues, scares me. Flipping the washer around mimics the OEM setup, so....

 

I did look into the KA bolt and Volvo washer setup JeffP did but after talking with Rebello, deemed it unnecessary.

 

I know red Loctite  is recommended for the install. Has anyone tried removing their damper after applying this? I imagine getting the bolt up to the required 550F to remove it would do some damage to the damper itself, am I correct?

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Posted (edited)
1 hour ago, Timecode said:

I ordered the BHJ damper for my 1983 l28et.   The damper bolt from the common Z vendors say for model years 80 and below. Some even have a spicific washer for 280zx vs other year Z's.  I was under the impression they all shared the same bolt size/type and washer. Is a different setup needed for the later 280zx model?

 

Also,  I was planning on getting the Kameari bolt or Nismo but the stepped washer, possibly creating clamping issues, scares me. Flipping the washer around mimics the OEM setup, so....

 

I did look into the KA bolt and Volvo washer setup JeffP did but after talking with Rebello, deemed it unnecessary.

 

I know red Loctite  is recommended for the install. Has anyone tried removing their damper after applying this? I imagine getting the bolt up to the required 550F to remove it would do some damage to the damper itself, am I correct?

As far as I know there is no difference between model years.  Thread size and pitch are definitely the same, but I won't swear as to the depth of the hole.

 

I would highly recommend one of the stronger bolt/washer combos, both for the higher torque capacity (at least in the case of the Kameari bolt), and the added thickness of the washer will hold that higher torque.  Not sure why rebello would say it wasn't required.  As far a worries about the stepped washer, yeah you need to measure things to make sure the washer doesn't ground out to the crank snout.  Flipping the washer does alleviate the interference issue, but also gives a bit less thread penetration for the bolt.  You can also machine the step down a bit to gain clearance. You also need to measure and make sure that the bolt doesn't bottom out in the hole, btw.

 

Also - ditch the oil slinger.  It will only cause problems for you.  The stamped steel will deform under use and cause you to lose clamping force.

 

People get way too freaked out by red loctite.  It will still come loose - you'll have to block the crank rotation well (have to do this anyway) and it'll fight you a bit but it will come out, especially with a bolt this size.  You'll find that it helps to reverse the bolt rotation a half turn every three or four turns on the way out.  You don't need to heat it to 550F.  At all.

Edited by TimZ

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OK, thanks for the tip.  

 

Has anyone here experienced issues revving to 7k and the OEM bolt backing out?  My current OEM setup hasn't given me issues backing out, my concern is with my old damper, which I feel will explode soon.  

I'm guessing most who run an upgraded damper usually run the stronger bolt setup as well. 

I know the stronger bolt allows more torque so less chance of the bolt backing out but is the OEM torque specs also accounting for the crank snout thread strength as well?  Rebello told me a new OEM bolt/washer works fine and they do 20+ engines a month the same way with no issues.  

 

Thread-lock companies say the bolt usually will break before the thread-lock gives way, hence my inquiry from others experiences. Typically, up to what size bolt needs heat to come loose without failure? I always use blue thread-lock but have little experience with red.

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9 hours ago, Timecode said:

I know red Loctite  is recommended for the install. 

 

By whom?  Thread lockers are neat, and good insurance, but Nissan didn't feel the need for any special instructions at all.  The basics of how bolts work is all you really need.  They're just clamping devices.  Don't make it over-complicated.  Much of the red Loctite usage probably comes from people who didn't do things right the first time, had problems, and are overcompensating the second time around.

 

Here is all of the effort that Nissan put in to their instructions.

 

image.png.2acdc46c2ef4b3a209f9dce4f7492733.png

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31 minutes ago, NewZed said:

 

By whom? 

 

By the posts I read here and on other Z forums, most of which are from the most experienced members this forums has.  I have nowhere else to go to get better info than this place, other than maybe the OEM service manual and all the Z modify books we all know of.   Going off the OEM service manual might be good for a stock car with the stock pulley but they might have completely changed the way they did things if the 280zxt was making 400 hp from the factory.  With the power levels my car now makes, I'll gladly take the communities advice when it comes to higher HP Z's and emulate what works for them.  

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I was just making a point.  The internet is full of advice about over-doing things.  If you're on a Ford forum they're fanatical about buying only Motorcraft parts, for example.  People slather anti-seize over every bolt if they've ever had a single stuck one.  People use lock washers and Loctite and over-torque, just to "be sure".  

 

The damper is a simple mechanism.  Just make sure the bolts fit correctly, the threads are clean, there are no burrs in any critical areas, use some blue Loctite or any other brand of threadlocker, and run with it.  Bolts don't just back out.  Most of the damper problems you read about are probably from poor fitment of the damper on the crank snout.

 

BHJ has some good stuff on their web site.  #5 in the first paper, and general installation instructions.  Notice that they don't even talk about the bolt in the installation paper, it's all about getting the damper correctly mounted on the snout of the crankshaft.  The bolt is assumed to be the easy part.  Just torque the right bolt down on top of the correct washer.  If the damper fit isn't right the Loctite won't save you, is the point.

 

I'm overdoing it myself, in this post.  Good luck.

 

http://www.bhjdynamics.com/downloads/pdf/tech/BHJDynamics_Damper_Info.pdf

 

http://harmonicdampers.com/downloads/pdf/tech/BHJ_DamperSteelInstallPress.pdf

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Take it from people who have actually raced these things. Well before the Internet was ever thought of. Put the Red loctite on. Especially if you are going to push the engine at all. 

Engine harmonics do bloody strange things. Nothing wrong with a little insurance.

 

I lost a $1,200 Tilton crank in 1977 dollars because a stupid engine builder ( not me ) used the wrong bolt on a Tilton Crank pulley. Tilton Damper had a thicker hub. Required longer bolt. Engine builder did NOT use Red Loctite. Probably would have held fine if he did.  

 

And actually... bolts DO back out. That's wire Race cars also use Safety Wire. As do Airplanes. When your life is on the line you want to make damned sure that a critical bolt doesn't come loose from Vibration.  Belts and suspenders every time.  

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You would be amazed what extended  running at high RPM's will work loose. I've seen  Accelerator Pump screws on Holley carbs back them selves off. And base plate screws work loose then fall into the Intake manifold. happens all the time. I use a Medium strength Loctite on those. Never had a single failure while racing.

 

 Rally cars have just about everything work loose if fasteners aren't Safety wired or use a Liquid retainer. Constant high RPM's and the pounding fro the roads and jumps took it's Toll. Guys who didn't Loctite everything or didn't use safety wire didn't finish Races or Rally's. 

 

You don't have to slather the stuff on. One or two drops is all that is necessary.  I use High Strength Red Loctite on Brakes and suspension mounting bolts ( Usually a larger size fastener ) and Medium ( Blue or Green ) Loctite on the small stuff.  You can't always go by colors. So always check the product Technical data. 

 

 But I'll tell yah.. I've never had a driveshaft bolt or half shaft bolt come loose or any other critical bolt in over 35+ years of Racing and Rallying that was Loctited. I have had fasteners  work loose that WERE properly torqued, had proper lock washers but Did not have Loctite or Safety wire applied. That only happened a couple of times before I learned my lesson. 

 

 

 

 

 

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Posted (edited)
14 hours ago, Timecode said:

OK, thanks for the tip.  

 

Has anyone here experienced issues revving to 7k and the OEM bolt backing out?  My current OEM setup hasn't given me issues backing out, my concern is with my old damper, which I feel will explode soon.  

I'm guessing most who run an upgraded damper usually run the stronger bolt setup as well. 

I know the stronger bolt allows more torque so less chance of the bolt backing out but is the OEM torque specs also accounting for the crank snout thread strength as well?  Rebello told me a new OEM bolt/washer works fine and they do 20+ engines a month the same way with no issues.  

 

Thread-lock companies say the bolt usually will break before the thread-lock gives way, hence my inquiry from others experiences. Typically, up to what size bolt needs heat to come loose without failure? I always use blue thread-lock but have little experience with red.

 

 Yep... seen it on Datsuns, Toyota's, BMW's and SBC.'s at various Race Tracks. Happens more on Road Race cars and Rally cars than Drag cars. Extended high RPM's and secondary vibrations are the culprit. Kinetic energy  and general destruction from a Crank damper flying off at over 7,000 RPM is NOT something you want to experience. 

 

 Edit. Red loctite on big bolts.The really critical fasteners that will result in death or destruction if it comes loose. Don't over use it. A drop or two is all that is necessary. You don't use High Strength Loctite on small fasteners because yes, you will snap them before the Loctite releases..

  

Proper Tools for the job. Proper strength Loctite for the job. 

Edited by Chickenman

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Posted (edited)

Thanks CM - you saved me a bunch of typing!

 

Interesting note on the Green (medium strength) Loctite - it is formulated to work similarly to a penetrating oil - it's intended to be usable on already assembled joints.  It's now my favorite as it's much more versatile.

 

Also on the Red Loctite - IME it's fine on "graded" (grade 5 or 8.8 or higher)  bolts 8mm (5/16") or larger.  I agree I wouldn't use it on bolts smaller than that.

 

Edited by TimZ

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1 hour ago, TimZ said:

Also on the Red Loctite - IME it's fine on "graded" (grade 5 or 8.8 or higher)  bolts 8mm (5/16") or larger.  I agree I wouldn't use it on bolts smaller than that.

 

 Yep. That's pretty much my Rule of thumb also. 

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It was a good discussion.  My preference is to do things to the appropriate level maybe with a little bit of insurance.

 

Duragg spends a lot of time at 7500 RPM, maybe higher.  He got deep in to transmission synchro design to get his trans to shift well up there.  Maybe he has some real-world L-series knowledge to pass on.  He has since switched engines but he used to have an L.  I don't know if the at's really work but it's worth a try.  Mine's just a test.

 

@duragg

 

@NewZed

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1 hour ago, NewZed said:

It was a good discussion.  My preference is to do things to the appropriate level maybe with a little bit of insurance.

 

Duragg spends a lot of time at 7500 RPM, maybe higher.  He got deep in to transmission synchro design to get his trans to shift well up there.  Maybe he has some real-world L-series knowledge to pass on.  He has since switched engines but he used to have an L.  I don't know if the at's really work but it's worth a try.  Mine's just a test.

 

@duragg

 

@NewZed

 

I'm confused - did you think that CM and I weren't talking about real-world experience?  WTF

 

Also I was relaying much of what BHJ TOLD ME TO DO when I had  one of their dampers fail.  You should know by now that I don't just make this shit up.

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I referenced duragg because he's a pragmatic guy who was actually running his race car (that he built) to 7500 RPM.  One more opinion.  

 

I've seen CM's posts since he joined various forums.  He used to be just a guy with lots of parts counter experience.  Now he writes like Carroll Smith, but driving also.  Very much like Carroll Smith, I have two of his books.  Smith's, not CM's.  The grain of salt is always in play.

 

Take it from someone who actually has spent a lot of time on the internet.

 

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I'm trying to find a good source for "red" Loctite on racing dampers, but many don't even recommend thread locker.  I used Loctite Red High Strength for ring gear bolts.  But I didn't even do that right when I look back (they say to spread maximum strength red around the bolt holes, I used high strength on the bolts themselves).  But can't find a reason to use it for damper bolts.  They don't mention it.  Just looking for the reason.  My initial point was "no need to overdo it".  Red seems like an overdo.  The overlooked details about burrs, and clean threads, and greasing the crank nose, and heating the damper before driving it on seem more important.  Red Loctite on oily threads is not much use.

 

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-4209-8.pdf

 

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6316-C351.pdf

 

 

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9 hours ago, NewZed said:

Might as well go all the way.  Don't want the crank nose end busting off and taking out a crowd of people.

 

image.png.b3c9c0fa82167688c1e2595b0a5b4b5f.png

 

 

 

I missed this the first time round, but the part you Highlighted here is the preferred solution that BHJ suggested, which I do intend to do next time I have the crank out. I guess they don't have any experience either and probably just rely in internet rumors on how to install their own dampers though.  I left that out before just because it is a bit more extreme than most will be willing to do - that and I honestly don't know that it's possible until I get a good look at the location of the oiling passages.  In absence of this solution I'll stand by what I said in my original response.

If you don't want to use loctite I don't really care - the original stuff works great if you're never going to rev past 6400.

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I already said why I even got in to this thread.  Don't overdo things.  The internet is full of people one-upping the last recommendation.  Recommending extreme measures.  Maybe he should just tack the damper to the crank with a welder.  I was surprised when you climbed on the Chickenman wagon.  I thought you would be down with the more scientific and fact-based approach.

 

All he needs is the right parts, cleaned up and installed correctly.  Blue Loctite on cleaned threads is probably fine.  Red Loctite on oily threads is probably not as good.  It's the fine details that matter, not just slathering on some red Loctite.

 

 

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8 hours ago, NewZed said:

 

All he needs is the right parts, cleaned up and installed correctly.  Blue Loctite on cleaned threads is probably fine.  Red Loctite on oily threads is probably not as good.  It's the fine details that matter, not just slathering on some red Loctite.

Th OP specifically asked about using a BHJ damper with expect use above 7000 rpm and what to use to  secure it.  I have very specific experience with this and offered my recommendation, based on several conversations with BHJ after having a  damper fail at the keyway.  He's got a BHJ damper ordered, so he's already in the realm of "over-doing it", and what to do if you're revving past 7000 is not going to be covered in the FSM.  Nobody but you said anything about "slathering on" a bunch of red loctite into a bunch of oily threads.  I ASSumed that the OP would be smart enough to chase the threads and clean it first, and it was already mentioned that you don't need to use a lot.

 

I guess I'm mostly offended my the insinuation that I'm an internet bullshitter with no experience.  Seriously?  Completely uncalled for.

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News Flash:

"TimZ and Chickenman possessed/channeling TonyD on HybridZ..."

My "ignore" button worked well... I had no clue what you guys were ranting about until I noticed the "You've chosen to ignore content by NewZed. Options" after the fact...

Imagine that, the day TonyD was not the ranting guy.

Imagine that!

  • Haha 1

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