Jump to content

Jeff G 78

Looking for ATI harmonic balancer users

Recommended Posts

A serpentine belt damper is interesting too and opens up a lot of other options

Share this post


Link to post
Share on other sites

There's a ton of opinions out there.  Sometimes the  methods used are really just making up for failings in other areas.  Proper fitment is the key for dampers, which the various instructions out there go in to detail about.

Even if thread locker is used, it too has to be used properly.  Loctite on oily threads isn't worth much.  So, it's not just a more is better scenario.  It's the details.  Red Loctite on a sloppy fit will probably fail also.  Some of these guys go "full red" Loctite, some don't even use it.  Why not just tack it on with a MIG?

One surface that's not mentioned much is the flat mating surfaces, where the clamping actually happens.  Not the bore.  Those surfaces need to be clean and flat and parallel so that no distortions are induced by the bolt.  It's a simple looking part with lots of complexity.

https://sdparts.com/attachment/306380-Installation Instructions

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

http://www.atiracing.com/instructions/Super-Damper.pdf

https://en.wikipedia.org/wiki/Thread-locking_fluid

 

  • Like 1

Share this post


Link to post
Share on other sites

I’d locktite the next stock bolt on the next rebuilt stock damper and call it good. Your not running forged pistons and running 9k rpms are you? If the problem was a bolt coming loose, lesson learned . 

I do plan on running some kind of fancy damper on my Rebello- if I ever see it- but I think I transplant my L24 damper( rebuilt) on to my L28 build. And make sure I locktite it! 

 

Share this post


Link to post
Share on other sites

Not running super high RPM, but it does run 5000-7000 for hours at a time. Races range from 7 hours to 25 hours. Once a race starts, there is no time to check over the car. That’s why most failures are pretty ugly. Had this been a street car, I would have felt a vibration or a slight miss and looked into it. In an endurance race, if it’s turning laps, all is good. Once it stops turning laps, there is a mad scramble to diagnose and hopefully get back on track. An average race costs $3000 to $4000 for prep, entry fees, tow rig fuel, and consumables. Luckily that is split between 3-4 teammates but when something breaks and you go home early, most of the weekend costs are sunk and you are left with nothing but a parts bill and a lot of future garage time. 

I appreciate all the help. 

Share this post


Link to post
Share on other sites

So was the damper a rebuilt one? It’s hard to tell from the pic. Could a out of balance damper help work a bolt loose? 

I know the Damper Doc bragged about how his rebuilds were good for 10k rpm and 400 ft lbs of torque. Never tested that , but a fresh bond on the damper makes me feel good about revving it out. 

This does make me research more about loose crank pulley bolts. 

Share this post


Link to post
Share on other sites

I feel better about the situation. Today, I filed and polished the galling and metal transfer off the snout enough that the gears will go on and off properly. It actually looks fairly decent other than one depression left from the rocking damper. 

Now to have the machine shop magnaflux the crank and fit a new damper. 

Still looking for bolt recommendations. 

ADDFAEC8-3F22-40C8-939B-E951F2C2ED05.jpeg

BF81F7A5-519A-4452-9763-6E852035DE89.jpeg

Share this post


Link to post
Share on other sites

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. 🤔

Share this post


Link to post
Share on other sites
12 minutes ago, Jeff G 78 said:

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. 🤔

On the bolt, what is the size and thread? I might match it that way. Order what you know you need in an 8.8 or stronger...

Share this post


Link to post
Share on other sites
3 hours ago, Jeff G 78 said:

I thought about not even tearing the bottom end apart, but I’d hate to get this far only to have micro cracks in the crank. 🤔

If this were a street car I would run it as is. Being a race engine I would replace the crank completely if it were mine.

I would not risk a expensive damper on that crank. IMO.

Share this post


Link to post
Share on other sites

Here is an alternate approach. Not saying it is the best.

Don't discount the fact that you have run hundreds or maybe thousands of hours on the track and haven't had a bolt come loose. Maybe you have your damper rebuilt, install it with a new factory bolt, torque it to spec, and re-torque after every race or so.

Just another perspective.

Wish you the best. Always enjoy reading your posts.

  • Like 1

Share this post


Link to post
Share on other sites

Get your new damper. Press it on.

As Patcon already mentioned. Measure the thread depth to face of damper hub ( Including washer )  with the depth gauge  of Vernier Calipers. Subtract 5mm from measurement to make sure bolt doesn't bottom . Call ARP and tell them you need a Crank damper bolt Xmm x Ymm x Z mm. I'm sure that they will have something close enough. They make all sorts of single use fasteners that are not listed Online nor in their Catalogs.  

Edited by Chickenman

Share this post


Link to post
Share on other sites

Thanks CM. I checked ARP’s site first and they list lots of damper bolts, but nothing specific in a M16x1.5. I will call them once I have the damper and see what they have. 

The washer seems to be just as important. I’m guessing they have a something that will work. 

I did verify that the Kameari bolt/washer is the right length for the BHJ damper that I am now going with. 

Jonathan, I thought about just using a rebuilt stock damper, but decided to try to make the engine more reliable this time around. 

Share this post


Link to post
Share on other sites
On 7/11/2018 at 12:19 PM, Jeff G 78 said:

Thanks CM. I checked ARP’s site first and they list lots of damper bolts, but nothing specific in a M16x1.5. I will call them once I have the damper and see what they have. 

The washer seems to be just as important. I’m guessing they have a something that will work. 

I did verify that the Kameari bolt/washer is the right length for the BHJ damper that I am now going with. 

Jonathan, I thought about just using a rebuilt stock damper, but decided to try to make the engine more reliable this time around. 

Ok, I know the OP has resolved their issue but here is my 2 cents in case anyone else is asking this question / reading this thread in the future.

 

I run an ATI super racing damper on my very modified street driven L28 because it really is one of the best non-fluid dampers out there.

 

Yes the bolt does need to be longer than stock and my engine builder had one machined for me.

 

The stock pulley is 150mm but the ATI is 70mm. So it is turning the alternator and water pump at less than half the stock rated speed.

 

Cooling:

 

Have I ever overheated idling in traffic on a 30c summer's day? No. Has the temp gauge gone higher than before - totally! The gauge has gone to just over three quarters which it never did with the stock size pulley - it rarely passed half way before.

 

The temp gauge fluctuates more on and off the power than with the stock pulley.

In reality a mechanical water pump / fan will be spinning at half the speed that the stock pulley would drive them.

Charging:

 

I had my alternator rewound / uprated to 90A constant capability and a slightly smaller pulley put on. At an idle of 900rpm the volt meter dances between 12v and 13v. At 1200rpm it's steady. The LED headlights do flicker at idle between 900-1100 rpm.

Most alternators do very little below 1500 spindle rpm.

Other options:

 

Kameari do a fluid damper with two pulley sizes one closer to stock and one that iirc is about 110mm (ATI is 70mm). See RHDJapan website for the street version.

 

Another benefit is that the fluid damper will never need to be rebuilt.

 

BTW - on my stock damper on original stock engine I found it to be loose and moving 1cm back and forth!! Gulp! So it does happen even on bone stock engines.

Edited by AK260

Share this post


Link to post
Share on other sites

Ok, I know the OP has resolved their issue but here is my 2 cents in case anyone else is asking this question / reading this thread in the future.

 

I run an ATI super racing damper on my very modified street driven L28 because it really is one of the best non-fluid dampers out there.

 

Yes the bolt does need to be longer than stock and my engine builder had one machined for me.

 

The stock pulley is 150mm but the ATI is 70mm. So it is turning the alternator and water pump at less than half the stock rated speed.

 

Cooling:

 

Have I ever overheated idling in traffic on a 30c summer's day? No. Has the temp gauge gone higher than before - totally! The gauge has gone to just over three quarters which it never did with the stock size pulley - it rarely passed half way before.

 

The temp gauge fluctuates more on and off the power than with the stock pulley.

In reality a mechanical water pump / fan will be spinning at half the speed that the stock pulley would drive them.

Charging:

 

I had my alternator rewound / uprated to 90A constant capability and a slightly smaller pulley put on. At an idle of 900rpm the volt meter dances between 12v and 13v. At 1200rpm it's steady. The LED headlights do flicker at idle between 900-1100 rpm.

Most alternators do very little below 1500 spindle rpm.

Other options:

 

Kameari do a fluid damper with two pulley sizes one closer to stock and one that iirc is about 110mm (ATI is 70mm). See RHDJapan website for the street version.

 

Another benefit is that the fluid damper will never need to be rebuilt.

 

BTW - on my stock damper on original stock engine I found it to be loose and moving 1cm back and forth!! Gulp! So it does happen even on bone stock engines.

IIRC, your engine builder used the Kameari crank damper bolt and washer Ali.

Share this post


Link to post
Share on other sites
IIRC, your engine builder used the Kameari crank damper bolt and washer Ali.

Nope Jon, he used the washer but the bolt was too short for his liking on the ATI so he had one made just like it but longer ...

 

f2c7ea42-c25f-4ee6-a1a2-7a06eb1f8fa4.thumb.jpg.ea8eaf04ad7ee77d7fb149d8a70f4d3f.jpg

 

Kameari on right new on left with washer on. You can just about make out that the new bolt is about a bolt head longer.

Share this post


Link to post
Share on other sites

Oh and I forgot to mention, if you are attached to the classic look of a mechanical fan like I am, then you have to space it forward by about 7mm to clear the stickie outie bolts on the front of the damper.

 

Share this post


Link to post
Share on other sites
Nope Jon, he used the washer but the bolt was too short for his liking on the ATI so he had one made just like it but longer ...
 
f2c7ea42-c25f-4ee6-a1a2-7a06eb1f8fa4.thumb.jpg.ea8eaf04ad7ee77d7fb149d8a70f4d3f.jpg
 
Kameari on right new on left with washer on. You can just about make out that the new bolt is about a bolt head longer.
I stand corrected. It works fine on the Kameari damper :)
  • Like 1

Share this post


Link to post
Share on other sites
Oh and I forgot to mention, if you are attached to the classic look of a mechanical fan like I am, then hounded to space it forward by about 7mm to clear the stickie outie bolts on the front of the damper.
That's true with the Kameari damper too. I clearanced the back of the fan blades by about 1mm to miss the damper. I couldn't space the fan forward because my fat radiator is in the way.
  • Like 1

Share this post


Link to post
Share on other sites

I got around to installing the BHJ damper today.  It went on great using the crank bolt to draw it in.  The 0.001" interference fit made it tighter than a stock damper, but it pulled in very easily with the bolt.  The Kameari bolt and washer were just the right length.  The only thing I need to do now is fabricate a new pointer as the scale on the damper it forward of the pulley rather than behind it like the stock damper.  Since the whole reason for the engine teardown and new damper was a loose crank bolt, I used red Loctitie this time around.  😏

IMG_1098.JPGIMG_1099.JPG

Share this post


Link to post
Share on other sites

That is one sexy bit of kit!!!!! Nice work.

 

This is what I had to do - it's rather large but it will never vibrate onto the damper especially as it's 2mm thick steel ;)

 

 

IMG_0140.thumb.jpg.4e44d0a2327f3fd0eea3d3226ed8e0a7.jpg

 

 

  • Like 1

Share this post


Link to post
Share on other sites

I had an ATI dampener on last year's race engine and we had no issues. This year's  engine is a rebuild using parts from an earlier race engine. That engine had a BJH dampener which if not kept oiled begins to rust pretty quickly.  Inspection of the crank months ago revealed no damage or scoring. Today I got a call telling me that the inside of the dampener was damaged. I will post a picture tomorrow once I get a chance to go see it. An ATI is on the way. We did not install the BJH so I'm unsure why.

  • Like 1

Share this post


Link to post
Share on other sites

The first photo is of the internal scoring on the dampener. There was no marks on the snout of the crankshaft and the machine shop was of the opinion that the damage was caused during the installation process.

The second shows how a three day race in the pouring rain can result in some serious surface rust.

Damp1.jpg

Damp2.jpg

Share this post


Link to post
Share on other sites

Wow!!!! That is a very poor show for a high end object of desire.

Maybe BHJ made it that way as a "feature" for it to feel at home in a Datsun! ;)

Will you be sending it back to BHJ?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.