zigspeed10

I'm installing an ATI Damper. 10% underdrive No AC. Part number 917279.

When installing the damper to the damper hub, there are 6 counter sunk torx bolts and I have installed those to the 16 ft/lbs. There are also 3 more counter sunk holes that are the same size holes as the 6 others. There are 3 supplied counter sunk torx bolts that are larger and don't fit in these holes.

The 3 threaded holes on the damper hub are sized for the larger bolts.

So the possible problem is that the 3 holes on the damper were not drilled and counter sunk for the larger size bolts. Attached are some pics to help illustrate. Hopefully these three extra bolts are not needed. ATI is not open today to take calls so I thought I would ask here.

Thanks

SouthernSon

I can't help you today but tomorrow maybe you should call Dale at TachItUp Motorsports in Dayton. He will be glad to answer your questions. Those guys have done a lot of good work for me on my 2 vettes. I like their work so much I haul the vettes up from Nashville, Tn. Never have done me wrong. Nice folks.

travisnd

Interesting... looks like the damper design has been changed slightly since I installed mine. Mine came with 12 holes in all. It attaches to the hub with 9 and the 3 remaining are to install another pulley on the end. The additional pulley would be used in a race application running a dry sump or a vacuum pump etc. I had 6 of the smaller ones like you've installed and then the 3 larger ones, and then 3 holes left open. Yours only has 9 holes. It appears the 3 others have a dimple where they would have been but weren't drilled. It's odd that you can't install the 3 larger bolts, but that the hub is drilled for them.

I just went to the garage and snapped a picture of mine...


Not to confuse you, but here's an install shot. The unit I received had been on the shelf for a long time and still had the 3 cap headed bolts that used to be used before they started using all counter-sunk hardware for y-body (Corvette) applications due to lack of space between the steering rack. I had to send the balancer back to ATI to have those holes machined to accept the proper counter-sunk bolts in place of the 3 cap screws. Even so, this picture still shows you the 9 bolts and 3 open holes vs. yours with only 9 holes in all and 3 "dimples".




EDIT - the white sticker on the front should have the installation instructions. If I remember correctly it says to use blue loc-tite on the bolts and has a slightly different torque spec on the smaller vs. larger bolts. I think it says to make sure you install all 9 bolts. What's yours say on that sticker? Either ATI changed the design for y-bodies and you only need the 6 of them or your damper wasn't machined properly.

RAFTRACER

Someone a little closer put your ATI dampner on

SouthernSon

Yeah, but he needs an answer quick.

zigspeed10

Called ATI today and they said my damper must have been machined incorrectly. I bought it through Summit and they are sending me a new one. I'll post up if I have anymore issues.

Thanks

travisnd

Let us know how it goes. Was it supposed to have only 9 holes and the 3 were too small? Or was it supposed to have 12 like mine?

davidfarmer

The old design didn't have the 3 bolts countersunk, and used normal hex head bolts. Problem was, the hex bolts would grind into your steering rack during hard braking.

I'm glad they added the countersunk option, although I always just left them out. With loc-tite and proper torquing, they never came loose. If you overtorque the however, it will vibrate the entire damper off of the front of the engine (this I found out the hard way after an emergency cam change)

SouthernSon

Good to know, David.

zigspeed10

Just to give you guys an update. I went through 3 dampers from summit, all with the same defect. We had the fourth damper shipped from ATI after confirming what they had in stock was not defective. It was a little frustrating but the customer service from both Summit and ATI was top notch. Here is a pic of the good damper installed.

travisnd

Well that's annoying as crap, but nice that you got it figured out.

davidfarmer

glad it worked out, but leaving the extra out works too. Just loctite and go! Saves a bit of weight too