Hub/Balancer Install

[RustmanZ]

No shortage of threads from a variety of sites on this topic but I'm still unsure on a couple of things.

If it is pertinent, this is for 96 Z28 OBDll.

From what I can gather;

the LT1 crank snout has a keyway but the factory hub isn't keyed. An after market Hub/damper (ATI etc) is likely to also have a keyway slot, will not come with the application specific key but I can likely get an appropriate one from my local Napa or similar.

indexing the damper to the hub is unnecessary as the holes in the damper are arranged in such a way as to make it impossible to bolt them together in anything but the correct orientation. If this is the case then If I can get the appropriate key, once assembled the timing marks on the after market damper should be correctly oriented? On my old SBC I would get the engine to TDC 1 before doing alot of things. Seems unnecessary for the LT1?

If I decide to reuse the old factory damper and I remove the factory hub how can I be sure that I put it back on in exactly the same spot short of scribing and index mark on both hub and crank snout? Does it matter?

I currently have the stock damper off, stock hub still in place a nice shiny looking keyed hub (ASP?) in a box and access to the correct ATI damper/Hub assembly NIB really cheap from someone who sold his car.

Kind of a lot of questions. Thanks for your patience!
Jon

[BALLSS]

If you want to put on a ATI damper you need to use a ATI hub. A stock damper won't bolt to a ATI hub. Also the ATI hub is specific to years/model of LT1. 96 hub is shorter because of CPS wheel. Also hub length varies between the F, B & Y body so just order the correct one for your car model/year. I have the ATI damber/hub, nice piece

you can press on the stock any orientation you want but I prefer to mark it and the crank while it is at #1 TDC. The damper will have one spoke that is pointed and that should be at 12 oclock with motor at #1 TDC. From a balance standpoint it doesn't mater, I just like to have the pointed spoke orientated correctly.

You can also have a stock hub keyed at a machine shop

ATI hub is keyed so just get a key for it. I can't remember if the ATI unit came with a key or I bought one at auto part store.

[RustmanZ]

Thanks for your reply .
As far as the key goes, I understand that it is insurance against the damper/pulley slipping. With the ATI is it required at stock power levels? If I have trouble getting the proper key can I just go ahead and install the hub?

Also, looking at pics of the ATI there is an arrow pointed at one of the holes.
if I remove the stock hub with the mark up at 12:00 do I install the ATI with the arrow up as well . Or is that for something else all together?
Thanks,
Jon

[RustmanZ]

...and I guess even if I didn't get the hub oriented precisely it's not like I'll ever use my timing light on it right? So, if "0" was a couple of degrees off it would 't really matter?
Jon

[Badazz 97 TA]

The LT1 hub serves no purpose like the old SBC motors as far as timing is concerned. It's basically a pulley for the serpentine belt. Stock form that is.

As long as the opti spark is installed correctly via the cam drive and/or the splines on the obd1 style then your timing is set. You cant adjust it like the old distributor days.

[BALLSS]

Rust

you can't bolt a ATI damper to a stock LT1 hub. Bolt pattern is different.

The stock hub is a press on "interference" fit and no key is used. It doesn't matter which orientation you put a stock hub on other than installed in factory position one spoke with the point on it is at 12 oclock when #1 or #6 cyl is TDC. There is no external distributor timing on LT1 car so timing marks can't be adjusted. That is done with pcm re-programming.

IDK if the ATI hub is "slightly" loser tolerance in hub ID thus relying on a key. I just use a key with it and install it just like the stock hub. The timing marks on the ATI have no use, just cosmetic, for these computer cars. It is the quality of the ATI, IMHO, that is good for rebuilt, internal (zero) balance motors that spin above 6k rpm. A stock hub & damper is fine for any stock or bolt on motor

[SSlowBoat]

Thanks for your reply .
As far as the key goes, I understand that it is insurance against the damper/pulley slipping. With the ATI is it required at stock power levels? If I have trouble getting the proper key can I just go ahead and install the hub?

Also, looking at pics of the ATI there is an arrow pointed at one of the holes.
if I remove the stock hub with the mark up at 12:00 do I install the ATI with the arrow up as well . Or is that for something else all together?
Thanks,
Jon
It's a 5/16x3/4 woodruff key, most hardware stores have them for a few cents each

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