VT knocking noise (with and without serpentine belt) - Video Clip

[losh1971]

Yeah I read the key way thing and wondered about that. I haven't seen or heard a key way problem so didn't comment on that.

 

[Skylarking]

... Reinstalled again with keyway seemingly lining up properly (as I was able to hold the HB by hand) for most of the tightening sequence finishing off with the ratchet strap and breaker bar, engine starts (and runs responsively) but a knocking noise is now present with and without the serpentine belt installed and increasing/decreasing frequency with RPMs.

Yeah not sure whether usig a ratchet strap that goes around the outside of the HM pulley is a great idea as it can damage the bond between the inner and outer hubs. I doubt the bond is designed to cope with the torque needed to get the crank bolt on. A damaged HB bond between the iner and outer hubs can cause the knocking sound you seem to be experiancing, as explained in the early part of the video below

I have checked the HB again today (in daylight) the all the bonding appears to be holding and turning as the centre assembly is rotated, but the card in the bike wheel sound remains a concern.

Maybe it looks ok when turning by hand but movement ocurs with teh engine running..

Alternatively, the reluctor rings may be bent or the CAS wasn;t alligned correctly so is hiting the reluctor rings when the engine is runnning making the card on bicycle spokes noise some kids use to love hearing... The following video may give you a hint

The keyway was clearly damaged but difficult to locate so I am guessing this isn't the first time the HB has been removed, are these replaceable I know the Buick 3800 engines have a replaceable crank/HB keyway, clearance issues for the crank position sensor also come to mind.... apart from the noise the car drives wonderful.

If the keyway was damaged, as you've found out it can throw out the timing and provide a level of unreliability youd not want. Depending on how bad the damaged keyway is, you may be able to use loctite quickmetal to reform the keyway else it may require a crank repair which is orders of magnitude more expensive.

The quickmetal repair was defined by Loctote and Mazda Auz back in the early 90's and used to resolve a problem with the 323 & Miata HB wobble caused by a incorrect crank bolt material and incorect crack bolt torque. This fault ultimately damaged teh crank keyway causing timing issues just to add to the woes.. Mazda Aus procuced a technical doc but haven't found a link to it (other than to this summary of the process)

So, check the HB reluctor rings aren't bent and check that the HB rubber bond is intact. Obviously this has to be done with the HB removed. Then check that the crank keyway isnt damaged (and if it is consider what to do, loctite repair or crank removal and repair). Then when these issues are ok, check that the CAS is correctly aligned with a test fit also checking that the HB is correctly positioned and aligned with the crank keyway and that the key is correctly inserted before doing the final fit.

Hopefully you'll work it out...

 

[tazwegion]

The keyway on the snout was damaged according to OP, I THINK it is a clearance issue with a fucked keyway. The noise sounds like it's coming from the outside of the engine, doesn't sound like rod knock to me, but I digress. This is the internet hard to tell without physically looking.

Indeed, this is the proposition I am leaning towards as well... unquestionably the key was damaged but I made it worse, so this next question is will the timing cover need to be removed to replace the woodruff keyway insert or is there a work-a-round?

Alternatively, the reluctor rings may be bent or the CAS wasn;t alligned correctly so is hiting the reluctor rings when the engine is runnning making the card on bicycle spokes noise some kids use to love hearing...

I was under the impression the CAS was only adjustable on the VN/VP as there is a locator pin behind the one on the VT.

 

[losh1971]

I was under the impression the CAS was only adjustable on the VN/VP as there is a locator pin behind the one on the VT.

Correct there is no adjustment for the CAS. Setting air gap was only applicable to VN Series 1.

 

[Skylarking]

Correct there is no adjustment for the CAS. Setting air gap was only applicable to VN Series 1.

Thats good to know... but I’d still check that alignment and clearance as much as is possible to ensure there isn’t some parts mismatch or quality issue so I can be sure that there is the required clearance to the reluctor ring(s).

 

[Skylarking]

Indeed, this is the proposition I am leaning towards as well... unquestionably the key was damaged but I made it worse, so this next question is will the timing cover need to be removed to replace the woodruff keyway insert or is there a work-a-round?

The question should be where is the woodruff key and has it drop into the depths of the timing cover running rampant making itself known to one and all when the engine is running?

In any case, it’s a PITA to fix a crank snout keyway and to get the surface running true because access is tight with most engines. But usually a damaged key way will impact timing and not so much cause the HB wobbling until the crank bolt starts to loosen, then he’ll can brake loose....

Put another way, if your key way is damaged and the HB isn’t wobbling, timing is about the only issue that should be occurring. So I’d be looking at the HB itself (for damaged bonding and/or bent reluctor rings) and at crank snout for keyway damage and searching for the woodruf key itself.

Unfortunately all this means the HB needs to come off again... More pics would be nice...

(ps: I should have made a disclaimer that I haven’t worked on a Holden V6 HB. The last HB problem I had was a 4 cylinder which made a mess of the keyway. I fixed the damage with quick metal after having a long discussion with a technical bod at Loctite (well before Mazda documented it’s fixed). That repaired crank was still going strong 100,000kms after the repair and using the original HB... Holden HB seem to be more prone to failure, guess because they a much heavier)

 

[tazwegion]

I will have time to work on the engine tomorrow, my first thought was grab a straight steel edge ruler and check for exact alignment with other pulleys, a visual check (with belt on) could easily miss a few millimetres discrepancy, failing to find fault with the alignment will see the HB removed again, this is my first V6 prior engines have always been straight 4's & 6's.