1Z TDI crank bolt etc

[monkey magic]

Hi all, rarely post but read here often.

So, I just side stepped turning my 1Z engine into scrap yesterday: after replacing the serp belt tensioner (bush had gone) I noticed there was a lot of pulley wobble (harmonic balancer) at the crank. Also recently starting has been difficult, and after reading about crank nose issues I found a post about the lower gear slipping, causing timing to shift and a light bulb appeared above my head. Id thought the hard starting was air in fuel or similar.

Anyway, I got the pulley off and it was the gear running out, the crank bolt came off with no effort at all, and the D shape inside the timing gear was no longer D shaped : (

The crank nose seems to be fine tho, just the timing gear appears chewed. so I plan on fitting the timing gear and harmonic balancer/pulley from an AHU I have spare. I understand as long as they fit properly (crank nose not chewed) and I properly torque the NEW bolt up, all should be well.

1st question, is there an issue with that? I assume theyre compatible (AHU bits > 1Z crank)

2nd question, somebody I know suggested using a crank bolt for a 2.5tdi, and also using a diamond washer. Anybody here ever done this? How would the washer affect the torque procedure? I like the idea of the kick ass washer, but also like the concept that standard is good enough, especially if it could mean I unwittingly over torque or under torque the new crank bolt due to the extra friction...

Cheers all, monkey 

[vanbcguy]

I personally would buy a new correct 12pt bolt at the dealer and torque it to spec. They work perfectly for the most part. If yours has come loose on a 1Z there's a good chance someone monkey'd with it in the past. This isn't an area of the engine to be trying out things some guy told you about, do it by the book.

The timing pulley is fairly cheap and available too btw, though your AHU parts should be fine. Just use a New bolt as they are torque to yield and therefore a throwaway item if ever loosened.

[monkey magic]

Thanks for that, it was the way i was leaning but was interested in a 2nd opinion.

The idea of the washer did interest me tho, but i fear you would reach torque earlier, with less tension in the bolt.

So correct bolt and procedure it is.

1 more question tho, do you think the harmonic balancer pulley could have become damaged by the timing gear wobble, ie do  you think i could reuse it? Seems i already fitted the one from my ahu years ago!

Thanks again,

ps vanguy loving your build thread, you're doing great work there

[410]

I think the crank timing pulley is only $40 new from a quality aftermarket supplier.  The crank might not look worn but you should be okay as long as the new gear or your AHU gear fits snug on the crank nose.  The stock bolt is more then good enough so I also agree to stick to the stock set up.  Good thing you caught it!  

I've come across a few cars with loose crank gear bolts.  My guess is someone with minimal experience changed a timing belt and felt a need to remove the crank bolt.  The bolt gets reused and wrapped with an impact gun which is not nearly tight enough.

[theman53]

The harmonic balancer should not have been damaged, but it is not like the crank sprocket and important to the timing process. So if you put it all together and the balancer is wobbling*not from the timing gear* and you feel it needs to be replaced, then all you have to do is take the serp belt off and the 4 bolts holding it. It has nothing to do with the timing so if money is an issue there is no need to do it right now.

[monkey magic]

Thanks all, appreciate the replies.

You read me right, money is tight, also im a yorkshireman, not spending money is in our genetics!

Truth is the 1z is a temporary engine, the ahu needs work, its getting a full rebuild in time (thread coming soon), every penny and every hour spent on this 1z is pushing the ahu build further away. Hence trying to re use available parts just to keep the van running.

You're right i was very lucky. Id put occasional poor starting down to a fuel supply issue, and the chirping belt down to cold temps. Read lots of the crank nose threads before now, but only ever associated that with the idi's. Must also admit i am also probably guilty of reusing the bolt in desperation (4am engine swap needing van to drive home). Lesson learnt!

Thanks everyone, 150bhp ahu thread coming soon!..

[monkey magic]

So, finally got this sorted.

Refitted the pulley/harmonic balancer and theres still some wobble there, not very much tho. The crank sprocket without pulley attached seemed to be spinning true, so its fair to assume the wobble is in the balancer pulley. How much would you guys allow before scrapping the pulley and fitting new? It cant be running out by more than a mm or 2, and the chirping has gone.