31 replies to this topic

[MAXR]

Another track day, another problem, another drive back home thoroughly disappointed.

 

1st Session:

 

It all started well, gearbox selection felt good, cables stayed on, new brakes felt good & my car now starts when hot...Great! 

Reduced 20 min slot due to sighting laps, bedding in brakes.

 

 

 

2nd session:

 

It all starts well, built up speed then after 8 mins on track lack of power, then oily smoke, back to the paddock I go.

I notice oil everywhere under the Supercharger area, the SC belt's off. Then a big frigging bolt is spotted on track & under red flag it's picked up. The man from LOT comes around showing all the drivers the rather large bolt asking who it belonged to. Then we realised that it was my main crank pulley bolt. It had sheared clean off & the oil was pissing out from I presume was the damaged bearing... Day Over!

 

Has anyone had this issue before? or am I the only lucky one?

 

 

I've one forward facing video clip & one rearward facing video clip. It clearly shows the issue unfolding, but alas, I can't hear jack in my car as I have ear fenders in my helmet as my car is so noisy. I'll try & post it at some point. 

 

 

 

 

[siztenboots]

crank pulley bolt is 100Nm then two more angle turns who did the cam chains last? woodruff key damaged? you might be lucky and the chain sprockets have kept timing otherwise could be very bad.

[Zoobeef]

Its a stretch bolt and a new one should be used.

 

Over tightened or fitted a few to many times would be my guess. If the timing has been kept it may be an easy fix once the left over bit of the bolt is removed (the hard part) or a new crank if it cant be removed.

[MAXR]

The engine still runs fine. The crank pulley remained on, not sure why. 

 

 

[chris_uk]

Pulley stays on because it sits in a keyway. The bolt is there to stop the pulley coming off. The oil will of come out of the crank seal but to be honest, the bolt being in or out shouldnt matter.. So maybe thats just coincidence. I do have a spare somewhere. Chuck it on the trailer max, dont think anything of it and i will have a look this weekend. I have a crank bolt we can replace that one with or we could fit a new timing chain and put new everything on, just to make sure everything is where it should be.

Edited by chris_uk, 21 June 2016 - 03:16 PM.

[vocky]

I think the hardest thing will be to get the rest of the bolt out. I have never seen or heard of this happening before on an Ecotec

 

Take Chris's advice and get a new GENUINE chain kit fitted, it's been six years since the last one was fitted

[Zoobeef]

Getting a stud torqued up to the tightness that one does out will not be pleasant.

The seal is on the outside of the oil pump housing so will be easy to change.

 

I've not heard of it either, even when the same bolt has been reused which may mean it's been reused more than twice.

[Zoobeef]

Just seen the bolt picture, that's deep inside the crank too!

[MAXR]

Chris,

 

would we be able to get a new timing chain when I'm up there, or does it need to be ordered now?

 

Neil,

 

It's your fault!  You shouldn't have built such quick revving engine for me that can take abuse...6 years, wow, that's gone quick! Nev thought that it could be fatigue from being caned so much at the top end of the rev range. I still say it doesn't rev high enough, but I guess it helps prevent too much wear.

 

 

 

Thanks everyone today for helping out. MrApex also had issues. Are our cars now just getting too old to be reliable or am I just a cheap skate not doing proper maintenance?

 

 

[Ormes]

Good to meet you... sorry about your issues! Fair play to LOT for walking around everybody everywhere asking if they had lost the big bolt off their car... very dilligent.

[techieboy]

Just seen the bolt picture, that's deep inside the crank too!

 

Guess it depends on whether the bolt had unwound itself first or sheared first?

 

What a p!sser though Max. Can you remember the last time you had a trackday only limited by how long you wanted to be there?

[MAXR]

 

Just seen the bolt picture, that's deep inside the crank too!

 

Guess it depends on whether the bolt had unwound itself first or sheared first?

 

What a p!sser though Max. Can you remember the last time you had a trackday only limited by how long you wanted to be there?

 

 

 

Matt, It's probably that my car is not treated as a semi race car, ie it should perhaps have for precautionary spanner work done. It's now an old car & pushed well outside the car original intended use. It does go to show that if such a big bolt can fail, then what else could let go at high speed? 

 

...All is forgiven though, when it completes a whole day on track! Now when was the last time that happened?

[techieboy]

I'm not sure anyone but an F1 team would check the crank pulley bolt as part of a spanner check though. As Vocky said, it's not a problem that's ever come up before and it's very much a fit and forget type thing once torqued up, if you haven't opened the engine in the meantime (when it would/should be replaced anyway). Just really glad the woodruff key held the pulley in place otherwise that would have been very messy. 

[chris_uk]

The rest of the bolt should come out pretty easy . I will do my best to get it out.. I cant say i will deffinatly succeed but i will try. I can probably get a genuine timing chain kit here tomorrow. I will pm you my number, just give me a bell when you get a sec.

[Zoobeef]

 

Just seen the bolt picture, that's deep inside the crank too!

 

Guess it depends on whether the bolt had unwound itself first or sheared first?

 

What a p!sser though Max. Can you remember the last time you had a trackday only limited by how long you wanted to be there?

 

 

Incredibly lucky if so!

 

If you shear a bolt doing it up it a piece of p*ss. If it's sheers itself while tight it can be a pain. Tapping round with a chisel or drilling a hole and hammering something in the middle to try and unscrew it is the normal way. You aren't going to get any weld on something that deep!

[vocky]

The rest of the bolt should come out pretty easy . I will do my best to get it out.. I cant say i will deffinatly succeed but i will try. I can probably get a genuine timing chain kit here tomorrow. I will pm you my number, just give me a bell when you get a sec.

 

don't forget Max has GM Racing vernier cam sprockets, which need to be re-used, thus you also won't need to muck about with his cam timing. Just set it up as if they are normal cam sprockets.

Any questions just drop me a PM

[Mr Apex]

Sounds as though you were really unlucky there Max, but hopefully a reasonably easy fix. My alternator died, but I was lucky enough to have some help from Nev, who drove back to his house, picked up a charger and delivered it back to the circuit. That gave me 20 or so hot laps, so at least I had a bit of fun. The car only made it a few miles from the circuit and is now stored in a locked compound courtesy of a lovely couple who went out of their way to help when I knocked on their door. Nev went a step beyond and lent me his daily drive to get home. New alternator on order, battery on overnight charge, cracking open a bottle of wine. Faith in humanity restored, faith in old cars mildly knocked. 

[VXT Tim]

It's probably being stripped as we speak, loaded onto a trailer and on its way to Eastern Europe Vx community though

[Crabash]

Will give Chris a hand too max as I'll be around anyway.

[Nev]

I didn't look at Max's engine for more than a couple of seconds, but I think his crank pulley may have been a solid after market one (i.e. without rubber doughnut). If so, the sheared bolt might have occurred due to NVH.