Turbo/manifold bolts coming loose

[SamHendry]

Bolts that hold China fold to k418t turbo have worked loose again, was after a few laps of Knockhill I noticed smoked coming into the cabin whilst sitting in pits, popped bonnet and one of the m10 a2 stainless fasteners has literally backed all the way out and that was after tightening them with a 1/2 inch breaker bar!

Considering how hot it gets down there maybe it's no surprise bolts are unwinding themselves, something else I noticed was my scuttle panel was starting to melt, I'm only doing a few laps then cool down but things get super hot very quick.

Anyway any suggestions on doing something to stop these bolts working loose.?

Sure more people had same issue but never heard of a fix

 

[<tuffty/>]

nordlocks

<tuffty/>

 

[superkarl]

Wire lock

 

[scotty_24]

+1 Nordlock washers.
4 trackdays this year, not one loose manifold bolt.
Checked after every trackday

 

[SamHendry]

nordlocks

<tuffty/>

Have nordlocks

Wire lock

Something worth looking into, thought about hi temp loctite but i think tells are just to high for that.

+1 Nordlock washers.
4 trackdays this year, not one loose manifold bolt.
Checked after every trackday

S3 is such a heavy ******* on track!? Any weight reduction tips?

 

[<tuffty/>]

If its coming loose with nords then either the bolts are wrong grade or stretched beyond useful life...

Replace bolts with the right grade stainless steel (don't recall what bill uses off hand) and new nords

I ran nords on my gt3071 for years with no issue

<tuffty/>

 

[SamHendry]

If its coming loose with nords then either the bolts are wrong grade or stretched beyond useful life...

Replace bolts with the right grade stainless steel (don't recall what bill uses off hand) and new nords

I ran nords on my gt3071 for years with nords

<tuffty/>

Yeah fresh bolts and washers and see what happens.

 

[badger5]

logged egt's??

 

[aragorn]

torque the bolts correctly, with a good torque wrench, to the correct maximum torque setting for the fastener your using. Swinging off them with a breaker bar isnt the correct way to tighten things, you'll just overtighten the bolt and push it into plastic deformation.

I'm not particularly convinced stainless steel is the correct material you should be using either. The factory bolts are a special type of steel for high temperature applications. Stainless generally has poorer tensile strength than normal steel bolts.

 

[badger5]

torque the bolts correctly, with a good torque wrench, to the correct maximum torque setting for the fastener your using. Swinging off them with a breaker bar isnt the correct way to tighten things, you'll just overtighten the bolt and push it into plastic deformation.

I'm not particularly convinced stainless steel is the correct material you should be using either. The factory bolts are a special type of steel for high temperature applications. Stainless generally has poorer tensile strength than normal steel bolts.

this is for a stainless steel manifold remember.
think relative expansions and 900+c temps

 

[scotty_24]

[QUOTE S3 is such a heavy ******* on track!? Any weight reduction tips?[/QUOTE]

All I have done at the moment is rear seats and boot carpets etc, and removed the Recaros (weigh a ton!) and fitted Carbeau Clubsport bucket seats.
Its heavy, nature of the beast. But on track I love how forgiving the car is and how stable you are coming out of corners

 

[QuattroCalum]

torque the bolts correctly, with a good torque wrench, to the correct maximum torque setting for the fastener your using. Swinging off them with a breaker bar isnt the correct way to tighten things, you'll just overtighten the bolt and push it into plastic deformation.

I'm not particularly convinced stainless steel is the correct material you should be using either. The factory bolts are a special type of steel for high temperature applications. Stainless generally has poorer tensile strength than normal steel bolts.

X2 on the stainless, we have so called “head engineer” at work and he keeps using stainless steel in a certain piece of equipment and they keep breaking.
This is despite the other engineer who is more experienced, telling him to use high tensile bolts, the guy just won’t listen.
This is without any heat involved, so stainless, not the right stuff.
None of those manifolds have relief cuts in them like the oem ones do, I don’t know if that’s a factor.


Sent from my iPhone using Tapatalk

 

[<tuffty/>]

Stainless bolts are used as the manifold is stainless so expansion rates are similar... you could try sourcing something more exotic like inconel but doubt that would be cheap..

Normal steel bolts (even 12.9) would stretch I believe...

<tuffty/>

 

[Stuart B]

Out of interest does tightening something up when it's red hot make a difference?

 

[Jutchops]

Yes, until it cools down again...

 

[Stuart B]

so "no" then, is the vibrations the issue rather than the heat expanding / retracting making them loose.

 

[Jutchops]

I don't think the vibrations have any tangible impact to them, it's the very extreme heat cycles that do it.

 

[SamHendry]

so "no" then, is the vibrations the issue rather than the heat expanding / retracting making them loose.

I think it's a combination of both mate, heat being the primary factor

 

[SamHendry]

Out of interest does tightening something up when it's red hot make a difference?

I did wonder this myself, banjo bolt on the coolant return from my turbo has being weeping ever so little, just drips now and then, not loosing noticeable amount of coolant but I've thought of trying to tighten it further when hot, maybe it would seal the crush washers better, not had a chance yet.

 

[<tuffty/>]

I assume you used new crush washers?... on BT builds you generally have to give all those fittings a tweak once they have seen a couple of heat cycles... bit trickier on a K04 of course

<tuffty/>

 

[SamHendry]

I replaced the washers with copper ones as opposed to the the oe aluminium but I've only had one leak and fortunately it wasnt on the turbo, it's the banjo on the block where coolant drains, I'll need to tweak it up hopefully sorts it, if not a bit of gasket sealer should suffice

 

[xDaNx]

I've just drilled and lock wired mine.

 

[SamHendry]

I've just drilled and lock wired mine.

I need to do this. Did you use a pillar drill?

 

[xDaNx]

I need to do this. Did you use a pillar drill?

I intended to but the chuck wouldn't hold the 1.5mm drill bit, ended up using a normal drill.

 

[GRELA]

I intended to but the chuck wouldn't hold the 1.5mm drill bit, ended up using a normal drill.

Holding up ok? I'm battling with mine, just ordered some A2's to try and more nords. If that doesn't work then i will have to do what you've done. You drilled out the cap head high tensile bolts or just the standard a2's?

 

[xDaNx]

Holding up ok? I'm battling with mine, just ordered some A2's to try and more nords. If that doesn't work then i will have to do what you've done. You drilled out the cap head high tensile bolts or just the standard a2's?

Drilled high tensile ones, 10.something

 

[xDaNx]

I give up with this now, never thought I'd say this but wish I had never got rid of the relentless v4.

Bolts still coming loose even though they're lock wired and it's impossible for them to move, could the threaded inserts in the turbo be moving?

 

[<tuffty/>]

I give up with this now, never thought I'd say this but wish I had never got rid of the relentless v4.

Bolts still coming loose even though they're lock wired and it's impossible for them to move, could the threaded inserts in the turbo be moving?

Running gasketless?

<tuffty/>

 

[xDaNx]

Running gasketless?

<tuffty/>

Not at the moment but have done before and was still the same.

 

[badger5]

I give up with this now, never thought I'd say this but wish I had never got rid of the relentless v4.

Bolts still coming loose even though they're lock wired and it's impossible for them to move, could the threaded inserts in the turbo be moving?

your doing something wrong dude..
They dont come loose for us, ever.
Have you got the correct length, and checked whether when you think you have them tight, that they're on in fact just bottomed out in the threads? I've seen this when test assembling the k04-380's...
A2 M10x65/70 with nordlocks done up tight, cold, and retightened hot is what we use. They stay put. Gasketless fitment, so no crusing relaxation goign on like we've also seen on customer installs who used copper gaskets for example. (cooper goes soft at these temps and extrudes from under the clamping, resulting in blown gasket/loose turbo)

 

[xDaNx]

Yep using the right size (65mm) bolts.

I tried gasketless but leaks too much without getting both faces skimmed flat so having to use a copper gasket, never had this issue when using the same gasket on the V4 though.

 

[antwan64og]

Yep using the right size (65mm) bolts.

I tried gasketless but leaks too much without getting both faces skimmed flat so having to use a copper gasket, never had this issue when using the same gasket on the V4 though.

Did you try what Bill said?
The bolts aren't backing out, the lock wire proves this.

Tighten up cold and retighten when hot.

The steel bolts are chosen as they expand at the same rate as the steel manifold. Not following the heat cycle tightening defeats the purpose.

Did you check the chinafold surface was flat if you ported it yourself?

 

[xDaNx]

Got a multilayer steel gasket coming, same as the oem one but larger bore and a bit thicker, so I'll redo it all again once that comes.

I didn't port it but checked it the best I could and it seemed dead flat.

 

[<tuffty/>]

IIRC Bill gets the mating faces resurfaced on his mani's to make them flat as chinese quality control is variable at best

<tuffty/>

 

[Stuart B]

Isn't there a simple paint on stuff which will highlight how close the mating surfaces are?

https://en.wikipedia.org/wiki/Engineer's_blue

 

[badger5]

Yep using the right size (65mm) bolts.

I tried gasketless but leaks too much without getting both faces skimmed flat so having to use a copper gasket, never had this issue when using the same gasket on the V4 though.

skimming required, pretty much always on both manifold + turbos hotside. Rarely do these come flat

 

[GRELA]

Mine seals perfect until the bolts do back out, A2 stainless will go in once i sort the clutch pedal that went to the floor the other week...

Also my local engineer said he can't skim the chinafold, it's just too tricky for him to get anything in there apparently...

 

[badger5]

Mine seals perfect until the bolts do back out, A2 stainless will go in once i sort the clutch pedal that went to the floor the other week...

Also my local engineer said he can't skim the chinafold, it's just too tricky for him to get anything in there apparently...

he's not trying hard enough.. lol
our local shop does moan about it but gets on with it

 

[GRELA]

he's not trying hard enough.. lol
our local shop does moan about it but gets on with it

Fancy sending my one in then Bill?

He's been saying that basically it ain't worth his time trying to clamp the manifold down straight and run a stone across it... That's the only sort of engineering shop here as well haha

 

[xDaNx]

Mine seals perfect until the bolts do back out, A2 stainless will go in once i sort the clutch pedal that went to the floor the other week...

Also my local engineer said he can't skim the chinafold, it's just too tricky for him to get anything in there apparently...

What gasket are you using? Or gasketless?