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1.4 16V exhaust manifold flange - spline bolts

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littlepolo
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1.4 16V exhaust manifold flange - spline bolts

Post by littlepolo » Fri Nov 24, 2017 8:54 am

I broke a couple of these off when removing the downpipe. Have just been to the dealer who advised they don't sell them separately as they are part of the manifold assy. Any idea where I might source them? Worst case I'll just use some regular hex bolts.

RUM4MO
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by RUM4MO » Fri Nov 24, 2017 9:33 am

I have looked at the EKTA parts listing to refresh my memory of how things are put together, and what I've found is that the top end of the "manu-cat" is secured to the cylinder head using nuts fixing onto head mounted studs, the down pipe secures to the lower end of the "manu-cat" again using nuts fixing on to studs that are part of the "manu-cat" assembly.

Is it the lower end that is the problem, ie you have snapped off a stud, if so it does look like you will need to get any broken studs cut out and new ones welded on as I'm thinking that being able to reach both the top of these fixings when bolting things back on to that car will be very tricky or impossible - which is why VW designed these studs or bolts to be part of that "manu-cat" - maybe get them all cut off and replaced with same size roughly and length bolts welded on to the "manu-cat"?

Edit:- remember just cutting any broken studs out and dropping bolts into these holes will work okay when everything is clean and free from rust, but, in 6 month's time, if these bolts need removing again it could get very tricky! That is why I'm suggesting getting any new studs(bolts) welded to the "manu-cat".

littlepolo
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by littlepolo » Fri Nov 24, 2017 3:58 pm

Yes it is the lower ones. I'll try an engineering suppliers for spine bolts (they are 10mm thread, looks like 11mm at the spline and 34mm long - of which 10mm goes through the flange). I might have some stainless steel bolts lying around so that could be an option. Access is not too bad.

littlepolo
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by littlepolo » Fri Nov 24, 2017 4:09 pm

Have just searched for trailer wheel hub stud and found it returns some bolts that might work.

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alexperkins
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by alexperkins » Fri Nov 24, 2017 4:18 pm

The bolts need to be high tensile and heat treated. Normal bolts will not cope with the heat on the exhaust manifold.

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alexperkins
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by alexperkins » Fri Nov 24, 2017 4:20 pm

You might be able to use Mk2 Golf exhaust manifold studs

M10x28

N 044 520 3

£1.46 each

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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by alexperkins » Fri Nov 24, 2017 4:21 pm

Image

littlepolo
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by littlepolo » Fri Nov 24, 2017 4:40 pm

That could be an option though I'd have to tap the flange to suit the thread.

The spline OD is 12mm so not sure there'd be enough material to cut the thread and retain strength.

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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by alexperkins » Fri Nov 24, 2017 5:41 pm

I’d look to helicoil it or get them welded into place

RUM4MO
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by RUM4MO » Fri Nov 24, 2017 6:28 pm

I've just worked out what you mean by "spline" - these special bolts probably have a round or hex head and the first 1/2" or so down the shank is splined - so that when that bolt is pressed into a hole in the manu-cat, it grips tight, maybe even welded at the top end.

Edit:- fitting any wheel hub bolt that looks okay might work, but only if the spline forced on the head of these hub bolts is exactly the same, I'd doubt if there is any standard for that sort of design - I could be wrong though, I'd guess a proper engineering place could sort it out for you for less money than a new manu-cat, but maybe get a price for that first so that you know makes most sense.

littlepolo
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by littlepolo » Fri Nov 24, 2017 7:40 pm

The bolt head (above the spline) is a flat round about 3mm thick. The spline length is about 10mm which is the same as the flange. They can be pushed in/removed using a socket and a vice. Whilst there is probably not a standard as such, they are likely mass produced to supply automotive markets so maybe not a lot of variation for a given diameter. I'll soon find out.

RUM4MO
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Re: 1.4 16V exhaust manifold flange - spline bolts

Post by RUM4MO » Fri Nov 24, 2017 10:45 pm

Good enough plan if you succeed then that will be another "handy to know" spare part not made available by VW Group.

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