Exhaust Blows

[maxstu]

Well Thanks for all the replies. 

The studs on that head had been replaced with bolts and the bottom bolt just fell out while in Henley at the trad rally. I picked up a new bolt from an exhaust centre and duly bolted it in but by the time we got home it was missing again! 
On further inspection I removed the top bolt and found that although a little loose in places the treads wer'nt actually stripped out just worn?
Fitted a new gasket and new bolts and managed to get it to hold. Bolts are still there to this day but it blows so obviously I just can't get enough purchase to nip it up enough.
Wondering now after all the replies if it could be possible to just re= tap the thread that is there?

Perhaps you are trying to over work the bolts and head threads?
With an early system without the support bars ( lost on mostly all vans now) this often happens.
Try releasing pipe clamps and loosening. Otherwise bolts are fighting the clamps and not seating naturally. Tighten manifold bolts. Then retighten clamps

[sump]

Sounds like that's worth a try. Would you advise JB weld as well or not?

Thanks for all the help from everyone

[maxstu]

Sounds like that's worth a try. Would you advise JB weld as well or not?

Thanks for all the help from everyone

Only a recent user of JB Weld. And that was to get rid of minor imperfections on the jointing surfaces of cylinder heads. So l dont know really.
If it were me, I would remove silencer. Remove the manifold pipe on that cylinder. Put a tap down both head threads to maximum depth and measure it. Then add exhaust flange depth too and cut to size a new 8.8 overlength bolt to go full depth. Use a washer too. Add exhaust pipe with new gasket. Firmly tighten top and bottom bolts in stages. Then tighten pipe join.
Finally l would put a very small weld tack between the hex bolt head and exhaust flange. That should stop it spinning out.
Finally remount silencer.

[sump]

Thanks for that Maxstu

Sounds like a doable plan Just hope I don't sheer any bolts have to soaked well.

[maxstu]

Plusgas wirebrush and heat are your friend

From the photo l can see one silencer nut. And it looks in top condition. Hope the rest are similar.

Keep the forum updated..we like to read a happy ending

[sump]

Will do. 

Never having done this before but sure I'm able (I think) What size tap do I need to buy and do you know the length of studs I need to aim for?

 

[maxstu]

Back to this shortly. Just chopping wood.

[maxstu]

M8 tap. But you will likely need to buy a complete set £25-30. However as you are following a pre-cut thread, here's a tip. You do have an angle grinder with cutting blade? Cut two notches 180 degrees apart in a nice new 13mm bolt which is over 25mm in length, thus. Ive used a short bolt to display cutting notches. Now you have a tap.




Using a ring spanner, two turns in and half a turn back. Two turns in and half back. Continue until it meets resistance. That will likely mean it fully home.

Now measure dept of manifold flange and add to depth of thread in head. Total around 30-32mm l would imagine. Cut a new 13mm bolt down to about 30mm. And thats is it. Use a washer.



Look at difference in length from standard manifold bolt and custom made. However, do not cut bolt too long. Otherwise it will pinch inside head before fully clamping exhaust manifold pipe to head.

You can buy these M8 13mm bolts from JK. Or any hardware store such as B&Q or Homebase.

My work is done

[sump]

A Brilliant description/explanation of what I need to do. Not sure when weather permitting it will get done but I will certainly report back on completion or excuse the pun exhaustion!

[tobydog]

Probably not top quality, but for occasional careful use and clearing tapped holes:

https://www.ebay.co.uk/itm/HAND-TAPS-HS ... SwBahVW1Z5

£4.86 set of M8 including postage or £2.04 for a plug tap

[maxstu]

Probably not top quality, but for occasional careful use and clearing tapped holes:

https://www.ebay.co.uk/itm/HAND-TAPS-HS ... SwBahVW1Z5

£4.86 set of M8 including postage or £2.04 for a plug tap

Certainly worth a punt. Well spotted.

[sump]

Well VW Heritage seemed to be the same price as JK so purchased 4 VW exhaust studs, 4 Copper nuts, 2 port to pipe gaskets and 2 pipe to box gaskets together with a metric tap and die set off eBay second hand so will have that for ever but probably never use it again!
Total outlay £40 Cheap if it works or expensive if it don't.

Tried to upload pic but the i button won't oblige maybe my new phone is taking to high res pics?

Will let you all know how it goes when the rain stops.

[sump]

Update

Started taking bits off the exhaust today but only to find the pipe which comes from No. 1 has a split in it.

Decided I may swell go for a new system so has anyone any knowledge of VW Speedshop SS exhaust as it looks quite good?

[maxstu]

Hi Steve,
I did read this yesterday but neglected to answer until now.
Many owners' go stainless, including myself. Yet they are not without their own issues. But going for a system with bolt together flanges is much better.
I have a push fit system with clamps and its a nightmare to remove and refit.
If in to long term ownership then yes, go for it.

Regards
Stuart

[sump]

Well thanks for your help and advice everyone

In the end I went for a new pipe and maifold in mild stuff from Mr Baxter and I must say that as usual the quality was superb
the parts fitted together really easily so well done if you happen to read this.

All quiet on the Norther front once again