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exhaust manifold bolts

4K views 21 replies 9 participants last post by  boom 
#1 ·
hi,

when i bought my car i checked the exhaust manifold bolts and 2 were quite loose so i tightened them up a little bit, i tightened them up very carefully and just nipped them

today after hearing a knocking i thought id check them again and 1 of them was loose,

i tried to tighten it up a bit but it kept going around without too much resistance, will look again later as i didnt want to keep turning it but it make tighten up, now very worried that the head will need helicoiling?

any one else had this problem?
 
#5 ·
Yes, no problem. you can just about do it with the head on the car but as you are removing it anyway it is much easier when done on the bench. It isn't really expensive but I've not had one done in years so I'm not sure of the exact price. Ask your local place and they should know all about it as it is such a common problem.
 
#7 ·
the actual process of fitting a helicoil only takes a few minutes really so i doubt a garage would charge too much for it. get a quote, then compare to the price of a helicoil kit. may work out cheaper to buy the kit and do it yourself. just a thought.
 
#9 ·
Using studs tends to lengthen the life of the threads in the head rather than using bolts so it is recommended to fit studs or you can fit long bolts and an extra nut on its length to use to tighten up the manifold.
Couple of years ago I got a T16 head cleaned up with a very light skim ( about 8 thou ) and the middle exhaust manilfold bolt had sheered off flush. The light skim, bolt drilled out (needed helicoil to rectify ) cost me 30 quid. Money well spent. I was then able to use five new studs and nuts to fit the exhaust manifold ~ recommended ... proper job ..;)

By the way, the 'engineer' who did the work for me ( as well as some other work since ) works out of a large well equipped shed in his large garden. I originally took that head to a pukka engineering outfit (many small outfits around Gloucester's many Industrial Estates ) but they were too busy with large contracts to help. The manager of one recommended this one man band guy with his garden shed. Very useful contact and reasonable charges.

I once had a turbocharger elbow bolt sheer off flush in the turbo. I did not overdo things... the very long one was nearly out and suddenly tightened up then sheered off! Very strange. Those bolts are made of very tough steel and none of my drills could cope. This Guy was able to whip out the remains of that very tough bolt in no time ... charged me a fiver. Jobs like these are a doddle when you have the right tackle...;)
.
 
#10 ·
hellicoil kits

You can buy hellicoil kits from most diy stores now days for about twenty quid, just make sure if you do that it is drilled square and that the tap comes with the kit. Its a simple job though, dont forget to reverse the fitting tool until the end breaks free and then remove it.
 
#11 ·
Following a change of ownership, my long time favourite Rover and MG parts supplier no longer caters for those cars' spares. I got 20 T16 exhaust manifold studs from my local Land Rover spares counter for less than a tenner. A little discount ... Also the new nuts.

Then replaced all those original corroded bolts and nuts on the exhaust manifolds of the family T16 turbos renewing the exhaust manifold gaskets at the same time. A better solution in my opinion once any damaged threads are helicoiled....
 
#19 ·
Normal bolts are hexagon shaped. If you look at some sockets they are also hexagon shaped too, but some are also bi-hex, i.e. they have 12 corners instead of 6. The nuts on the turbo are also bi-hex (which is a bit unusual). If you have a bi-hex socket, or ring spanner then they should fit fine. I managed to undo the missus turbo bi-hex things with a little ratchet spanner but then sometimes I don't know my own strength!.
 
#21 ·
i had this problem over this weekend with 2 of my manifold to head studs when i done my head gasket..i noticed that the studs only go in and use up about 10mm of thread but the head is drilled and tapped in about 35mm,i just found longer bolts and they tightened up fine without having it hellicoil
 
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