I was going to suggested this but the pushrods tubes will get in the way. I was going to suggest re-thread and then use the 2 nut method already mentioned above. I would try lots of penetrating liquid and a bit of heat.
I have replacement pushrod tube seals sat here anyway and so wouldn't be too much of a problem if I had to remove the pushrods to give better access. Think I'll get the whole exhaust/heat exchanger system removed so that I have better access, and will then have a good look and take it from there depending on how brave I'm feeling on the day!
Strange - how do you do that then, as I have a T4 but thought heads had to come off. Is there a vid on YouTube showing how its done?
I have a vid on YouTube showing how to set the valve clearances Type 4 engines pushrods tubes push through the heads. You have to remove all of the head gear, then they shove straight through
Razzyh - I don't know of any videos, but this page describes well how to remove the pushrod tubes and replace the seals without having to remove the engine or the heads: http://www.type2.com/bartnik/pushrod.htm
No problem Hoping I don't have to do it, but at least I know I can and have the seals ready just in case....
Turns out it isn't a dodgy lifter making the noise as I thought it was - it's this leaking exhaust manifold that is making a noise that sounds like a knocking! Did a bit more investigation on Wednesday and using some tricks that Zed suggested to me (e.g. listening to specific places under the engine with a piece of hose) discovered the leaking exhaust port rather than lifter noise. Trying to tighten the manifold bolts to see if it would fix the leak was what led me to discover the threaded stud and probable reason for the leak - it can't be tightened! So hopefully fixing the stud and getting the heat exchangers fitted properly will fix my knocking noise I'm a bit stupid really - Zed made his suggestions a couple of months back but with all the jobs I need to do on the van I hadn't got round to getting under there and have a good listen. In the meantime a couple of people had listened to my engine and both agreed it was lifter noise and so taking that diagnosis I've been collecting bits for re-building a replacement engine which I probably won't need now!
Dicky - I'd say a bit less than the depth of the nut and they are at the end of the stud- so maybe 5 or 6mm. At the moment I've got the HE held on by padding out over the threaded bit with washers and having the nut over the remaining threads, but those threads don't look that good and so I'm reluctant to tighten too much.
Two options I think worth trying if you dont want to take it out without committing to head off etc. Use a long 8mm nut like the one in this picture but dont get carried away tightening it. or secondly re cut thread to 7 mm (not 6 as you wont get anything on this before it snaps!) Not sure where youd get one from but I know they are used on old lambrettas and vespas see here: http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0.Xlong+cylinder+head+nut+lambretta&_nkw=long+cylinder+head+nut+lambretta&_sacat=0&_from=R40 use die nut to cut 7mm - these come in differing sizes which may or may not fit into the space you have. If you are successful I would advise using a brass nut! http://www.ebay.co.uk/itm/1x-Hex-Die-Nuts-M4-x-0-7mm-High-speed-steel-HSS-Hand-Power-Tools-/320989447525?pt=LH_DefaultDomain_3&hash=item4abc764565 Nut - example http://www.ebay.co.uk/itm/LAMBRETTA-BRASS-EXHAUST-NUT-7MM-BRITISH-MADE-x-2-/320822166282?pt=UK_Motorcycle_Parts&hash=item4ab27dc30a local exhaust place may have them. Worth a try.
I've got the same noise, albeit one stud is gone. Not using the bus at moment so it will be an over the winter/engine out job if need be. Best of luck with getting yours sorted.
