Mo Murphy Posted October 27, 2008 Share Posted October 27, 2008 Morning Gents, The rocker shaft broke in my 300 Tdi at the weekend, does anyone know why it would break ? I'm trying to figure out why in case there is an underlying reason for it's failure. Cheers Mo Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 27, 2008 Share Posted October 27, 2008 The underlying reason is that it is a terrible piece of design, possibly the worst bit of a 300Tdi. Anyone who designs a hollow rocker shaft with holes drilled through it should be shot. Normally the failure is caused by the bolts pulling out of the head so you might have to helicoil them. If you want to see what LR stuffed up, look at the head on a 2.25 engine. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted October 27, 2008 Share Posted October 27, 2008 Fatigue Mo. Have you fitted heavier aftermarket valve springs or a higher lift cam? Any increase in load across the rockers will increase stress on the rocker shaft. IIRC 200Tdi have a hollow shaft too don't they? Don't most engines? Chris Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 27, 2008 Share Posted October 27, 2008 I've only ever seen one break and that was where some numpty in green trousers had fitted a 200Tdi rocker setup on a 300Tdi engine which was probably not all that bright an idea Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 27, 2008 Share Posted October 27, 2008 Your rocker shaft and assembly was supplied and fitted by me, Mo. I can supply a new item under guarantee. Les. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 27, 2008 Author Share Posted October 27, 2008 Thanks Jim, It has indeed broken at one of the holes I haven't fitted any springs or a hotter cam and as far as I know it's a 300 rocker shaft. Anyway I've graced the local Land Rover franchise dealer with my money rather than buy a sh*tpart replacement. Cheers Les, I've sent a pm to you. Cheers all Mo Quote Link to comment Share on other sites More sharing options...
MECCANO Posted October 27, 2008 Share Posted October 27, 2008 Does a high lift cam even exist for a 200/300tdi? Quote Link to comment Share on other sites More sharing options...
imspanners Posted October 27, 2008 Share Posted October 27, 2008 Has it had a cambelt breakage in the past? I daresay the impact of piston on valve, may well generate a fair amount of force in the rocker shaft, right up to the point the pushrod bends. Quote Link to comment Share on other sites More sharing options...
FridaT Posted October 27, 2008 Share Posted October 27, 2008 Rocker shafts usually break because of contact between the valves and the piston(s). Check the valve timing. FridaT www.turner-engineering.co.uk Quote Link to comment Share on other sites More sharing options...
chard Posted October 28, 2008 Share Posted October 28, 2008 Morning Mo, The rocker shaft broke on my 300Tdi a year ago on the way home from the last Sodbury. There was no indication that it was going to go, but it made a right mess where valves hit pistons etc. The timing stuff was all intact so no clue to why it should happen. The delightful Frida ^^^^ sorted me out, in an engine sort of way, before you jump to any conclusions. Not a lot of help I know. Quote Link to comment Share on other sites More sharing options...
v8bertha Posted October 28, 2008 Share Posted October 28, 2008 Just a teenzy weenzy bit too much torque on the studs that hold the shaft in place and you are in thread-stripping terratory As has been mentioned this means a helicoil needs to be fitted to the head. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted November 16, 2008 Author Share Posted November 16, 2008 Well, Gents an update. There was indeed a sheared thread in the head on the rearmost stud (the shaft broke at the next hole forward which makes sense) which I've duly helicoiled. Bad light stopped play yesterday so I'll check the others carefully today. Thank you all for your help and suggestions. Mo Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2008 Share Posted November 16, 2008 Did the stripped stud break the shaft, or did the shaft breaking shear the stud? Les. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted November 16, 2008 Author Share Posted November 16, 2008 Your guess is as good as mine Les The other threads were OK though and it's now back together and running sweetly Mo Quote Link to comment Share on other sites More sharing options...
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