matt bristol Posted August 29, 2009 Share Posted August 29, 2009 I have spent the last couple of days removing the skin from my knuckles and adding oily fingerprints to every thing as I changed the head on my 300TDi disco. I tried to do everything properly rather than my usual 'yeehar f**k it that will do' approach but I now have a misfire and a funny almost blowing noise form the air intake. The one job I haven't done is re-set the tappets which needs doing as they are a bit noisy. The replacement head had been pressure tested and skimmed approx 800 miles ago and I have no reason to doubt the chap I bouhgt it off. I followed the tightening sequence and the 60 deg + 6- deg + 20 for 1,2, 7, 8 etc so I think I got it back together correctly. Under hard acceleration it chugs out a lot of smoke - a sort of grey brown colour and plenty of it whilst accelerating badly compared to before I cooked the engine. I looked at the pistons and bores and they all seemed ok - I am no expert - there were no obvious cracks or bits missing and hte bore still had machine/honing marks so can't have been too worn I assume. Please can some one point me in the direction of what the problem is likely to be, I am hoping tappets not closing the valve fully or some odd land rover trick with the injection system but I have no clue where to begin! thanks in advance Matt Quote Link to comment Share on other sites More sharing options...
trike17 Posted August 29, 2009 Share Posted August 29, 2009 I have spent the last couple of days removing the skin from my knuckles and adding oily fingerprints to every thing as I changed the head on my 300TDi disco. I tried to do everything properly rather than my usual 'yeehar f**k it that will do' approach but I now have a misfire and a funny almost blowing noise form the air intake. The one job I haven't done is re-set the tappets which needs doing as they are a bit noisy. The replacement head had been pressure tested and skimmed approx 800 miles ago and I have no reason to doubt the chap I bouhgt it off. I followed the tightening sequence and the 60 deg + 6- deg + 20 for 1,2, 7, 8 etc so I think I got it back together correctly. Under hard acceleration it chugs out a lot of smoke - a sort of grey brown colour and plenty of it whilst accelerating badly compared to before I cooked the engine. I looked at the pistons and bores and they all seemed ok - I am no expert - there were no obvious cracks or bits missing and hte bore still had machine/honing marks so can't have been too worn I assume. Please can some one point me in the direction of what the problem is likely to be, I am hoping tappets not closing the valve fully or some odd land rover trick with the injection system but I have no clue where to begin! thanks in advance Matt Quote Link to comment Share on other sites More sharing options...
trike17 Posted August 29, 2009 Share Posted August 29, 2009 HI.Are you sure you have timed it correctly Quote Link to comment Share on other sites More sharing options...
eddyoz Posted August 30, 2009 Share Posted August 30, 2009 HI.Are you sure you have timed it correctly Timing would not have been altered if only changing the head.First up,I would check the tappet clearances. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted August 30, 2009 Share Posted August 30, 2009 Blowing back through the inlet manifold could be inlet/exhaust gasket failure (to the exhaust), or valve not closing (tappets). Check pushrod location as well - both on the rocker and in the slide. Les. Quote Link to comment Share on other sites More sharing options...
matt bristol Posted August 31, 2009 Author Share Posted August 31, 2009 all push rods checked, and gaps reset, its better but still mis-firing which seems to get gradually worse the more you drive it - not that I have been any great distance - probably about a mile in all. Luckily I now have the J on the front prop shaft to also repair after that gave up this morning on a test run! Quote Link to comment Share on other sites More sharing options...
matt bristol Posted September 1, 2009 Author Share Posted September 1, 2009 ce again I am here asking inane questions, having sorted the tappets I now have to contend with the rear stud that holds the rocker cover on stripping the thread in the head - I think this was prior to my ham fisted repairs as it went almost as soon as I applied pressure to the spanner! Anyway my question for today is, can I drill out the hole through the rocker to take a bigger thread or will it need a helicoil, and if helicoil required can this be done in situ as this part of the head sits under the bulkhead typically. thanks for all the advice so far chaps by the way Matt Quote Link to comment Share on other sites More sharing options...
Les Henson Posted September 2, 2009 Share Posted September 2, 2009 Helicoil is better or else you would have to drill right through the support pillar as well to accept the larger stud. The special nut would have to be replaced for a larget item too as that holds the rear of the rocker cover on. Les. Quote Link to comment Share on other sites More sharing options...
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