fats_40 Posted June 3, 2009 Share Posted June 3, 2009 hello boyz n girls,i own a p38 with 118.000 on clock n reg auto 4.6 petrol,the time has come to change the big ends and mains as i have knocking on acceleration.now i know you are supposed to take the front off to get at the bolt by the oil filter to release the crankcase holder(dont know what they called).is there any short cut to get bolt out.i havent got time to play to much as i need car back on road asap.also the tourqe settings for conrod bolts and crank would be helpfull.i have them for a 3.9 but not certain they are the same for 4.6.the oil i intend to use is 15/40 semi synthetic,is this any good.thanks for replys. ps it only knocks on acceleration from 500-800 rpm,i suppose its more like a rumble than a knock. Quote Link to comment Share on other sites More sharing options...
tommeke Posted June 4, 2009 Share Posted June 4, 2009 Are you sure that it's the big ends? Could be a hydraulic valve lifter? Where does the sound come from? Quote Link to comment Share on other sites More sharing options...
disco_al Posted June 4, 2009 Share Posted June 4, 2009 big ends would give a rumble that gets louder the longer you accelerate, rather than a single rumble/noise when you start off. c Quote Link to comment Share on other sites More sharing options...
fats_40 Posted June 4, 2009 Author Share Posted June 4, 2009 Are you sure that it's the big ends? Could be a hydraulic valve lifter? Where does the sound come from? soundd from the bottom half of engine,pretty certain its the ends.you can hear it on tickover and also when you pull away,but increase the revs to 800 the noise dissappears.i changed the main shells about 4 months ago but didnt do the front one by the oil filter.also didnt change the conrod shells,(was told there was no need)so im doing the works this time. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted June 4, 2009 Share Posted June 4, 2009 If you fit new shells to a journal that worn with ovality (almost certain) then your wasting £s as they will rewear at an alarming rate at best a short term fix, more likely a bodge. Additionally, as others have said Mains / Big ends don';t tend to go quiet as RPMs increase, worth investaigating further Nige Quote Link to comment Share on other sites More sharing options...
rocksteady Posted June 5, 2009 Share Posted June 5, 2009 I was in a P38 last weekend, it was making the same noise at the same revs. After a quick look, i found it to be the cats rattling. Quote Link to comment Share on other sites More sharing options...
fats_40 Posted June 6, 2009 Author Share Posted June 6, 2009 I was in a P38 last weekend, it was making the same noise at the same revs. After a quick look, i found it to be the cats rattling. had cats cut out Quote Link to comment Share on other sites More sharing options...
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