Jack Posted June 12, 2007 Share Posted June 12, 2007 Hi folks. Over the weekend I picked up a horrible knocking noise from the GMC - it doesn't sound good. I am slightly confused as I am not to sure where about is coming from. It knocks when it is under load but if you throttle off it goes. So I am not sure if this is engine or transmission as the engine sweet and when you are stationary and rev the hell out of it then there is nothing but when you drive there is so perhaps it is the transmission??!! I have made the decision to pull it from the Bolero weekend and I don't want to completely screw up my GMC and I don't want the hassle or the risk of it going bang anywhere along the journey - it goes without saying - I am gutted. Any help very much appreciated. Best wishes. Jack. Quote Link to comment Share on other sites More sharing options...
G506 Posted June 12, 2007 Share Posted June 12, 2007 Jack, what a nightmare :-( Without being there to listen its difficult to say for sure. I hate to say it, but what you describe sounds an awful lot like big end bearings, early symptoms being knocking during acceleration under load. At stand still the engine isnt under load, therefore no noise. Of course, you could be lucky, and its only the ignition timing thats slipped, this can give a very nasty noise under heavy load that can sound similar G506 Quote Link to comment Share on other sites More sharing options...
G506 Posted June 12, 2007 Share Posted June 12, 2007 Forgot to ask, what does the oil pressure guage say, and have you noticed a drop in pressure? G506 Quote Link to comment Share on other sites More sharing options...
Bodge Deep Posted June 12, 2007 Share Posted June 12, 2007 Damn & B*gger :-( Is the power down at all? Quote Link to comment Share on other sites More sharing options...
Jack Posted June 12, 2007 Author Share Posted June 12, 2007 Thanks chaps. Oil pressure fine and have lost no power and just throttled back to ease up on the knocking but I too thought of the big ends as I had them go in one of my land rovers once. What I don't understand is that the knock isn't a fast knock. What other symptoms are there of big ends going? Quote Link to comment Share on other sites More sharing options...
Bodge Deep Posted June 12, 2007 Share Posted June 12, 2007 A long shot... Have you wandered round the truck & checked the tyres havent picked up a rock? The cloverleafs on the dodge can get hold of a golf ball sized rock & merrily clatter away as you drive along producing a very alarming & expensive noise... been caught out that way a couple of times :dunno: Quote Link to comment Share on other sites More sharing options...
G506 Posted June 12, 2007 Share Posted June 12, 2007 Thanks chaps. What I don't understand is that the knock isn't a fast knock. Does the noise seem fairly well matched to road speed? You say it isnt a fast knock, so presumably not proportional to engine speed, so maybe final drive related - have you got a dodgy universal joint maybe? Quote Link to comment Share on other sites More sharing options...
YK55 Posted June 12, 2007 Share Posted June 12, 2007 Sounds like a big-end to me too. Take off each ignition lead in turn and run it on the remaining cylinders, does the knock go away when a particular lead is removed? What other symptoms are there of big ends going? The knock gets louder and then the conrod comes out the side of the block. :eek2: Quote Link to comment Share on other sites More sharing options...
Jack Posted June 12, 2007 Author Share Posted June 12, 2007 Sounds like a big-end to me too. Take off each ignition lead in turn and run it on the remaining cylinders, does the knock go away when a particular lead is removed? Great idea - I can do that but how does that demonstrate that it is that specific big end? I also thought that it could be a UJ...but were ok when we greased them not so long back. Quote Link to comment Share on other sites More sharing options...
Mark Posted June 12, 2007 Share Posted June 12, 2007 Are the UJ's in phase Jack?? Quote Link to comment Share on other sites More sharing options...
Jack Posted June 12, 2007 Author Share Posted June 12, 2007 Are the UJ's in phase Jack?? What does that mean Mark :oops: Quote Link to comment Share on other sites More sharing options...
Mark Posted June 12, 2007 Share Posted June 12, 2007 Try this easier than explaining :whistle: http://www.custompistols.com/cars/articles/ts_ujoints.htm Quote Link to comment Share on other sites More sharing options...
Mrs Hardyferret Posted June 12, 2007 Share Posted June 12, 2007 Jack Give Jerry a ring on his mobile as sone as you get a chance - he wants to see about coming over ASAP. Between the three of us we should be able to nail exactly where it is and what is causing it and then hopefully we can see about fixing it. You can not miss out on Bolero - it just aint an option mate. Quote Link to comment Share on other sites More sharing options...
YK55 Posted June 12, 2007 Share Posted June 12, 2007 Great idea - I can do that but how does that demonstrate that it is that specific big end? Removing the load (by not firing) should make it quieter. If all's quiet with one particular lead removed then that is where the problem lies. (if it is a big-end going) You say it's not a 'fast knock', at 1000 rpm a big end will be knocking at 8.3 times a second, at 2000 rpm 16.6 etc. Quote Link to comment Share on other sites More sharing options...
R Cubed Posted June 12, 2007 Share Posted June 12, 2007 Very sorry to here about this strange problem, :cry: :cry: maybe we could get the low loader to you and at least take it up there for everyone to hear and judge, then maybe fix it up there, probably a wealth of knowedge up there could be invaluable !!!!!!!!!!!!!!!!!!!! What a thing to do in the evenings tools and fixing and beer, cant think of anything better on a sunny summers evening :-D At least you have a ride back home on the low loader as well :dunno: Let me know ? R Cubed Quote Link to comment Share on other sites More sharing options...
Jack Posted June 13, 2007 Author Share Posted June 13, 2007 Thanks to everyone for their advice so far - have enough ideas to look at now as to where the problem is coming and will get to that at the weekend... Also my rear brake cyclinders a leaking break fluid like hell.....on BOTH sides :evil: What flippin next. Quote Link to comment Share on other sites More sharing options...
Mark Posted June 13, 2007 Share Posted June 13, 2007 Ahh the joys of this hobby......................................and you dont go anywhere :evil: Should have got a Reo Quote Link to comment Share on other sites More sharing options...
R Cubed Posted June 14, 2007 Share Posted June 14, 2007 Whats going on with the truck, have you given up with it ? I presume you are NOT going to take it to the show by lowloader then, so if not there is still a spare place on it to Bolero who is interested. Quote Link to comment Share on other sites More sharing options...
Jack Posted June 14, 2007 Author Share Posted June 14, 2007 Whats going on with the truck, have you given up with it ? I presume you are NOT going to take it to the show by lowloader then, so if not there is still a spare place on it to Bolero who is interested. Hi Rich - no the situation is the same this end until I have solved the problems.......so yes folks there is a place spare on the lowloader! Quote Link to comment Share on other sites More sharing options...
Jessie The Jeep Posted June 14, 2007 Share Posted June 14, 2007 You've got two weeks! you could have the engine and transmission rebuilt in that time!! :whistle: Why don't you bring it anyway, it could be dragged around behind a wrecker all weekend!! ;-) Steve Quote Link to comment Share on other sites More sharing options...
R Cubed Posted June 14, 2007 Share Posted June 14, 2007 If we could get it up there I could bring a compressor up and over the weekend we could spray the truck Pink, he he he :whistle: :whistle: it would then match the cushion................ Quote Link to comment Share on other sites More sharing options...
Joris Posted June 15, 2007 Share Posted June 15, 2007 Lads, let me remind you how grumpy Jack gets when you talk about his "mens" truck this way. :evil: Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted June 15, 2007 Share Posted June 15, 2007 I have the answer gentleman. Jack could use the famous pink cushion to mop up the brke fluid, then place it on the engine to deaden the knocking noise. No leak, no noise, no worries. :-) Quote Link to comment Share on other sites More sharing options...
Jack Posted June 17, 2007 Author Share Posted June 17, 2007 Now here is the latest - Solved one of the problems as the was also a rattling noise coming from the engine - sort of metal on metal noise :evil: that turned out to be the nut missing of the alternator so I have to found a nut to replaced it :computerterror: lucky enough it has worn the keyway or thread so please with that so I am hoping that the new nut will nip it up enough to solve that problem. The knocking noise. Don't think it is the big end as I fired it up and stood next to it for 10 - 15 minutes with no knocking - I would be hearing something at this point wouldn't I :dunno: I mean it would be apparent wouldn't it? So I crawled underneath and all oil levels are perfect. One thing that had 2-3mm play in it was the front prop UJ at both ends - if your opinion could this be the cause or is a 2-3mm tolerance acceptable? Best wishes. Jack. Quote Link to comment Share on other sites More sharing options...
Joris Posted June 17, 2007 Share Posted June 17, 2007 So now you _are_ taking it to Bolero? Quote Link to comment Share on other sites More sharing options...
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