Blue cedar Posted March 3, 2017 Report Share Posted March 3, 2017 Like a loose Conrod .....because the bolts loosened and the shells bounced ......bang....... Quote Link to post Share on other sites
oldtuckunder Posted March 3, 2017 Report Share Posted March 3, 2017 In the pictures that were posted, something looks odd, kind of chewed up, about that protruding section of the hollow dowel in the connecting rod thru which the bolt passes. I wonder if that could be related somehow. Like a loose Conrod .....because the bolts loosened and the shells bounced ......bang....... Hang on that a bit of a leap in the dark as so far we have only seen shots of #4 main cap off, unless the new moderators are deciding who can see individual posts? Alan Quote Link to post Share on other sites
villa.1 Posted March 4, 2017 Author Report Share Posted March 4, 2017 (edited) checked big ends on number 2 cylinder have looked healthier... Edited March 4, 2017 by villa.1 Quote Link to post Share on other sites
Blue cedar Posted March 4, 2017 Report Share Posted March 4, 2017 I'm making a guess at a trashed BE bearing shell, only because I have seen similar scrap in my sump :-( Try looking at #5 next (only because it and I have been in a personal battle for a couple of years that I may just have won) Alan Alan, no I think myself and Poolboy were solely making/offering our thoughts based on the information provided by villa.1. and not looking to win a 'personal battle'. I've seen his comments and direction in the past and like mine always read with sincerety. Villa.1 choose to act on our post in preference to your 'guess'. He may decide to come back and act on your post, but most of all my fingers are crossed that villa.1 is getting closer to solving his problem. Hopefully enough said and we can get back to focusing on helping villa.1. Quote Link to post Share on other sites
Motorsport Mickey Posted March 4, 2017 Report Share Posted March 4, 2017 What's the crankshaft main bearing journal like ? from the condition of that bearing I'd expect it to be heavily scored ? even if not measure around it in two different planes and check for it being oval. Then If you can, bolt the cap back on to the rod and see if you can measure what the big end housing dimension are and whether or not it is "round" (you'll need to check it in two opposite planes again) . It may be of academic interest only because if it does show up as oval you'll need head off to replace the rod and remedy anyway, and if the cranks scored or oval, engine out will be the way forward anyway ( as called by Neil). Mick Richards Quote Link to post Share on other sites
villa.1 Posted March 4, 2017 Author Report Share Posted March 4, 2017 (edited) Thanks everyone for your help, I have arranged for the chap that rebored the engine and reground the crank for me a few years back to come out and have a look whilst the engine is still in to see what he thinks about the bottom end, from the state of the BE shell is suspect the crank will need some attention. Just when you think your back on the road Edited March 4, 2017 by villa.1 Quote Link to post Share on other sites
mike3739 Posted March 4, 2017 Report Share Posted March 4, 2017 Not great for sure Cheers Mike Quote Link to post Share on other sites
oldtuckunder Posted March 4, 2017 Report Share Posted March 4, 2017 checked big ends on number 2 cylinder have looked healthier... Ah I had one like that in 2015, well actually not quite as bad, but the sudden onset and noise descriptions were the same.! You may be able to ascertain from your shell, but the conclusion on my one was that the shells picked up on the crank and then spun in the BE cap, so gets very hot and its actually the metal backing that squeezes out and folds over the sides of the cap. The rod went .008 oval and was scrap, and the crank which was hardly marked needed straightening before the regrind. Alan, no I think myself and Poolboy were solely making/offering our thoughts based on the information provided by villa.1. and not looking to win a 'personal battle'. I've seen his comments and direction in the past and like mine always read with sincerety. Villa.1 choose to act on our post in preference to your 'guess'. He may decide to come back and act on your post, but most of all my fingers are crossed that villa.1 is getting closer to solving his problem. Hopefully enough said and we can get back to focusing on helping villa.1. Sorry if I sounded argumentative, just from symptoms it sounded like BE but we hadn't seen any pictures yet. But from the now posted pic it appears we were both correct it was a BE and it was #2. I had no idea about which BE it was, my comment about it being #5 was almost in jest because it and I have had running battles for a few years. Alan Quote Link to post Share on other sites
oldtuckunder Posted March 4, 2017 Report Share Posted March 4, 2017 (edited) Edited March 4, 2017 by oldtuckunder Quote Link to post Share on other sites
Blue cedar Posted March 4, 2017 Report Share Posted March 4, 2017 Alan....me too ! You, me and the man watching from the garden gate, are all keen to help. Cheers. Peter Quote Link to post Share on other sites
Guest ntc Posted March 4, 2017 Report Share Posted March 4, 2017 Unless you strip the whole engine you will be throwing good money away. Quote Link to post Share on other sites
oldtuckunder Posted March 4, 2017 Report Share Posted March 4, 2017 +1 Neil is right, there is way too much hidden potential damage to not strip it. Get a very good machine shop to check the crank, not your average crank grinder. Alan Quote Link to post Share on other sites
astontr6 Posted March 4, 2017 Report Share Posted March 4, 2017 +2 Neil is right, also there has been metal pick up on that main bearing shell which we were shown in his photo??? What was the oil pressure like? I have only ever seen shell bearings like that when an engine has seized. Are there any other causes? Bruce. Quote Link to post Share on other sites
oldtuckunder Posted March 4, 2017 Report Share Posted March 4, 2017 It only takes a couple of secs with a dry bearing to do the initial serious damage (and engine had been sat for six months before restart) and then n+ miles with the shells rotating in in the rod end to get nice and hot and squeezed out. On mine (although competition induced) it was obvious that the tangs on the shells had just sheered off as they were still stuck in their grooves, at that point I think the shells prefer rotating around the crank rather than the crank in them. Unusual on a road engine, but not quite so in competition engines. Doesn't even seem to need a visible loss of oil pressure to occur, i.e. people data logging oil pressures have been unable to spot an event occurring. Interesting that #2 is reported as being a common failure by the racing 2Ltr 6 pot owners, whereas before all the mods for me it was #5. Starting an engine that has been stood without doing a rigorous pre oil is potentially worse than starting a fresh rebuild as then its likely to have a fair amount of assembly lube in it to take the initial loads. Will be interesting to find out when stripped if any obvious causes, in all my occurrences there was none, serious damage was isolated to a single journal, apart from the obvious traces where fine shrapnel from the failed bearing had been carried through the other journals. Alan Quote Link to post Share on other sites
Guest ntc Posted March 4, 2017 Report Share Posted March 4, 2017 (edited) It only takes a couple of secs with a dry bearing to do the initial serious damage (and engine had been sat for six months before restart) and then n+ miles with the shells rotating in in the rod end to get nice and hot and squeezed out. On mine (although competition induced) it was obvious that the tangs on the shells had just sheered off as they were still stuck in their grooves, at that point I think the shells prefer rotating around the crank rather than the crank in them. Unusual on a road engine, but not quite so in competition engines. Doesn't even seem to need a visible loss of oil pressure to occur, i.e. people data logging oil pressures have been unable to spot an event occurring. Interesting that #2 is reported as being a common failure by the racing 2Ltr 6 pot owners, whereas before all the mods for me it was #5. Starting an engine that has been stood without doing a rigorous pre oil is potentially worse than starting a fresh rebuild as then its likely to have a fair amount of assembly lube in it to take the initial loads. Will be interesting to find out when stripped if any obvious causes, in all my occurrences there was none, serious damage was isolated to a single journal, apart from the obvious traces where fine shrapnel from the failed bearing had been carried through the other journals. Alan +1 However it is number 2 that twists and fail,the car stood for that length of time and then to go to 5000 rpm + to test the system it was inevitable Edited March 4, 2017 by ntc Quote Link to post Share on other sites
villa.1 Posted March 4, 2017 Author Report Share Posted March 4, 2017 Hi There, Based on what you guys have been suggeting, below is some more background that may help: The car is a NA imported in 94, i bought it as an unfinished project 10 years ago, about 7 years ago 1. Engine completely stripped and rebored and #2 was sleeved, new pistons. 2. Crank ground and balanced and mild fast road cam new push rods and follows. 3. Head skimmed to increase compression 10:1 (74 CF engine), new valve seats and polishing. Ive used it sporadicall doing only a 3k miles before i took off the road last sept The engine probably went a max of 4 weeks without turning over enough to get the oil pressure up. I decided to switch to Emerald EFI instead of the webers, really impressed with the kit, its transformation of the cars drivabilty in the 30 miles i have completed. I finished the new fuel system last month The engine has done 10 miles with the car in gear on the ramps ( I was checking my sticky clutch was sorted before i put the interior back together) so no load and very few revs and at least a couple of hours on tick over whilst getting the basic setup right. So i think it had a reasionably sensible run in ahead of the failure. On the question of oil pressure, it normally holds good pressure on tick over but i noticed by the time i had limped home it was down through the floor on tickover. Im glass half full.. now im over the initial depression.. at least it will give me an opportunity to get the engine and head finished off, as the budget didnt allow last time round. Will probably have the engine out next week so will make sure i update you with any other findings on this thread, on that note thanks again all for your helpful pointers! Steve Quote Link to post Share on other sites
oldtuckunder Posted March 4, 2017 Report Share Posted March 4, 2017 On the question of oil pressure, it normally holds good pressure on tick over but i noticed by the time i had limped home it was down through the floor on tickover. Great write up, fills in a whole load gaps so people aren't guessing. Interesting on the oil pressure, when my big ends have spun its made little or no difference to oil pressure, as it hadn't opened up a clearance between the shells and the journal, but between the shells and the cap. However mine wasn't as far gone as yours so that might explain it, however whilst stripped I would be looking at all possible low oil pressure issues. At 5K+ a momentary loss of oil pressure is all it takes to toast a bearing, and much more likely if the oil (not engine!) isn't up to full working temp, within sensible limits its flow you want not pressure. Let us know what you find. Alan Quote Link to post Share on other sites
villa.1 Posted March 7, 2017 Author Report Share Posted March 7, 2017 Im now thinking the loss of Oil pressure may be the cause of the BE failure rather than a side effect. Quote Link to post Share on other sites
foster461 Posted March 7, 2017 Report Share Posted March 7, 2017 Im now thinking the loss of Oil pressure may be the cause of the BE failure rather than a side effect. Be sure to check the oil pump when you take the motor apart. We have seen problems with some pumps that did not have the rotor pinned to the shaft and it allowed the shaft to slip down and eventually drop out of the slot in the drive dog. Stan Quote Link to post Share on other sites
Stanpartmanpartwolf Posted March 7, 2017 Report Share Posted March 7, 2017 Rather late to the party here, but one observation: You mention that #2 had been sleeved previously- that says to me there's been a previous accident of a similar nature, only more severe. I'd be looking very closely at the crankshaft oilways & their alignment. If you would like it inspected, I am half-an-hour away. PM if so. Regards SPMPW Quote Link to post Share on other sites
Nick Jones Posted March 7, 2017 Report Share Posted March 7, 2017 Rather late to the party here, but one observation: You mention that #2 had been sleeved previously- that says to me there's been a previous accident of a similar nature, only more severe. I'd be looking very closely at the crankshaft oilways & their alignment. If you would like it inspected, I am half-an-hour away. PM if so. Regards SPMPW Agreed - an offer worth accepting. Nick Quote Link to post Share on other sites
GT6M Posted March 8, 2017 Report Share Posted March 8, 2017 Just mek sure it aint a full moon, !!! M Quote Link to post Share on other sites
villa.1 Posted March 9, 2017 Author Report Share Posted March 9, 2017 (edited) Rather late to the party here, but one observation: You mention that #2 had been sleeved previously- that says to me there's been a previous accident of a similar nature, only more severe. I'd be looking very closely at the crankshaft oilways & their alignment. If you would like it inspected, I am half-an-hour away. PM if so. Regards SPMPW Thanks, i know the history of the #2 cylinder: I had it rebored when I last had the engine out about 8 years ago, which exposed a small defect/pitting so we sleeved that cylinder. I didnt however change/check the oil pump, live and learn! Engine is out now and the crank is being reground and balanced next week so hopefully back on the road soon. Just in case i'm about to make a similar error on this rebuild.... is there anything else you guys suggest i do whilst i have the block stripped down? Regards Steve Edited March 9, 2017 by villa.1 Quote Link to post Share on other sites
Alec Pringle Posted March 9, 2017 Report Share Posted March 9, 2017 Hi Steve, yes, let Jon (SPMPW) have a look - he's a damn good professional competition engine builder ! Cheers Alec Quote Link to post Share on other sites
villa.1 Posted March 10, 2017 Author Report Share Posted March 10, 2017 Rather late to the party here, but one observation: You mention that #2 had been sleeved previously- that says to me there's been a previous accident of a similar nature, only more severe. I'd be looking very closely at the crankshaft oilways & their alignment. If you would like it inspected, I am half-an-hour away. PM if so. Regards SPMPW Hi sorry i missed the offer of coming to have a look when i first read your post, I would really appreciate your input and will PM you. Cheers Steve Quote Link to post Share on other sites
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