Colin Lindsay Posted October 19, 2020 Report Share Posted October 19, 2020 2 hours ago, Iain T said: No not a lot of oil coming out, the problem seems to be in the block. If that's the case there's no point in fitting the external oil feed, then, as there won't be enough oil to do anything at the rockers? Link to comment Share on other sites More sharing options...
Iain T Posted October 19, 2020 Report Share Posted October 19, 2020 Colin, not sure how it will be fitted. I'm taking decisions remotely, I'll visit the guy tomorrow. Iain Link to comment Share on other sites More sharing options...
Iain T Posted October 19, 2020 Report Share Posted October 19, 2020 I know where I will end up in 'X' months/years, I'll build a new separate short block and change over when the dust has settled and my wife isn't cackling in my ear.... 1 Link to comment Share on other sites More sharing options...
poppyman Posted October 19, 2020 Report Share Posted October 19, 2020 6 minutes ago, Iain T said: I know where I will end up in 'X' months/years, I'll build a new separate short block and change over when the dust has settled and my wife isn't cackling in my ear.... Where have i heard that before Surely your engine builder should know whats going on Iain? Tony. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 19, 2020 Report Share Posted October 19, 2020 i feel a song coming on "oyl be seeing you "in all the old familiar places Hmmm !! if the cams out it cant be that hard to pressure up between the head face and cam journal zone to see if the block has a crack /leak in between Pete Link to comment Share on other sites More sharing options...
Iain T Posted October 19, 2020 Report Share Posted October 19, 2020 The engine is in the car complete so not easy to check...again! The oil way is definitely clear. The block doesn't leak oil externally but there must be an internal crack that is letting oil escape. With the fix in place the engine builder assures all will be OK. The new oil pump has excellent pressure and coupled with the new relief valve it seems a fix that will work. The builder has done thousands of engines from standard to full race and this according to him it's the only reason for the oil problem. I can feel a huge bill coming 😥 Iain Link to comment Share on other sites More sharing options...
SpitFire6 Posted October 19, 2020 Report Share Posted October 19, 2020 An internal crack within the head? Link to comment Share on other sites More sharing options...
NonMember Posted October 20, 2020 Report Share Posted October 20, 2020 I can't for the life of me see how changing the relief valve will help with the spawn feed, and I don't think I'd trust an "engine builder" who thinks it would. Link to comment Share on other sites More sharing options...
Clive Posted October 20, 2020 Report Share Posted October 20, 2020 18 hours ago, Iain T said: No not a lot of oil coming out, the problem seems to be in the block. The new relief valve spring is a lot stiffer than the original so perhaps this was part of the problem causing pick up on the mains/big ends farthest away from the pump. I will reduce the diameter of the banjo bolt hole. The only other option is new block, bore, hone, pistons etc etc The oil is pumped up to the rockers via a flat on the camshaft (oh gawd, hope my memory isn't playing tricks) so you don't get huge amounts anyway. But if an external feed is fitted it needs the head or block oilway closing up, usually a grub screw, but requires head off. Otherwise much oil will be pushed back down into the block, wasting a lot of the pressure/flow. Not sure how harder PRV spring helps, that only controls maximum pressure, but I suppose when cold it may help, but when hot the valve will be shut even with a std spring in there. And remember the key is good oil flow and pressure to the crank, hence the need to restrict the external rocker feed right down. The rockers need virtually zero pressure, just a slow feed to keep them lubricated. (John Bonnet had an engine built by a respected race engine builder. He fitted an external feed, caused huge issues. I suggested he tried it without, sure enough the head feed had not been blocked off, and so the rockers still got an adequate supply. The excessive oil use and smoke stopped too) Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 20, 2020 Report Share Posted October 20, 2020 i agree with rob if there is a crack in the block or head then any extra from a spawn feed will still migrate to the sump from where ever it happens to leak from , with the head off and the cam slot obstructing the cam feed a simple pump oil can down the hole in the block would soon show if theres a leak into the sump or cam chest if the oil escapes quickly adding a external feed will just mask whats going on and again remove much needed pressure from the crank someones looking for a get out not a solution agree with the Smoke we had one on the Vit6 ...not for long before we joined the spawn of satan club Pete Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 At work today so time is money! I think I have two distinct problems, first the oil pump and prv weren't changed when rebuilt and secondly worn camshaft journal. The first I believe caused a lack of pressure so the furthest main and big end shells picked up. The second allows oil to leech out so very little volume or pressure can be maintained to the rockers. The solution to the first is easy replace the items, now done but should have been done when rebuilt especially given the provenance of the engine. The second could have been identified by checking the block cam journals with a bore gauge. Again obviously not done but if measured I could have made an informed decision on wether to scrap or line bore and fit bearings. Both old and new cam bearing diameters are the same but the engine with even the old cam had only done 5k miles and being much harder it will always be the block journal that wears. Not a good outcome but could have been worse as if run much farther it could have resulted in a catastrophic failure. Grrrrrrr Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 Just spoken to the engine builder and he did measure the block cam journals and they were OK. ???? Link to comment Share on other sites More sharing options...
Nick Jones Posted October 20, 2020 Report Share Posted October 20, 2020 I give zero credence to the crack theory I’m afraid. Just get hold of another standard, used rocker assembly preferably from a known runner and try it on to see what comes through. Alternatively, have the oil-gallery plug out of the back of the head with the engine running and see what comes out. Should be a steady trickle rather than a gush. Nick 1 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 20, 2020 Report Share Posted October 20, 2020 2 minutes ago, Nick Jones said: Just get hold of another standard, used rocker assembly preferably from a known runner and try it on to see what comes through. That's what I'd have done as a first step. If you need one I have a complete 6-cylinder rocker assembly straight from a GT6 Mk1 that you can borrow as a tester? Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 When I first tested I took the rocker assembly off and with plugs out cranked the engine over for some time and a mear dribble came out. I do have a video but for some reason won't upload. This and the feeling the engine was not running smoothly first set me off on the latest escapade! The builder ran the engine up using a gun out of the car and again after an initial spurt out of the head rear oil cross drill bolt flow reduced to virtually nothing. Colin, thanks for the offer but the new refurbished bushed rocker assembly from TRGB has been rechecked and is fine. It's the oil volume and pressure which is the issue. The engine will be run up again today with the reduced flow ext feeder and I'm visiting tomorrow to chew the cud. I don't mind the ext feeder as a get out of jail fix. I do however wonder how the mains/big end picked up. Am I right in saying if the prv spring was soft then oil will be dumped back into the sump hence lack of oil in the system? Iain Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 20, 2020 Report Share Posted October 20, 2020 18 minutes ago, Iain T said: I don't mind the ext feeder as a get out of jail fix. Am I right in saying if the prv spring was soft then oil will be dumped back into the sump hence lack of oil in the system? Iain I still reckon if there's insufficient oil at present then the external feeder won't really do anything. If you've tried the engine with the blanking plug removed, and not obtained a good flow of oil that looks as though it would travel up through the feeder to lubricate the rockers, then there'll still be too little oil to make any difference. I don't think that it's going to be a magic cure-all. The PRV spring opens at a set pressure to allow excess oil back into the system; a weak spring will open earlier but I can't see it being so weak that it would critically affect the oil pressure. They're cheap and simple to replace for peace of mind. If you've tested the oil pressure at the block switch, and it's fine, then replacing it won't make any great difference. Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 Thanks for all your input, I understand the logic. The plug bolt that was removed was the one at the end of the head to check the flow. I need to visit the builder tomorrow. Iain Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 Anyone got an oilway diagram? Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 20, 2020 Report Share Posted October 20, 2020 as the low pressure warning is around 8psi then triumph believed thats enough to save the engine and keep rotating bearing having a cushion of oil so poor oil pump and prv spring is of no consequence over the big end failings they only give optimum as 40-60 at 2000 rpm not even if thats cold or hot i would hazard a guess that two journal failures are for condition.fit and quality problems not down to ancilliaries being a bit below parr pity you cant prove the snags by DIY rather than rely on the wallet and maybe some bull Pete Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 I did have intentions to build the block up but other things got in the way! Me coming into my old company during lockdown and getting comments being one, even though I was about 60 feet away from the nearest other person. Iain Link to comment Share on other sites More sharing options...
Gully Posted October 20, 2020 Report Share Posted October 20, 2020 Here's the oil circulation diagram from the workshop manual: 1 Link to comment Share on other sites More sharing options...
Nick Jones Posted October 20, 2020 Report Share Posted October 20, 2020 Just to clarify...... your failed bearings were at the timing chain end of the engine? Nick Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 17 minutes ago, Nick Jones said: Just to clarify...... your failed bearings were at the timing chain end of the engine? Yes to you and I number 1 farthest away from the pump. Link to comment Share on other sites More sharing options...
Iain T Posted October 20, 2020 Report Share Posted October 20, 2020 2 hours ago, Pete Lewis said: so poor oil pump and prv spring is of no consequence Well if as I am told the prv spring was extremely weak then that could result in low oil pressure. 2 hours ago, Pete Lewis said: as the low pressure warning is around 8psi then triumph believed thats enough to save the engine and keep rotating bearing having a cushion of oil I would beg to differ, an hours blast at that or near that pressure could be enough to trash some shells at the end of the oil line. It will be an interesting visit tomorrow, I am not angry just concerned it doesn't happen again! I knew that engine stand would come in handy! Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 20, 2020 Report Share Posted October 20, 2020 even 8 psi would produce a flow to the rockers at idle and a low psi rocker oil will pool at the back of the head and overflow down the back of the head why would there be a low warning that allows you trash the engine , it may not be at its best , it wont fail as a catastrophe but too many are paranoid about the pressure , if you can put a pic of the failed shells it makes clues better than random waffle I am certain weak prv , and wonky oil pumps do not give you whats happened they may not be up to blue print but my view is the engine failure is elsewhere more likely stems from a poor rebuild and cleanliness etc the fact it seems the reliability of a simple drilled hole between cam journal and head face cannot be proven is awful with respect it aint rocket science on the same waffle is there actually a oil supply to the rear cam journal ?? as that raises another question Link to comment Share on other sites More sharing options...
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