dannybaker Posted August 27, 2009 Share Posted August 27, 2009 Does anyone know if the oil pressure is affected if you fit the external block to head oil pipe. And if so by how much. Link to comment Share on other sites More sharing options...
willcolumbine Posted August 27, 2009 Share Posted August 27, 2009 The external rocker feed is viewed with quite a bit of suspicion by quite a lot of people on here and elsewhere. The general consensus seems to be that as standard they flow too much oil to the rockers and may well deprive more vital parts of the engine of oil. If people use them they have tended to reduce the hole in them somewhat to restrict the oil flow.Personally, I haven't got one because I'd rather replace the rockers at around £30 than have to replace a £700 engine because the bearings lost out on oil... Link to comment Share on other sites More sharing options...
lordleonusa Posted August 28, 2009 Share Posted August 28, 2009 about 10 psi as far as I recallL Link to comment Share on other sites More sharing options...
Ridgetone Triumph Posted August 28, 2009 Share Posted August 28, 2009 dannybaker wrote:Does anyone know if the oil pressure is affected if you fit the external block to head oil pipe. And if so by how much.Yes it does reduce the pressure, I have removed my external oil feed and have increased the oil pressure reading by about 10psi when cold. The other problem I had was excess oil inside the rocker cover, which in turn overflowed out the breather pipe and into the breather bottle, there was always a stronge smell of engine oil. Others may have different views, but hope this helps you a little Link to comment Share on other sites More sharing options...
dannybaker Posted August 28, 2009 Author Share Posted August 28, 2009 I have fitted one after rebuilding the engine and wondering now if I should remove it. I suppose I could try reducing the hole in the pipe although I'm not sure the best way to do that. Anyone have any tips on that. Link to comment Share on other sites More sharing options...
mikeyb Posted August 28, 2009 Share Posted August 28, 2009 johnd or one of the other seasoned racers should be able to give a more expertience based answer - but I believe the prescribed best way to do it is to fit one that has a restrictor and tap a thread into the oilway in the top of the block and fit a plug - otherwise don't bother! Link to comment Share on other sites More sharing options...
piman Posted August 28, 2009 Share Posted August 28, 2009 Hello RT, cold oil pressure tends to be too high anyway. It is hot oil pressure that counts. I found no difference to oil pressure with an oil feed fitted, but it did cause some exhaust smoke at idle so I eventually removed it. I feel that if there is a drop in oil pressure with it fitted then the engine itself is suspect, as the oil pump has an excess capacity to the engine's requirement. Alec Link to comment Share on other sites More sharing options...
sparky_spit Posted August 28, 2009 Share Posted August 28, 2009 I used to have one fitted on my 1300 engine. I then fitted an oil pressure gauge and thought the pressure a bit low. After removing the feed, the pressure increased by about 10 psi, as mentioned above by others.The consensus of opinion seems to be that, if you must fit one, block the existing feed between block and head with a tapped and loctited grubscrew, and make a plug for the new rocker feed with 0.8mm hole in it to act as a restrictor. You would obviously need to be handy with a bit of engineering work to achieve this. Link to comment Share on other sites More sharing options...
Straight Six Posted August 28, 2009 Share Posted August 28, 2009 I had one fitted to my Vitesse and it too suffered from low oil pressure. Although I can't prove it, I strongly suspect that it was responsible for the increased wear found on the crank & bearings when I stripped the engine down after about 20,000 miles.I agree with Willcoumbine entirely: I'd rather replace a rocker shaft than the bottom end of an engine. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 28, 2009 Share Posted August 28, 2009 the original design has an interupted flow controlled by a flat on the rear camshaft journalthe Triumph design ha served well for 40 years why change it,if you have roller rockers there is some discussion for the need of extra lubrication, there are no stem seals so too much oil will give smoke from oil escaping down the inlet guides .if you do fit one of these pipes it must have a restrictor in the union/banjo bolt or wherever drilled to 0.5mm diameter certainly not more than 1mm but its best in the bin like many things in life its one of those "Ive jus got to have one of them" NO YOU DONT Pete Link to comment Share on other sites More sharing options...
Mj17 Posted August 28, 2009 Share Posted August 28, 2009 Used to have one fitted, used to top-up the oil every 5 minutes, used to blow blue smoke, used to keep plastering the rear valance with oil.Removed one, hardly have to top-up the oil, don't blow blue smoke, don't have a black rear valance any more.So far as I can tell the Triumph SC engine didn't have a reputation for killing rocker shafts when in production? Link to comment Share on other sites More sharing options...
thescrapman Posted August 28, 2009 Share Posted August 28, 2009 Mj17 wrote:So far as I can tell the Triumph SC engine didn't have a reputation for killing rocker shafts when in production?No, but they did kill the poor quality replacement ones, so the external oil feed was invented to provide a solution to a problem that shouldn't have existed.I think!CheersColin Link to comment Share on other sites More sharing options...
JohnD Posted August 28, 2009 Share Posted August 28, 2009 danny,Wait a moment while I fetch my bell, book and candle.Prepare to be exorcised, for you are possessed by the Spawn of the Devil!Just think a moment. If adding that external feed to the head reduces the oil pressure, then it must have exceeded the ability of the oil pump to provide enough oil to keep the pressure where it was. And where is all that oil going? Up to the the rocker shaft.And where is the oil really needed? Yes, in the crank. So, you are starving the crank of an oil supply by shoving an excess of undeed oil into the rocker cover.There may be, there just maybe, a case for en external feed if you have a very peaky camshaft and/or rocker rollers, and if you do use it, it is ESSENTIAL (as pete and sparky say above) that you block up the normal supply route from the rear cam bearing and fit a restrictor in the line. How small a restrictor? No idea, but it has been suggested that you sould fit smaller and smaller restrictors until the oil pressure is NOT dropped , and then go one size smaller. And that is pretty small - Andy Vowell (when he didn't know better) blocked upo the normal supply and fitted an external line. His restrictor is 1mm (from memory - AV? Confirm?)The external feed is a relic of Kas Kastner's "octupus" of external lines to the main bearings of his race engines. He didn't use a head feed, and the flow through his lines to the crank were carefully engineered. It just happens that the way that Triumph drilled the head to provide the rocker oil feed and blocked the drilling with a threaded blanking plug allows anyone to bolt on an external head feed. Looks spiffing - I've got a race engine, me! - but as explaijned above is an engine killer.Bets wishesJohn Link to comment Share on other sites More sharing options...
GT6 M Posted August 28, 2009 Share Posted August 28, 2009 The oil pressure should be ok on a 4 cyl engine, but the oil pressure is /may well be down on a 6 cylI have not really noticed it, but the oil pressure does drop with hot oil,/ giving it some stick,.but comes back up again, when its cooled a little, about 10 psi,. Im sure the 4 and 6 pumps are the same, so the pump has lots of reserve capacity for the 4 , but not the six, as its feeding two extra journal, at three levels,.I got one on mine, but it was cos I got the roller rockers on,but I still reduced the feed hole , to about 1/2 a mm, this was done easily, by ..soldering it up, and then drilling it ootI also put it at the end of the block, no 6 , as this is the nearset to the feed end, and is also away from the usuall spot its took off,, thus allowing oil to flow to the front,.which it has been documented, that the oil pressure , at higher revs is marginal,.IT does increase oil consumption, , as more oil is in the rocker box , so more will get sucked doon the valve giudesunless ye got ..oil seals on .. [ piper, do a spring seat/oil seal , all in one, what i use ]the feed pipe, is at the rear, in pic below,.regards Marcus Link to comment Share on other sites More sharing options...
dannybaker Posted August 28, 2009 Author Share Posted August 28, 2009 Thanks Guys, I think I will remove it. Link to comment Share on other sites More sharing options...
rhodes Posted August 28, 2009 Share Posted August 28, 2009 Well, I'm not going to argue whether or not it is beneficial but I have had one for the last 12000 miles on a 1500. I did a test a while ago to see if it made a difference to the oil pressure and I could not detect any, so I left it on. With oil temp around 90 degrees the other day it still gave 50 psi at 2000 rpm. There is no blue smoke but I do have seals on the inlet valve stems. If the feed makes a difference to the oil pressure then you probably have a worn rocker shaft. Link to comment Share on other sites More sharing options...
lordleonusa Posted August 29, 2009 Share Posted August 29, 2009 I can report with absolute certainty that it noticably lowered the oil pressure on both my Herald and on my Vitesse, both with and without various restrictors.L Link to comment Share on other sites More sharing options...
AndyV Posted August 29, 2009 Share Posted August 29, 2009 JohnD wrote:Andy Vowell (when he didn't know better) blocked upo the normal supply and fitted an external line. His restrictor is 1mm (from memory - AV? Confirm?)Best wishesJohnYes, 1mm, it was the smallest drill bit I had.Andy Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 30, 2009 Share Posted August 30, 2009 just one day check the oil feeds drillings in the rockers are clear , these gunge up and that gives the lack of lube and helps wear the rocker tips pete Link to comment Share on other sites More sharing options...
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