Davemate Posted April 10, 2012 Share Posted April 10, 2012 If a car boils over I know you should not just pour cold water into the rad as the cold water going into a hot engine can warp heads and cause head gaskets to go.But I seem to recal reading something about putting cold oil into a hot engine can cause the same thing to happen to the big and main bearingsIs this correct or is it total bollo$ksThe reason behind this is that after running continually at 4000 revs for 40 minutes the other day on the way home from Radders the oil preasure dropped off to the point that the oil flickered when the engine was idleing.On the way to Radders the last 10 minutes of the drive was a 40 mph and around some back streets so the oil had a chance to cool off a bit and the preasure was fine, as opposed to off the motor way and 1.5 miles later I am home.After 15 minutes I went out and started the car and the preasure was fine.I am going to fit an oil cooler but when the stat opens will it not just be putting stone cold oil into a hot engine !!!I know all,if not most racing type cars have them but it's a niggle in to back of my mindThis could just be a "bloke down the pub said" thing Link to comment Share on other sites More sharing options...
Clive Posted April 10, 2012 Share Posted April 10, 2012 Having a oil stat in the garage waiting to be fitted, it appears that when it opens some of the oil goes through the cooler and some bypasses back to the engine. I could be wrong.....(it is a partial guess, but makes sense from the construction)Besides, the oil will not get cold from going through the cooler, just lose some of the heat. Which is a very good thing.Besides, you don't worry about the water rad making the engine get cold water, same idea, if you follow. Link to comment Share on other sites More sharing options...
piman Posted April 10, 2012 Share Posted April 10, 2012 Hello Dave, it won't do any harm; first time that I've heard of hot oil into cold engine will damage it. They used to do that all the time racing cars in the fities and sixties endurance races.Alec Link to comment Share on other sites More sharing options...
JohnD Posted April 10, 2012 Share Posted April 10, 2012 Dave,If your engine boils over, it's not a good idea to open the rad cap at all!The remaining water, at high temperature and high pressure, will flash-boil as the pressure drops, and explode all over you and your car! That would make sure that almost no water was left in the cooling system. Let the car cool down until you can open the cap without a deadly hiss and spit, and the remaining water will buffer any cold you add. I think this is an old wives', or very old motorists' tale, from days of yore!I have to say that an oil cooler isn''t the answer to your problem. Road running at 4K won't excessively heat the oil, though low pressure after doing so may indicate a worn engine. But, courage mon ami! It's fairly common for our engines to have a flickering oil pressure light when hot and idling. Our bearings have much greater tolerances that a modern, even when new. Invest in an oil pressure gauge. If pressure is in the 40 range while running, that's fine.And what oil? Synthetics are no use to our engines, just too thin and low pressure. JohnPS An oil cooler MUST have a thermostat for road running. Otherwise, the oil will pass through the cooler all the time, not only under stressful conditions, and the oil will be far too cool to work properly. It is designed to work at approx water boiling point. I admit that I don't have a 'stat on the race car, but then I KNOW I'm going to stress the engine! Link to comment Share on other sites More sharing options...
Davemate Posted April 10, 2012 Author Share Posted April 10, 2012 Clive I have bought a oil kit which has the stat in the adaptor/sandwhich plate(I think)So that should be fine.JohnI use a normal 20/50 oil (macess £8 for 5ltrs) just cheapie stuff and I change it regularly Then engine does not smoke and I done a compression test which gave readings of 180 lb in all four pots.After 15-20 minutes running(going to work) the oil preasure is still up at 50 lb when over 1000 revs and at tickover(750-800) it sits at about 30,which is why I thought that the oil may be getting over hot After longer but gentle runs the preasure drops to about 20 lb but after a 4000 rev blas for 40minutes it drops right off Link to comment Share on other sites More sharing options...
Clive Posted April 10, 2012 Share Posted April 10, 2012 Dave, if you intend thrashing the car, invest in some better oil. Honest.I am seriously considering something like VR1 or even a 20-60 oil (penrite?) Link to comment Share on other sites More sharing options...
mikeyb Posted April 10, 2012 Share Posted April 10, 2012 Dave, I would echo the comment about the oil. I used to have the smae trouble of dropping pressure after along run. I now use Miller semi synthetic 20/50 sport classic, oil pressure does not budge now even on events such as 10CR or RBRR. Bit dearer than yours though at £30 - £35 per gall.I'm currently working towards a bulk buy as my stocks are low. Let me know if you want a few Link to comment Share on other sites More sharing options...
GT6 M Posted April 10, 2012 Share Posted April 10, 2012 Biggest ye can get . cos even with a 13 row you be over heating it.and loosing pressureyip as Clffty says a good oil.Note, even if its a 20, / 40 /50 / 60 oil, its all really just a 20 weight oil with long chains, that bond together when hot,to make it thickerworn oot oil, will revert back to a 20 oil and the hotter it gets,the sooner it will break doon.M Link to comment Share on other sites More sharing options...
Howard Posted April 10, 2012 Share Posted April 10, 2012 MikeyB wrote:Dave, I would echo the comment about the oil. I used to have the smae trouble of dropping pressure after along run. I now use Miller semi synthetic 20/50 sport classic, oil pressure does not budge now even on events such as 10CR or RBRR. Bit dearer than yours though at £30 - £35 per gall.I'm currently working towards a bulk buy as my stocks are low. Let me know if you want a fewMike,Please put me down for a couple of galls.H Link to comment Share on other sites More sharing options...
thescrapman Posted April 10, 2012 Share Posted April 10, 2012 DaveMike beat me to the recommendation, I put the Millers in my Spitfire, went to the south of France in 40 degree heat and did not loose oil pressure after 10 hours of driving.Have also done 2 10CR's on the stuff, thrashing up the passes, no issues.CheersColin Link to comment Share on other sites More sharing options...
Davemate Posted April 10, 2012 Author Share Posted April 10, 2012 I normally buy whatever is on "special "last visit it was the the black one down from £14 to £7.50Everything that everyone has said will duly be noted and observed.Mike,I'll be in touch ! Link to comment Share on other sites More sharing options...
Richard B Posted April 11, 2012 Share Posted April 11, 2012 I've been using VR1, very impressed with the oil pressure when hot. Link to comment Share on other sites More sharing options...
Steve Cureton Posted April 11, 2012 Share Posted April 11, 2012 1344 wrote: ... engine does not smoke and I done a compression test which gave readings of 180 lb in all four pots.After 15-20 minutes running(going to work) the oil preasure is still up at 50 lb when over 1000 revs and at tickover(750-800) it sits at about 30,which is why I thought that the oil may be getting over hot Thise are good pressures and are not a problem1344 wrote: After longer but gentle runs the preasure drops to about 20 lb but after a 4000 rev blas for 40minutes it drops right off You don't say at what revs the pressure drops to 20 but losing all pressure at any revs is obviously not good. The problem could be either cheap oil (highly likely) or a faulty pressure switch. There are other causes but these are the most likely. Start with putting some decent oil in there. Also is your tickover set properly? A Triumph engine ticking over too slowly is likely to have a flickering pressure light on tickover when hot Link to comment Share on other sites More sharing options...
Velocita Rosso Posted April 11, 2012 Share Posted April 11, 2012 Repeat...Dave,use a good oil . We us e Millers CSS 20/60. Keeps good pressure. Driving abroad ,never misses a beat and use a thermostat in the oil cooler and in winter I partially blank off the oil cooler Link to comment Share on other sites More sharing options...
Davemate Posted April 11, 2012 Author Share Posted April 11, 2012 Steve_Curton wrote:1)You don't say at what revs the pressure drops to 20 but losing all pressure at any revs is obviously not good. The problem could be either cheap oil (highly likely) or a faulty pressure switch. There are other causes but these are the most likely. Start with putting some decent oil in there.2) Also is your tickover set properly? A Triumph engine ticking over too slowly is likely to have a flickering pressure Steve1)under 1000 rpm it drops to about 20lb,over that it's sits around the 50lb(75 when stone cold)2)Thats 750 -800 Flickering light is only after a long blast a few months ago I drove to Lowestoft(120 miles)I took an easy ride on the m25 and the a12 to Ipswich then went a bit mad on the upper a12 but just took it easy for the last 15 minutes or so due to a tractor When I pulled up outside the mother in laws all was fine oil was about 15-20lb and no light flickering on tickover.It just seems to be if it has a so called hard run and does not get to wind down at bit before I let it idle.I'll try a better oil before I fit the cooler. Link to comment Share on other sites More sharing options...
Richard B Posted April 11, 2012 Share Posted April 11, 2012 What engine are you running Dave? Link to comment Share on other sites More sharing options...
mikeyb Posted April 11, 2012 Share Posted April 11, 2012 Dave, I forgot to say - I would have no worries about a 15-20lb tickover. If your light flickers at this pressure, try another sensor. Link to comment Share on other sites More sharing options...
Davemate Posted April 11, 2012 Author Share Posted April 11, 2012 Richard_B wrote:What engine are you running Dave?RichardIt's spit 1500 in my herald. Link to comment Share on other sites More sharing options...
Richard B Posted April 11, 2012 Share Posted April 11, 2012 Do you still have the 4.11 diff?Do you have an oil cooler? 1500's in Heralds need all the help they can get. ;D Link to comment Share on other sites More sharing options...
Davemate Posted April 11, 2012 Author Share Posted April 11, 2012 MikeyB wrote:Dave, I forgot to say - I would have no worries about a 15-20lb tickover. If your light flickers at this pressure, try another sensor.Mike, When the preasure is 15 -20 lb the light does not flicker After a long blast the preasure drops of to 10 or just under that's when the light flicks,but if I then drive for a bit longer and let things mellow out a bit the preasure rises to 10-15 and the light stays off.We are ONLY talking about on tickover !!!!!!!The preasure of 10(flicky light)only happens when its catching it's breath as it were after a hard runI can drive like a total mad pratt,reving the bollo€oks of it going to work,which is about 5-6 miles and the preasure is still at 20-30lb at tickover Which is why I thought it mayby due to over heated oil as it is only happens after a constant longish run at a high rev ,I put a stop at 4000 revs for constant running On a constant run normaly I'll run at 3500 and the above problem does not happen In the future I'll be doing track days,auto solos and other such fun things so a good amount of heat will be generated and I don't want the this worrie Link to comment Share on other sites More sharing options...
Davemate Posted April 11, 2012 Author Share Posted April 11, 2012 Richard_B wrote:Do you still have the 4.11 diff?Do you have an oil cooler? 1500's in Heralds need all the help they can get. ;DRichardIt's all spitDiff,overive gearbox and engineIt has a standard herald rad but it has been re-cored with a three core matrix and I have no cooling(water) issues.Oil cooler being picked up on Friday,hence this thread Link to comment Share on other sites More sharing options...
mikeyb Posted April 11, 2012 Share Posted April 11, 2012 Dave, I'd wager that the good oil will sort you out then! Link to comment Share on other sites More sharing options...
jeroensprint Posted April 11, 2012 Share Posted April 11, 2012 if you have one of those external oil feeds fitted for the rockershaft, loose it. They do more harm than good and can drop oil pressure at idle (and revs)Jeroen Link to comment Share on other sites More sharing options...
aar0sc Posted April 11, 2012 Share Posted April 11, 2012 Mine is 20psi at 500rpm hot idle, 35 at 900rpm, 70psi at 1100 cold, and 70 - 85 when hot or cold above 1500rpm :)(Used to be oil light on at idle no matter what! Link to comment Share on other sites More sharing options...
Davemate Posted April 27, 2012 Author Share Posted April 27, 2012 Just an updateAll the pictures are after a 5mile drive to work At TickoverAt 1000 revsAt 1500 revsWill the new millers and the oil cooler fitted but after only 5miles the stat would still be shut but at least is there if its required At tickoverThe presure is now Link to comment Share on other sites More sharing options...
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