paul mc Posted November 11, 2010 Share Posted November 11, 2010 After stripping the top end of my 1987 3.5 V8 Efi I can't manage to get the oil pressure back up, both the oil pressure warning light and my electric gauge are showing low pressure so I'm fairly happy it's not as simple as a dodgy pressure switch. I have tried priming the oil pump with vaseline by removing the oil filter housing, taking out the two cogs and packing with vaseline, then putting the cogs back in so that there really is an much vaseline in there as i can manage then turned the engine over but still no pressure. I also put a new pressure relief valve and spring in just in case it was that sticking open, although i don't think it was. However, i did notice that when the spring is at full extension the valve cylinder itself seems to stick in the closed position, though if this is a problem it should be causing high pressure if anything. I would greatly appreciate any tips or tricks for getting pressure back up, or any reason why i might be having problems? Also if i am priming the pump manually using a drill, which way should i be turning the oil pump, i.e. does the distruibutor turn clockwise or anti-clockwise? Thanks, Paul Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 11, 2010 Share Posted November 11, 2010 Have you started the truck? Sorry, it's not clear from your post... You will struggle to get pressure up on just cranking speed, if that is what you are trying, especially with cold, thick oil. As for the drill priming, take the dizzy cap off and see which way it spins when cranking Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 11, 2010 Author Share Posted November 11, 2010 I have started it and it runs fine, i have let it warm up and still no pressure but obviously i don't want to over do it if there's no pressure. Regarding which way the rotor arm spins its just a bit fiddly to turn it over and see the dizzy when i'm by myself, I've no doubt i can keep the key turning with an elastic band or something i was just hoping someone might know off the top of their head. Quote Link to comment Share on other sites More sharing options...
luke keeper of badger Posted November 11, 2010 Share Posted November 11, 2010 hi paul the distruibutor turns clockwise you should feel the pressure coming on with a drill within a few seconds 10 or 20...... i like this way best less wear did you have the heads off? blocked strainer! Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 11, 2010 Author Share Posted November 11, 2010 I did have the heads off to do new gaskets etc and valve grinding. I haven't checked the strainer for blockages, i suppose i should do that on the weekend but would this likely to have been blocked? I have done a couple of oil and filter changes as i've been rebuilding it to try and keep debris from getting around the engine. Quote Link to comment Share on other sites More sharing options...
luke keeper of badger Posted November 11, 2010 Share Posted November 11, 2010 you wont cause any damage with your dill try this method before looking in sump. ive seen blocked strainers after head gasket changes, what grade oil are you using? ive always used 20W50....and decent stuff at that. Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 11, 2010 Author Share Posted November 11, 2010 I'm using a Halfords 10W-40 part-synthetic which i have always used in the engine and worked fine previously. Unless anyone has any other ideas i'll drop the sump, clean it and the strainer out and then do an oil flush before changing the oil filter and new oil again, hopefully that will sort it, or at least cross it off the list Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 11, 2010 Share Posted November 11, 2010 10w-40 is FAR too thin for the Rover V8, use 20w50, nothing less. As above, don't use the cheap cack stuff, expect to pay at least £15 for 5 litres, I use either Millers or Valvoline in mine, which goes out at about £25 for 4.5l. If it's an oldish engine then don't bother doing a flush, probably cause more problems than fix.... Yes to cleaning the strainer, if you remove it, you will need to re-prime it again. Are you driving around with no oil pressure then..............? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 11, 2010 Share Posted November 11, 2010 20W50 or 15W40, get the drill on it and just keep going - it can take quite some time and more than one packing with vaseline. My uncle had some success squirting oil into the pressure switch hole before refitting & priming. I have a remote filter head so I can prime it by undoing the pipe & pouring oil back down it from above, makes life much easier. Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 12, 2010 Author Share Posted November 12, 2010 10w-40 is FAR too thin for the Rover V8, use 20w50, nothing less. As above, don't use the cheap cack stuff, expect to pay at least £15 for 5 litres, I use either Millers or Valvoline in mine, which goes out at about £25 for 4.5l. If it's an oldish engine then don't bother doing a flush, probably cause more problems than fix.... Yes to cleaning the strainer, if you remove it, you will need to re-prime it again. Are you driving around with no oil pressure then..............? No, its an ongoing rebuild and its still not back on the road. In all honesty i don't know how long the pressure has been low for but it started sounding quite tappety the other day and the pressure light came on so obviously i've been trying to sort it since and not running the engine much. Halfords oil is £20 for 5 litres and from various comments i've read previously i thought it to be amongst the better value oil in that it is both good and reasonably priced. Is Halfords oil proven to be bad or is it a bit of prejudice against the brand? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 12, 2010 Share Posted November 12, 2010 Halfords, if a 20w50, will be fine. I'd still be suspicious of the pressure release valve TBH... try tapping it gently with a hammer with the engine running to see if you can get the light to go out. Quote Link to comment Share on other sites More sharing options...
missingsid Posted November 13, 2010 Share Posted November 13, 2010 I have seen comments that state that putting a new relief valve and spring into an old scored pump body will not improve anything and in fact may stick even worse. I have just added a John Eales tadpole valve to my engine though it does require slight modification to the pump cover. It seems to be working very well so far. JE Deelopements can provide a new modified cover and tadpole or modifiy your cover for a reasonable price. They are also looking at re-offering their remote filter cover also modified if required. Marc. Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 13, 2010 Author Share Posted November 13, 2010 To be honest i only changed the relief valve as i bought one ahead of time thinking that could be the problem, but when i stripped the filter housing i found the existing valve to be perfectly smooth and running freely, but i thought i may as well change it while I was there. Quote Link to comment Share on other sites More sharing options...
SteveRK Posted November 13, 2010 Share Posted November 13, 2010 Assuming the pressure relief valve is o.k. its time to drop the sump. To prime the pump will require more 'flow' (not pressure) than once the pump is primed. It may be that the gauze strainer has been partially blocked, or the O ring gasket on the pipe is not sealing such that for a 'primed' engine there is sufficient flow but when starting from scratch it cant quite get enough flow to remove air from the system. Quote Link to comment Share on other sites More sharing options...
Roverbo Posted November 15, 2010 Share Posted November 15, 2010 Hi Paul, I had a V8 once that wouldn´t prime after a "rebuild". To put it short (it took me over a week to find the cause - and, say 20 liters of oil... ), it was an air leak in the front cover who caused the problem. I had only used the paper gasket. After I re-assembled the front cover with a smear of hylomar, the pressure came straight on (using a battery drill via the distr.drive). I didn´t need to re-pack with vaseline. But don´t run the engine if you haven´t got oilpressure - use the drill trick. Regards Bo Quote Link to comment Share on other sites More sharing options...
luke keeper of badger Posted November 15, 2010 Share Posted November 15, 2010 No, its an ongoing rebuild and its still not back on the road. In all honesty i don't know how long the pressure has been low for but it started sounding quite tappety the other day and the pressure light came on so obviously i've been trying to sort it since and not running the engine much. Halfords oil is £20 for 5 litres and from various comments i've read previously i thought it to be amongst the better value oil in that it is both good and reasonably priced. Is Halfords oil proven to be bad or is it a bit of prejudice against the brand? hi paul its not the brand thats most important its the viscosity...sorry didnt realize this engine has had low pressure over time,, worn bottom end (bearings) is the usual cause of low oil pressure,loads of people go straight for the pump..the oil pressure is built(backed up) up by the bearings. with your thin oil and wear your gonna have low pressure... try thicker oil mate Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 15, 2010 Author Share Posted November 15, 2010 I think I might be confusing people here, even with the 10W-40 the oil presuure used to be fine before the rebuild, it is since the rebuild that i have had NO oil pressure and am having trouble priming the pump. Talking of oil grades, i went back through the workshop manual to try to figure out why i was using 10w-40 if everyone says it is too thin and the manual itself recommends 10w-40 or 20w-50, although i would have thought that the 10w-40 is more suitable to the British climate as it is suitable from -10degress to 50degreees, whereas the 20w-50 is only recommended above 0degrees, and anyone who was down my way last night and early this morning can attest that less than zero is quite likely anytime from November to March. Having said that, i have now drained the old oil and replaced with 20w-50. But anyway....... I was very busy this weekend so i didn't get to do much but i did drop the sump and remove the oil pick up and gave them a thorough clean out and soak in petrol, and i have to say they both weren't in that bad a state so i'm not very hopeful that was the cause of having no pressure. But i did clean it all out and i even bent the pick up strainer a touch to make sure that it wasn't sucking against the bottom of the sump in case i had damged it previously. Now everything is back together and just waiting on the weekend so i can get a chance to prime the pump again. Can you please tell me if what i am doing is wrong to prime the pump.............. - remove the oil pump cover - remove the 2 oil pump gears - pack the empty housing with vaseline - replace the gears - replace the cover - turn the engine over for about 30 seconds with fuel pump relay removed and LT lead disconnected I don't think there is an air leak between the timing cover and the block as I used gasket paste to form the gasket, not just a paper one. Any help much appreciated thanks, paul Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 15, 2010 Share Posted November 15, 2010 You'll struggle to get oil pressure on just engine cranking, in my experience, the drill method would be much faster, and no need to pack vaseline beforehand. Whilst in there I would stick the original pressure relief valve back in, the 'new' one may be causing you problems. Quote Link to comment Share on other sites More sharing options...
Roverbo Posted November 15, 2010 Share Posted November 15, 2010 Hi Paul, I would def. use the drill through the dizzy to turn the pump, you can feel the resistance very sudden, when the pressure builds up. And you won´t scrap your camshaft/lifters... What I did was I took the oilfilter off, and placed a bin under. It gives you some idea of what´s going on (or not going on). Because of the air leak, I had a thin stream coming, filled with bubbles. And - to the viscosity discussion - it makes no difference with type or make here...just what´s available cheap (until youve got it right). Bo Quote Link to comment Share on other sites More sharing options...
David Wright Posted November 16, 2010 Share Posted November 16, 2010 When I rebuilt my 3.9 engine I followed the oil pump priming instructions and it primed immediately but I have a colleague who had exactly the same problem as you are having with the priming operation. His final solution was to pressurise the crank case with an air line - this of course meant blocking off all the breather system and getting about 10 psi in the crank case - this primed the pump when all else had failed. Quote Link to comment Share on other sites More sharing options...
paul mc Posted November 28, 2010 Author Share Posted November 28, 2010 Well I have finally got the oil pressure back, in the end i did take off the pump and oil pick up stariner and clean them both thoroughly with petrol and i blew through the oil pick up line to ensure it was not blocked, i also blem the airline through the holleft behind once the oil pick up pipe was removed to ensure the oil passages within the engine were clear. I also put the old pressure relief valve back in as it was in good condition and was a tiny bit looser than the new one, probably becuase it was warn in. I then primed the oil pump with vaseline, and fixed the cover back on with a new gasket and then fitted a new oil filter. I know it was a bit oif a scattergun approach but it only cost me a couple of quid for the new filter and relief valve and its sorted now. Thanks for all the advice! I do have new probelm though which i'll start a new thread on, the engine isn't running great and i have had to set the timing very advanced to run at all Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.