Morris Minor Owners Club

my 1098 engine was fully rebuilt under 4000 miles ago , it was in the car when i bought it , i have all docs to prove mileage , it runs perfectly and has good oil pressure hot and cold but when it has sat overnight or even for more than 4 hours the oil light is slow to go out , it has a new switch and it's the same on a gauge around 15 to 20 secs , i have removed the sump and front plate to check the main bearings which are perfect not a single mark on the shells or crank and the same for the big ends , the oil filter is assembled correctly and there are no metal particals in the sump or oil filter ,it did the same before i changed the oil and the oil i took out was clean as was the filter , any thoughts or is this just normal for an A series

Hmm -not good - it should go out almost immediately. Have to wonder if a new oil pump was fitted...not easy to check unfortunately. I assume you are using 20W50 oil and the level is well up. What is the HOT running pressure after a good run at 40 mph in top gear?

oil pressure sits around 40 psi , comma 20/50 oil ,fram filter all the other components i can see in the engine appear clean and or new , the camshaft looks new , the rocker shaft and rockers look new so guess the oil pump was as well and looking at how neatly the engine was assembled i would think it was a good unit ,

40 psi is very low - it should be 60 psi at 40 mph in top gear after a good hard run....Rising to 70 psi at 60 mph. You can have a look at the relief valve in case there is a bit of swarf wedged over the seat - but it is grasping at straws... Was the engine 'rebuilt' or just 'refreshed'..?

definatley rebuilt with many new parts , i will check the pressure release valve and recheck , it does not rumble or make any noises at all , i was also thinking about the quality of the new oil pump given a lot of members are have part quality issues , i suppose it's not the end of the world to pull the engine out and check the pump , as it's such a sweet engine i don't want to wreck it

Indeed not .. has it always been so slow to put the light out from cold - or has this crept up on you ? The 40 psi is not 'deadly' - but the 15 seconds with no pressure from cold is definitely worrying. I have heard of oil pumps where the shaft is not keyed to the impeller - instead relying on an interference fit - and they have been known to 'break free' and slip on the shaft....

Meanwhile I would churn the engine over on the starter with no choke to get some oil around the engine before starting it.

it has always been slow since i bought the car 4 months ago , i have only put approx 500 miles on since then as i have been re commissioning the car as it stood for while ,

problem solved i went to carry out another oil pressure test this morning and as i removed the oil switch i noticed something in the end of it , a piece of ptfe tape ! and guess what was partially blocking my oil pressure test adapter more ptfe tape !!, it would appear that as the oil switch was screwed in tape left in the thread was pushed up the oil way and of course went straight back to whatever was screwed into the hole , i have cleaned out the thread and checked down the oil way and all is clear , now start from cold 2-3 secs oil pressure showing 70 psi drops to 55 hot idling and picks straight up to 70 when reved , left to sit for 5 hours straight up to 70 psi 3-4 secs max , the gauge started to move as i cranked the engine and was showing 20 psi as it fired so a nice simple fix ,

Think you'd better steer clear of ptfe tape in the future. Incidentally did you know there is a correct way to wind it onto the thread?

it was not me , i use liquid ptfe thread sealing compound on this type of fitting and when i use tape i only put one wrap on and i leave the first turn of thread clear so it is always away from important areas ,

Great news and well done finding the problem! Never heard of that one before!!! Great success !!!!