| Author | Message | ||
     lucien mc fadden New User Username: lucienm Post Number: 2 Registered: 7-2005 |
Yesterdy my 76 shadow LRE 25894 OVERHEATED, i let it cool down, added a couple gallons of water and got the car home. checked water level it was fine,-scary part: just as i got home,oil light came on and the car died. today, with motor cold, started car- oil light comes on after a couple of minutes car dies. Have i cooked the motor? | ||
| Mark Herbstreit Frequent User Username: mark_herbstreit Post Number: 74 Registered: 5-2005 |
I would suspect faulty oil pressure switch. If you turn on the ignition and pull the wire off the oil pressure sender, do the fuel pumps start to click? As a safety the pumps will stop if oil pressure light comes on. Replace the oil pressure switch to be sure. Oh! and investigate where the water went. | ||
| lucien mc fadden New User Username: lucienm Post Number: 3 Registered: 7-2005 |
i changed the oil pressure switch, the oil light still comes on and shortly the engine dies. any ideas? | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 63 Registered: 6-2006 |
Pull the wire off the oil switch so the light is off, then run the engine. Does it still cut out? Don't drive it yet if it doesn't cut out. Let us know what happens. Good luck, Paul. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 729 Registered: 9-2004 |
On start up are the hydraulic tappets quiet. Long shot through the boiling fault it may have stirred up debris and blocked the oil pickup strainer within the sump! Best do an oil pressure test just to make sure first. | ||
| lucien mc fadden New User Username: lucienm Post Number: 4 Registered: 7-2005 |
i will try disconecting the wire- while i had the old switch i did check to see if the oil pump was working-it squirted oil just fine out of the switch hole.... | ||
| lucien mc fadden New User Username: lucienm Post Number: 5 Registered: 7-2005 |
i disconected the wire to the oil switch with key on, i heard no clicks (my hearing is terrible anyway) oil light came on dimly before starting-started car,oil light came on-car quit after about 30 seconds-i think the tappets are quiet as well. also the fuel gauge is now not working-don't know if its realated or not. | ||
| Douglas Majors Experienced User Username: rollerman Post Number: 11 Registered: 12-2006 |
Hi Luciene, sorry if I'm stating the obvious but have you checked the colour of the oil in the sump? If it is frothy and milky, you will at least know where the couple of gallons of water went and will know to start looking at a cracked head or blown head gasket. I know of a similar problem in an earlier Shadow some years back shortly after it arrived from the UK( Sudden loss of water and then engine died within seconds of starting) Oil pressure was fine, no obvious water leaks but when the engine was stripped down the rings on at least two pistons had broken and as soon as any compression was loaded, the engine died. Prior to this there had been no outward signs of anything amiss apart from a few puffs of smoke at start up. It appeared that the water loss was due to a blockage somewhere in the block / heating system and the sudden loss of coolant round the bores caused overheating. | ||
| lucien mc fadden New User Username: lucienm Post Number: 6 Registered: 7-2005 |
Greetings Douglas! :} Ouch! thats a nasty story; I think that the reason for the boil over is that i did not tighten the cap.When I had the oil sensor out, to check that the oil pump was working i started the motor for a second- the oil that squirted out did not appear to have any water in it... | ||
| Kelly Opfar New User Username: kelly_opfar Post Number: 6 Registered: 7-2004 |
Lucien, despite searching through my printed materials and a lengthy internet search, I can't seem to find the reference source for this information. I believe I read somewhere that if the aluminum Shadow motor overheats, it is possible for the main crankshaft caps/bolts to expand and subsequently lose proper torque. This can then increase the bearing clearances, causing a partial or total oil pressure loss. Engine rebuild to follow shortly. Has anybody else read that or did I just make it up? | ||
| bob uk Unregistered guest Posted From: client-86-29-91-3.brig.adsl.tesco.net |
Ones imagination can run riot in cases like this. So lets apply engineering common sense. If when the engine was started it sounded quiet and oil is squiting out of the oil switch hole. Then the oil pump must be working and the lack of noise means that the brgs are OK. Big petrol engines rely more on quantity of oil flowing rather than oil pressure to stop contact. What happens is that a wedge of oil builds up in the brg.Ther is a high pressure side and a low pressure side. the oil is squirted into the low pressure side. The oil guage cannot measure the high pressure only the pump pressure. At idle the the oil pump will be about 5 psi on a hot engine however the high pressure side of the brg will be more. The presence of oil lubricates the brg not the pressure. I think RR avoided oil gauges because 5 psi could make some panic. When the revs pick up the pressure goes to about 30 max. Which is ample for an 8 cylinder engine. When engines get cooked about the last thing to be kippered are the brgs. First is the top of the engine-- thats where the petrol is burnt---- and a sure sign that an engine has been cooked is blue fog and piston slap. Check for blistered engine paint. I used to on purpose paint engiens so that all the time the paint is nice I know the engine is not overheating while I am not there to watch it( as in youths who thrash engines ) no fancy piants exterior grade gloss enamel -Dulux best. Also I had little stickers that change colour with heat cheap and available for engine shops. If the plugs are brown and not white which indicates cooking.------- However can turn black when pistons pick up the bores and oil gets past the rings-------- Then I would suggest that the engine is not cooked and that the loose cap allowed the water to evapourate until you noticed the steam. And of course when you opened the bonnet there was steam every where to add to the drama. Also turning the engine off means that the water pump can no longer pump water so the exsisting water in the engine boils quick time. The engine stalling after starting could and probaly is something not related. Bearing in mind that ulimately the front bumper ias connected to the rear bumper and the whole car is a machine. Checked the fuel pump for 12vdc with ignition on. If no 12 volts jump the pump with wire from live feed and then get engine to run. If pump has 12vdc then the pump is faulty. Once engine running with out stalling then the whole lot can be checked and also get garage to pump up cooling system to look for leaks. Also worth getting a exhaust gas check of the coolant any traces means maybe headgasket( the cheapest fault) Antifreeze when happy. Note my car 1974 SRH 17668 the fuel pump does not sense oil pressure so low oil pressure does not shut pump down. (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 730 Registered: 9-2004 |
Sods law may be here. With changing moisture content around the engine bay. Long shot do check the ballast resister, when they start to fail they let the engine die after engine startup. But hang on have you carried out an oil pressure test when cranking engine? (Message edited by pat lockyer on 19 August 2007) | ||
| lucien mc fadden New User Username: lucienm Post Number: 7 Registered: 7-2005 |
update re my 76 shadow:a local mechanic friend(most all rolls mechanics here in the area (NY) just want you to leave the car and come back with a fat checkbook when its ready) told me to short-out the oil sensor,which i did,no change--friend mechanic then swore that the problem had to be electrical so i went over all the fuses again and replaced #11 fuse--gas gauge then worked,cars runs with oil sensor shorted out-will not run with oil sensor connected........many thanks by the way for all the advice and knowledge contributed so far-its an interesting problem-at least for me--have searched and searched for the ballast but have not found it-it may have been elimated when the distrubtor was converted via pertronix(?) | ||
| lucien mc fadden New User Username: lucienm Post Number: 8 Registered: 7-2005 |
 Joy! Today i drained all the oil from the sump and changed the oil filter-started the car with oil sensor shorted out and let it run to get the new oil circulated. stopped car,replaced wire to oil sensor and started car-no oil light!! I let the car run for a few minutes and checked the oil level and for any leaks--NONE!! Many thanks to all of you who have tried to help me solve the problem-no cooked motor-i like my eggs 3 minutes anyway... | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 731 Registered: 9-2004 |
Sounds like the pick up strainer in the sump was a suspect with blockage. |
