[Mgs] oil pressure delay question

[Charley & Peggy Robinson]

Paul,

Let me begin by asking if you were responding to an earlier post of mine?

If so, note that  wrote, "almost dry" not  "dry. "   What I meant by 
thet was that the bearings were not floating in oil, as they would have 
been after a day or so of inactivity.

  I think the OP was speaking of a MGB 4 cyl engine.  That's post I 
responded to.

Yes, in the case of my engine and the original OP's,  AIR, if the engine 
isn't cranked for 10 - 15 seconds before allowing it to start,, the rods 
will rattle after starting,  until the oil flow & resulting pressure 
comes up.   That's why I make a practice of cranking the engine for 
10-15 seconds  unchoked, before choking and starting it.  This is only 
if the engine has not been started for more than two days.

I hope this clears any confusion for you,

CR


On 5/21/2013 2:58 AM, PaulHunt73 wrote:
> Oil does leak down from the system, be it galleries or filter, the 
> longer it is left parked.  The quality of the oil filter has a major 
> impact on this, but even switched off fully hot and left for a few 
> days my V8 bearings were still swimming on oil when I removed the big 
> ends and main bearings, so to say they are 'dry' at start-up is 
> definitely not correct.  That engine is notorious for low oil pressure 
> and a slow rise, the factory moved the gauge tapping from the output 
> of the oil filter to the output of the pump in order to allay customer 
> fears - but making absolutely no difference to the bearings of course, 
> even so even when just left overnight it takes several seconds for the 
> gauge to even start rising, and takes maybe 10-15 seconds to reach 
> full pressure.  Left overnight the roadster is pretty 
> well-instantaneous to register pressure, after a couple of weeks or 
> more it is about five seconds from the start of cranking, having fired 
> up after 3 or 4 seconds.
>
> 15 seconds to see oil pressure is way too long.  Can you hear the 
> knocking straight away?  Or only after a few seconds of running and 
> before pressure builds?  If straight away it's likely that worn 
> bearings are the cause of the slow rise.  If only after a while then 
> it's likely that the residue of oil on the bearings is being lost 
> before oil is available again, and that is causing bearing wear.
>
> PaulH.
>
> ----- Original Message -----
>> ...  Result: no oil in the main gallerie untl the engine runs a bit, 
>> the passages fill up and the pressure comes up to normal.  You hear 
>> the almost dry rod bearings rattle until they get oil.
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