****Engine Help needed**** Engine experts please

[number1]

OK i got a problem with my freshy rebuilt hybrid motor, i sometimes have no oil pressure on a cold start up, oil light goes out, but pressure gauge does not rise, theres a big end knock too, this goes on for about 5 mins, i turned it off, and back on oil pressure goes up to about 2-2 1/2 bar and after about 15 seconds the knock disappears and it drives absolutley spot on with no knock under load etc...

Its an F7r 710 bottom end with a F7p 722 oil pump which i took apart and cleaned prior to fitment, looked fine and tolerances were ok, once engine is warm its fine, done about 400 miles in it and not missed a beat, apart from this stone cold start problem...

Please Help i havent a clue where to start on this one...

[number1]

Forgot to mention, bottom end was untouched, didnt change shells rings etc had done 70k

Dave

[MAXIBOY]

if theres a big end knock you have a problem mate. difficult to say what it is but theres a problem. oil pump is first culprit if it goes away.

[number1]

best get the old sump off then :(

[number1]

Just fitted a geuine filter, oil pressure is about 0.75 bar at idle when fully warmed up and 3.5 bar at 3k which was pretty much the same as with the fram filter, but the fram filter didnt have a one way valve and when i took the filter off there wasnt a great deal of oil in it, fitted the genuine filter which had a one way valve, and now i have to wait till it gets stone cold, to try again...
Hope it aint nothing bad cos im on holiday from work (mechanic) and i dnt wanna spend it underneath a clio lol

Dave

[MAXIBOY]

are you sure its a knock and not piston slap when cold.

[number1]

sounds like big end knock, had that before, but surely big end would be more noticeable when the engine is warm and the oils thinner? see where your coming from maxiboy, i was thinking if the oil pumps confudgeled then the pressure warning light would come on? it goes off when cranking..
Engine had done 70k ish miles (cambelt failure)
F**king cars!!

[MAXIBOY]

can you get a video up mate.

[MatBrown]

Engine had done 70k ish miles (cambelt failure)
F**king cars!!

If the engine suffered a cambelt failure, the pistons hitting the valves could have bruised the bearings.


Mat.

[number1]

When i start it later, when its stone cold i'll video the noise
I expect you have hit it on the head mat! hope i dnt need a crank regrind!

It's quicker than a valver, but dnt feel that much quicker.... hmm