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number1
23-05-2007, 23:16
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
23-05-2007, 23:19
Forgot to mention, bottom end was untouched, didnt change shells rings etc had done 70k

Dave

MAXIBOY
24-05-2007, 00:15
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
24-05-2007, 09:10
best get the old sump off then :(

number1
24-05-2007, 14:40
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
24-05-2007, 14:50
are you sure its a knock and not piston slap when cold.

number1
24-05-2007, 15:11
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
24-05-2007, 15:24
can you get a video up mate.

MatBrown
24-05-2007, 15:26
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
24-05-2007, 15:30
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

MAXIBOY
24-05-2007, 15:49
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.

but why only knock when cold. oil not getting there when thick but getting there once warm.

MatBrown
24-05-2007, 16:02
God knows. lol.


Mat.

number1
24-05-2007, 17:02
Ordered new shells, as to be on the safe side, looks my run to the sun weekend may be taken up with fitting new shells!!

Just got another oil pump too, was rebuilt not long ago and fitted to a mates engine that the rings went after 10k
gonna strip it, clean it and measure everything and change that whilst the shells are being done

number1
24-05-2007, 22:24
UPDATE: just fired it up, from stone cold knock is still there although has about 2 1/2-3 1/2 bar at idle knock quietens after a couple of minutes...
Could well be piston slap if it sounds the same as big end.. but i'd defo say big end knock sound

Dave

stan
24-05-2007, 22:43
Is it doing it when idling? If so, probably isnt big ends noise.

Is it DEFINATELY coming from the bottom end??

bass_direct
25-05-2007, 03:56
when my old megane bottom end was knocking, it wouldn't knock on idle, only after you rev it... on idle, it was fine

number1
25-05-2007, 11:51
not doing it on idle no, between 1500 and 3000rpm gonna go and get a long listening tool, (screwdriver) and locate the noise later. must admit im swaying away from big ends... got about 3 1/2-4bar (according to the gauge) this morning, noise quietened after 2-3 mins and after 5 or so, couldnt hear it..

stan
25-05-2007, 22:40
If it was the big ends, it wouldnt disappear. It will get progressively louder over literally a very short period.

Its probably piston slap, or the little ends showing a little wear.

OR you've totally got the worng area and its your cam followers!

Craig

number1
26-05-2007, 10:47
Craig got a feeling it is mate, just realised that when i started it yesterday it had a slight misfire, exhaust popping more than usual, (maybe as if a valve werent fully opening) did over 140 miles yesterday and not missed a beat once warm

Dave

VIPERONE
26-05-2007, 11:14
lol

i hadnt started my clio for a week the oil drained from the lifters..started it up sounded pants

thought my bottom end had deceased..knock knock knock

left it idling for 30mins

fixed itself

nothing worse than a fault that could be 100 things and difficult to pin point.

best of luck.......

number1
26-05-2007, 12:08
gonna go out n fire it up in a sec, see if its missing, gonna drive it with the noise, would be pretty self explanatory if it is tappety tap tappet, sure it aint big end now, anyone wanna buy a set of genuine shells??
lol

Dave

VIPERONE
26-05-2007, 20:48
gonna go out n fire it up in a sec, see if its missing, gonna drive it with the noise, would be pretty self explanatory if it is tappety tap tappet, sure it aint big end now, anyone wanna buy a set of genuine shells??
lol

Dave

i would have said yes..needed a set for my turbo...but need valver shells @ .25

number1
26-05-2007, 23:57
Valver shells, williams shells and megane shells are all identical im told, but there standard size, might give my old 1.8 a full rebuild and sell it,

Not worrying about the noise no more, must be a follower, was a tap this morning and everyday it's getting quieter...


Dave

stan
28-05-2007, 21:01
Some of the megane conrods/caps have no tab slots for the bearing locators...so they arent totally identical.

number1
28-05-2007, 22:57
In that case i have williams std shells for sale, as thats what he sold me lol

Dave