Running when cold until warmed up
Discussion
Being picky now !
When cold my engine sounds fine when not under load and even with a few revs.
When on the move and cold pulling away, it sounds slightly harsher.
Sort of a knock or bang at each firing.
Accelerating at low revs and in a high gear does not make it worse, so doesn't sound like big ends or mains.
It has just been rebuilt with new pistons and bearings etc, by a respected specialist, so I doubt problems in that area.
It remains for 5 mins maybe ?
Gone by 70 deg on temp gauge
Any thoughts anybody ?
Could it be a bit of piston slap?
To far advanced ignition ?
Anybody near Woking with a 500 that I could listen to when cold ?
Cheers
When cold my engine sounds fine when not under load and even with a few revs.
When on the move and cold pulling away, it sounds slightly harsher.
Sort of a knock or bang at each firing.
Accelerating at low revs and in a high gear does not make it worse, so doesn't sound like big ends or mains.
It has just been rebuilt with new pistons and bearings etc, by a respected specialist, so I doubt problems in that area.
It remains for 5 mins maybe ?
Gone by 70 deg on temp gauge
Any thoughts anybody ?
Could it be a bit of piston slap?
To far advanced ignition ?
Anybody near Woking with a 500 that I could listen to when cold ?
Cheers
mickh32 said:
I would take it back to the specialist so he could have a listen just for peace of mind.
In an ideal world I would, but he is 150 miles away in the middle of no where and I would have to leave the car so it could be started from cold. Edited by WokingWedger on Monday 16th February 10:43
Richard 858 said:
Could it just be pinking (detonation), if so get timing checked to correct spec. for rebuild.
This is what I am hoping, although the timing was set by the engine builder on his dyno, so it should be spot on.However when installed in the car, things may be different, I suppose.
Worth trying.
I have marked the existing distributor position.
phazed said:
If it is pinking it'll sound like an obvious rattle under load that dissapeared as you back off the throttle.
Its not actually pinking ( I have experienced pinking before).The best way I can describe it is that it feels like each firing is coming through the drive line in a sort of 'hammering fashion'. A harshness if that makes sense.
When warm its fine.
I see you are another Peter in a Chim in Surrey.(must keep an eye out and wave)
Sometimes the engine mounts settle.
There is very little clearance inbetween the manifolds and the top chassis rails, also inbetween the bottom of the Y piece and the diagonal brace on the chassis iirc.
Check you have about 10mm clearance there, maybe a tad less.
I have had my manifolds sit on the chassis rails giving a harsh sound/feel when the mounts aged.
If this is your problem, you can loosen the mounts, jack up the engine and retighten as there is movement in the connections.
I'll be looking,
There is very little clearance inbetween the manifolds and the top chassis rails, also inbetween the bottom of the Y piece and the diagonal brace on the chassis iirc.
Check you have about 10mm clearance there, maybe a tad less.
I have had my manifolds sit on the chassis rails giving a harsh sound/feel when the mounts aged.
If this is your problem, you can loosen the mounts, jack up the engine and retighten as there is movement in the connections.
I'll be looking,
Pinking will increase or appear with a rise in engine temperature so its fair to assume over advanced ign timing is not the problem here, personally I think you should approach the engine builder about this 
maybe a silly question but have you checked the oil level does your oil pressure indicate normal?
maybe a silly question but have you checked the oil level does your oil pressure indicate normal?Peter, good thought, but they are brand new mounts and spaced correctly !
Perhaps its just a function of a big engine, light body and until the oil is fully warmed ( engine and gearbox) you just feel it through the structure.
(Or me getting paranoid after spending so much).
Do you notice (feel or hear) any difference when cold to when warm ?
Perhaps its just a function of a big engine, light body and until the oil is fully warmed ( engine and gearbox) you just feel it through the structure.
(Or me getting paranoid after spending so much).
Do you notice (feel or hear) any difference when cold to when warm ?
phazed said:
My engine starts and feels quite lumpy when cold but the engine noise doesn't really change, just gets progressively smoother.
Mine is the same, I have noticed that it is worse when the temperature is around +5,my thought is that the fueling is not as accurate as it should be, but the map comes good when up to temperature.
WokingWedger said:
s p a c e m a n said:
Cracked manifold? Mine has a tiny hole in the middle of the 4 branch and is much more noticeable when cold, guess when it's warm the metal expands and closes the hole up.
Can you describe what this sounds like spaceman please.
Gassing Station | Chimaera | Top of Page | What's New | My Stuff