hi 4.6hse problems

hi all i got a 4.6 hse p reg lpg converted im getting a tinny rattling noise i think its coming from the exhaust but the exhaust is not blowing anywhere as u apply more revs the rattling seems to speed up wiv the revs now i think the big ends has gone cause for the first 10 sec from cold the engine knocks after its ok and geting poor mpg about 100-110 miles to £20 of lpg could they all be connect or would u say they are diffrent faults any help to any of the above would be a great help

thanks in advance

chris

scooby-ra said:

hi all i got a 4.6 hse p reg lpg converted im getting a tinny rattling noise i think its coming from the exhaust but the exhaust is not blowing anywhere as u apply more revs the rattling seems to speed up wiv the revs now i think the big ends has gone cause for the first 10 sec from cold the engine knocks after its ok and geting poor mpg about 100-110 miles to £20 of lpg could they all be connect or would u say they are diffrent faults any help to any of the above would be a great help

thanks in advance

chris

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Small ends can give a tinny rattle, but big ends have a lot more bass associated with them, it's all a case of frequency. Big ends sound like someone hitting a hammer on a thick lump of steel. Small ends sound like someone hitting a hammer on a thin sheet of steel.

Tinny rattles could be caused by loads of things, maybe loose baffles in a silencer, maybe something loose on the engine or bodywork, why assume it's something internal to the engine ?

BTW, can't see how small or big end problems could influence mpg.

well the knock for the first 10 sec from cold sounds like a hammer hittin a thick lump of steel so that could confirm what i thought but i know the rattle is not just some think lose iv'e checked most things it sounds like the exhaust is blowing but it looks ok and if i had to have a guess it was coming from the driver side near the down pipe

thanks for ur reply

Sounds to me like your Cats are breaking up. A rattle on start up is normal for the lifters until they get enough oil pressure to take up the clearances. Is it a new rattle or has it always been there ?

no had the knocking from cold and the rattling since i had it which has been about 3 months

Sounds like its your lifters then. No need to worry about them, as long as they take up the slack quickly, they are fine. A tinny rattle from the exhaust usually points to the cats breaking up in side. If you fit new ones yourself, take the old ones to a scrap dealer to get some money back on them.