Raising the compression?

[Jonesy]

Annoying rattle

I've got an annoying rattle which sounds like it is coming from the top end.
It only happens at around 3000 rpm and only on light throttle as soon as the boost builds up the rattle clears. Also if you boost it from lower revs up past 3000 rpm there's no rattle.
The car idles nice and quiet, also if you rev the car while stationary theres no rattle. So it has to be under load to rattle, although when you boost it there's no rattle.

As above it sounds like it is coming from the top end, i've had the rocker cover off and there was nothing obvious wrong, checked the valve clearances all ok.

Cranked the engine over there was a couple of cam lobes not getting sprayed with oil, Although the oil pressure only built up to a bar. Cleared the oil spray bar holes out anyway, and the oil flowed out all the holes. Theres no signs of wear to cams.

Checked compression aroud 140 psi on all 4 cylinders.

Oil pressure ok.

There's nothing obvious loose or rattling in the engine bay.

Any ideas :-D

 

[ashills]

sounds like my end not to worry u but when i stripped it ther ewas damage to ring lands and knackered big ends
one way to try and pin point which cylinder it is disconnect 1 injector at a time that will take load off that cylinder and may make noise go away while sounding like a scooby lol

 

[Jonesy]

There is a bottom end knock on start up, but that clears as soon as the oil pressure builds up.
Wouldnt the big ends knock rather than rattle, also wouldnt it be all the way through the rev range and on idle.
Woudl there not be any other signs if it was the ring lands.
It doenst seem to be getting any worse has been like this for a couple of months.
Also there was no metal deposits in the oil when it was changed.
I'll try disconnecting injectors see if that narrows it down to one cylinder.
Cheers

 

[boucherie]

the only thing you'll need to do is modify the oil return drain, this can be easily done using the right tools and theres plenty of links to topics via the search button

 

[Smo]

I have the exact same problem and it's really starting to bother me. I believe I've narrowed it down to where my timing chain is (by cylinder 1? - Far left when stood at the front of the car looking into the engine bay).

 

[MORF114]

ashills has a good way to do the oil return using copper fittings best way ive seen done.

 

[Jonesy]

I thought my rattle was coming from the opposite end, but that was just listening in using a screw driver.

 

[Jonesy]

I have the exact same problem and it's really starting to bother me. I believe I've narrowed it down to where my timing chain is (by cylinder 1? - Far left when stood at the front of the car looking into the engine bay).

Sounds like that could be your timing chain tensioner or guide.

 

[pulsarboby]

if its the big ends (without worrying you) they are notorious for rattling / light knock at around 3k on part throttle then coming off again as there released from being under load!
if i were you i would whip the sump off and check the state of the bigend bearings before its too late and you muller your crank.
cranks are very difficult to get hold of in good nick and if that is the prob then you maybe lucky and get away with a new set of bearings, but if there ok at least you can dismiss them from causing the problem!

 

[jjs]

can you drop the sump of in place or do you have to take the gearbox out, if i remember right there is two bolts behind the fly wheel, that hold on the alloy sump plate, ?think this has to be removed to allow access to the big ends .

 

[Jonesy]

if its the big ends (without worrying you) they are notorious for rattling / light knock at around 3k on part throttle then coming off again as there released from being under load!
if i were you i would whip the sump off and check the state of the bigend bearings before its too late and you muller your crank.
cranks are very difficult to get hold of in good nick and if that is the prob then you maybe lucky and get away with a new set of bearings, but if there ok at least you can dismiss them from causing the problem!

Ok looks like we will be popping the sump off for a look then. What about the above question ?
Cheers

 

[GTIR-LOZ]

there is a metal plate in the bottom of the sump at that position just remove that and you gain access to the two small nuts

 

[Jonesy]

Ok cheers.

 

[rx jamie]

will you not have to grind some of the block back ike i had to do with my gt2871

 

[Fusion Ed]

nothing needs griding with the 3071, at least the ones i deal with anyway.

 

[gtirjoey]

thanks for your input guys really helpful cheers

 

[Jonesy]

Where's the best place to get big end bearings from, i know erics performance parts do them. But could do with getting them pretty quick once the sump is off and see what size is needed. So the car is not off the road to long. Assuming that is the problem anyway.
Cheers

 

[pulsarboby]

if you need bearings then use acl race bearings i think agra engineering do them in scottyland or h-dev sell them also

 

[Jonesy]

Ok cheers for that, i'll get in touch with them.

 

[Jonesy]

H-dev have got them listed for £79 not sure what delivery cost is. Eric's is only £23 pound works out around £40 delivered within 3 to 5 working days, may just go with that.