novacaine
|
| posted on 19/7/11 at 09:22 AM |
|
|
Alfa Engine rattle - help with diagnosis?
Hi all,
My beloved 156 has developed a nasty engine rattle that has got me all worried 
It starts fine, no noises at tickover, nice and smooth but the noise starts at around 2-2.5k rpm and gets louder with revs
Heres a youtube clips for help explaining the noise
Youtube Linky
really hope its not bearings
thanks in advance
***edit to say - its the 2.0 TS manual if this helps at all with diagnosis***
[Edited on 19/7/11 by novacaine]
And you run and you run to catch up with the sun but its sinking, Racing around to come up behind you again, the sun is the same in a relative way but
your older, shorter of breath and one day closer to death
|
|
|
|
|
ashg
|
| posted on 19/7/11 at 09:28 AM |
|
|
sorry to tell you mate the big ends have gone
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
|
|
|
T66
|
| posted on 19/7/11 at 09:38 AM |
|
|
Thats not good if your attached to it...
|
|
|
Thinking about it
|
| posted on 19/7/11 at 09:47 AM |
|
|
Sounds like bottom end
|
|
|
britishtrident
|
| posted on 19/7/11 at 10:22 AM |
|
|
Big end bearings are more of a solid knock rather than rattle ----- as it is an Alfa suspect the camshaft variator wear as this gives a
rattle from the top end
[Edited on 19/7/11 by britishtrident]
|
|
|
Alfa145
|
| posted on 19/7/11 at 10:24 AM |
|
|
Could be bearings but didn't seem a consistant enough rattle to me, a few other options to check before your wallet panics.
Sounds like something was loose somewhere to me, check everything is tight that you can get to. Maybe something inside the cam belt cover? Cam belt
tensioners were always a weak point on this engine. 36k miles for belt changes is recomended, check its still tight and not jumped.
Also look up the cam variator this tends to go on the petrol engines and rattles. Although when mine went on my 1.6 I don't think it sounded
like that.
AlfaOwner.com forum might provide more help with specifics of this engine.
|
|
|
novacaine
|
| posted on 19/7/11 at 10:31 AM |
|
|
the cambelt and variator were done less than 5000 miles ago,
oil level is ok too, ever so slightly on the low side but a good 4mm above the min mark on the dipstick
Will post this on alfaOwner, thanks for the recommendation
Thanks for your help everyone
And you run and you run to catch up with the sun but its sinking, Racing around to come up behind you again, the sun is the same in a relative way but
your older, shorter of breath and one day closer to death
|
|
|
Alfa145
|
| posted on 19/7/11 at 11:25 AM |
|
|
Do you still get the rattle when you've topped the oil up? I know mine had a slight rattle when the oil was below 1/2 on the dip stick. Alfas
normally don't like running on low oil levels. It could be the variator isn't getting enough oil pressure to turn the cam which might be
causing the rattle. But thats just a random guess.
|
|
|
MikeRJ
|
| posted on 19/7/11 at 11:34 AM |
|
|
Variators tend to produce a constant diesel-like rattle when worn, and also tend to be most noticeable at lower engine speeds.
Does it get worse when the engine is hot? Have you checked the oil pressure?
|
|
|
UncleFista
|
| posted on 19/7/11 at 01:02 PM |
|
|
quote:
Originally posted by ashg
sorry to tell you mate the big ends have gone
Sounds like it to me too
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
|
|
|
big_wasa
|
| posted on 19/7/11 at 01:23 PM |
|
|
ouch.
|
|
|
whitestu
|
| posted on 19/7/11 at 02:17 PM |
|
|
Isn't it possible to drop the sump and change the big ends in situ?
If they have just started rattling the crank may be OK.
Stu
|
|
|
ashg
|
| posted on 19/7/11 at 03:34 PM |
|
|
there isnt any ifs or buts the big ends are shot, simple as that really the sound of dead big ends is rather distinctive. get the sump off and have a
look, im 100% sure the shells will be shot. if your lucky the mains will be ok. there are three routes to fixing it. take the engine out measure
and check everything and re machine where necessary flush and blow out all the oil ways and crank to make sure there is no swarf from where it picked
up then reassemble. option two take sump off clean it out along with the strainer fit new shells and hope there is no swarf hanging around in any of
the oil ways, refit sump and start. or option three stick another engine in it.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
|
|
|
martyn_16v
|
| posted on 19/7/11 at 03:52 PM |
|
|
quote:
Originally posted by novacaine
oil level is ok too, ever so slightly on the low side but a good 4mm above the min mark on the dipstick
On this engine, that's not OK. The bottom end is made of chocolate, and will eat itself well before the oil gets near the min mark (or the oil
"warning" light thinks about coming on)
|
|
|
steve m
|
| posted on 19/7/11 at 04:32 PM |
|
|
I go with the big ends as well,
Normally it is a fairly easy fix with the engine in the car, i would also change the mains, or at least the ones you can get to
Steve
|
|
|
