I recently rebuilt my 95 wrx with a new crank, bearings and various bits but i am getting a tapping noise when cold which dies down when it warms up.
I doubt it is the bottom end because i plastigauged the bearings and they are within specs. I have now done 300 miles and it is still tapping when cold. What could it be???

 

tappet?

might quieten down on decent oil.. you still on run in oil?

Simon

 

I have done about 20-30 miles on silkolene pro s 15/50 but it is still tapping when cold. Could this have anything to do with the cam belt

 

do sometimes get the cambelt tension tap or it is more of a knock when cold when it has failed..

 

would it be worth checking the tensioner pulley? I am 99% sure the bearing on the pulley is ok but i might have tensioned it wrong.How do you know when the belt is tensioned correctly?
cheers for the replies

 

my scoob often taps on start-up.......cant decide whether its tappety or piston slap (never had piston slap before so not exactly sure wot it sounds like )

BUT, if I stop the engine and restart i acouple of seconds later, the noise aint there and all is well!

 

just removed the cambelt cover today and the tensioner does have a small ammount of play even if i do the bolt up tight Is this normal??

 

I assume you re-compressed the tensioner and inserted a retaining pin which you then removed after re-fitting the tensioner, to tension the belt? There is a set procedure for compressing the tensioner piston which is a slow and deliberate task. failure to do this may cause damage and render the tensioner U/S
On the other hand, it may just be some piston slap!

JohnD

 

yep thats what i did. what is piston slap?

 

are you sliding the tensioner to the fully tight position?

 

As Simon stated above - make sure you move (with a screwdriver) the Tensioner fully to the left (against the idler),tighten the bolts and then release the pin.
This is to make sure the tensioner rod is not working at the end of its travel.

Mick

 

Ill give that a try tomorrow

 

i had a look today and i dont think its the cambelt as the tensioner is hard over to the left and its still tapping.