I had the engine rebuilt 750km ago aprox.. All bearings new. It has 6 long studs, wrc head gasket, msd stage2 chip closed loop. Pistons are 92mm (if i remeber correctly) wossner

Oil pressure is good. Around 4-5bar in cold at idle and a little over 1bar in hot. In revs is good.

It started to make this noise driving fast anotherday. It does it above 3000rpm.
For the moment i had checked camshafts as the workshop had to repair many cam threads, but all was in place and with good torque.


2018: update on post 13

 

hmm,don't sound good,
i'd check the oil for the shiney stuff

 

Sounds like piston slap.
1bar hot idle is low mine has done 93k and is 2bar hot at idle.

Not sounding good sorry.

 

Sounds like big ends

 

A rebuilt engine with such low use should NOT be making noise like that. Take it back to whoever did the engine rebuild and get them to check it out.

 

Minimum hot idle is ment to be 24psi, about 1.7 bar. !

 

the only thing that had not been rebuilt were bores and pistons, I bought a second hand 200 block which was supposed to be rebored and installed new pistons 15.000km ago so I let them

Oil pump is std with kent cams spring HP

I will make a last test today because I think I've a bad camshaft and cleaning all tuppets (but reading your comments probably has nothing to do) and if it continues doing the noise I will have to remove engine out of the car

 

drop the sump first,have a look,

 

On 4wd probably is easier to remove all engine at a time

I remember a problem I had a few months ago.. Injector wires of cylinder 4 had a problem touching the manifold causing the injector to being open all time.. Flooding the piston. I will check that conrod is straight.

 

which oil did you use...i had similar issue with oil and after i used 10w50 sound disappeared..

 

I'm using castrol 10w60

 

try replacing the oil...with fuchs titan pro s..you sure it is not belt tensioner?

 

I don't like seeing threads without final info, so I'm uploading this. Removed engine a few months ago after 2 years with the car parked and found this:





Many gasket sealant found on oil pickup, probably I put too much on sump....


bought a crank said to be std needing a polish from a facebook group and was A LOT worse than mine, so sent mine to regrind 0,5 main and 0,25 in conrods now

now engine sounds better of course, but is not perfect, It has some knocking when accelerating from idle but not on constant rpm. The same sound I had on another engine with too much ignition advance on idle. I've to check oil pressure.


compression pressure measured on new engine: 10, 9.5, 10, 10 bar (in psi 145,138,145,145)

 

Tappet noise on start up is common on Cosworth YB engines but usually only lasts a short time. Your engine was in a bad way from the look of your photos!!