Toward the end of top end rebuild

[tito911s]

Gents,

Toward the end of a top end rebuild. Before I put the engine back in I am a little bit concerned about a sound I'm hearing. When I use a socket wrench to turn the engine I hear a ever so slight clicking close to TDC. I didn't split case and am hoping to god that I don't have a fouled main bearing or something. Anyone have ideas on what it could be and some thoughts on how to test ideas?

I would hate to have to take things apart, but of course know, that might be an eventual outcome if I can't figure out what is causing this sound.

Thanks in advance all.

[smooth]

Could be in the timing chains, slack taking up by tension from the valve springs. Make sure chains are tight, an easy check, sort of. Good luck!

[Flat6pac]

Did you measure your cam gears to the intermediate shaft so the chains are parallel?
Bruce

[cgarr]

One of the cam gears on backwards could do it too but by doing the above should also tell you.

[E Sully]

Do you have an idea where the noise is coming from? Did you check the valve to piston clearance? Waynes engine rebuild book covers this in section 8. I did a leak down test on mine before I put it in the car. The numbers may be a little low since it is not broken in, but it will give you an indication if a valve is not seating well or if a ring was broken on install. Distributor cap and rotor seated properly?

[boyt911sc]

Originally Posted by smooth

Could be in the timing chains, slack taking up by tension from the valve springs. Make sure chains are tight, an easy check, sort of. Good luck!

smooth,

Check the tension on both timing chains during rotation. The chain tensioners might not be putting enough pressure to the chain sprockets at this time due to lack of hydraulic fluid (???). Does this noise also occur with the mechanical tensioners in place? Keep us posted.

Tony