Very light knock

[stuckwithgsx]

So i've been helping a friend with his car for a while now. Got it running sunday, and it's made it around the block about 4 times so far

Still fixing all the little stuff, and while the car is idling, there is a slight knocking sound starting at ~2k. Gradually gets a little worse at higher rpm's. I've had lifter tick before and this ALMOST sounds like it.

Now the confusing part. Using a screw driver and "listening" around. Can be heard on the top of the valve cover, but not very clear. And listening to the intake manifold runners the sound doesn't change... But listening to the top of the IM the sound is the most clear and loud the furthest to the right...cyl #1.

Now to top this off the sound cannot be heard inside the car while driving. And cannot be heard at idle. Only when idling, and revving. The tick is not very loud at all, it's just there...and it's bothering us.

Car specs:
ACL race main/rod bearings
.050 over pistons
bc 280 cams
7 bolt block and head
Cometic hg

A local shop put this engine together for someone else...then we picked it up. Took the engine apart just to check things out. First off there was a 9/16 socket hanging out inside one of the intake runners to an intake valve...then it did have new bearings, but the oil galley's for the rods still had metal shavings in them from previous rod failure...and a few gauges in the piston tops on the outer sides (not too bad, and possibly not their fault)....needless to say it's been a fun project.

And also currently the little ball in the pcv valve keeps rattling around intermittently. Tried 2 different valves and same problem with both.

So does anyone have any ideas on this mystery tick? I know it's timed correctly. Lifter could possibly be bad but all 16 had good oil flow and seemed good before startup (putting drill on oil pump with vc off) and we didn't have the valves out but they were known to be fine before and all looked seated correctly. Neither of us can quite figure it out.

Another possibility is 5-20 oil with all the assembly lube still in it. Would that crazy thin oil possibly be causing a lifter to not pressurise properly?

Opinions or thoughts??

 

[stuckwithgsx]

Bump (check?)

 

[delta448]

You shouldn't bump unless you have more info to add.
You also shouldn't post multiple threads about the same thing.
If you don't get an answer to a thread, have searched for the answer, and have tried to fix it on your own, -at that point you can start PMing and asking for help in your thread.

Has the oil been changed?
Try that, and maybe go with some 20w40?

Honestly, the way you've described it makes it sound very unlikely to be a big problem. A little lifter tick isn't going to hurt anything, just sounds annoying to particular people.

 

[Calan]

Was it a complete rebuild (with dry lifters)? Sometimes it takes a while for the lifters to fully pump up and quiet down.

BTW - 5w20 oil is very thin. Do what Zack suggested and put some good 40w in it.

 

[stuckwithgsx]

Zack (?) Sorry for "bumping". It was partially a test just to see if I could reply (problem: see other thread)

Anyways the lucky friend went to sema and is back today, so we'll be trying a few things. And no, the problem does not sound serious. It's just not perfect.

The rebuild consisted of new bearings main/rod, cometic hg, and bse. Nothing too major just getting her back on the road

All of your ideas are good, and we'll try them out and see what we come up with. I am just really curious as to why the sound is most clear/loud from the intake? Not the intake runner either, the topside next to "multi".

I'm thinking it's not a lifter, but it very well could be as i'm not coming up with anything else. Eventually this engine will have all new parts. 3g lifters included.

He just wants his car to run and be "reliable" for right now.

The goal is run it for a while with the parts it has on it now. Then with time and money start building up the wonderful upgrade path (usually consisting of replacing broken parts with performance, even though it would be nice to actually follow the "proper steps" )