I just did a stock rebuild on my motor ( new rings and bearings). The motor only had about 16,000 miles on it when I got it. I just wanted it freshened up for the H/C I was putting on over the winter. Well anyway one of the sponsors from the board is supposed to be tuning it here in a few weeks, and they wanted me to drive it for a couple hundred miles to seat the rings.

Well any way on to the problem. I probably put about 100 miles on it or so, and I got on it when I was leaving my buddies house this Friday. Well right after I let off from that I started hearing a knock at 2500 RPMs and up. Its a really faint knock but its there. I drove it about three miles home, where I walked away from it for a day ( to let myeslf cool down).

Well today I drained the oil out of it and ran it through a strainer. I got a couple very small (1/16"X1/16")pieces of copper colored metal. I had gotten some pieces that looked like that before I pulled the motor apart to rebuild it too, maybe these could have been from before. All I did was check clearances and install new rings and bearings, I didnt have the block machined in anyway except for ball honing. I just wanted a cheap rebuild until I could have a Forged bottom end built. The oil had the copper colored metallic mist in it. I did a couple of searches, and assume that I had a main bearing go. Because it doesn't knock below 2500 or when its NOT under a load. Also before it had about 50-60 PSI of oil pressure when I was bringing it home it had around 30-40 PSI.

I havent pulled the valve covers or anything yet to see if anything is wrong there, or checked the flexplate to see if that came loose.

Is it normal to have the copper colored mist on a freshly rebuilt motor?
Just kind of wondering what all I should be checking into?
The engine was running really rich due to the Heads and Cam, could fuel have washed past the cylinders and diluted the oil?

Sorry about the long post, just trying to get as many details in as possible.
Thanks for any responses.
Bill
Also here is a list of mods in the engine now.
Patriot Performance 5.3 heads shaved .015"
Lunati 230/237 .543/.544 112lsa
rollmaster timing chian
LS6 ported oil pump
LS6 intake
7.400 chromoly pushrods
1.7 Harland sharpe rockers
stock lifters
ARP main studs and head studs
ARP connecting rod bolts.

 

sounds like a cam bearing, I just did it as well, I had 30-40 psi all the time and thought it was low..opened it up to change cam and heads and noticed the front cam bearing had backed out a bit and the cam took a half moon chunk out of it. Pressed in a new one and had 70 psi immediately. I hope for your sake its the front cam bearing.

 

Did this cause a knocking noise in your engine?

 

It is a bearing somewhere for the copper material in the oil........

 

Sounds like you lost a bearing.

 

would a cam bearing going out casue a knock in the engine?

 

Prolly not but if it did come apart & send scrapnel thru the oiling system it can cause havoc for the other bearings.

If it's got a lower end knocking at RPM's it's likely a rod bearing or a piston pin.

 

How many pulls do they usually have to do to tune a car? I know this is gonna sound stupid, could I just unplug the Knock sensors and let them tune it? That way it would be ready to go, just throw in a Forged 347 from AP Engineering or one of the other sponsors? I dont know if it runnign so rich on a fresh rebuild might have something to do with it or not. Id rather just have the AF ratio right from the beginning on the new motor.

 

my cam bearing went and it had no noticable knock

 

I would not get that tuned until you assembled the new engine. I do not think that running rich caused your bearing to go. I replaced the bearings in a car and low and behold it started knocking soon after I had the engine put together and running. From now on I will either take it to a pro to have them assemble my short block or have someone machine and check the clearance for me so that I do not have these types of problems again.

 

No offense intended here - but wow - you built an engine w/o gaging bearing tolerances? And a high performance engine at that? That's way scarey to me. I've only built 2 motors - both 4's - and one of the 2 times the bearings I bought didn't match the tolerance on the package. Found it plastigaging. Saved me another $800 dollar rebuild for 15 minutes extra of work.
Dan

 

The last thing any computer tuner wants to work on is a motor that's not running right.

Tuners can work over the computer, but they can't work past stuff like dead sensors, ignition problems, valvetrain geometry issues, tranny issues, or - a knocking engine.

Please don't take your motor to a tuner with a knock. He'll thank you for it.

 

A pretty common mistake is not properly torquing the cam bolts. You need to either loctite the hell out of them or take them to 30ft-lb if memory serves.

Once the cam starts walking, it eats the cam bearings and disrupts the oil passages. You have volume but no pressure and the rest of the engine eats itself. I've seen several LS1s destroyed that way.