Just took my new 69 out for my 1st drive since I bought it. Put 20 miles on it - ran good.

Pulled up to my garage, I hear a knocking at idle.

This just ruined my nite :( :( :( .

Engine had 350 miles since rebuild.

Where/how do I start the diagnosis process.

Thanks

got oil...
check the oil pressure.....
thats all good..get out the stheascope-spelling?
like the doctors use to listen to your heart.
they make them for listening to your engine..
try to find out where its coming from..
go from there...let us know..
GOOD LUCK..MARK

knocking at idle... off idle does knock, sound increase with rpm? if its not a ticking as per upper end, or an exaust leak, ext. but that horiffic internal engine knock sound. i'd drop the oil and filter and check for metal, strain the oil, cut open the filter, open the paper like a book and check for metal. without hearing it I can't say, but better safe then sorry.

Listen to the speed of the knock.
does it keep speed with say a timing light flash or is it about 4 times faster?
Slow&deep bottom end rod/crank
Fast & ticking lifter/rocker/fuel pump/exhaust leak

I had that same feeling. Sounded like a rod hammering. It ruined my weekend. Luckily mine ended up being a noisy lifter.

Update.

I pulled the valve covers off to take a peek. Driver seems ok - all rockers seem to be moving same amount. Pass -side. The last rocker (closest to fire) wall only move a little bit, and the push rod was not rotating :( :( .

Will this cause a knocking sound? Its not ticking, but knocking.

Also, not much oil squirting out at idle -it comes out though when revved. I'm getting under 20lbs at idle when warm - is that OK?

And what do I do from here?

Thanks

Originally posted by Vince g:
Update.

The last rocker (closest to fire) wall only move a little bit, and the push rod was not rotating :( :( .

Will this cause a knocking sound? Its not ticking, but knocking.
Sounds like you probably wiped a lobe off the cam or you have a dead lifter :(

this happen to me about a month ago.
had a knock,
same stiuation, the lifter was damaged, took it to a good classic car mechanic, I had wiped the cam, 2 lifters were shot( one with a hole right threw it!) and I can't even explain what the push rod looks like.

I put a new comp cam kit in it. It runs about $400.00 maybe a little less depending on your set up. It comes with lifters, springs, new timing chain, and a cam.
Had the mechanic do it, and it runs great.
Cost about $700.00 in labor and he painted the engine for me.. looks good! :D
sound like the samething, top end!!

Did you mechanic have any concerns w/shrapnel passing through the lower end?

We'll everbody, I confirmed what I originally thought - wiped out cam lobe. It was the very last lobe graemlins/angry.gif .

Should I pull the engine for the cam change? Does the oil pan need to be removed?

Can somebody recommend a stout cam for my 396? It has RPM intake, Holley 650 DP, 10:1, and headers.

Thanks ya all for all the great help.

Personally, I would pull the motor, completly disassemble it, and clean it thoroughly. Blow out all the oil journals in the block and the crank with air, and flush them with some carb cleaner and blow them out again. But as long as there is no metal in the oil, which is highly unlikly if it wiped out a cam that fast, just pull the motor, take the top end apart, and put the new cam kit in.
You could also permanently fix the problem of wiping a cam lobe by putting a roller setup in it :D :D :D .

Chances are good that the metal from the hard cam lobe is now imbedded into the bearings and pistons.
Do it right, pull & start all over

Hi I wiped out a couple lobes on a cam last year, only to find out that alot of metal ended up in the sides of my alum. pistons. I had to replace pistons. I hope yours doesn't have the same problems. Dave

a friend of mine has a 454 in his chevelle with heavy valve springs new hydralic cam wiped out the lifter bent the push rod nearly to a 90 degree angle and took off the lobe all be cause when they first started it up and ran it he didnt get the cam hot enough to form the cam need less to say sumit cam in hand and has a roller cam comeing.this all happend with in 91 miles