Anyone know what this sound is? Just rebuilt the motor and installed it into the car and now this sound appeared We think it is something (crank, rod bolt) hitting the windage tray in the rear of the oil pan but not sure. What do you guys think? This is an LT1 with stock crank and rods with ARP rod bolts and main studs ,stock ported heads, mr gasket .26 head gaskets, sealed power lifters with around 2,000 miles on them, stock length push rods, custom LE cam 600/600 on a 107 LSA, 1.6 rockers, comp springs good to .650+ Car has been through about 8 or so heat cycles and 1 oil change and I haven't seen any metal flakes in the oil. Any help would be appreciated!! http://tinypic.com/player.php?v=24v2o1i&s=6

 

it is a 350, no stroke or overbore.

 

It's not a upper end issue. Valves, lifters and rockers sound good. The sound doesn't sound like the typical bearing or rod issue but seems to be coming from the lower end. I'd check to see if the starter needs to be shimed or repositioned back a little from the flexplate or flywheel when the motor is running. Pull the dipstick and start it, just to confirm the dipstick isn't hitting the crank. Is it the stock oil pan with no dents that could be hitting the crank.

 

The oil pan is stock and has no dents at all. At first we thought it was the flex plate so I replaced that and still got the same sound. I'll check the starter clearance, I do have a power master starter.

 

It might be worth and shot. Since it's a stock stroke rod clearance shouldn't be an issue. Could be the windage tray, I doubt the oil pump pickup is the cause. The noise has a constant beat with the RPM of the motor. If you don't find something quick I'd pull and teardown the motor, the issue should be easy to find just look for the shiny metal that doesn't belong. With the big lift and .026 head gaskets did you use forming clay to make sure the valves weren't close to the piston tops?

 

I didn't use the forming clay to test clearance because many guys run a similar setup and don't have any issues and my heads/block aren't decked at all so it the valves should have plenty of room but I may have to pull a head and check.

 

pull the belt off and see if it still does it just for ***** and grins and are you running your fans full time? it sounds like a fan blade hitting something almost... that is a really odd sound i thought flexplate bolt at first but guess not..

 

I listened to your video several more times and the more I listened, the more it sounds like it is coming from the pan, inside the motor because of the hollow sound. Maybe the crank counterweights are hitting the windage tray or were the ARP bolts thread length longer than the stock bolts? Because the noise doesn't have the metal on metal hammer when a bearing or rod cap is letting go. Good luck and keep us posted on what the problem is when you find it.

 

I agree with 93lt1vette. The arp main stud windage tray mount is two nuts sandwiching the tray right? Id be willing to bet it was set too close and the rods or counterweights are just nipping it.

I had a very similar sound with a 383 SBC and that's what it was.

 

That is a real possibility, since it does not look like the stock tray mounting studs were used.

 

I would take off the asscessory belt off to rule out those things. However it does sound like something under the oil pan. I would think windage tray also.

 

There was a woodpecker hiding in your block when you put it back together.

 

Any more ideas? I am fixing to tear into this and need as many ideas as I can get.

 

Id pull the pan already Didnt you spin the motor after assy