what the heck is this noise???

[Greasemoneygarage]

Ok, here's the deal. Working on a 1987 Grand National. It was all most done but had to let it sit for 4 years. When I went to work on it again and got it running for some reason 4 push rods bent and one collapsed lifter. Why it happened Not sure but I do remembering it back firing ??I?/? Ok so I pulled the intake and changed the lifters and since I was there I did the cam. I installed the comp cam High energy flat tappet Part # 69-248-4 . with matching push rods part # 7869-12 and lifters (As per Comp). So now its all back together and after the car warms up, it sounds like a dam rod knock. With that being said I pulled the pan everything looked good. pulled the timing cover to make sure something wasn't hitting. everything looked ok so back together it went. I check the turbo, pulleys, ac. ect not the noise. Pulled each spark plug wire while it was running and the noise remains the same. The only thing I didn't do is change is the springs. Comp cam said I didn't need to. But who knows at this point. Anyone have any ideas?

 

[blackazz]

Cam sensor maybe . I had one let go an sounded just like a rod knock.

 

[turboclam]

What valve springs are on the car? Do you have an oil pressure gauge? Did you prime the motor again after taking the front cover off? Check the flywheel and torque converter bolts.

 

[LIL6cyl]

X2 converter bolts? It will sound like a deep bottom end knock...... Happened to me.

 

[Greasemoneygarage]

I pulled the cam sensor and it looked fine. The oil pressure is running 20 lbs at idle. I did pull the converter cover and visually checked the flywheel I think that's what I'm going to do next is disconnect converter and see if it still makes noise.

 

[Greasemoneygarage]

 

[Greasemoneygarage]

 

[Ktbregal]

Get a listening device and put it to your ear. Go around and try to find it.

Posted from the TurboBuick.Com mobile app

 

[Phoneguy]

Damn that sounds nasty.......

Bryan

 

[notacarlo]

Deleted

currently cutting it the F loose

 

[87-WE2]

Sounds like something banging on the valve covers from the vid.

 

[Greasemoneygarage]

\I had it running with the valve covers off. To make sure the rockers weren't hitting. I also checked the engine with the stethoscope and I still can't pin point the noise.

 

[oldguynewtoy]

Really sounds like a torque converter knock to me, especially when you sped it up, it quit.

I would double check the converter bolts or slide the converter back all together, also pull the belt and start it up to eliminate anything on the front end.

Have you checked the intercooler fan driven off the crank? could be hitting assuming its still on the car.

Just some things I would check...

 

[gsgnnut]

that does sound nasty ! It doesnt sound like a lower end knock. , I dont believe in coincidence so if it wasnt there before swapping the cam and lifters and push rods, Im afraid you have to pull the intake again and carefully inspect the valvetrain, because something is banging in there and it seems related to oil pressure or rpm-maybe collased/damaged/ incorrect lifter. Also could be a lifter hanging up in the lifter bore at low engine speed getting whacked by the cam lobe and at higher rpms the lifter is moving faster and springing back faster and able to better follow the cam?

 

[turbogray]

keep up posted on this and let US know what you find out. I'm curious..

 

[tonka]

Wrong front cam bearing journal/front cam bearing combination bleeding oil pressure off to half the lifters? Sounds relatively quiet once rpms (oil pressure) come up somewhat...

 

[dank GN]

That happen to me when I installed new springs I believe it the lifters they bleed down . Keep a eye on oil pressure did u add any zddp ?

 

[87GNSteve]

Bad (new) lifter? The best ones everyone like to use are the AC Delco and its not just a name brand thing.I would say pre load but it goes away with RPM increase....
Get a stethoscope and listen w/ the valve covers off. Place the tip on each rocker.

 

[nonoss38]

X2 converter bolts? It will sound like a deep bottom end knock...... Happened to me.

Me to!

Posted from the TurboBuick.Com mobile app

 

[Greasemoneygarage]

ok I disconnected the toque converter Started it up still had the same dam noise. Gonna pull the intake Im thinking its bad lifter.