another "Whats that noise?" thread

[hinkv10]

http://www.youtube.com/watch?v=xJ4wLoUHkBE

I've always heard this noise from the dr side valve cover area but it seems to be much louder. I'm saving up for a new engine but want to diagnose this noise until that happens. Thats me revving the engine and the rapid rattle noise is loud enough to be heard over the very loud exhaust in the cab now.

[yt]xJ4wLoUHkBE[/yt]

 

[J Knight]

Weird! Remove the valve cover and see if any rocker cup is wore out or anything else for that matter.

 

[89Suburban]

Sent from my iPhone using Tapatalk

 

[hinkv10]

Here is a bad video with the valve cover removed. The noise doesn't change much. I put a screw driver to the valve cover after I put it back on and I didn't hear anything. It sound like it is deeper in the block and I can hear it when I'm driving now. I'm pretty sure the engine is about to grenade so I have to make up my mind pretty quickly on what to do.

http://www.youtube.com/watch?v=9H4Qd0vr25s


[yt]9H4Qd0vr25s[/yt]

 

[bigcountryguy19]

What is your oil pressure? I noticed from the vid that oil is not flyin of your rockers and makin a mess everywhere. Could be oil pressure related and causing your lifters not to pump up, therefore giving you the clattering sound. IMO it could be a bad oil pump or a blockage somewhere. Oil passes around your distributor to get to the lifter galley, it's a longshot bit maybe it got blocked there.


Sent from my iPhone using Tapatalk

 

[gpmorgan]

Kind of sounds like the header gasket is leaking. Also make sure that the spark plugs are tight.

 

[chunkyrzr]

I have to 2nd what bigcountry said-with the valve cover off you should have oil all over the place. Either the oil pump needs to be replaced or you have a blockage some where. I would stop driving it until i checked the oil preassure and before it grenades. Oil pump is alot cheaper than a new motor

 

[hinkv10]

I bought the truck a year ago and oil was leaking from everywhere so I replaced everything including the oil pump, front and rear main seals, valve cover gaskets etc. My engine is an 84 so 2 piece rear main and its bearings were a little scored when I did the job.

My oil pressure has always been a little off. The sending unit is not plugged in and I have a mechanical guage installed somewhere on the back of the block. It came that way when I bought the truck so I have never messed with it. It reads around 50 psi when I start it up but drops when it starts to warm. I have only around 5 psi at idle sometimes 10. I'm not confident in the guage's accuracy but it doesn't surprise me that I have low oil pressure.

There is never a good time to fork over $2k but I was hoping to do it next summer as I drive the truck in the snow.

 

[89Suburban]

Try running some 15W40 oil and see if it helps get you through the winter. Does it run fine otherwise? Like its not missing or misfiring?

 

[hinkv10]

Try running some 15W40 oil and see if it helps get you through the winter. Does it run fine otherwise? Like its not missing or misfiring?

I was thinking that as well. It runs like a raped ape, well for a 305. Perfect throttle response and no miss.

 

[89Suburban]

Take a rag and push down on each rocker arm as the engine is running and see if that noise changes.

 

[hinkv10]

Fixed it

Well it ended up being an easy fix. I kept watching the first video I posted and listened to the noise as it started to rattle as the rpms dropped. I do believe the oil pressure is low but thats probably cause the bearings are pretty tired. I'm not going to rebuild a 305 so now hopefully it will last me thru the winter when I can drop in a crate 350 in the spring.

gpmorgan nailed it on the head. The header bolts are half 8mm allen key heads and half 9/16ths bolts. The PO used whatever he had laying around and I've had a couple bolts fall out already and noticed that the motor mounts didn't have any nuts on the bolts. Anyways, I tightened up the header bolts and she is ripping again. Thanks for the advice and Merry Christmas!

 

[89Suburban]

Good job! Gotta love the easy fixes!

 

[Irishman999]

Try the Lucas oil engine restore stuff, I am very curious to see if it actually works like I have herd it does. My old big block had a similar problem, super low oil pressure. It finally just went one day, it was an ugly sound. I went as far as running straight weight oil in it with no change.