I had the car running almost perfect yesterday so I take it out for a cruise and I notice that at high RPM's I hear some sort of chattering from the passenger side of the car. I thought it was the exhaust since I didnt have it hung up properly yet. Well, as I pull into my driveway I hear the imfamous valve tap.

I gave it a couple of revs to make sure it was the valves and the car started making a awful "screeching" sound thats definately coming from the lifter valley (or below) area. The noise is hard to explain but it sounds kind of like a rusty door hinge opening real fast. The noise increases with RPM and the rocker arms chatter really bad with it. I couldnt tell exactly which rocker(s) were making the noise so I adjusted all the valves and it makes no difference. The springs are fine, the studs aren't coming out, pushrods are straight, and the rocker arm nuts arent coming loose.

I'm not too fimilar with hyd roller cammed motors so I'm hoping they'll make different/more noises if a lifter seizes/callapses? Does anyone have any idea whats causing this? The noise is really scary I'm hoping I didn't damage the camshaft.

Thanks,
Chris

 

Sounds like maybe your cruise was a little too enthusiastic...

How's the oil pressure? Is it any different than before? if it's lower, expect to find a spun rod bearing.

Check the oil for metal particles. It will look like fine silver dust in the oil. If you see that, the motor is toast.

Don't drive it any more until you identify and repair it.

 

The oil pressure is perfect. I changed the oil yesterday and did notice that there was a very VERY slight metal feeling to it. Also the oil was pretty old looking even though it was only about 200 miles old.

Crap ...I've had this car on the road for only 2 weeks and I'm going to have to tear it down again I'm really praying its a lifter but it really doesnt seem like it.

 

Anyone have any more ideas? I may tear it down tonight depending on the weather.

 

Next possibility is a broken crank.... they'll break right at the front of the #1 rod journal, if the pieces happen to be shaped such that they can't move apart from each other, the engine will continue to run; obviously crippled, but good oil pressure.

Tell us about this "cruise". Instinct tells me there's a clue in there somewhere.

 

I didnt do anything crazy on my cruise. I was driving the car all day long and it was getting that chattery sound at high RPMs ...It sounded like my exhaust since it was coming from the passenger side and I didnt connect it to the mount on the transmission yet.

I just let it run again and its the #6 intake valve that isn't adjusting and is chattering. Its possible that more rockers are doing the same. It was hard for me to tell by myself. At idle the car runs on all cylinders but if you rev the motor it doesnt miss it just sounds like it completely stops firing on one cylinder (seems to revs fine just has a completely different exhaust note)

Maybe I killed the cam? But how the heck would I do that?

 

I finally got around to pulling the intake manifold and I'm at a complete loss here. There is nothing wrong with the lifters and from sticking my finger in the lifter bores the cam feels smooth and there are no metal shaving or particles anywhere.

The only thing I did notice was that the rocker stud looks like it has some wear on it compared to the others... I'm thinking this is a result of my current problem and not the cause? Everything looks normal to me I'm completely confused now...

Note the rocker stud has no gashes or anything. It just that the black finish has been rubbed off. None of the others are like this.

 

check the rocker that came off of that. looks like it wasn't gettina any oil and started to burn the stud up.

are they roller fulcrum rockers are do they have the pivot, ball? either way it looks like that rocker stopped getting oil. you have to find out why, check the pushrod, to see if the oilpassage is clear. start there,and work down.

 

The rockers are the stock ones. They look fine no marks on them or anything. The oil passages in the pushrod and everywhere else are also fine.

 

Is the pushrod bent? Does the lifter look different than the others? Maybe you should check the lift on that lobe? and how does the pivot points on the rocker look?