Pushrod or Valve?

[greaseandmetal]

Lets pretend somebody attached something to a 1987 2.9 valve cover with a rivet. Then it drove fine for a half mile then started shaking (engine vibration) and lost some power, and now shakes like a poorly loaded washing machine on spin cycle. Then that person pulled the valve cover off to find that it looked like a rocker arm got stuck on-top/on/under that rivet end. I include "on" because by the wear mark on the rivet it very well could have lodged literally in the center of it rather than getting stuck under/over it. So in this "hypothetical" situation would this: (A) bend a pushrod (B) cause piston to valve impact, or (C) other. In the case of A, would that cause cam damage also? In the case of B, would that cause valve stem, valve seat, head, rocker, cam damage? In the case of (C) is suicide the only rational repair?

Where would an idiot look first for the damage in a situation like that? Assuming he has no compression tester, just wrenches and eyeballs (attached to a poor brain.)

 

[kimcrwbr1]

Have you tried running it with the valve cover off is the rivet on the pushrod side or valve side of the rocker? Hypothetically

 

[greaseandmetal]

reply

I have not tried with the valve cover off. However, the rivet is no longer in place. It's on the outer side of the engine, was impacting the rocker at the spring... valve side? Should I run it with valve cover off to see what it does? That won't make it spray oil everywhere?

 

[kimcrwbr1]

You will know immediately if it runs better or if the valve is sticking?

 

[kimcrwbr1]

They have a zero valve lash it is possible the valve stem got bent, the rocker got tweaked or the pushrod got bent you just need to determage the extent of the damage if any it is possable the rivet was just keeping the valve from closing all the way. Disconnect the coil wire and have someone crank on the starter as you wiggle the pushrod. As long as it stays seated in the rocker and the valve closes all the way it may be OK.?

 

[adsm08]

I would say, in this hypothetical situation, that someone needs their rivet gun taken away since on the face of it putting rivets in valve covers is not very smart.

At the very least it didn't hit a piston, the 2.9 is a non-interference engine.

 

[RonD]

There is no stress on the valve or rocker, if the rivet was just holding valve open a bit.
Or on the cam and push rod.
Push rod could have come out since upper end was loose, but I don't think it could lodge under anything to get bent.

So no, I don't think anything would have been damaged.

Should have used a 6" lag bolt, rivets never hold

 

[Kowboy]

I thought that vacuum pressure was maintained within the valve covers. Putting a rivet in there would cause a vacuum leak, wouldn't it.

 

[RonD]

I thought that vacuum pressure was maintained within the valve covers. Putting a rivet in there would cause a vacuum leak, wouldn't it.

Slight negative pressure is in the crankcase and valve covers, that's what the Positive Crankcase Ventilation(PCV) valve is for, along with the Vent hose.
A hole sealed with a rivet wouldn't cause too much of a leak, valve cover gaskets and oil pan gaskets leak more

 

[adsm08]

Yeah, I was referring more to the oil leak, and the idea of punching a hole in clean metal on a part that seems to be getting prone to rotting out.

Seems like I have seen a lot of 2.9 and early 4.0 owners looking for good valve covers lately because theirs have rotted out.