More info on valve springs.

[jlona]

This started when we heard a knocking in the motor. (like a broken rod or something) SO we took it to our neighborhood mechanic and he said it is definately not a broken rod. He said it sounds more like a broken valve spring. So after taking the valve covers off (an hour or so ago) we noticed no broken springs although we did notice a bent push rod. So my question is would a bent push rod make a hard knocking noise like what we heard, or is this just something else we need to fix, and then find out what the knocking noise is? Thank Yall very responding

[cobraF100]

The PushRod could/will make a loud noise like it's slapping rod in there But why did it do it?

Are there any others that are bent?
Is this a stock engine or does it have a new Cam or Intake?

Lifter could of been pumped all the way up and didn't have any give to it ,so it was like it was a "Solid" lifter.

[FORDification]

Another reason for a bent pushrod would be if the engine over-revved, causing valve float. The valve didn't have time to close before the piston came up and slapped it, and since something had to give, the pushrod gave it's life instead of other damage like snapping a rocker arm.

Or possibly the timing chain slipped a notch putting the cam out of sync with the reciprocating assembly...but you'd have noticed it running very rough, if at all.

[cobraF100]

This is from another Forum but has to do with what your haveing Problems with and may help.

Author:
techinspector1
Senior Club Hot Rod Member

1. piston to valve interference. There isn't any practical way to determine this after the motor is together, other than doing a compression test as Don suggested. If all the cylinders (and particularly the cylinder where the bent pushrod is) are within 5 or 10 psi of each other, then you can pretty much eliminate p/v interference as the culprit.
2. retainer to guide interference. This will require some close observation with a good strong light and a buddy turning the motor over by hand. Umbrella valve seals will make this impossible on the intakes, but maybe you can see the exhausts. Unwind a thin paper clip and smash the end flat with a hammer, then stick the end betwen the retainer and guide, moving it continuously and ever so slightly as your buddy turns the motor over. If your clip gets pinched, you've found the problem. Do not continue to turn the motor over once the clip is pinched. You'll just do further damage.
3. springs stacking solid at full valve lift. If you can't get a thin feeler gauge between the coils, you've found the problem.

So the credit of this goes to "techinspector1"

[willowbilly3]

If there has been no recent work done then I am with Keith, your foots too heavy.