My dipstick pops up three inches, when I put the hammer down, no problem otherwise. Is this normal? Should there be an o-ring or some other fastener to lock down the dipstick? Engine is small block with dipstick on driver's side, 350 bored out to 355. Engine recently rebuilt, 700 miles on it. Oil pressure = 60 psi, till engine warms up; oil pump is new, same mileage. Tiny question, I know, but there it is. Saw the other posts on the subject, but puzzled.

 

Dipstick popping is related to one thing and one thing only , excessive crankcase pressure . If the PCV system is clogged/missing that's a likely candidate and if the PCV system is in place and perfectly functional the next likely suspect is excessive blow by at the piston rings . It takes a pretty good build up of pressure to push one out at all , but to be pushing it 3 inches out I'd figure the pressure has really gotta be building up in there .

 

Yep, you are building some pressure in there.

Does it pop at all under normal driving conditions?

 

It's okay, unless I put the pedal to the floor.

 

Yup, classic blowby...

There's 3 main places that can occur:

1. Rings. Need I say more.
2. Exhaust valve guides.
3. Intake gaskets.

Check #2 & #3 before jumping to the conclusion of #1. Although, it's uncomfortably common.

Of course there's the oddballs; holes in pistons, cracked castings, and so forth. Let's leave those aside for the time being.

 

#3 could lead to positive crankcase pressure only if he's running forced induction, correct?

 

No, not necessarily: in most stock heads, there's an exhaust passage that passes through the intake gasket. If that part of the gasket fails, exhaust goes right into the crankcase.

 

oh yep....didnt think about that effect from crossovers and heat riser passages. Luckily all that crap is in my past!

 

A small o-ring on the top of the dipstick was missing. Bought a new dipstick; no problem now.