C-3 LT-1 Lifters

[steve beech]

This may seem like a dumb question, but looking from the top of the engine valley, what is the visual difference between solid lifters and hydraulic?

[Craig S.]

Re: C-3 LT-1 Lifters

None that I am aware of. However, if you have your maifold off, you can remove the rockers and lifters (or at least one) to drain the oil to verify. Also, the lifters rattle if there is no oil and they are mechanical....Craig

[steve beech]

Re: C-3 LT-1 Lifters

Manifold is off. Lifters each have 6 small holes around the dished in center where the push rods seat.

[Wayne P.]

Re: C-3 LT-1 Lifters

A square spring holding the insides together would be hydraulic. No spring would be solid.

[Clem Z.]

piddle valve solid lifters

also use a spring to hold in the top. see if you can compress the lifter push rod cup and if you can it is a hyd lifter

[steve beech]

Re: piddle valve solid lifters

Clem--I pulled a lifter, and with all my strength cannot push the cup down using a pushrod. Solid??
BTW the pushrod has the number 48829 on it. Whats that mean?

Steve

[steve beech]

Re: piddle valve solid lifters

Looking at all of the lifters as installed, the ones at the high spot on the cam are depressed a bit internally. Does that mean hydraulic for sure??

[Clem Z.]

Re: piddle valve solid lifters

if the pushrod cup is below the snap ring it is a hyd lifter and it takes a lot of pressure to move the cup when the lifter has oil in it.

[Clem Z.]

48829 most likely a aftermarket part #

but off hand i am not sure what company.

[Duke W.]

Re: piddle valve solid lifters

It's easy to confuse a piddle valve mechancical lifter with a hydraulic lifter because both are two-piece designs that are secured with a visible snap ring. The edge orifice mechanical lifter is a one piece design with no snap ring, so it is easy to differentiate.

The LT-1 cam was orignally equipped with the edge orifice type, so if you have a LT-1 engine with smap ring equipped lifters, I would be suspicious as to what cam it actually has.

I suggest you disassemble at least one lifter to verify its type.

The piddle valve lifters have an inertia valve ("piddle valve") that controls overhead oiling, and they deliver about 20 percent more oil to the rocker boxes than the edge orifice type. The piddle valve type was used with BB mechanical lifter cams, but all SB mechanical lifter cams engines were originally built with the one piece edge orifice type that controls overhead oiling on the basis of lifter to bore clearance.

The BB needs the additional overhead oiling because its valvetrain is more highly stressed, but the edge orifice type are best on SBs, especially if you don't have the larger capacity oil pan that was used on mechanical lifter SBs.

Duke

[steve beech]

Re: piddle valve solid lifters

Thanks Duke

[Jeph South]

Re: C-3 LT-1 Lifters

I can send you a picture of an LT1 piddle valve solid lifter if you would like.
Jeph

[steve beech]

Re: C-3 LT-1 Lifters

Jeph, I'd love to have a pic of the lifter. If you can, an E pic would be good. Beech5@comcast.net

[Joe L.]

Re: C-3 LT-1 Lifters

Jeph-----

LT-1s did not originally use a piddle valve type lifter. They used an edge orifice type mechanical lifter. The only Chevrolet small block that ever used a piddle valve type mechanical lifter was the 67-69 Z-28 302 cid engine. All big blocks with mechanical lifters used the piddle valve type, though.

[Jeph South]

Re: C-3 LT-1 Lifters

Joe, you are always right on this stuff, so I bow to your knowledge.
This means that the lifter I have is not GM P/N 5231585?
I remember being in Steve's shoes when I opened up the valve train and found what I thought were hydraulic lifters. I must have stoppped asking questions when I found out they were solids. Are there any complications from running a piddle valve solid with the rest of my LT1 valve train? Thanks as always.