20mercury

Question please (likely a dumb question, but, )

Got a 72 LT-1 with right engine stamp, looks all legit and so should have solid lifters, eh?

But, it sure is pretty quiet, no tapping, maybe some pro adjusted them before I got it.

Question; can you tell the difference between solid lifters and hydraulic lifters with only the valve covers off and by looking at the lifters??

I understand some have replaced the solid lifters with hydraulic lifters on the LT-1??? (looks like that would take the fun out of having to adjust lifters frequently though)

thanks!

lowes-yellow77

Im almost 100% sure hydraulic lifters cannot be swapped out for solids unless the camshaft was changed...

Easiest way I cant think of is to pull the valve after the engine has been off for some time and see if you can push down on the rocker arm. If it moves you have hydraulic lifters if they don't you might have solids. If this is inconclusive you can look through the pushrod hole with a flashlight and see if you see a clip at the top of pushrod this will be a tell tell sign of hydraulic lifters

Easy Mike

I don't want to rain on your parade, but with only the valve covers off, you can't see the lifters.

7t9l82

if you pull a rocker and can get something to push down on the lifter several times and see if it is solid or has some movement that should tell you. also see how loose the rockers are ,if you take a feeler gauge on a loose rocker see if there is space . a hydraulic would require a little force to fit it in.

SpartyGW

Pull the intake, then you can pull out the lifters and look.

Or you could pull a valve cover, loosen a rocker arm enough (or completely) so that the spring isn't compressed then use the pushrod like a plunger and see if the lifter compresses.

Don't rely on valve lash. Some bozo might've been the last guy to set it.

63split63

An experienced mechanic should be able to hear if they are solid lifters . Unless there is a lot of engine wear noise or a noisy exhaust system .

Bill

cardo0

Ive never been able to compress a hyd lifter. Ive used a p-rod and block of wood and all it did was put a dent in the wood. Im surprised how many people will say u can compress the cup by just pushing on it as i think they have never tried it themselves and are just imagining it.

Anyways if u have solid lifters then just move the dampner to TDC on #1 cyl (0 degrees advance on the timing tab). This puts #1 and #6 at top dead center. One cyl is on compression stroke and ready to fire with both valves closed. This will be seen as the vlv springs are not depressed at all and the rockers for a solid lifter are loose to the feel - some 0.020" or whatever the spec is for a stock solid lifter/cam. The lifters for hyd lifter on the same cyl (on compression stroke) will not be loose at all - due to the pre-load adj. The opposite cyl (#1 or #6) will be on the exh stroke and have both vlvs open in overlap and u should be able to see the vlv springs a compressed a little - do not use this cyl for comparison.

Do u understand the crank has 2 cyls at TDC every 90 degrees rotation? U can use the firing order 18436572 to see how they pair up. As the crank rotates each 90 degrees cyls 1 & 6, then 8 & 5, then 4 & 7, finally 3 & 2 come to TDC at the same time but one will have both vlvs shut and the other will have both vlvs open in overlap. The cyl with both vlvs shut will have loose rocker arms for a solid lifter cam - the hyd lifter cam will not have any loose rocker arms.

Whew! Hope this helps ya.

7t9l82

thats why you have to push on them several times to bleed them down. but your right it requires a lot of force. if you try sharp blows they won't bleed down. no imagination .

20mercury

duh,......now that I think about it, you right

20mercury

Yep, this makes sense and I will try it. Much thanks for all of the responses!

namvet6869

won't a solid lifter have adjustment screw and locknut on rocker arm? At least they did in the old days and you can see that by removing the valve cover

PeteZO6

Not on a Chevrolet, stud mounted rockers. Adjustment, solid or hydraulic, is by a locknut on the stud. Do a Google search for "stud mounted rocker arm". Plenty of images to show you how they work.

Pete

lowes-yellow77

I can see the top of my lifters with the valve cover off. If you shine the light in the hole next to the pushrod slot and lool in a different hole, just have to be at the right angle.

20mercury

Good to know thanks!

lars

You can test the solid versus hydraulic as follows:

Bring one cylinder (any cylinder, but #1 is easiest) up to TDC on compression. Both valves will be fully closed at this point as cardo0 points out above. At this position, both a solid and a hydraulic setup will have both valves a little "wiggly," and you can get some side-action wiggle out of both rockers. Try it out and get a feel for the "sloppiness". Then, take one of the valves and simply run the adjuster down 1 full turn. This will make that rocker really tight and solid on both a solid and a hydraulic lifter. Feel it and feel how rock solid it is: It is holding the valve open just a tad against spring pressure. Now, disable your ignition system by either pulling the coil wire or disconnecting power to the distributor, and use the starter to "bump" the engine over 4 full revolutions. This will put the lifter through 2 cam lift cycles on that cylinder, and will allow a hydraulic lifter to bleed down to its "0" lash position again. Once you're back to TDC after 4 turns of the crank, grab that rocker arm and wiggle it again. If it wiggles just like it did when you first tried it out, you have a hydraulic lifter. If it's as rock solid as it was when you ran the adjuster down 1 turn, you have a solid.

Be sure to back the nut off the 1 turn setting before you start the engine.

Other comments:
You cannot compress a hydraulic lifter, even after the engine has been off, unless the bleed hole in the body is exposed. You can only do so by rotating the engine over and cycling the lifter through its stroke. Also: Solid lifters have an inner plunger retained by a snap ring, just like a hydraulic lifter. You cannot visually tell them apart.

Modern "tight-lash" solid lifters run about as quiet as a hydraulic. Even a very experienced mechanic would be hard pressed to tell a solid from the sound.

Lars

20mercury

So the hydraulic lifter will adjust as designed and of course the solid lifter can not!

Much thanks!

(I would buy you a beer if you were closer, but I see you are in Lafayette, Colorado and not Lafayette, Louisiana! LOLZ!)