Valve Lifters. Squishy or Stiff?

Breaking down the 996 and have pulled the liters on bank 1. Notice that the check valves on 2 of the 12 lifters are able to be pushed in while the other 10 are stiff. What should they do on a healthy and properly operating lifter? Thanks

Quotes source post: 17128777

Tell us more about the car/engine... year? rebuild? repair? Could you post an image?

01 C2 manual I'm repairing the variocam chain guides and checking lifters is easy to do while in there.

The lifters should be hard, but sometimes depends on the cam cycle, could have been under tension in the valve train causing it to drain down!

This is interesting to me, as I am rebuilding a B5S4 engine right now and the as-found condition of the lifters were most of them solid and a few could squish. I would think they would all need to squish (these are technical terms). We bought a lower mileage engine and we are rebuilding it. 28 of the 30 lifters squish on the "new" engine, 2 were solid. I bought a set of intake and exhaust lifters for one head before we bought the spare engine, out of those 15, about 5 squished from the factory. The other 10 were solid. I would like to know more about this, but would figure they would squish. Here is a video I made showing the lifter differences. I can tell you that the lifter moves only about 0.080" (video states 0.120") and the valve did not come in contact with the piston, so that was not the issue. You Tube

Paul Hydraulic lifters work by inflating using the engine oil pressure until all the slack between the cam and the valve is taken up , a one way valve then holds the lifter button in this position by holding the oil pressure inside the lifter which holds the button in this position, nee lifters will hold pressure for a long time and when as engine is re started it is quiet as all the valve lash is dealt with by the lifters . As the lifters get older and worn or get debris inside the one way valve can't hold all the pressure and they then leak down when the engine is switched off, when the engine is re started the engine oil pressure will re inflate the lifters after a few seconds taking up the slack again but can be noisy for a while. Larry on lifters cam hold no pressure and never inflate and that's when you get a permanent lifter noise, new lifters may need to be inflated when first installed and lifters on a cam cycle where pressure is being exerted by the valve spring when the engine is off can get deflated under the pressure , which may be what you have there. Cleaning the lifters and re inflating them to see if they hold pressure will test if they are still good , or you could just fit new as a precaution!

Squishy = baddie

Quotes source post: 17131002

That is exactly opposite of what I thought. I know they have an approximate amount (say 0.080") that they can take up, just didn't know why they wouldn't squish with no oil. But if it's a check valve that holds it....I guess that makes sense. Still weird that for new ones that I bought some where hard and some where squishy.

To summarize then... with the lifters out of the engine and broke down, you should have squish. Once back in and under oil load, the check valve will keep them hard as needed. Main thing is to ensure no damage or obvious wear when on he bench

Any time you have a lifter out of the engine clean & test it by heating them up in a electric skillet filled with new engine oil. Before putting the lifters in the pan check for wear on the bottoms. Once they are as hot as you can stand, take a pushrod & compress the lifter like it will be in normal installation while watching to see anything coming out of the small hole on the side. Keep compressing them until clean oil comes out. I have a set of lifters tested this way for sale if anyone wants to buy them

this is what works for me on Harley builds and would do this if I build a M96, but I know eventually I will be going LS3 if the time comes. Harley's have a huge problems with lifters, fits and valving, I take a lifter and take it apart and clean it out completely, then use ATF or calibration oil (No motor oil) and stick it in a container filled with oil and run a vacuum to eliminate all the air from the lifter, then I have a tool that is fabricated to support the lifter in the drill press at the same tolerance as the lifter block on the motor, cut a push rod and install on drill press, also set a dial indicator on the set up to measure travel, now the important part is to measure the travel of the lifter for a given time, most important is setting a weight on the arm of the drill press so the lifter see the same amount of pressure all the time, most chinese junk lifters don't make it, I am looking for less than .050 travel in 1 minute and 5lbs of weight on my drill press. Note: on a buddy set up we took the lifter holder and plumbed a Sure Shot can to it and pressurized the lifter with 30 psi of pressure during the testing, don't think we gained anything other than different timing for the same travel. the same could be done for the M96 lifter. research would have to be done to get a time and travel with a good and bad lifter, also enough can not be said about the cleanliness of the lifter insides , have come up with left over machining many of times on new lifters.

@JohnCA58 Your clearly well versed at this process. Are you running a shop? If you were less equipped with the tools to accomplish what you are doing, what would you suggest for DIY guy?

I am retired FAA license A&P, before retiring ten years ago spent 10 years as Trainer for Cummins Diesel, Still maintain my ASE Master Tech cert. so now I am a DIY gearhead now learning more and more working on my and step-son P-car and enjoying it, I do still build high H.P. Harley engine. this is my latest with 152 h.p. 120 c.i. and my P-car