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#1
09-09-2006, 05:33 PM
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Bad hydraulic lifters -- How can you tell?
I am in the process of replacing worn rocker arms and I am wondering about the lifters. According to the manual, you check them pushing with a hammer handle and making sure they do not "drop too fast". Mine do not move at all ... does that mean they are OK or just the opposite?. I also tried "Herr Fuchs finger test" but I cannot make sense of it. The rockers are out now, is there any other way I can check the lifters?
Your advice/opinion will be grately appreciated. Also, does anybody have a lifter go-no-go test gage that you would like to sell/rent? (I tried in the tool rental section with no luck) Thanks. Jl 
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#2
09-09-2006, 06:11 PM
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they are technically adjusters not true lifters. and i think if they dont go down they are working as designed. the oil pressure supports them and brings them up under the ends of the rockers to keep just the right amount of pressure on the rocker so that it doesnt rattle.
tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.  [SIGPIC]..I also have a 427 Cobra replica with an aluminum chassis.
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#3
09-10-2006, 08:31 AM
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What is it about the 'finger test' that you dont understand? It is used to get an estimate of the amount of compression in the ball stud when the tip of the cam lobe is pressing down on it, versus no pressure from the heel of the cam.
__________________
Chuck Taylor Falls Church VA '66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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#4
09-10-2006, 10:40 AM
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Tom,
Thanks for the explanation, I have a better picture of how it all works now except for the lifter/adjuster itself. I suppose it is pushed up by oil pressure when the engine is running and it holds pressure when the engine is off, and what we test is the ability to hold pressure. Chuck, I am not implying that it does not work. I guess I am not good at it. I just could not tell if there was any difference or not between lobe up and lobe down, probably because of the way I was doing it. Maybe I should have measured displacement with calipers or something. I misspoke, I should have said that I could not make sense of the results. Jl
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#5
09-10-2006, 09:22 PM
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tough crowd!
yes, i think you have the idea now. good luck tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual. [SIGPIC]..I also have a 427 Cobra replica with an aluminum chassis.
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#6
09-10-2006, 10:10 PM
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Well, that's the point. So it sounds like you did understand. If you could not feel a difference, then the ball studs are probably OK. And they also passed the hammer handle test.
Personally, I would put it back together - be sure you know that the oil tube fittings are OK - and see how it sounds with the new rockers.
__________________
Chuck Taylor Falls Church VA '66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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