Engine Knock Help!!!
#51
01-27-2011, 03:23 PM
Chris-bob is right. The cam and lifters create a specific wear pattern to ech lobe of the cam. If you put fresh lifters on an old cam you risk the chance of wipeing out the lobes on the cam. The only time i would put new lifterns on an old cam would be a roller lifter because in theory there wouldnt be any wear or specific wear pattern. Same goes with a cam you never replace a cam without new lifters youre just asking for problems if you do. I have wiped out a couple cams just replaceing lifters in them, each one lasted about 500 miles so dont be cheap if you do change out that stuff.
#52
01-27-2011, 03:46 PM
If thats the case with Discos they must use an unusual metal on the cams. I have replaced lifters without replacing camshafts at least 4-5 times in my life. once just because I wanted to see if Rhodes lifters gave my big block Monte Carlo any more vaccume at idle - not really( 2 in). Another I remember because I had a lifter that just wouldnt pump up anymore and was causing the engine to run on 7 cylinders. Remember most cam surfaces are harded or nitrided sometimes. 8 new lifters one bottle of GM EOS and you should have no problems
#53
01-27-2011, 08:16 PM
What may be one person's experience, is not necessarily the correct way. I once solved a ticking noise on a vehicle by removing the zip-ties drom the driveshaft. Does that mean it will fix your ticking noise? The OP has to make the decision ultimately. Sometimes you can get lucky, sometimes you don't. I tend to doubt my luck and do things the right way. If it were me, I'd change the oil and run Marvel Mystery oil to see if that fixes the sticky lifters. Then go from there.
I couldnt agree more! I would also avoid a tear down and try something like Marvel or Rislone or CD2
#54
01-27-2011, 09:11 PM
Baja
Join Date: Mar 2010
Location: Pittsburgh PA suburbs.
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When I first got mine, I did a couple of oil changes. On the second oil change I used some 5W30 Quaker State that was left over from my wife's Explorer. The 5W was too thin and it was real noisy. I ended up getting MaxLife by Valvoline and it has never been quieter. Even feels more responsive and down right peppy now. Of course that is with new plugs and 8 mm wires. and new air filter.
#55
06-25-2013, 10:17 PM
I'm a little late to the thread but I just went through the same scenario on a 95 with the 3.9. It tested everything in the engine for a loud knock that only happened at certain frequencies. I ended up listening with a stethoscope from the valve train through the exhaust and heard the rattle coming from within the cat. I checked that with a hammer but it didn't rattle. I was sure of my ears so I pulled the y pipe off and ran it up the road. It was awesomely loud and ferocious! And no knock. I cut a hole through the cat but the honey comb was all intact. My friend is gonna try and source a pipe and well bolt it up and see
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