They are annoying!!! clik clik clik...
I got some additive thats supposed to clean the valve springs
hoping to get rid of this noise and no luck, oil levels are fine,
replace the pcv valve and valve cover gasket thinking it could
be losing oil pressure and still there. The oil pressure runs at 30psi
when running and drops to 15psi at stop lights, or when i hit the clutch.
I'm thinking that last thing to do is replace the lifters but i really don't
want to mess with the camshafts or mess up my timing, has anyone
done this before, is there a way to remove/replace the lifters without
taking the camshaft/gears out?
Member # 11301
This "knocking" sounds more like the classic Miata HLA tick.
Your car has hydraulic lifters and sometimes you can't get oil into them fast enough for them to stay totally inflated, so they tick.
When you check the oil, make sure the car has sat for a few minutes NOT RUNNING. For an accurate measure, I like to wait about 5-10 minutes.
There are a number of "solutions" to the HLA clatter, and every one of them involves changing your oil.
My favorite is to do 2 oil changes.
On the first, put a cheap filter in the car and put 1 qt of really thick oil and 3 quarts of auto tranny fluid (yes, ATF) in the engine and run it for about an hour.
Drain that out. While the drain plug is off, run about a gallon of kerosene through the engine to flush it out good.
Then, put your good Mazda OEM, Mobil1, or Purolator (NOT FRAM!) oil filter on the car and fill with your favorite oil (dino or synth)
Others will just tell you to adjust the viscocity of the oil.
I have found the adjusting the viscocity only moves the problem to one end or the other. If you go thicker to address the hot tick, you're more likely to cold tick. If you go thinner to address cold tick, you're more likely to hit tick.
I believe that the lifters tick because the hole in them that allows the oil in is too small, and over time this hole closes up a little due to varnishing of the oil and other deposits.
The strong detergents in the ATF help to dissolve these varnishes, restoring these holes to closer to their original size.
I have no proof of this, but in my experience, my method works for longer than the others I've seen. I usually get 3-4 oil changes at 3-5000 miles before ticking comes back.
The ticking won't really hurt anything, we're talking about thousandths of an inch here, but it sure is annoying to have your nice pretty car clacking at the stoplights...