how to: Valve adjustment K20a

how to: Valve adjustment K20a

This weeks blog entry is going to be another addition to our valve adjustment series, where we will go through each Honda engine series and showing you how to do a valve adjustment on it. This week is on K20’s! I will be doing two valve adjustments at once. If you’ve been keeping up with the blog at all you will have seen the articles on my brothers EG with the K20, I figure since his car is nearing completion (again) I want to make sure his car is all within specs before I send it back out to him. If you want to read any of the articles about his car you can click on the links below.  <–complete build write-up   <— dyno day at churches auto

As for doing one on my car… I’m pretty hard on it so I try to keep it in tip-top shape, which means I’m doing maintenance in intervals of every few months rather than every few years. It’s actually a lot of fun for me to pull of the valve cover and do a valve adjustment, ill pretty much just use any excuse to be in the garage working on a car. I figured it would be cool to do a write-up on both the cars at the same time and sort of break up the boringness of just showing pictures of one car.

So real quick let me give all you new readers a back story about our k20s. We purchased them together at the same time from HMO ( Honda Motors Online ) about 4 years ago. Both of our swaps are JDM DC5 K20a swaps, with only bolt ons. As you can see from the valve terrain picture below they are incredibly clean, this is why I only recommend people get their swaps from HMO. Erics car alone has been across the United States a total of 4 times, and mine has seen countless hard miles on the track. So essentially these motors are just stock DC5 swaps with a tune, thus keeping that OEM reliability. With regular maintenance it’s easy to keep them long-lasting for may years to come, which brings us to the valve adjustment HOW TO.

Starting off lets clear a few things up. Unlike B series There are a few different style of K series, so if you have something other than a K20a, k20z3, or k20z1 things might be a little different BUT… The motions are pretty much the same, just need to look up specs based on your motor. You will also notice that mine is not in a civic SI, or RSX type S. If you are doing a valve adjustment on any of those there will be more things to take off. i.e. plastic intake manifold cover, vacuum lines from intake to valve cover, and possibly others. you should be able to figure out how to remove those with how me showing you.

Here’s the tools I used, but again you might need some others depending on what you have to take off. all the valve cover bolts, coil pack, and ground bolts/nuts are 10mm. You’ll also need a 19mm for the crank pulley bolt (this will be used to turn the engine manually). A spark plug socket, long extension, ratchet, jam nut valve adjustment tool, feeler gauges, magnet, breaker bar, a rag, and some Honda bond



The most important tool you need to make this go easily is the Jam nut valve adjustment tool. Some people claim that you can use a 10mm closed end wrench and a flat head screwdriver (which is essentially what the jam nut tool is), and I’m sure you could do it this way, but its keeps the frustration low throughout the whole job if you just use the correct jam nut valve adjustment tool. Having angled feeler gauges makes life a lot easier too.


I also have a few other tools in the picture that I used because I had to snip some zip ties, and need to take my strut bar off too.

Step 1: 

You are going break the front right wheel loose. Jack the front of the car up, and rest on jack stands. Remove wheel, this is going to gain you access to the 19mm crank shaft pulley bolt. (if you don’t want to jack the car up you could also just turn the wheels full lock to the right, and you could sneak a ratchet in that way. But in keeping with our “low frustration” motto,  just remove the wheel and it will be so much nicer.)


Once you remove the wheel you will gain easy access to the crank pulley bolt which is a 19mm. To make life a little easier I pair a 19mm socket with a 3/4 ratchet just to make turning it a little easier.


I will leave the ratchet on there throughout the whole process of the valve adjustment. You will need to turn the engine manually with it to TDC (top dead center) each cylinder. JUST DON’T FORGET TO REMOVE IT BEFORE YOU START THE CAR!!!!!!!!!!!!!! SERIOUSLY!!




Step 2:

Removing the valve cover. Like I said earlier your car might have some other plastic pieces on it that mine doesn’t, but I’m not going to show you how to remove those. They should all just come off with a 10mm socket. As you notice I don’t even have a spark plug wire cover, so I’m just going to jump right in to removing the 10mm nuts holding the valve cover on. There are 6 total that you need to remove.

Then remove the two 10mm holding the coil pack harness (yours might not be bolts, it maybe 10mm nuts on studs)

Now remove the 10mm bolts hold each coil pack to the valve cover.

Remove the 10mm ground wire bolt.


Now one at a time you can lift the coil packs out enough to un-clip the plug. be careful not to pull too hard on the coil pack harness.

Next you will carefully move the coil pack harness back towards the fire wall. Your valve cover should look like mine now. I did forget to mention that you also need to remove the dipstick. Notice that I have removed all bolts, yet I have left the grommet washers on still. Next I will show you how to remove them without losing them or having them fly everywhere. ( yes that’s a chip in my real spoon valve cover )


Now I’ll show you how to take off those washers without losing them. Take the magnet that I told you to have handy, and take each washer off with it one by one. You can leave the rubber grommet on though, they should stay in the valve cover as you remove it. Just be careful and pay attention when removing the valve cover so you don’t lose any of them. If your valve cover grommet and washers are old, this would be a great time to replace them. I will be reusing mine since they are fairly new.


I remove the spark plugs because for two reasons. One I get to inspect them and see how the engine is running, and two removing them will help you rotate the engine around using that ratchet on the crank pulley much easier. This is because compression won’t build in the cylinder since the spark plugs are gone. Again technically you don’t need to remove them, but let’s not get frustrated. It’s also easier to get the marks on the timing gears to line up because the compression when the engine reaches TDC won’t push the piston back down slightly. (take all 4 out plugs out)


Now you are going to remove the valve cover. It will be on there pretty good, especially if you’re valve cover hasn’t been off you engine for 100k miles. DO NOT take anything metal and try to pry between the valve cover and the head, you can easily scar the head where the valve cover gasket seals and this might cause there to always be a leak. I take me hands and place them like this.


I shift the valve cover back and forth to break the seal. You could also use a plastic scraper, or interior panel remover to pry lightly between the head and valve cover. shifting the valve cover forward and backwards will also cause the grommets to move up the studs allowing the valve cover to shift back and forth more, you’ll know when its lose enough to remove. I tried to illustrate below how the valve cover is slightly shifting front to back (that’s why it’s a little out of focus)


The valve cover should now just lift off. I don’t recommend replacing the spark plug hole gaskets because they are pain in the ass to hammer in, and I usually end up destroying them. You shouldn’t need to replace them anyway, unless oil is pooling in your spark plug tube.


Step 3:

A valve adjustment should be done with the engine is COOL, below 100 degrees F. Realistically you should do it in the morning before you even start your car. As we all should know heat causes metal to expand, thus throwing off your measurements in the valve lash setting. Plus if you let the engine sit all night most of the oil will drain out of the head so when you remove the valve cover it won’t leak out as much. (no matter what some is going to leak though)

The K series engine (like most all Honda engines) has a firing order of 1, 3, 4, 2. Cylinder #1 is the one closet to the timing chain/gears, and cylinder #4 is closet to the transmission. There are 4 valves per cylinder ( 2 exhaust and 2 intake ) and there are 4 cylinders so that gives us a total of 16 valves. To do a valve adjustment you must TDC (top dead center) each cylinder and only one cylinder can be TDC at a time. I’m going to show you how to make sure, you are making sure, that you are correctly setting each cylinder to top dead center. There are marks on the timing gears, and the lobes on the cam will point a certain direction. (sticking something in the spark plug hole and watching it rise as you turn the crankshaft bolt will tell you when the piston is all the way up, but that’s not necessarily TDC. It might not be on a compression stroke. therefore please don’t use this method, you might incorrectly adjust you’re valves that way)

below is cylinder #1 at TDC


The arrow is pointed up. and there are two lines on each timing gear and they will be pointing towards each other


Then the cam lobes will be point inwards towards the spark plug tube. (exhaust side) pointing towards theoretical 2 o’clock and (intake side) will point to theoretical 10 o’clock. Use the VTEC lobe for guidance as it is the easiest to see. (largest middle lobe)


Now we are moving to cylinder #3 (remember the firing order 1, 3, 4, 2)  take your ratchet on the crank pulley and rotate it clockwise till the arrows on the cam gear moves 90 degrees and looks like this.


also note the lines on the cam gears, the one you can see (intake cam gear) line is pointing upwards, and the exhaust side (which you can’t see due to the shock tower being in the way) will be exact opposite point downwards. Remember this is TDC for Cylinder #3.


again take note of the VTEC cam lobe and how they point inwards towards the spark plug tube Theoretical 2 o’clock for exhaust cam, and theoretical 10 o’clock for the intake cam.

Now let’s move to TDC on cylinder #4 (remember the firing order 1, 3, 4, 2 ) and cylinder  #4 is the one closest to the transmission. Take you ratchet on the crank pulley and rotate clockwise until the arrows has moved another 90 degrees pointing downward.


Take note of the lines on the cam gear and how the one on the intake cam point forwards towards the radiator, and the exhaust one (which again can’t be seen because of the shock tower) point the opposite way backwards towards the fire wall.


And the cam lobes for cylinder #4 will be pointing the same direction as the previous cylinders. Inwards towards the spark plug tube theoretical 2 o’clock for the exhaust side and theoretical 10 o’clock for the intake side.

The markings for the fourth and final cylinder, cylinder number #2 look like this. remember take your ratchet on the crank shaft bolt and rotate it again in a clockwise motion until the arrow has moved another 90 degrees like this.


Now you can see the line on the exhaust cam gear is on top pointing upwards, and the line on the intake cam gear will be opposite pointing downward. (which can’t be seen because the paper pointer finger is blocking it)

now let’s look again at the cam lobes and see what it looks like when Cylinder #2 is TDC.


you guessed it, same exact thing as the other three cylinders. Vtec lobes pointing inwards towards the spark plug tube, and theoretical 2 o’clock and 10 o’clock.

Now that you know what markings to look for that indicate which cylinder is at TDC, and you know that the firing order is 1, 3, 4, 2. You also know the fail proof way to ensure the each cylinder is at TDC by looking at the orientation on the cam lobes. Go ahead and try to freestyle, see if you can rotate the ratchet on the crank shaft a few full rotations and test yourself to see if you can guess what cylinder is at TDC. It’s also worth noting the engine is mounted naturally at a lean so use the engine as the reference point for which direction the marks are pointing on the cam gears, not the actual car as reference. But as long as you make sure the lines on the cam gears are exactly opposite in the directions they point, and the cam lobes point the correct direction you can’t mess this up. remember the cam lobes will only be pointing inward at 2 o’clock and 10 o’clock when that cylinder is at TDC.

Step 4:

Now that you know how to make each individual cylinder TDC, I’m now going to show you the process of actually adjusting the valve. I am not going to go over each valve rather just show you how to adjust a few valves. You will be doing 4 valves per cylinder (2 intake and 2 exhaust) The valve lash specs are.

Intake: 0.21 – 0.25mm (0.008 – 0.010 in.)
Exhaust: 0.25 – 0.29mm (0.010 – 0.011 in.)

Again this might be different for your k series motor please double-check the manual. I set my intake to .008 in. and my exhaust to .010 in.

Some people say that if you can’t fit and .011 inch feeler gauge in the intake side, and you can’t fit and .012 inch feeler gauge in the exhaust side then you don’t need to adjust that individual valve. However I figure that you might as well adjust every valve since you have already gone to all the work to removing everything. Plus I run the tightest clearance so that the valve can be open that milli second more to allow for the maximum amount of air and fuel to be drawn in, thus producing a better combustion equalling max potential power. It’s also a great opportunity to just go over each adjustment nut and make sure none are loose. When you torque the lock nut down after you have set the clearance only torque to 14ft/lbs, be careful to not over tighten you can actually snap this relatively easy.

To adjust the valve you are going to take the feeler gauge and slide it in-between the top of the valve spring/valve and the bottom of the rock arm.


There should be some drag on the feeler gauge, if it slides in and out easily then its too loose and you will need to adjust.


Seen above im trying to show the movement of sliding the feeler gauge back and forth.


You are going to adjust by using your nifty jam nut valve adjustment tool, loosen the 10mm lock nut then use the flat head to turn clockwise to tighten to counter-clockwise to loosen the gap. The way I usually do it is, loosen the nut then slowly turn the flat head while sliding the feeler gauge back and forth until the desired drag is on the feeler gauge, then hold the flat head steady (not letting it rotate in either direction) as you tighten the lock nut. The drag should be pretty noticeable, but the feeler gauge shouldn’t actually be stuck or really hard to pull out, or put in.

So as you can see in the pictures above, you need adjust the 2 intake valves (specs are 0.008 – 0.010 in.) remember do not over tighten the lock nuts, torque spec is 14 ft/lbs for them


Then adjust the two exhaust valves ( specs are 0.010 – 0.011 in.) remember do not over tighten the lock nuts,  torque spec is 14 ft/lbs for them

I’m not showing me adjusting every valve since it would be redundant. I only showed what each cylinder looks like at TDC for you to be able to reference. Let me quickly list the steps to “actually” do the valve adjustment now that you know how to set each cylinder to TDC, and how to adjust the valve.

  1. Set cylinder #1 to TDC, adjust the 2 intake valves for cylinder#1, and the 2 exhaust valves for cylinder #1
  2. Set cylinder #3 to TDC, adjust the 2 intake valves for cylinder #3, and the 2 exhaust valves for cylinder #3
  3. Set cylinder #4 to TDC, adjust the 2 intake valves for cylinder #4, and the 2 exhaust valves for cylinder #4
  4. Set cylinder #2 to TDC, adjust the 2 intake valves for cylinder #2, and the 2 exhaust valves for cylinder #2

Step 5:

Reassembling everything. Now that you have adjusted a total of 16 valves, 4 per cylinder, 2 exhaust, and 2 intake per cylinder. I advise that you go through a full cycle of each cylinder at TDC and just stick the feeler gauges in to double check to make sure you are all within spec and that the resistance on the feeler gauge is similar for each valve, on each cylinder. At this time I also double check that I tightened down all the lock nuts, so they don’t come loose once the engine is running, this would make you very frustrated.

Take a clean rag and wipe away/clean all oil and debris around the head where the valve cover sits. * pro tip is to get it as clean as possible so the valve cover gasket can completely seal allowing no oil leaks.


you can see how I take my index finger and wrap it in the towel, and go around the whole head (especially on the header side of the head since this is where most oil will leak out when the valve cover is off).


You also want to make sure you clean all the old Honda bond/RTV silicone off the area where the valve cover gasket meats the head.


you can see above that there is a small piece of dried Honda bond that needs to get picked off. Make sure it doesn’t fall into the head!

At this point its completely up to you if you want to get a new valve cover gasket or not. like I said earlier mine is fairly new so i’m not replacing mine. Eric’s is at least 5 years old and i’m not replacing his either. It’s not so common the actual valve cover gasket to leak, as long as you are re applying new Honda bond/RTV silicone sealant you shouldnt need to replace the valve cover gasket. If you do decide to replace the valve cover gasket DO NOT get an auto-zone, pep boys, oriely, ETC.., they will all leak (eventually). ONLY USE OEM one form HONDA. Here is the part number from Acura 12030-PNC-000, this includes new valve cover grommets, and washers too! If you want to search for it, it is called GASKET SET, HEAD COVER.

If you decide to reuse the valve cover gasket (like I did) just make sure you pick off all the old Honda bond/RTV silicone sealant, to ensure a proper seal between the valve cover and the head. When re installing the gasket onto the valve cover it can only go one way, so pay attention!


Above you can see the fresh Honda bond (grey silicone) I applied, notice that it only needs to be on those 4 area’s, and just a little bit will suffice. DO NOT put Honda bond around the whole thing. Also notice how clean and dry my “old ” gasket is, make sure yours looks like this too. Where the valve cover sits on the head should also be completely dry, and the valve cover gasket should be all the way dry. (except obviously for the 4 area’s with Honda bond) This will ensure the best seal.


You will want to clean the oil off these as best as possible, to ensure the best seal.

Now go ahead and set your valve cover back on the head, making sure you are not pinching any lines, or wires between the valve cover and the head. Now you are going to put the rubber grommets on all six holes.


make sure that each one fits completely into the valve cover, above you can see the centering part of the grommet that must completely seat into the valve cover. Make sure you fully seat all six and re check to make sure they are pushed in before you even start tightening your valve cover. Doing this will ensure the valve cover is centered, will seat properly, wont pinch any part of the grommet (which could cause an oil leak),  and once tightened there will be even pressure all around. Once you are sure they are all seated in the valve cover properly, go ahead and put the metal washers on. Screw on the 6 nuts by hand to just get them started. (be careful these can strip easily, which could cause and oil leak because you will not be able to tighten them to correct torque specs) Now using a ratchet tighten the six nuts in a star pattern (just like you would do tightening lug nuts) Tighten in a 3 step process, snugging them all down, then a bit firmer, and then The final torque spec is 7.2 ft./lbs.

  • Reinstall the spark plugs
  • bolt the ground back on to valve cover
  • Install the valve cover breather hose (if you have one) and oil dipstick. Be sure to wipe the dipstick clean first.
  • Install the coil packs by seating them over the spark plugs and connecting the wiring harness. Tighten the 10mm bolts for the coil packs to 8.7 ft./lbs.
  • Install the ignition coil cover and its (4) 10mm bolts. Their torque spec is 8.7 ft./lbs.
  • Take the ratchet off the crank pulley, and re install the wheel.

And If you have a stock car

  • Install the 10mm bolts holding the cruise control cable and power steering pump bracket.
  • Install the intake manifold cover and its (2) 10mm bolts.


Here is how everything looks all back together


I hope this helps you over come your fear of adjusting your own valves, Get out int he garage this weekend and give your car some TLC! and as always please like, comment, share. if you have any questions please don’t hesitate to ask, I would love to help you!

And lastly if you want to check out the S2000 (F20C) valve adjustment DIY click the link below.

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