B16A Valve adjustment

B16A Valve adjustment

I have done a few valve adjustment “how to’s” on the blog, K series, and F series, but none have ever been more anticipated than this one. That’s right, its finally time, I now present to you… How to do a valve adjustment on a B16 (or any other variant of a DOHC VTEC B series)

Let me start by sharing the links below of the other two articles I have written on valve adjustments.

K series:

http://functiontheory.com/2019/03/how-to-valve-adjustment-k20a/

F series:

http://functiontheory.com/2019/02/how-to-valve-adjustment-on-s2000/

If you’re new to the blog, Welcome! If not, then you will know why it has taken me so long to finally put together this B16 valve adjustment, but for all the new people let me give you a quick backstory. I have been tracking my 4 door with a D16y8 in it for the last two years, and the more serious I got the more I realized that I needed a LSD (limited slip differential). Rather than spend tons of money of building a SOHC LSD trans I decided to just make the switch the a B16. This would not only open my options up for LSD transmissions, but it would also give me a slightly better power band than my D16 was able to offer. It also took me so long to finally do a DOHC VTEC B series valve adjustment because, quite honestly no one I knew had a B series in their car. Now though, as I finalize my B16 and get it ready to swap into my car I was able to do this B16 Valve adjustment how to.

Starting off, I’m doing this while the engine is on my Vein engine stand. The process will be the same if you are doing it while the motor is in your car, its just better this way for pictures. Also please read though the whole article, this will give you a better grasp on the whole project and it will make a lot more sense to you, rather than treating it as a step by step how to.

Here is where I will begin. Make sure that when you do the valve adjustment the engine is cool (100 degree F, or below)

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Remove the spark plugs. This will make rotating the engine around manually much easier. *PRO TIP: leave the spark plugs in the engine, just make sure they are all the way un-threaded. Leaving them in will help prevent stuff from falling into cylinders (like nuts, or washers)

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Remove the x8 10mm nuts that hold the valve cover on.

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Make sure you remove the grommets before removing the valve cover. If you don’t, it’s possible these will fly off when you go to remove the valve cover and you can lose them.

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carefully remove the valve cover. If it is difficult to get off, STOP, recheck to make sure you have removed all x8 nuts holding it on. If you’re doing this while the motor is in the car then there will also be a ground wire you will need to unbolt from the valve cover. If all nuts are off and it is still difficult to get off… You can CAREFULLY pry, but be careful to not mare, score, scratch, or damage in any way where the valve cover meets the head. This could cause leaks upon reinstallation of the valve cover. I suggest prying with a plastic something.

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Now that the valve cover is removed you want to be very careful you don’t drop anything in the exposed valve terrain. If you do and fail to retrieve it… most likely you’re going to cause some damage to your engine when you start it back up.

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Remove the x2 10mm bolts holding the middle timing cover on. (this is not necessary, but it will just make lining up all the timing marks a little easier. Plus it’s only two bolts and literally just comes right off, so why not?)

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This is what it should look like.

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Below I will go through what the above diagram is showing.  You will start off adjusting cylinder #1 to TDC. To ensure you have cylinder #1 at TDC (top dead center)  you must make sure all of the marks below line up as they are in my pictures.

Up arrows on both cam gears are pointing up.

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The small grooves in the cam gears will point inward towards each other.

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And the last way to double check if you can adjust the valves on cylinder one is by looking at the cam lobes.

Exhaust cam lobe will be at a 10 o’clock orientation.

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and the intake cam lobe will be at a 2 o’clock orientation. This will ensure there is no pressure on the valves so you can properly set the clearance. Keep in mind that as you progress to the next cylinder the lobes will move, and you must ensure that for each cylinder you are adjusting the valves on, the cam lobes will be a the 10 o’clock and 2 o’clock position.

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There are 4 valves per cylinder. Two exhaust and two intake.

  • You will adjust the Intake valves to 0.006-0.007 in
  • you will adjust the exhaust valves to 0.007-0.008 in

I personally am setting mine to .006 for the intake, and .007 for the exhaust.

 

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Below is valve #1 of the exhaust. you will not need to worry about the VTEC lobe (middle larger lobe) see the feeler gauge

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And below is valve #2 of the exhaust. see the feeler gauge

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Next you will need to use this tool. There is other ways of doing it, but this just makes life so easy.Capture On a DOHC VTEC B series head there is no way to get a wrench in to loosen the jam nut, and using a socket wont work because you will need to be able to get a flat head screwdriver in to hold the adjuster screw so it doesn’t turn as you tighten the jam nut.

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Once you have adjusted the exhaust valves, move on to the intake valves (there is no proper order, you can do either intake or exhaust first)

 

Below you can see how you will slide the feeler gauge in between the camshaft lobe, and the rocker. you are adjusting the gap between the two. and you are using the valve adjustment tool to loosen the jam nut, then adjust the screw so there is a small amount of drag on the feeler gauge as you move it back and forth.

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remember you are not doing anything with the middle lobe. That is the VTEC lobe.

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So again, just to make things clear. you are adjusting only 4 valves per cylinder. 2 intake and 2 exhaust. you will do this for all four cylinders, but you must ensure each cylinder is at TDC when you adjust the valves for it.

Below is intake valve one and two.

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again, again… below you can see how the paper finger is pointing to the middle lobe (VTEC lobe) there is nothing to adjust for the one. just the lobes on each side of it.

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Below you can see how the feeler gauge is inserted, and then how I have the tool in place to loosen the jam nut and adjust the screw.

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Break the jam nut lose. Then use one hand to turn the screwdriver, and the other hand to move the feeler gauge in and out to properly gauge the drag on the feeler gauge. Once the desired drag is achieved, you then place both hands on the tool. One hand holds the screw steady so it doesn’t move as you use the other hand to tighten the jam nut down. The torque spec for the jam nut is 14 lb/ft. DO NOT over tighten, you can snap the adjuster screw.

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Now cylinder one is all adjusted.

time to move on to cylinder three (the firing order that you need to follow is 1-3-4-2)

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Use a 19mm and rotate the engine counter clockwise (only 90* on the cam gears)

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The marking on the cam gears should now look like below.

The up arrows will now point towards the front (exhaust side) of the engine.

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The grooves in the cam gears will now be opposite of each other (exhaust cam gear will have it on top, and the intake cam gear will have it on the bottom)

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Also remember the cam lobe orientation of the exhaust at 10 O’clock

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And the intake cam lobe at 2 O’clock

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Below you can see how I use both hands to break free the jam nut.

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The picture below shows a great view of how the screwdriver part of the tool fits, and the socket part of the tool fits on the jam nut.

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and again below you can see the feeler gauge.

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Make sure you adjust the intake side.

Now we can move on to cylinder #4. Manually crank the engine another 90* counter clockwise. this will make cylinder number 4 at TDC.

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The cam gears will now look like this. both “up” arrows will now point down ward.

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and the cam lobes will be at 10 O’clock (exhaust cam) and 2 O’clock (intake cam, not pictured)

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Now just as you did for the last two cylinders: slide the feeler gauge in (make sure you are using the correct size for intake and exhaust, refer to the top of the article where I give the specs)

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Once you make your adjustments and tighten everything back down, make sure you double check to ensure the valve lash clearance didn’t get tighter as you tightened down the jam nut.

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Now finally, move on to cylinder #2.

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Manually crank the engine counter clockwise another 90 degrees on the cam gear.

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See how the “up” arrows are now pointing to the rear (intake side) of the engine.

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and again double check to make sure the cam lobes are pointing the correct way. Exhaust cam lobe towards 10 O’clock pictured below. and intake cam pointing towards 2 O’clock (not pictured)

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Make your adjustments.

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below you can see how I use one hand to turn the screwdriver, and the other hand to slide the feeler gauge in and out until the desired drag is met.

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now on to the intake side. make sure you are using the correct sized feeler gauge.

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Below you can see how I have two feeler gauges. One is the size needed for the exhaust, and the other is the size needed for the intake. The intake will always be a tighter gap than the exhaust.

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Cylinder #2 should have been the last cylinder you needed to adjust the valves for.  Remember, you should have started at cylinder #1 then followed the firing order (1-3-4-2) ending with cylinder #2. When you are sure you have done all 4 cylinders, go back and double check that you tightened all the jam nuts for all 16 valves. Four valves per cylinder, and four cylinders.

Now it’s time to reassemble. Starting with the middle timing cover.

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Install x2 10mm bolts that hold it on and torque to 7.2 lb/ft

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Now install the valve cover. follow the procedures below that go over putting liquid gasket or Honda Bond on the corners of all 4 half circles (that means you will be applying it to 8 areas) use a very small amount.

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Put the x8 grommets, and x8 nuts back on. tighten to 7.2 lb/ft

Then make sure you re tighten the spark plugs, and reinstall the ground strap to the valve cover.

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Congratulations! you just learned how to do a valve adjustment on a DOHC VTEC B series engine. This article is meant to be a guide to help you better understand what you will be doing when you do a valve adjustment. Once you figure it out on cylinder #1 it’s pretty much just repeating the same sequence 3 more times. the most important things to remember are.

  • Ensure you have the cylinder you are adjusting the valves for at TDC.
  • Make sure the engine is cool 100 degree F or below before adjusting.
  • you should follow the firing order (1-3-4-2) when doing the valve adjustment.
  • Make sure you are using the correct size feeler gauge for the corresponding valve you are adjusting.
  • you are not adjusting anything on the middle lobe (Vtec Lobe)
  • Even if the valves appear to be within spec, I go ahead and break the jam nut loose, and adjust the valves anyway. You have already gone to the trouble of taking everything apart to get access to the valves.

 

I hope you find this article to be helpful, and I hope that this has inspired you to get out io the garage and work on your car. As always I’m here to help… Email me at Billy@functiontheory.com, DM me on instagram @Functiontheory, or just comment below, I WILL respond.

 

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