[DIY] B Series VTEC Valve Clearance Adjustment

[ChargeR]

DIY: B series valve clearance adjustment

What follows is a guide to adjusting the valve clearance on a B16A. It seems to be a job that a dealer will charge an arm and a leg for and do a shoddy job of so it is worth trying yourself. The procedure is nearly identical for any other B series VTEC motor and also similar for the K series except they spin the other way.

ClubITR and myself take no responsibility for any mischeif or misfortune that may befall you if you attempt this diy, please only proceed if you have the correct tools and adequate mechanical knowledge. If you are unsure of anything then just ask. If you think there are any errors or omissions then please post up and let me know.

Here are the relevant pages of the EE8 CRX VTEC supplement, be sure that you follow the manual for your own car so the valve clearances are correct:





Here are the tools you will need:



10mm socket
3/8" drive ratchet
Various extensions
19mm socket
1/2" drive slide bar
Angled feeler gauge
Spark plug socket
Torque wrench (I used this one for the wheel nuts, you will need a smaller one for the valve locknuts)
Pliers
Valve adjustment tool (I got mine from eBay)
Jack (not pictured)
Jack stands (not pictured)
Hondabond (not pictured)


1. Loosen the wheel nuts on the front passenger site wheel. Raise the front of the vehicle using a floor jack and support with safety stands, pictured in Figure 1 (note that you might not be lucky enough to have a manky old CR-X). Remove the front passenger side wheel as depicted in Figure 2 and any splash shields that might be in the way of the crank pulley, you should be faced with something like what is pictured in Figure 3.


Figure 1: The car safely on stands




Figure 2: The wheel




Figure 3: The crank pulley




2. Remove the spark plug cover by removing the 4 10mm bolts, pictured in Figure 4. Remove the valve cover by removing the 8 10mm nuts along with any random bolts holding brackets around the periphery of the valve cover as pictured in Figure 5. Remove the valve cover breather that goes to the intake by firstly moving the spring clamp with pliers and then gently pulling the tube off, as in Figure 6. Lift off the valve cover, you should be looking at something that looks like Figure 7. Note that in my case the old manky valve cover gasket stuck to the head, you should remove this too but I left it there as I didn't care if I messed it up because I was replacing it.

Figure 4: Plug cover removal




Figure 5: Valve cover removal




Figure 6: Breather removal




Figure 7: The valvetrain

[ChargeR]

3. Remove the spark plugs using the spark plug socket shown in Figure 8, this is not essential but I chose to do it as it makes rotating the crank much easier and more precise. Now we need to turn the crank until cylinder one is at top dead centre on the compression stroke, do this by turning the crank counterclockwise using the 19mm socket, extensions and slide bar, pictured in Figure 9, until the white mark on the crank pulley lines up with the line on the lower timing cover, I couldn't get a good picture of this but you can refer to the picture below (Figure 10) for what it looks like. The cam gears will have both "UP" marks pointing upward when the crank is in the correct position, as pictured in Figure 11.


Figure 8: Spark plug removal




Figure 9: Turning the crank




Figure 10: The top dead centre mark




Figure 11: The cam gears with cylinder 1 at TDC




4. You are now ready to adjust the valve clearance on cylinder 1, the cylinder nearest the timing belt. Insert the feeler guage (0.007" exhaust and 0.006" intake in my case) from the plug side between the cam lobe and the rocker as depicted in Figure 12 and fit the valve adjustment tool to the jam nut/screw. Loosen the lock nut and then adjust the screw until there is slight drag on the feeler guage as you try to slide it back and forth (front to back of the motor). Once the clearance is correct tighten the lock nut whilst holding the screw in place with the screwdriver. Recheck the valve clearance then tighten the lock nut to 20Nm. Repeat for the other exhaust valve and both intake valves. Cylinder 1 is now done.

Figure 12: Adjusting the valve clearance




5. Now the motor must be turned over another 180° so that cylinder 3 is at top dead centre on the compression stroke, do this using the socket and slide bar arrangement as in Figure 9. The "UP" marks on the cam gears will now be pointing toward the exhaust side of the motor as in Figure 13. Repeat step 4 for cylinder number 3.

Figure 13: Cylinder 3 at TDC




6. Turn the motor counterclockwise a further 180° and then adjust the clearances on cylinder number 4 as per step 4. Turn the motor a final 180° degrees and adjust cylinder 2. The clearances are now done as in Figure 14. Double check the tightness of all the lock nuts.

Figure 14: Done!




7. Re-fit the valve cover. Put a small amount of Hondabond or similar on the corners of the valve cover gasket sealing area where it rises up over the cam caps, 8 individual points need a blob of goo. Place the cover back on along with the rubber washers and tighten up the 8 nuts and various bolts/brackets. Re-fit the spark plugs with a small amount of anti-sieze on the the threads. Reconnect the valve cover breather. Reinstall the spark plug leads in their original positions. Reinstall the spark plug cover. Put the wheel back on, lower the car, torque the wheel nuts to 120Nm or so and you are done.

[TODA AU]

In my experience, for best results, (Performance & quite running)
Valve clearances should be measured between the tip of the valve & the rocker arm.
The Honda method shown is correct per Honda manual for a standard engine & fine if followed correctly,
But the reverse is true for aftermarket cams, EG: Skunk2, Toda etc
That is the tip method is standard practice for most aftermarket cam manufacturer's.
Also, when the clearenec is set/measured between the tip of the valve & the rocker arm,
There is little to no chance of having a noisey engine after valve clearence adjustemnt.
(Which is common when a lot of shops use the Honda menthod)
IMO, based on experience, the tip clearence method is better than Honda's cam/rocker.
Anyway, take it as advice or not.

[ChargeR]

Hmmm okay. I was just following the manual which says to set the clearance between the cam and the rocker as you can see above. So you are saying I should have had the feeler between the top of the valve and the rocker? That is not what the manual instructs, although it is what it says for the single cam motors obviously.

EDIT: The B18C and 2nd generation B16A manual (which lists the same clearances I used) states very clearly that the listed clearance is to be measured between the camshaft and the rocker arm. Can you clarify?

[tinkerbell]

an interesting empirical test would be to recheck the clearances between the tip of the valve & the rocker arm and see whether they correlate?

[tinkerbell]

a more subjective test would be 'how noisy is it' as it is now? (cold & warm)

[ChargeR]

an interesting empirical test would be to recheck the clearances between the tip of the valve & the rocker arm and see whether they correlate?

It will obviously be larger by a factor of whatever the rocker ratio is.

a more subjective test would be 'how noisy is it' as it is now? (cold & warm)

Motor is quiet, the noisiest thing is the injectors and what sounds like a dodgy bearing in the PS pump or alternator. Where have you always measured your valve clearances Dave? 12 years seems like a long time for something like this to be incorrect in a whole lot of workshop manuals, so I think the way I did it is correct for B series VTEC motors, so the title should more accurately read: [DIY] B Series VTEC Valve Clearance Adjustment.

[tinkerbell]

i do mine (and everyone else's i do) at the valve tip...

and use 0.007 & 0.008 (i.e. set slightly 'loose')

[tinkerbell]

here is the tool name: Powerbuilt - Jam Nut Valve Adjustment Tool - 648827 - 10mm

[felixR]

Nice one Tom!

Added it into the DIY thread.