Honda C27 & C35 Series Engine "VALVE/ TAPPET NOISE"

[hughezee]

Tick tick Dave’s got me thinking about noisy valves   

 

Just thinking out loud here folks in 99.9 % of cases of tappy ticky engines I will prescribe a valve lash adjustment and maybe an oil change for good measure. Now the Honda C series is not adjustable and I can’t help but notice there plenty of avid users of ATF in hydraulic tappet engines. However reading USA forums there’s no real clear answers how often you have to use it to keep the lifter noise subdued or how long does it last or even if its safe to use with catalytic converters with the sulphur content in some ATF’s Personally I’ve used specific hydraulic lifter fluids and they work until the oil is changed and in most cases just using a different grade oil and the noise never returns.

 

ATF is very thin on the scale of 5w20 engine oil and as result will get into the small hole that fills the hydraulic lifters and subsequently quieten them down & not necessarily free them up as they are already worn. So by the time you need to drop more ATF in the engine, if the ticking or tapping has returned the engine oil has pretty much diluted it by now and what I’m suggesting & thinking has anybody tried thinner oils or additives at any point to resolve this

 

 

Works a treat for me

[Retro Rich]

That's interesting, non-adjustable tappets. I would of thought Honda would supply a kit or recommend  a new valve train at 100k miles or something? Like you say, by the time it's noisy, wear has already occurred. Do other manufacturers fit non-adjusting tappets?

[hughezee]

Honda no longer offer this option in favour of manual adjustments and recommended adjustments at certain intervals also there are a number of manufacturers that offer hydraulic lifters in their engines buddy

[Laird_Scooby]

You can adjust the pre-load of the hydraulic lifters on the C27, there's a procedure somewhere in the Rover WSM for doing it. Allegedly it quietens them down but to my way of thinking, it's treating the symptom, not the cause and can result in valves being open too long and a few other nasty things.

 

The Wynns HLA Treatment does work well but to quiet them down between oil changes, i usually use between 250-500ml of Dexron II which works because it's thinner and has some sort of "seal-swell" in it that helps revive the "O" rings that some hydraulic tappets have. By reviving the tappets this way, the original clearance is restored so the valves open when they should as far as they should. So far i've not noticed any ill effects on the cat but i have noticed hat after a few times of using it with engine flush at each oil and filter change, eventually the tappets become nice and quiet by themselves, without needing any interference.

The Dexron also has a cleaning effect and helps revive the other seals in the engine too so i've not found a downside yet to using it.