Valve Lash Adjustment
 

been contemplating valve lash adjustment for my 1997 5 speed civic lx. i've never performed or even paid for this service, never even felt the need. got some questions and comments tho...

is this service more imperative for imports, especially 4 cyl engines?
it seems i've done well in regards to fuel economy in domestic V6 vehicles irrespective of needing this service or not(it's unknown to me).

my disappointment w/ this vehicle's fuel mileage has sparked interest in this topic. it's well maintained including recent tune-up, but leaves me wanting more than ~40mpg.

for reference, my 2000 5 speed chevy prizm got consistently well over 40, sometimes reaching 44-45. the car's motor had only ~60k miles, where as the civic has just reached 200k, tho i'm not certain if it has the original motor.

the car burns VERY little or no oil(less than 1/2 qt at 3k+ miles, but a front seal leak so...), has perfect idle, but has hesitation during med to full throttle. the prizm DEF had much more pep, but did have an intermittent hesitation issue which i figured out before i sold it(could have achieved better FE in other words).

would this service yield enough mpgs to make it cost affective?

Re: Valve Lash Adjustment
 

valve lash adjustment is imperative for any vehicle that says it needs it. newer vehicles apparently don't need it anymore because it's always being readjusted (apparently?) like for the 2007+ Camry V6. First thing you'll need is some feeler gauges and the helms service manual. I have a PDF version of the manual if you are interested in it. As for the hesitation, that may or may not be because of the valve lash.. Every car is unique but at least for my civic, I have not adjusted the valve lash yet I notice no such hesitation. Why don't you just make a laundry list of all the things you've done to the car thus far? Take some pics of the spark plugs so we can make sure that each cylinder is getting proper air fuel ratio and that you're not leaking any oil.

Re: Valve Lash Adjustment
 

My Vx has 220k now. I bought it at 187? or so and did a valve adjustment just afterward. It may have been done, but the valves were very close to spec and were all pretty even to one another. I noticed no change in driveability/ hesitation afterward. It's worth doing, and was much less hard than I though it would have been with the proper digrams/manuals. I just wouldn't expect it to be a smoking gun; more, something you can check off the list as not being the issue.
B

Re: Valve Lash Adjustment
 

well i can tell you when my truck is ticking away (good ol 2.2L GM lifter issue) it drives kinda funny, like when i push in the clutch after i get going it kinda stumbles then shoots to idle speed.

never has stalled, just sounds really really bad.

https://www.fuelly.com/attachments/fo...c179eb3895.jpg

dead of winter mind you, summer its hardly noticeable but does do it.

goes away once its fully warmed up

Re: Valve Lash Adjustment
 

That tick sounds more like rod knock. :eek:

Oddly diesel-ish tone when you rev it up, and nice tone for a 4-banger otherwise.

I don't remember my transmission donor's 2.2 sounding like that at all but I really didn't run it much.

Re: Valve Lash Adjustment
 

Some if not all engines require you to re torque the head before making valve adjustments and many times head bolts are single use items once they've been torqued once they stretch and won't re torque correctly without replacing the head bolts. It's up to you whether to make the adjustment or not, but unless I had an indication of a problem I wouldn't bother. My 516K+ Escort has never had a valve adjustment. Hooking up a vacuum gauge to the engine manifold should alert you to any valve related problems.

https://www.secondchancegarage.com/public/186.cfm

Re: Valve Lash Adjustment
 

it aint rod knock, it wouldnt go away once oil warmed up.

plus its been doing that for the last 60K miles so i aint too worried.

that tick has plagued alot of GM's engines that use hydrolic lifters once the lifters get old and thier seals stop working so they leak down after a period of time and take a while to get pumped back up

Re: Valve Lash Adjustment
 

one thing i left out is tires...i have new, VERY deep "treaded " michelins that are likely hurting mileage. couldn't resist as they were on sale for the price of good 60k mile tires...the michelins are rated at 100k miles.

worth 3 or 4 mpgs? i doubt it.

Re: Valve Lash Adjustment
 

Since I replaced the original Goodyear tires on my '97 Escort wagon with 70K mile BF Goodrich tires my mileage has been down considerably sometimes not even breaking 40 mpg on the highway. Before the tire replacement I almost always got 42+ mpg on the highway and even had my all time high of 49.85 mpg. Seems like an unfair trade off to get less mpg just because you're riding on a little more rubber.

Re: Valve Lash Adjustment
 

Probably because of the tread squirm and that the tires flex too much, wasting energy or something of the sort.. Also it could be that your fuel economy didn't drop and that since the tires have increased the gear ratio, the car is slightly underreporting the miles it has traveled.