Passed18

I have an 04 civic LX 120k finally decide to change the timing belt and water pump. Get the parts from local Auto zone. So I after a lengthy fight I get the new belt on, keep the marks lined up and get it all back together. Start it up and it runs same as always. In the same week I change my tires fro 215-40 r 17 to 215-45 r17.
I always keep track of my fuel milage, normally can get 380-400 miles out of a full tank. A week goes by and i notice I have to fill up at 300 miles.

My question is could the timing belt be too tight or just wrong being that its not factory? Or could the new tires cause that much of a differance in registered milage?
Thanks all input is appreciated

ezone

You went to a taller tire, that alone affects calculated mileage.

And, you could be a tooth off with the timing belt.

mikey1

no, the belt can not be too tight, it is automatically tensioned by the spring, and an aftermarket belt wouldnt matter either,

kinakoes2

Does it throw a code?

My only guesses: the tensioner wasn't tensioned properly; idle learn procedure needs to be done; or the wheel/tire combo is heavier than before (there's extra rubber both in the tread and in the sidewall if you're going new and up in aspect ratio). On driven wheels esp, if you like to use heavy throttle, the extra mass might be penalizing you... and even more if something else is wrong along with it.

lowlife9

was the valve lash touched ???

ezone

Maybe it NEEDS touched!

lbs

kinakoes2

Hmm... if it ran fine before the belt swap and tire change, but lost 1/4 of its range after, it's probably not lash issue (unless the OP d*cked with it, of course). I've seen tire brand changes cause non-trivial range loss with solid lifter sportbike valvetrains, which are a lot more stable than the screw-&-locknut D17s...

Was pleasantly surprised to fine S&L valve lash adjusters in my Honda... so easy to snug up, no cams to pull.

mikey1

pull the timing cover and double check the timing marks,

you could be off a tooth


.

Passed18

I have pulled the cover and put it at 1 tdc and checked the marks the are close but not perfect. Now my problem is i blew a head gasket, exhaust is going into the cooling passages. So now my plan is to replace all parts with oem parts. Including the timing belt tensioner and water pump.

I was also looking in a Haynes manual to reset the valve lash but could not find the clearances, d@mn cheap book. So does anyone know what size feeler gauges to use for the intake and exhaust valves?

And I also did expect a little differance in mileage from the larger tire just did'nt belive it could take 1/4 of my mileage.

Thanks again for all of the advice and input

lowlife9

i believe its intake; 0.18-0.22 mm (0.007-0.009 in) exhaust; 0.23-0.27 mm (0.009-0.011 in) i hate that haynes manual it tells you the procedure but doesn't give you the clearance its worthless.

ezone

Agree

kinakoes2

Funny thing -- on the powersports side Honda gives one measurement for valve lash clearance... in this case, it'd be 0.008" IN / 0.010" EX. They've since come to their senses and specified a range, like the other Big Four had been doing since the beginning. BTW, rocker arm powersports Hondas like the TRX400EX and radial valve XRs like VC on the tight side, while shim-&-bucket CBRs, VFRs, and RC51, like them in the middle.

I'm adjusting my 7gen on the tight side, as it gives a tiny bit more duration for a given cam profile while still being within spec.

In the Haynes manual... there aren't VC specs anywhere in the book? Perhaps it's in a separate section... that's crazy if a supposed service manual doesn't list VC specs anywhere at all.

ezone

It's funny, they give metric specs but I have never been able to easily purchase metric feeler gauges that have increments smaller than 0.05mm, whereas I can find std. feelers all day long in increments of 0.001"



Speaking of that, I can't find go/no-go feeler gauges anymore either. Only old timers seem to know what those are.


I'm quite familiar with your reasoning......but there are a couple caveats:
1) Tight valves can cause a drop manifold vacuum, this raises MAP voltage, and can cause rich codes.

2) Anymore, Hondas criteria for periodic valve adjustment is to do it when you hear them get noisy....
Problem with that is, they rarely get noisy.
The majority of Hondas cars tend to tighten up valves over time.
So you might have to check them more frequently if you start off on the tight side.


This is why I lean toward the loose end of the specs.
Loose valves might make a little bit of noise....but tight valves burn. That's worse than noisy.

JMHO. YMMV.

kinakoes2

Yeah, the specs I gave there were in thousandths of an inch, which were in later FSMs (at least the powersport ones after I became a tech). In earlier ('80s & early-to-mid-'90s) they were all metric IIRC...

Ah -- if there's a tendency to get tight, it does mean they've changed something about valve face hardness since the TRX in the late '90s... IME they don't have a problem with this. Which to be fair, its motor is derived from the excellent XR400R *plus* it was Honda's 50th Anniversary in '98... so HMC was still very much over-engineering parts on their machines. After that though... perhaps not. My old '92 Toyota Paseo's valves drifted maybe 0.002" - 0.003" in its entire 265K-mi life -- but it was a shim-over-bucket-head.

With your exp on the auto side, if the D motor's VC does tend to get tight between adjustments, then I agree and will stay on loose side of spec... you do NOT want a tight exhaust valve on a motor that has soft valves (all Kawasakis even in 2014), or seats that tend to drift up in their pockets (certain Kawi and Yamaha heads prior to ~'96-'97)...

BTW... I do miss my go/no-gos feelers! Lent them to a rival team during an endurance race in Portland in 2007, and never got them back. Guess he (the team owner) was sour about a certain pass that put them off the podium. I think Snap-On/Blue Point still makes them, but my stolen ones were Craftsman.

ezone

I meant their entire automotive product line, not just that one engine.

It was a general observation.


This was told to me by an old timer, back when I was a pup. Old timer was a Honda tech too.
I'm guessing they have been this way for several decades (valves get tight).

Passed18

Thanks for the specs Lowlife. That helps alot. It will be a few day till I get the parts in and installed. I will update this thread with the outcome.

Thanks again everyone for your input

kinakoes2

That's disappointing but not at all surprising... after all autos are made in much, much greater volume than moto/quads, so the cost to Japanese suppliers to constantly make very high quality components to the same spec as moto ones, in the same volume, would be very difficult if not impossible (without a huge premium a la German marques, and even they aren't built to the same standard as pre-'96). There's also the issue of Japanese industry as a whole falling off the '70s/'80s bubble and back down to earth regarding engineering margins (Toyota being the worst example post-'96). Not gonna be overbuilt with pricey techniques like the B motors were...

I know the Honda moto side still had very good VC stability up until 2010 when I got out of dealer wrenching, but as above, the R&D/manufacturing cost per unit for a Honda moto engine is still way above their cars. VC drift on the moto side isn't as bad for that reason, even though those tiny valves go routinely to 10, 12, even 14K rpm. They did start out as a moto company, after all.

lowlife9

its funny i bought the haynes manual specifically for the vc specs and they weren't in there.