Topic: Bent valve? (Read 6052 times)

Jorsher · « **on:** May 21, 2010, 09:54:08 AM »

I didn't overrev it but it started running strange yesterday.

Lower RPMs feels like no power, vtec feels fine. Also sounds a bit different, kinda has a grumble now at WOT in lower RPMs. Can smell gas and it seems to idle lower although the idle is stable.

Will do a compression test this weekend but just curious if there are any other suggestions or if anyone's seen a valve been without overreving?

92CXyD · « **Reply #1 on:** May 21, 2010, 11:31:00 AM »

Too many possibilities. $:-\$

Wait for the compression results first.

My first though was timing belt slip but you said runs good in v-tec. $:-\$

Maybe check the plugs and see which ones wet with fuel.

Jorsher · « **Reply #2 on:** May 21, 2010, 11:52:30 AM »

Quote from: 92CXyD on May 21, 2010, 11:31:00 AM

Too many possibilities. $:-\$

Wait for the compression results first.

My first though was timing belt slip but you said runs good in v-tec. $:-\$

Maybe check the plugs and see which ones wet with fuel.

I'm thinking/hoping it's a timing belt slip. Honestly, when my friend's CRV was off one tooth, lower RPMs felt like shit then it would *seem* to run well at the higher ones.

I did misshift a week or two ago when a k-fail Civic tried to pass me and RPMs shot up (don't think I had it fully in gear) but it drove fine afterwards. Yesterday I beat on it fooling with an Audi, but I only took it to 8500rpm, nothing too ridiculous. Sometime after that, I'm not sure when exactly, the car started sounding different and I feel like the wore out D16A6 is back in there :/

I'll check timing first, then compression. I hope it's just timing...

Valves usually bend when the float and get smacked by the piston, correct? This is a relatively low compression build (9.7:1) and has dual valvesprings so I'm not sure they'd float enough to smack a piston even if I overrevved, which I didn't.

crxvtec91 · « **Reply #3 on:** May 21, 2010, 12:45:30 PM »

That y49 is killing you....

magik123 · « **Reply #4 on:** May 21, 2010, 01:10:45 PM »

I dont know the build and am to lazy to search, do you have a boost gauge on there? Is vacuum bouncing around erratically? Leak-down test will show you valves much better than a compression test ;D.

bigdaddyvtec · « **Reply #5 on:** May 21, 2010, 01:44:06 PM »

2 bent intakes (BARELY BENT)

got me weak vacuum at idle, and under boost the car would breakup BADLY under boost... It would cycle too, like it was running on 3 at idle and kind of "lope" in a not sexy way.

Jorsher · « **Reply #6 on:** May 21, 2010, 02:11:14 PM »

Yeah some of the symptoms of a bent valve don't apply to my situation but I know it really all depends on how bad it's fucked.

Symptoms -

- engine sounds different at WOT in pre-vtec RPMs, has a "growl"
- weak as fuck at lower RPMs
- smell gas occasionally
- idles around 300-500 RPM

Idle doesn't lope, I haven't noticed any smoke, and don't hear any odd noise from the valvetrain.

Not boosted currently so don't have a boost gauge to check vacuum.

Will check timing first then compression, but I'm hoping the timing belt somehow skipped a tooth.

crxvtec91 · « **Reply #7 on:** May 22, 2010, 12:24:48 AM »

comp test/ leak down is your friend!

Jorsher · « **Reply #8 on:** May 22, 2010, 04:48:46 PM »

Checked timing and it was straight.

Checked compression and had all 170-180.

Drove it, still seemed a little off, went to hit vtec and heard a horrible noise.

Took back home, took off the valve cover, and saw the exhaust cam gear bolt backed out, and the key and groove on the camshaft was chewed up.

Fortunately I have a spare GSR cam and just need to find a key.

keelay · « **Reply #9 on:** May 23, 2010, 04:36:04 PM »

I'm gonna guess you may have a cam gear bolt back out and timing getting erratic.

Joseph Davis · « **Reply #10 on:** May 23, 2010, 04:54:06 PM »

Peniswhistle.

Jorsher · « **Reply #11 on:** May 24, 2010, 09:48:34 AM »

Quote from: keelay on May 23, 2010, 04:36:04 PM

I'm gonna guess you may have a cam gear bolt back out and timing getting erratic.

Did you guess that by reading it on the local forum?

True though, good thing I had a spare cam and stole a key.

keelay · « **Reply #12 on:** May 24, 2010, 06:09:40 PM »

No, I was actually being a smart ass. What local forum are you on, HSV or ARS?

Jorsher · « **Reply #13 on:** May 25, 2010, 10:12:52 AM »

Quote from: keelay on May 24, 2010, 06:09:40 PM

No, I was actually being a smart ass. What local forum are you on, HSV or ARS?

HSV...

Well, good damn guess. It definitely wasn't something I was thinking of...

Runs smooth as butter again.

chris · « **Reply #14 on:** May 25, 2010, 02:42:07 PM »

type r heads dont bend valves

Jorsher · « **Reply #15 on:** May 25, 2010, 03:36:42 PM »

Quote from: chris M on May 25, 2010, 02:42:07 PM

type r heads dont bend valves

Why not?

I thought it was highly unlikely with the lower compression, dual springs, and the fact that it was fine after being over-revved but broke with "normal" driving.

Just curious.

chris · « **Reply #16 on:** May 25, 2010, 03:53:35 PM »

Just a joke since its a type r

You will not have any worries reving that motor out to 9000 with that valvetrain in that head.

Jorsher · « **Reply #17 on:** May 25, 2010, 04:04:55 PM »

lol, should have figured.

It's been past 9000 once already, oops.

I snapped a cam holder bolt too, second time I've done that.

crxvtec91 · « **Reply #18 on:** May 25, 2010, 06:24:13 PM »

Quote from: Jorsher on May 25, 2010, 04:04:55 PM

lol, should have figured.

It's been past 9000 once already, oops.

I snapped a cam holder bolt too, second time I've done that.

Why is vtack to much for you to handle

chris · « **Reply #19 on:** May 25, 2010, 06:48:33 PM »

No more like you have to be careful with those bolts when taing out cams. Impact on those bolts=big no no

Jorsher · « **Reply #20 on:** May 25, 2010, 07:42:04 PM »

Yeah I did 20lbs on each, torque wrench had a nice subtle pop on all of them except the one that snapped. Shoulda followed my gut and stopped sooner but oh well, will extract and slap in a new one.

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Author Topic: Bent valve? (Read 6052 times)

chris

chris

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