I'm sorry if this is a little bit off topic, but I figured the ITR guys might be able to help with diagnosing my issue. Thanks, and I apologize if this is out of place.

<U>Motor setup-</U>
B18c1 OBD 2
Mild port/polish
CTR Intake/B17 Exhaust Cams
ITR Valvetrain

I was driving on the freeway the other night and out of nowhere, my CEL started to blink. Immediately, I let off the throttle and exited. As I made my way off, the car sounded like it was running on 3 cylinders, or as others would describe it, like a WRX.

Once getting the car back to my place, I checked the CEL and did a compression test. My CEL blinked a 72 and 74. I checked the compression and blew 215 across all cylinders except for cylinder 4. Cylinder 4 barely blew a reading on my gauge.

I checked the lash on those valves in cylinder 4 and they were within spec, none too tight or loose. I put the valve cover back on and still, no compression on cylinder 4.

Now, is this likely a bent valve or is there a chance that this could be fixed without removing the head? I did not over-rev the motor prior to this happening and no mis shifting at all. The car has been running fine and strong since the headwork was done about 45K miles ago. This is all surprising for me. Any help is more than appreciated. Thanks!

 

Sounds like a valve burned out. I'm surprised its not cylinder 3 though.

Does the car have an extremely rough idle that shakes the whole car?

If this is the case it requires removing the head and checking for damage. This happened to me and luckily there was no internal damage. I just payed to have the head cleaned, inspected and 1 new valve and valvesprings across the board.

 

Yep, my guess would be theres a hole in a valve.
Does it sound like an exhaust leak?

Head needs to come off.

 

Defiantely sounds like a valve problem. The head will need to come off for it to be repaired.

 

Same thing just happened to my car w/149k miles on it.
Except it was on cyl #1. (https://honda-tech.com/zerothread?id=1860531)

http://www.typer.us/Acura/pages/IMG_2889.html

I got new Supertech stainless steel nitrite coated valves, springs, and manganese bronze guides. Hopefully this will prevent it from happening again.
I guess I could've just had the head cleaned and the one valve replaced, but since I had the head off already I decided to get all new parts and do it right.

I hope to get my head back next Friday so I can get my ITR back on the road.

Pull the head and let us know what happened. I hope you have help because it too me a workday to take everything part myself. Good luck ! and take lots of pictures.




Modified by arren123 at 9:09 PM 1/19/2007

 

Ok so i'm unfortunately pulling off the head by myself. Not a huge deal, but I wish I could rely on someone to help.

Anyhow, to answer a few questions -

-No, does not sound like an exhaust leak. The exhaust sputters and smells like unburnt fuel coming out of the exhaust.
-The car does idle rough and the motor/car does shake.
-The car feels like it should when one spark plug is dead/fouled.
-No compression in Cylinder 4, Compression reading 215 across the board in the other 3 cylinders.

Question- How much should it cost to bring this to a machine shop and have the valve replaced, re-seated, and head resurfaced?

Also, any shops in the SO CAL area anyone can recommend?

Thanks to those who posted. I'll post pics, results, and findings as soon as I get through it all.

 

Just another set of Questions - Could using Seafoam through the brake boster line have caused my valve to bend or burn?

Is there any possibility the valve is stuck and maybe able to be remedied by pouring seafoam or some additive in the crankcase?

If not, then following a leakdown test, i'll just continue as planned and pull off the head.


Modified by EnjoyTheRideDC2 at 3:36 AM 1/22/2007

 

Just a Re-cap -

-The exhaust sputters and smells like unburnt fuel coming out of the exhaust.
-The car does idle rough and the motor/car does shake.
-The car feels like one spark plug is dead/fouled.
-30 psi compression in Cylinder 4, Compression reading 215 across the board in the other 3 cylinders.
-Valve clearances/lash is not off spec.
-No valve springs are excessively compressed
-Ignition and Fuel are present
-Timing Belt is fine and Timing is correct.

New Questions-
How much should it cost to bring this to a machine shop and have the valve replaced, re-seated, and head resurfaced?

Could using Seafoam through the brake boster line have caused my valve to bend or burn?

Is there any possibility the valve is stuck and maybe able to be remedied by pouring seafoam or some additive in the crankcase?

If not, then following a leakdown test, i'll just continue as planned and pull off the head. Thanks for the replies so far and all help is greatly appreciated.

 

well you can see this, remove all cams and do one last compression test if it fails you can keep on removeing the head cuz the problem is in #4 like you stated, is it possiable for you to get a leak down test done be4 you do any thing else?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnjoyTheRideDC2 &raquo;</TD></TR><TR><TD CLASS="quote">Just a Re-cap -

How much should it cost to bring this to a machine shop and have the valve replaced, re-seated, and head resurfaced?

: </TD></TR></TABLE>

Cost about $300 for me. They pulled the whole head apart and check all tolerances. I think they gave me the valve free.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robfrmny21 &raquo;</TD></TR><TR><TD CLASS="quote">well you can see this, remove all cams and do one last compression test if it fails you can keep on removeing the head cuz the problem is in #4 like you stated, is it possiable for you to get a leak down test done be4 you do any thing else?</TD></TR></TABLE>

Yes, I am performing a leak down test before I pull the head. But with that in mind, if I perform a leak down test and the results dont show a significant leak percentage, what would I look for next?

 

UPDATE - My 18c has now been be-headed...

Ok, pulled the head from my motor, and checked the block...


So far so good, least I didn't have to change a piston...

So next, flipped over the head to check the combustion chambers....


A close up of each combustion chamber helps finding the culprit...


So there you have it, the loss of compression and reason for misfire was due to a chipped exhaust valve in cylinder 4.

<U>NOW - More questions :</U>
-Why do my exhaust valves have all that white build up forming on them?
-Should I just replace the one chipped valve, or all exhaust valves, or all 16 intake/exhaust valves?
-If I change the one chipped valve with a new OEM one, is it necessary to have the seats cut?

 

You have options, just depends on how much you want to spend.
At a bare minimum you could replace just the one valve (assuming none of the others are bent/damaged), and the seals. Thats actually what I'm doing right now, but only because they checked out the rest of the head pretty thoroughly and everything was good. Its gonna cost me 125$ + the cost of the valve (30$) + seals (unknown $$, I think they come in the upper gasket kit). You could replace the guides too, which is gonna be extra $ for the guides themselves, + extra labor (around 50-75$).
Just find a good machine shop and have them tear it apart and tell you what needs replacing.

 

IMHO, If you are planning to keep your car a long time, I would do this.
You already have the head off. The same thing happened to me after 149,000 miles on the stock valvetrain. So you know there's a good chance it'll happen again to you again in the future. I'm guessing you want to prevent this from happening again, or happening to your other valves, right ?
I'd probably spend the cash to replace all the stock valves, guides, springs, and seals with something else. So buy new valves that are specially treated.
I know its a ton of cash, but since you have everything apart, you might as well prevent further agravation in the future.
This is the path I'm going and while I'm at it, I'm doing the belts, water pump, dizzy, gaskets and seals, spark pluges, hoses and fuel filter.

This is in my humble opinion only. At the minimum get your head cleaned and the one valve done, knowing your other valves may have the same problem later.

 

arren123 and andyt - I appreciate your replies and opinions, Thanks.

To reply, I have been doing the math on upgrading valvetrain. With machine work and cost of parts, its going to be killer. The net result in performance wont be existent until I pick up a really good set of cams. Otherwise, spending the money, for valvetrain upgrades on a set of CTR cams is not justifying enough to me.

Now that my negative side has been expressed, I have to think about the whole situation. I'm spending about $250+ in Oem Acura parts (Gasket Set, Timing belt, misc. other parts that are easy to replace now) and I dont want those parts to go to waste if a similar issue occurs anytime soon. Also, i'm already getting a valve job done at the machine shop, might as well have the seat cut for a new set of valves as well. I just dont want to have to spend all this money again if I decide to change 1 valve and another decidec to go..

Just doesn't make sense why this happened. My previous DB8 lasted 296,000 miles and never had an issue like this...