Valves leaking air into intake manifold.
#1
Registered!!
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Reno, NV
Age: 41
Posts: 1,255
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 242 Valves leaking air into intake manifold.
Nevermind, no text. ^_^ I did a leak-down test on TDC exhaust stroke instead of compression stroke. *facepalm*
Last edited by Cleft_Asunder; 09-11-2014 at 02:02 PM.
#2
Registered!!
Join Date: Jun 2014
Location: Guam
Posts: 81
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 0
#3
Registered!!
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Reno, NV
Age: 41
Posts: 1,255
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 242 Re: Valves leaking air into intake manifold.
Cylinders 2/4 were leaking the most past the intake valves, while 1/3 not so much. I did a valve adjustment recently to minimum spec, but it was based on valves that had carbon deposits on them. After inspecting the clearance today, a few of the intake valves had no clearance, causing the valves to be open.
So I adjusted the clearance to maximum allowable so that I can clean the valves through hard driving, allowing them an opportunity to seat in. (.009/.011) The car is already idling properly, which it wasn't before. After about 2 weeks of hard driving, I will do another valve job and put them back to minumum spec. (007/.009)
Yeah, nothing serious. At 165k I've got really good compression:
160
160
155
155
So I adjusted the clearance to maximum allowable so that I can clean the valves through hard driving, allowing them an opportunity to seat in. (.009/.011) The car is already idling properly, which it wasn't before. After about 2 weeks of hard driving, I will do another valve job and put them back to minumum spec. (007/.009)
Yeah, nothing serious. At 165k I've got really good compression:
160
160
155
155
#4
Re: Valves leaking air into intake manifold.
I'm curious why you are setting them at the minimum. I would think the increased chance chance of burning a valve wouldn't be worth it.
Last edited by pjb3; 09-12-2014 at 12:07 PM. Reason: spellling
#5
If you think a good mechanic is expensive, try hiring a bad one
Re: Valves leaking air into intake manifold.
I set Hondas valves to the loose end of the spec range because most of them tend to tighten over time and miles.
They aren't noisy when I do it, and it allows more time and miles before they need adjusted again.
Loose valves might be just noisy.
Tight valves are quiet..... BUT too tight can also lead to P0172 rich codes and burned valves.
They aren't noisy when I do it, and it allows more time and miles before they need adjusted again.
Loose valves might be just noisy.
Tight valves are quiet..... BUT too tight can also lead to P0172 rich codes and burned valves.
#6
Registered!!
Join Date: Jun 2014
Location: Guam
Posts: 81
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 0 Re: Valves leaking air into intake manifold.
I set Hondas valves to the loose end of the spec range because most of them tend to tighten over time and miles.
They aren't noisy when I do it, and it allows more time and miles before they need adjusted again.
Loose valves might be just noisy.
Tight valves are quiet..... BUT too tight can also lead to P0172 rich codes and burned valves.
They aren't noisy when I do it, and it allows more time and miles before they need adjusted again.
Loose valves might be just noisy.
Tight valves are quiet..... BUT too tight can also lead to P0172 rich codes and burned valves.
#7
If you think a good mechanic is expensive, try hiring a bad one
Re: Valves leaking air into intake manifold.
#8
If you think a good mechanic is expensive, try hiring a bad one
Re: Valves leaking air into intake manifold.
Some of the things that tight valves can cause: Low vacuum, low fuel trim numbers, high MAP voltage, low compression, misfires, stalling, burned valves, codes related to any of the above, and probably more I didn't think of right now.
Tight valves caused excessive engine vibration in trucks like mine LOL.
Tight valves caused excessive engine vibration in trucks like mine LOL.
#9
Registered!!
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Reno, NV
Age: 41
Posts: 1,255
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 242 Re: Valves leaking air into intake manifold.
Any way, the reason I set them low is because the engine is significantly more responsive and tight. You can tell on these low HP engines. But you have to push the car hard before a valve job or you will not adjust properly.
#10
If you think a good mechanic is expensive, try hiring a bad one
Re: Valves leaking air into intake manifold.
Correct. Anywhere within the specified clearance adjustment range is still "in spec".
#11
Registered!!
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Reno, NV
Age: 41
Posts: 1,255
Likes: 0
Received 0 Likes
on
0 Posts
Rep Power: 242 Re: Valves leaking air into intake manifold.
And the torque on the nuts is very important. Don't hand-tighten. 13 ft. lbs. is the spec, and it's very tight for such little nuts because they will come loose if you torque lower due to the excessive movement and the oil on the threads.
Last edited by Cleft_Asunder; 09-21-2014 at 12:07 PM.
#12
If you think a good mechanic is expensive, try hiring a bad one
Re: Valves leaking air into intake manifold.
I adjust to the loose end of the specs simply because so many of the engines tend to tighten the valves as they wear. That hopefully allows more miles between needing adjustments.
Any way, the reason I set them low is because the engine is significantly more responsive and tight. You can tell on these low HP engines.
(My average dealership customers don't employ the butt-dyno.)
And the torque on the nuts is very important. Don't hand-tighten. 13 ft. lbs. is the spec, and it's very tight for such little nuts because they will come loose if you torque lower due to the excessive movement and the oil on the threads.
Everyone doing this should look up the correct specs for their particular engine before the job begins.
"Too loose is too loose, and too tight can be too loose too."
Thread
Thread Starter
Honda Civic Forum
Replies
Last Post
crowtoo
Mechanical Problems/Vehicle Issues and Fix-it Forum
3
05-11-2015 06:50 PM