Stuck valves

redondoaveb · 03-12-2021, 06:17 PM

I decided to do a leak down test on my spare motor that's been sitting for a couple of years. All tested perfect except #3 cylinder. I have the upper intake removed but the lower is still on. When I pressurized number #3, air was pouring out of the #3 intake runner. Ok, stuck intake valve. I sprayed wd40 down the runner onto the stems and seats and turned the engine over by hand a bunch of times. I reinstalled the leak down tester and it appears I freed up the intake valve because now I can hear it coming out of the exhaust port

It must have been stuck open a little bit but I couldn't hear it before because the intake valve was stuck open more. I sprayed the exhaust valve stems and seats and turned it over again but so far it hasn't freed it up. I'll let it soak for a while but does anyone know of a better penetraring oil or a good way free up the stuck valves without pulling the valve cover or head?

Rusty · 03-12-2021, 07:58 PM

Pb Blaster.

Or try some of that Blue Waffle juice.

redondoaveb · 03-12-2021, 08:23 PM

Quote:

Originally Posted by Rusty

Pb Blaster.

Or try some of that Blue Waffle juice.

I'll try the PB Blaster, I'm saving the blue waffle juice for Rusty's kokfest

SonicVQ · 03-23-2021, 09:18 AM

Pop off the valve cover and have a quick look for the gap between the valve bucket and cam lobe/VVEL slider.

I assume the engine is out of the car, and with the upper intake off, it should be fairly quick to remove it.

03-12-2021, 06:17 PM	#1 (permalink)
redondoaveb A True Z Fanatic Join Date: Apr 2017 Location: So. Commiefornia Posts: 6,360 Drives: 2014 Nismo Gunmetal Rep Power: 2684374	Stuck valves I decided to do a leak down test on my spare motor that's been sitting for a couple of years. All tested perfect except #3 cylinder. I have the upper intake removed but the lower is still on. When I pressurized number #3, air was pouring out of the #3 intake runner. Ok, stuck intake valve. I sprayed wd40 down the runner onto the stems and seats and turned the engine over by hand a bunch of times. I reinstalled the leak down tester and it appears I freed up the intake valve because now I can hear it coming out of the exhaust port It must have been stuck open a little bit but I couldn't hear it before because the intake valve was stuck open more. I sprayed the exhaust valve stems and seats and turned it over again but so far it hasn't freed it up. I'll let it soak for a while but does anyone know of a better penetraring oil or a good way free up the stuck valves without pulling the valve cover or head? __________________ Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo 700+whp

03-12-2021, 07:58 PM	#2 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 35,180 Drives: 2011 Nismo GM 6M Rep Power: 2684437	Pb Blaster. Or try some of that Blue Waffle juice. ZontheRocks likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

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03-23-2021, 09:18 AM	#4 (permalink)
SonicVQ Base Member Join Date: Jan 2016 Location: Ontario Posts: 230 Drives: G37 Sport Rep Power: 6720	Pop off the valve cover and have a quick look for the gap between the valve bucket and cam lobe/VVEL slider. I assume the engine is out of the car, and with the upper intake off, it should be fairly quick to remove it.