Adjusting valves on '86 L98
Thread Starter
Pro
Joined: Apr 2001
Posts: 663
Likes: 0
From: Omaha, Ne GO BIG RED
Adjusting valves on '86 L98
OK, labor day weekend is a 4-day for me, I already have Friday and Saturday set aside to change a leaky water pumpm, but I also picked up some new valve cover gaskets, because I want to adjust my valves due to a slight ticking in one on the drivers side. The helms manual is very specific about non-running adjustment based on TDC and timing, but I have heard other methods. Could someone please explain some of the other methods for an '86 L98 and give me any results/pros/cons?
Thanks in advance
Thanks in advance
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Adjusting valves on '86 L98 (86Coupe)
Just to pass a note, be sure the ticking you hear isnt a injector firing, injectors can tick pretty loud sometimes and people have mistaken the noise for a lifter.
Burning Brakes
Joined: Feb 2000
Posts: 958
Likes: 1
From: SF Bay area, CA USA
Re: Adjusting valves on '86 L98 (86Coupe)
I would recommend adjusting them running. If you do it this way you will need to have the engine idling. I would only remove one valve cover at a time because oil will be spraying out the pushrods. You can buy oil deflectors to clip on the rocker arms to help control the oil.
You will first loosen an adjusting nut until the lifter just starts ticking, then tighten 1/2 turn and move on to the next rocker. Many people will have opinions on how far to turn the adjusting nut. I use 1/2 a turn some use 1 full turn.
Tryinng to adjust the valves cold with oil in the lifters is difficult. It is difficult because finding zero lash (the point when the lifters start to tick) is hard to determine by feel when the lifters are full of oil.
Removing the valve covers can be a bit of a pain. The a/c compressor is in the way on the passenger side and the smog pump is partially in the way on the drivers side.
Buy good gaskets is the best advice I can give you.
You will first loosen an adjusting nut until the lifter just starts ticking, then tighten 1/2 turn and move on to the next rocker. Many people will have opinions on how far to turn the adjusting nut. I use 1/2 a turn some use 1 full turn.
Tryinng to adjust the valves cold with oil in the lifters is difficult. It is difficult because finding zero lash (the point when the lifters start to tick) is hard to determine by feel when the lifters are full of oil.
Removing the valve covers can be a bit of a pain. The a/c compressor is in the way on the passenger side and the smog pump is partially in the way on the drivers side.
Buy good gaskets is the best advice I can give you.
Thread Starter
Pro
Joined: Apr 2001
Posts: 663
Likes: 0
From: Omaha, Ne GO BIG RED
Re: Adjusting valves on '86 L98 (Bill's86Coupe)
What can I do to make sure it isn't the injector? I'm fairly certain it's the lifter, but I have a slight doubt, how do I make sure?
And I already picked up the gaskets, I opted for the ~$35 permaflex over the ~$12 cork...
And I already picked up the gaskets, I opted for the ~$35 permaflex over the ~$12 cork...
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Adjusting valves on '86 L98 (86Coupe)
Stethescope or a long screwdriver against your ear and put it where the noise is.
Another is, unplug the injector that may be suspect when its running and see if it(ticking) goes away, but there will be a slight stumble to the car running when doing so since it wont get gas for a moment.
Btw, not sure of the gaskets youre getting...if its the rubber kind that you stretch on, t has a tendency to pop off as you go to place the cover back down..its tricky holding the gaskets in place with your fingers while placing the cover on.
SOme people use weatherstrip glue adhesive, just a ittle bit and stretch the gaskets on and let it dry a bit to hold it in place.
Either methods are good.
My fel pro rubber gaskets were like this...had to stretch them and hold them carefully while placing the cover on...they NEVER leaked on me...made me very happy.
:D
:cheers:
Another is, unplug the injector that may be suspect when its running and see if it(ticking) goes away, but there will be a slight stumble to the car running when doing so since it wont get gas for a moment.
Btw, not sure of the gaskets youre getting...if its the rubber kind that you stretch on, t has a tendency to pop off as you go to place the cover back down..its tricky holding the gaskets in place with your fingers while placing the cover on.
SOme people use weatherstrip glue adhesive, just a ittle bit and stretch the gaskets on and let it dry a bit to hold it in place.
Either methods are good.
My fel pro rubber gaskets were like this...had to stretch them and hold them carefully while placing the cover on...they NEVER leaked on me...made me very happy.
:D
:cheers:
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
Re: Adjusting valves on '86 L98 (86Coupe)
86 Coupe,
To determine where the ticking is coming from use a screwdriver or prybar as a stethoscope. Place the screwdriver against the injectors and your ear, one at a time, you will often find one that is loudest, this may be what you are hearing. Do the same thing right on the valve cover, if everything is OK, it will sound like a washing machine in there, no ticking or anything. Best of luck.
To determine where the ticking is coming from use a screwdriver or prybar as a stethoscope. Place the screwdriver against the injectors and your ear, one at a time, you will often find one that is loudest, this may be what you are hearing. Do the same thing right on the valve cover, if everything is OK, it will sound like a washing machine in there, no ticking or anything. Best of luck.
Thread Starter
Pro
Joined: Apr 2001
Posts: 663
Likes: 0
From: Omaha, Ne GO BIG RED
Re: Adjusting valves on '86 L98 (Ski2Tee)
If it ends up coming from an injector, does that mean it's terminal? If so, I assume it's highly recommended to replace them all, or can I just change the one that is bad?
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Burning Brakes
Joined: Feb 2000
Posts: 958
Likes: 1
From: SF Bay area, CA USA
Re: Adjusting valves on '86 L98 (86Coupe)
Some ticking is normal from the injectors. If one is much louder than all the others that might be a problem. I would not recommend replacing only one because of the amount of work involved with removing the runners and plenum. You can have the old injectors cleaned and flow tested. Do a search on the forum for recommended shops to send them to if you go that route. As the other post metioned you can disconnect the wire from each injector to see if the ticking stops. You can also measure the resisitance of each injector. They should all be close to the same. I think in the neighborhood of 14 to 16 ohms. But don't quote me on that.
