Adjusting Valve Train
Thread Starter
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Adjusting Valve Train
I have driven my new engine about 500 miles now and have a slight ticking from the left side of the engine when it warms up. It is the valve train. It sounds like I need to tighten up a rocker arm or two. Is there an adjustment procedure I need to follow or can I just tighten the nuts a quarter turn or so? Hopefully I will get this done today.
Thanks for anyhelp.
Thanks for anyhelp.
Abby Normal
Joined: Dec 2001
Posts: 53,521
Likes: 92
From: Press "2" for English
Re: Adjusting Valve Train (Eddie 70)
go ahead and adjust it. i saw XE262 in your sig so i'm assuming that is the hydraulic version. i think it would be a good idea to adjust all 16 at this point. with the engine running and something under the car to catch all the oil, remove one valve cover and back off each rocker until you hear a distinct 'tap' on that rocker. then tighten just to the point it goes away, then go a 1/4 turn past that, let the engine idle stablize, another 1/4, stabilize and finally another 1/4. a total of 3/4 past the 'tap' is supposed to be ideal.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Re: Adjusting Valve Train (Eddie 70)
Instead of running the car can`t I just go back and start over like I did when I put it together. Finding top dead center on one, should the intake or exhaust be open? Or should they be both closed with I or E coming open? This should be a little easier shouldn`t it.
Racer
Joined: May 2000
Posts: 452
Likes: 0
From: Oak Hill, VA 20171
Re: Adjusting Valve Train (Eddie 70)
Check out Lars' paper at Corvettfaq.com He says you can do it without running the engine but many do with a modified set of valve covers so as to prevent oil splash.
Safety Car
Joined: Feb 1999
Posts: 3,632
Likes: 14
From: Fountain Hills AZ
Re: Adjusting Valve Train (Eddie 70)
Sounds like it's time to do a running adjustment. While the initial adjustment is usually good for many thousands of miles because of the wide range that a hydraulic lifter can operate in, further adjustment is sometimes needed. The initial adjustment may have been off, there could be a difference in an individual lifter, or there might be a difference in oil pressure or volume between valves.
Doing a running adjustment is pretty simple but it can be messy if you don't prepare for it. Ideally, get an old valve cover (wrecking yard for a couple $) and cut the top off of it and glue a cheap gasket to it with RTV. But a set of clips for the rockers to block the oil spurting, and set your idle rpm down as low as you can. The lower idle speed with reduce the amount of oil spurting from the rods and also allow you to better distinguish between the sounds of the different rockers. Do one bank at a time. Slowly back off on the adjusting nut until you hear it clacking. Slowly tighten the nut until the clacking stops and give it another 1/2 - 3/4 turn. Repeat the process for the rest of the valves.
Doing a running adjustment is pretty simple but it can be messy if you don't prepare for it. Ideally, get an old valve cover (wrecking yard for a couple $) and cut the top off of it and glue a cheap gasket to it with RTV. But a set of clips for the rockers to block the oil spurting, and set your idle rpm down as low as you can. The lower idle speed with reduce the amount of oil spurting from the rods and also allow you to better distinguish between the sounds of the different rockers. Do one bank at a time. Slowly back off on the adjusting nut until you hear it clacking. Slowly tighten the nut until the clacking stops and give it another 1/2 - 3/4 turn. Repeat the process for the rest of the valves.
