Adjusting Valves

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Mar 5, 2003 | 10:25 PM

87Vert

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From: Everett WA

Adjusting Valves

I'm going to be putting in new valve cover gaskets on my 87 soon. A friend suggested that I might consider adjusting the valves while I've got the covers off. I do have a little bit of clatter there, but not a lot. My friend's experience is with older generation Chevrolets, and he wasn't sure if adjusting the valves while the vehicle is running is recommended on my 87. Any suggestions out there for the best procedure to adjust the valves? :confused:

Mar 6, 2003 | 04:35 AM

65Z01

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From: SE NY

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Re: Adjusting Valves (87Vert)

Some feel that adjusting the valves on a warm running engine is the best way, but it can be messy without the proper precautions. Back off the lock on a rocker till you hear clatter, tighten till it just becomes silent then tighten 1/2 turn more.

I prefer the static method with them cold:
-crank the engine till an intake valve is closing and adjust the exhaust valve
-crank the engine till the exhaust valve is opening and adjust the intake

I back off the lock till I can spin the push rod freely between my thumb and finger, tighten until I just feel some resistance (this is zero lash) then tighten 1/2 turn plus 1/8 turn (this positions the piston midway in the lifter).

However, my advice is "don't fix it if it ain't broke".

Mar 6, 2003 | 11:02 AM

KYVette90

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From: BowlingGreen KY

Re: Adjusting Valves (65Z01)

The motor will probably not idle right if you adjust 1/2 turn past zero lash. I could only get maybe 1/3 of a turn past zero lash. Do yourself a favor and go buy a set of clips to put on the rockers while your adjusting them. The clips keep oil from coming out of the pushrod tips while running. It saves mess. :cheers:

Mar 6, 2003 | 11:10 AM

scorp508

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From: Boston, MA

The clips work great. :yesnod:

One thing to keep in mind for an '87 is that if you adjust the rockers with the car running you will have to remove the EGR tube to get the valve cover off. You'll have some really hot exhaust gases coming at you unless you connect the tube with the VCs off. :)

The factory manual states 1 full turn past 0 lash for the stock stamped rockers. I got 1/4 turn past 0 lash with my roller rockers.

Mar 6, 2003 | 11:23 AM

KYVette90

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From: BowlingGreen KY

Re: (scorp508)

1/4 to 1/3 turn should do it. There is no way you could get 1 full turn like the books say, something would probably break. :cheers:

Mar 6, 2003 | 12:53 PM

C4Crazy787

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From: Olathe, KS USA

Re: Adjusting Valves (87Vert)

:iagree: I cut some cardboard (no clips) and laid in the head no problems.
BTW 1 full turn from zero won't break any thing but I swear I lost some power
so I went back in and set to 1/2 turn. :seeya

Mar 6, 2003 | 10:22 PM

r15752

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From: winter haven fl

Re: Adjusting Valves (87Vert)

I beleve 1 full turn will bend some push rods or damage your lifters. 1/4 to 1/3 should do it unless you have some lifter problems already.like it was suggested don't fix it unless it is broken. :auto:

Mar 7, 2003 | 03:06 AM

CorvetteZ51Racer

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From: Houston TX

Re: Adjusting Valves (r15752)

What my question is, is why do you feel like you need to adjust your *hydraulic* lifters. The whole point of a hydraulic lifter is that it's self-adjusting. You have a roller cam in your '87, so your cam lobes won't be worn enought to warrant it. Unless your rocker adjuster nuts have backed off, there is no reason to need to adjust them. If you're hearing some mild clicking noise when you're under the hood with the engine running, I'd put my money on the injectors making the noise, not your lifters.