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Valve lash on a high mileage engine

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Old Apr 6, 2014 | 07:41 AM
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87cam305's Avatar
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From: Summerville, South Carolina
Car: 1987 Camaro Sport Coupe
Engine: 305 (LG4)
Transmission: 700R4
Valve lash on a high mileage engine

Hi sorry if this has been covered before. I am doing the intake gasket on my 87 Camaro with the LG4, and once i pulled the intake I was looking around since it is the first time I have had this engine apart in 13 years. I noticed the push rods are a bit loose. Would it hurt any thing if I were to adjust the valve lash on an engine with 255,000 miles on it? I don't think it would, but I want to get a few other opinions. thanks
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Old Apr 6, 2014 | 08:14 AM
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Re: Valve lash on a high mileage engine

Why would you stop taking care of your car just because it has lots of miles?

It is considered routine maintenance, like tune-ups, regardless of mileage.
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Old Apr 6, 2014 | 08:36 AM
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87cam305's Avatar
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From: Summerville, South Carolina
Car: 1987 Camaro Sport Coupe
Engine: 305 (LG4)
Transmission: 700R4
Re: Valve lash on a high mileage engine

That is pretty much what i figured. I was just more worried about screwing something up. this is my only car I drive 60 miles a day. I can't afford for something to go wrong that is all.
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Old Apr 6, 2014 | 08:42 AM
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From: Il
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Valve lash on a high mileage engine

Was the valvetrain ticking the last time you drove it??
Is it a hyd cam? If so, the oil psi will tighten them up when it runs.
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Old Apr 6, 2014 | 10:44 AM
  #5  
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: Valve lash on a high mileage engine

Originally Posted by 87cam305
That is pretty much what i figured. I was just more worried about screwing something up. this is my only car I drive 60 miles a day. I can't afford for something to go wrong that is all.
you are good to go. just do it correctly and it should run better
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Old Apr 6, 2014 | 11:15 AM
  #6  
87cam305's Avatar
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From: Summerville, South Carolina
Car: 1987 Camaro Sport Coupe
Engine: 305 (LG4)
Transmission: 700R4
Re: Valve lash on a high mileage engine

I don't recall gearing any ticking, but it has always had a extremely rough idle almost like it has a mild cam in it which I know it doesn't. I have never been able to get it to idle smooth. A couple of them were beyond oil pressure I could wiggle the rocker arm quite a bit. I just completed it following the factory service manual to the letter so it hopefully runs better. thanks y'all
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Old Apr 6, 2014 | 12:49 PM
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From: Bright, IN
Car: '86 Bird, 96 ImpalaSS, 98 C1500XCab
Engine: LG4, LT1, L31
Transmission: 700R4, 4L60E, 4L60E
Axle/Gears: 3.73 Tors, 4.88 spool, 3.73 Eaton
Re: Valve lash on a high mileage engine

It depends on what you mean by "loose". Just because you can spin the pushrods doesn't mean they're loose. With that kind of mileage, and even on some new engines, within a few seconds after shutdown the lifters will bleed down almost instantly. So on the ones not holding a valve open, being able to spin a pushrod or pivot a rocker slightly around its stud doesn't necessarily mean the preload isn't correct. If you can rock the rocker arm side to side with little effort, that's loose.
I would adjust them; just make sure you understand what zero lash point feels like.
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Old Apr 6, 2014 | 04:31 PM
  #8  
87cam305's Avatar
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From: Summerville, South Carolina
Car: 1987 Camaro Sport Coupe
Engine: 305 (LG4)
Transmission: 700R4
Re: Valve lash on a high mileage engine

Well she runs. there were 3 of them i could move about 1/4 inch each way. Once the Carb got fuel she fired right up no hiccups let it warm up, and set the timing. Now it idles quite a bit smoother than before still not perfect. I know there a couple vacuum leaks in some of the emissions stuff but ill take care of that another day.
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