Help deciphering engine "build sheet"

  #11  
Old 04-14-2019, 10:45 AM
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thanks very much
 
  #12  
Old 04-14-2019, 06:17 PM
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In 73 the 350 in the Z28 was hydraulic lifter, previously solid lifter, motor. So if the donor motor is from a 73 Z28 it would be hydraulic

I personally prefer to find "zero" lash by the up/down PR method vs the "spin between fingers". Tighten poly with fingers until there is no more up/down movement of the PR. By the time you feel resistance with spinning it, you pasted zero.

Stock lifters are 1/2 to 1 1/2 turns of preload past zero lash. I go 3/4. There are hydraulic racing lifters (Comp "R" series) that require 0 to 1/8 turn max of preload if you have those kind

FWIW I have always done my valve lash on cold motors be it on fresh builds on engine stand or in car for a valve spring or rocker swap. Never needed a running motor valve lash.

Once you lash a valve on hydraulic lifter motor and move on to other valves....a previously lashed valve can have a lose PR as the lifter bleeds down. Normal. Do NOT re-tighten the RR without first loosening the poly and letting the lifter come back up
 
  #13  
Old 04-15-2019, 06:55 AM
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Thanks very much SoCal76. Good advice from everyone.
 
  #14  
Old 04-21-2019, 11:36 AM
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So I followed SoCal76's instructions and I think I did a pretty good job. However, now when I start it up I get a loud popping sound "I assume it's missing" Sometime it's constant and sometime it's intermittent. Is it possible this caused by one of the valves not being properly adjusted, or should I search for other problems, specifically electrical? Distributor, wires, plugs? I've examined those and don' see any obvious problems. I pulled the plugs in the vicinity where I thing the popping is coming from and the gap is correct. Wires and distributor are fairly new "low mileage". I'm thinking I got a valve adjustment off - would that cause misfiring and/or a loud popping?
APpreciate any input guys.
 
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MISFIRE.MOV (4.73 MB, 5 views)
  #15  
Old 04-21-2019, 02:14 PM
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From this side of the internet....IDK what "kind" of popping sound you have. Does it come out tail pipe or carb?....or is it just a rough running motor with a mis?

Valve adjustment is not rocket science but is a "learned" skill. "If" your adjustment is off, basically lash to tight keeping that particular valve..lets say intake from closing so you likely would get a backfire back up through carb. Exhaust valve not closing all the way then unburnt gas gets in exhaust. To lose of a lash will just cause valve train noise but otherwise run ok

Plug wires swapped will cause car to run rough..

What method did you use to have the valve you were lashing to have the lifter on the base circle of cam?
 
  #16  
Old 04-21-2019, 05:02 PM
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Originally Posted by Buchananr View Post
So I followed SoCal76's instructions and I think I did a pretty good job. However, now when I start it up I get a loud popping sound "I assume it's missing" Sometime it's constant and sometime it's intermittent. Is it possible this caused by one of the valves not being properly adjusted, or should I search for other problems, specifically electrical? Distributor, wires, plugs? I've examined those and don' see any obvious problems. I pulled the plugs in the vicinity where I thing the popping is coming from and the gap is correct. Wires and distributor are fairly new "low mileage". I'm thinking I got a valve adjustment off - would that cause misfiring and/or a loud popping?
APpreciate any input guys.
Sounds like a loose rocker to me, pretty short clip so hard to tell.
With the valve covers off and at idle you can usually find the loose one by taking a piece of wood or something like it (hammer handle works well) and pushing down on the rockers on the pushrod side one by one 'till you hear a change. Readjust as necessary.
 
  #17  
Old 04-22-2019, 11:40 AM
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does it make the sound with the valve covers off?
 
  #18  
Old 04-23-2019, 07:08 AM
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Thanks SOCal67 and Y2KEglide. Really do appreciate your guidance. Will check today and let you know. Definitely coming thru the carb, not the exhaust.
 
  #19  
Old 04-23-2019, 04:13 PM
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A $4 stethoscope from Harbor Freight. Hold it over each valve on valve cover....that will narrow down which cyl the noise is coming from if its a valve train generated noise

Then pull valve cover and look
 
  #20  
Old 05-08-2019, 04:36 PM
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Finally determined the cam is shot and the bottom of 2 lifters are worn clear thru. Working on a rebuild now. thanks again for your help.
 

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