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YOU KNOW MY NAME!
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This is an excellent pic of how a lifter is NOT suppose to look. Note that the lifter hasn't been spinning...and this is how a cam wears real quick. This lifter is out of one of my personal engines...and I broke the cam in correctly. The lifter MUST spin. This one didn't...and the engine had maybe 1,000km's on it when we pulled it and found this. The original cam in the engine was fukd when I bought the car...and was down about 20 pounds on that cylinder. I still pounded the sh!t out of it at the track for a couple of years while I learned what made these things tick...sorry for the pun. Dan has the cam hanging up at his shop and the one lobe is pretty much round. Some of the 109 blocks had one or more of the lifter bores out of whack from the factory thus causing cam failures. This block I have is one of them. I don't know whether to chance a reverse taper flat tappet cam or go roller. I'll likely hand it to JB Racing and have Joe put a roller in it.
 

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Older than dirt
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Exactly the reason I check rotation B4 the engine is buttoned up.
A. I use a Goodson lifter bore sizing tool. This polishes the bore, and sets the size.
B. I install the lifters, mark them, load them w/ the p rods and springs, then rotate the crank. I need to see at least 1 rev of all the lifters, for each 10 revs of the crank.

You won't believe the slick bore finish once the Goodsen tool is pulled thru the bores. [Done w/ a home made slide hammer.]
 

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OK! Who Farted Again??
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What I don't understand is how is it a problem in only 1 out of 500 blocks??
I mean they all came from GM & were all built to the same specs? :dunno:
 

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OK! Who Farted Again??
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JB's right,no question.
I still have No Idea why 1 in 500-1000 blocks show this abnormality unless the GM Molds were worn out after X amount of blocks were produced, yet they kept using them?? I thought they used a sand mix so all were exactly the same over & over when firing the molds?? :dunno:
 

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aka: mOtOrHeAd MiKe
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I still have No Idea why 1 in 500-1000 blocks show this abnormality unless the GM Molds were worn out after X amount of blocks were produced, yet they kept using them?? I thought they used a sand mix so all were exactly the same over & over when firing the molds?? :dunno:
Core shift is one possibility... but, I would imagine it was the extremely accurate machining processes of the 1980s that is more likely to blame; or a combo of the two. Because if there was a core shift which moved a reference point it could create an issue during machining; moreover worn out/poorly serviced tooling could also contribute.

Remember the warranty period was a lot shorter 25 years ago so little f*ck was given.
 

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Older than dirt
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What John said....

It's strictly a poor machining thing,no ifs,ands or buts about it.
If anyone has ever worked in a mass production facility, they know well whhat kind of nonsense goes on w/ machine operators, supervisors..
I spent several yrs at a QC position w/ Cat.
NEVER a dull moment. Either the idiot on the machine was running w/ broken, dull tooling, or a super was breathing down my neck for parts for the assy line. Good, bad, or just plan OOS, they'd use it.:yup:

SAME HERE!
 

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OK! Who Farted Again??
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Remember the warranty period was a lot shorter 25 years ago so little f*ck was given.
My brother in law has been with GM his whole life & he does have some funny stories about Quality Control or the Lack of it especially on Mondays & Fridays.
 
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