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Immortalities First Rescue...

immortality

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Borrowed from the ZZP website.

Each 1/2 turn of the rocker bolt is ~.050 of lifter preload. Your goal is to have between 1/2 turn and 1.5 turns if you have stock lifters .

LS7 lifters are preloaded and have to be installed between 3/8 and 3/4 turn (vs. 1/2 to 1.5 turns on stock lifters)



So that means stock lifters want 0.050" to 0.150" pre-load and the LS7 lifters want a bit less, about 0.0375" to 0.075" pre-load.

If zero lash is 6.9235" a 7" long push rod would give me 0.0765" pre-load which would be perfect for stock lifters and just a touch much on a LS7 lifter.

That means the even with the old worn pushrods in theory I'm still within the normal lifter working range. Seems though one doesn't like the extra compression and possibly the heavier valve springs.
 

UTE042_NZ

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Can't you buy some different thickness steel or brass sheet and cut your own shims? It's what we used to do back in the '70s on our old british and american rocker arm brackets (car, bike, however many cylinders).
 

immortality

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When doing the push rod length check last night I had to turn the motor over to get No1 cylinder onto the compression stroke, damn it was hard turning her over using a socket and ratchet. This biatch seems to have some compression in it. maybe it's reasonably healthy.

Can't you buy some different thickness steel or brass sheet and cut your own shims? It's what we used to do back in the '70s on our old british and american rocker arm brackets (car, bike, however many cylinders).
Yup. That is about the only local option I have I think. I might have to check my local supplier this evening and see if we have any .015" shim steel.

Received emails back from 2 local suppliers, neither have the pushrods in stock in the length I need. :( Might have to come from the US.
 

immortality

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Just ordered a filter service kit for the 4L60e, some O2 sensor bungs and a step drill bit to facilitate the fitting of O2 sensor bungs and some valve spring shims should I feel the need to shim up those springs in the future.
 

immortality

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Can't you buy some different thickness steel or brass sheet and cut your own shims? It's what we used to do back in the '70s on our old british and american rocker arm brackets (car, bike, however many cylinders).
Managed to find some .020 shim stock.
0-02-07-9d7be102f999f57d1f67e6046e8f41a8cd4f4c3e35c7b9ccc81f95129ca3d337_c4e549ca08ec4f13.jpg
Now to turn it into something usable under the rockers guide plates.

But that's a job I'll start on the weekend as I'm working nights at the asylum atm.
 

immortality

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A bugger it, it's a beautiful day outside (22° in the shade, clear blue skies). Why not go work on a car and get a tan/burn!

Quickly stripped out the rockers and started on a plan. Getting good at stripping out rockers, literally a 10 minute job now.
0-02-07-7c5db8b378780e7128dad40d837242cceffd8ca482e6b37c29d5cea72f0b0e3e_41bb4c7fe8a98824.jpg
Shim steel is close to the correct width to make a shim plate for 3 rockers in one.
0-02-07-b5ea1fef543936e144c98c95826c67d684f9420c85e6ab1398cabd02582f79a6_bbf8f8e648ccd113.jpg
So the plan is to cut 4 strips of shim steel, 30mm wide, 135mm long, turn down a 5mm edge so the shim will sit in place on the rocker boss's on the heads without sliding away to make assembly easier and drill some holes to suit.
0-02-07-3b00c77136106bc592ff61630a0b40d069cd257c67f152970871ef43e4f6bc63_1a98284fd7e8fe29.jpg
 

immortality

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Had a spare moment this evening.



Was a real Pain to drill the holes but we got there in the end. Will test fit tomorrow and if it works out I'll make a few more.
 

Deuce

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If you were really fancy you would make this tool in 2 different sizes and then just start punching out single shims for each rocker.

Punch a big shim out, and then a small hole through the centre for the bolt obviously.
12 times of course.
 

immortality

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That would Work for individual Rockers but on the ecotec, Like the LS the rockers are mounted on a single rocker guide plate and it would be really difficult to try and keep individual Shims located correctly under the plate. I went this way for ease of assembly.
 

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Was a real Pain to drill the holes but we got there in the end. Will test fit tomorrow and if it works out I'll make a few more.
Holes don't have to be round really, do they? I used to use snips and cut in from the side making square (ish) ones. As long as you don't allow any edges of the cut-ins to overlap you'll be fine (you can allways trim a little extra so there's a gap like in this rough image).
shiminy.jpg
 
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