correct lifter preload
#616593
02/18/10 12:29 AM
02/18/10 12:29 AM
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Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
dave571
OP
master
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OP
master
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
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OK trying to rememebr this, but coming up dry...LOL I'm assembling a 383 for a friend. It has been decked a fair bit to get some comp out of it. Stock pushrods are too long. I have used an adjustable pushrod to figure out how long I need one to be for zero preload. How much longer do they need to be for the correct preload? I normally go 1/2 turn on my adjustable rockers, but this motor is still stock rockers. Thanks 
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Re: correct lifter preload
[Re: dave571]
#616598
02/18/10 11:22 PM
02/18/10 11:22 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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Quote:
I fear they may be bottoming. It's close for sure.
For the cost of a set of pushrods, I'd rather go that way.
close to bottoming out would be WAYYY too long then, if you're looking at custom pushrods. they should be "just barely pushing down" on the plunger inside the lifter...remember "zero lash plus 1/2-3/4 turn on the rocker"
make sure that you're checking them with valves closed on the base circle, I forget the sequence, but it's something crazy like TDC #1 compression stroke, check intake on #1 and exhaust on #7, rotate crank 90 degrees, check intake on #3 and exhaust on #4, rotate crank 90 degrees.
if you want, I can look it up in my rebuild book and post the correct sequence if you need?
**Photobucket sucks**
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Re: correct lifter preload
[Re: 70Cuda383]
#616599
02/19/10 12:15 AM
02/19/10 12:15 AM
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Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
dave571
OP
master
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OP
master
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
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It's the stockers that are almost bottoming, and yes they are way too long. That is why I was asking how much I wanted with the right pushrods. These are About .120" too long by the looks of it. I get the base circle thing/sequence , so we're good there. I had a similar issue with my 400, that I milled down. I ended up using an off the shelf pushrod(for a differenet application) for that one. They gave me .015 preload if I remember right, and that worked, (although I was worried that it wouldn't be enough) I've got an adjustable one, adjusted to zero. I took it in to the local parts/machine shop, so they could measure it, and get me ones that are .030" longer. It should work out. 
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Re: correct lifter preload
[Re: dave571]
#616600
02/19/10 03:30 AM
02/19/10 03:30 AM
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Joined: Jul 2003
Posts: 1,869
Carmichael, CA
NotEnufGarage
top fuel
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top fuel
Joined: Jul 2003
Posts: 1,869
Carmichael, CA
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Can't this be resolved by shimming the rocker shaft out 1/2 the amount the head was milled? Or would that change the rocker geometry too much?
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Re: correct lifter preload
[Re: 70Cuda383]
#616601
02/19/10 07:43 AM
02/19/10 07:43 AM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
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Quote:
if you want, I can look it up in my rebuild book and post the correct sequence if you need?
I need to determine PR-length on a 383 - 496 stroker with Indy heads in the near future and would appreciate if you could post that info...
Thanks,
Frank
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