Lifter Preload??? Factory spec???

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Shainesboostin

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Ok, just put in the cam, and Harland Sharp NON Adjustable roller rockers. When checking lifter preload we were seeing about .100 with stock pushrods, I'm looking to buy new. I keep seeing different opinions from .03-.06, and some have said factory spec is .08-.09. If anyone had a good source or info I'd appreciate it.

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Just a stab in the dark but maybe call the place that the lifters and cam were supplied from and ask them about the preload.
Manton pushrods is a great company to deal with.
 
I don't think there is a factory spec for lifter prelaod. With all of the variations in rocker ratios, the crappy deck height and head surface machining, I don't see how in the world a spec could have been adhered to.
 
what cam did you go with again? i see your still using the stock heads did you cut down the valve guide area?
 
As long as you have .040 you'll be ok.

Use more preload it it bothers you to hear lifters tick when cold starting


Use less if you don't care about cold start lifter tick.

I've run as little as .010
 
measure your lifter plunger travel. you want shorter pushrods for .030"-.060" preload. maybe there is a factory spec for the 1970 340 six pack cuz it had hydraulic lifters and adjustable rockers
 
Marcohotrod said:
measure your lifter plunger travel. you want shorter pushrods for .030"-.060" preload. maybe there is a factory spec for the 1970 340 six pack cuz it had hydraulic lifters and adjustable rockers
Click to expand...

An average for most stock hydraulics is tighten till there is no clearance, then another 1/2 turn.
The ones in my Magnum roller are right about .040 and if it was worth going back in for it I would probably rather have 50 or maybe even 60.
 
I run the 1/2 turn, now.
I used to run 1/4 turn but that was no good. A couple of weeks later, I would tighten one and then a couple of weeks later another and so on until several were 1/2. So I just caved in and set them all to 1/2turn. Never had to tighten any since. If I told you that was a decade ago, would you believe me? Ok I'll tell; a couple are noisy again but I don't care.......lol
 
Get shorter pushrods. There. It's figured out.
 
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