Oem magnum roller lifter preload

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jake17201

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How much preload are y'all running on the stock hydraulic roller magnum lifters? I am hearing as much as 2 turns and as little as a half turn? Why such a range compared to flat tappet? Thanks
 
They certainly take more than the flat tappet stuff, but 2 turns to me sounds tight. I like to go about 3/4 to 1 full turn.......but then, I also don't like to gauge preload by the turns of the rocker nut. I look at the lifter plunger and judge from that. Go down 1 full turn watching the plunger. If I think it's too far, I back off to 3/4. You can even mark the pushrods at zero lash and adjust that rocker and remark the pushrod and measure between the marks to get a good idea of what it takes. Flat tappet hydraulics general rule of thumb is .020-.060 preload. I would say .040-.060 for a hydraulic roller. I just recently built my little Ford 302 roller engine and it uses OEM hydraulic roller lifters. I ended up going down between 3/4 to 1 turn. The reason I prefer to measure rather than guess with the number of turns is because of variances in everything from threads to pushrod length, you name it. Best to be as accurate as possible. It might take a little more time, but the end result is worth it.
 
RustyRatRod said:
They certainly take more than the flat tappet stuff, but 2 turns to me sounds tight. I like to go about 3/4 to 1 full turn.......but then, I also don't like to gauge preload by the turns of the rocker nut. I look at the lifter plunger and judge from that. Go down 1 full turn watching the plunger. If I think it's too far, I back off to 3/4. You can even mark the pushrods at zero lash and adjust that rocker and remark the pushrod and measure between the marks to get a good idea of what it takes. Flat tappet hydraulics general rule of thumb is .020-.060 preload. I would say .040-.060 for a hydraulic roller. I just recently built my little Ford 302 roller engine and it uses OEM hydraulic roller lifters. I ended up going down between 3/4 to 1 turn. The reason I prefer to measure rather than guess with the number of turns is because of variances in everything from threads to pushrod length, you name it. Best to be as accurate as possible. It might take a little more time, but the end result is worth it.
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Solidly honest advice,wish the best of luck. I worked hard,to get back to a adjustable valve train. That eliminate's idiocy, gives me what I wanted.
 
somewhere on hughes homepage i found the info these hydraulic roller lifters take .080", that´s what i adjusted when i assembled my engine....no problems so far.

[ame]http://www.hughesengines.com/Upload/productInstructions/New_Camshaft_InstructionsMar2010.pdf[/ame]

Michael
 
That's a buttlug of preload. ....and it's probably correct, but I could not bring myself to go that far.
 
They're Hydraulic does not matter as long as you do not top out or bottom out
unless you are racing and want them to act more like a solid- anti pump up and all that
all good advice above
factory wants no noise for a long time
 
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