lifter preload w/adjustable rockers

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dart_68

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I've been doing some research into this and can't quite find the answer I'm looking for. I have stock 273 adjustable rockers and I wonder how far to turn them after 0 lash to get the proper lifter preload. I've seen anywhere from 1/4 to 1 1/2 turns. Which is it or what's the best way to measure for preload?

360 LA with Oregon Cams hydraulic roller cam with stock hydraulic roller lifters. Gross lift is .539 int & .558 exh, 235/247 duration @ .050".

Thanks!
 
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What he said! I don't know what that is in thousand's of an inch but it's a hydraulic lifter. You need some but not too much. Chevy's always did 1/2-3/4 turn and I bet they had fine thread like Mopar did. If they clatter at 1/2, give them a little more.
 
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What he said! I don't know what that is in thousand's of an inch but it's a hydraulic lifter. You need some but not too much. Chevy's always did 1/2-3/4 turn and I bet they had fine thread like Mopar did. If they clatter at 1/2, give them a little more.
I think it's close to .030 or .040"
 
Nope. Hydraulic rollers work best with 1.5 to 2 turns down. They like a lot of preload.
 
Nope. Hydraulic rollers work best with 1.5 to 2 turns down. They like a lot of preload.
Damn you would have to throw that "hydraulic roller" business in there. We read through the post too quick trying to beat you with an answer. We both knew you were lurking in the shadows ready to pounce. :poke::poke::rofl:
 
That seems like a ton of preload to me. I've only built one roller engine, but I set it at 3/4 and it was quiet as a church mouse. Interesting though.

Roller profiles are such that they try to "throw" the lifter when the ramp comes around. By reducing the amount the plunger can travel, you counteract that inertia.
 
It makes sense to keep the lifter from bouncing on the cam lobe. Learn something new everyday.

I always follow what the lifter maker says.....BUT the general consensus is that hydraulic rollers benefit from heavier preload.
 
360 LA with Oregon Cams hydraulic roller cam with stock hydraulic roller lifters. Gross lift is .539 int & .558 exh, 235/247 duration @ .050".

Thanks!
So you're using stock lifters with this camshaft? Just curious, but why? I would think stock lifters wouldn't be too happy with this camshaft.
 
Thanks for the replies. I too have read that hydraulic rollers like more preload. Oregon Cams said the stock lifters would be fine but I could upgrade to more race type hydraulic lifter but pretty expensive. This is a motor that I intend to race but I have to keep it relatively streetable to drive to the track. Plus the occasional get together.
 
As long as the oil groove on the lifter isn't exposed at peak lift, the stock lifters should be fine. Here are a couple cams folks on this site are running with stock replacement roller lifters. Maybe they'll chime in.

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My thinking;
I currently have a little smaller cam, a Hughes HE3038AL,which is an HFT, and with 1.6 Mopar arms, .549/.571 lift 230/237/110@.050.; and with their HD circlipped lifters.
I run the lifters on the edge of ticking, so they are pretty much fully pumped up. That way, even if the valves float a bit, as long as there is enough built-in valve to piston clearance,the engine won't go down.
I think the idea is working, cuz I've been revving this thing to 7200 since 1999.
Your results may vary.
I once missed third gear and saw the tach needle swinging across 8000....... on it's way back down.... After that I bought a rev-limiter..... and fixed the dang shifter. The engine idled just fine..... and no, I never tested it again,lol.
I see;
360 LA with Oregon Cams hydraulic roller cam with stock hydraulic roller lifters. Gross lift is .539 int & .558 exh, 235/247 duration @ .050".
a pretty heavy 12* split there; can I ask what the thinking is on that?
 
My thinking;
I currently have a little smaller cam, a Hughes HE3038AL,which is an HFT, and with 1.6 Mopar arms, .549/.571 lift 230/237/110@.050.; and with their HD circlipped lifters.
I run the lifters on the edge of ticking, so they are pretty much fully pumped up. That way, even if the valves float a bit, as long as there is enough built-in valve to piston clearance,the engine won't go down.
I think the idea is working, cuz I've been revving this thing to 7200 since 1999.
Your results may vary.
I once missed third gear and saw the tach needle swinging across 8000....... on it's way back down.... After that I bought a rev-limiter..... and fixed the dang shifter. The engine idled just fine..... and no, I never tested it again,lol.
I see;

a pretty heavy 12* split there; can I ask what the thinking is on that?
I went with what Oregon Cams recommended. They recommended 2 cams and I chose the smaller of the 2 because we thought it would better fit my needs. Why such a split...I don't know.
 
I run a bullet hyd / roller they told me to run little or NO preload , it was a little noisy so now I run around a third of a turn,



My thinking;
I currently have a little smaller cam, a Hughes HE3038AL,which is an HFT, and with 1.6 Mopar arms, .549/.571 lift 230/237/110@.050.; and with their HD circlipped lifters.
I run the lifters on the edge of ticking, so they are pretty much fully pumped up. That way, even if the valves float a bit, as long as there is enough built-in valve to piston clearance,the engine won't go down.
I think the idea is working, cuz I've been revving this thing to 7200 since 1999.
Your results may vary.
I once missed third gear and saw the tach needle swinging across 8000....... on it's way back down.... After that I bought a rev-limiter..... and fixed the dang shifter. The engine idled just fine..... and no, I never tested it again,lol.
I see;




a pretty heavy 12* split there; can I ask what the thinking is on that?
 
There is some math you can do with the thread pitch of the adjuster to figure out how many turns equals the preload you want. That cam isn’t what I would call wild so the stock lifters will be fine as long as the oil band isn’t exposed. I run mine at 040 preload and it’s quiet. It’s a magnum though.
 
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