Re: Small block 59 Degree Racers - lash settings?
[Re: Cab_Burge]
#3190791
11/14/23 11:07 AM
11/14/23 11:07 AM
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Posts: 9,888 Weddington, N.C.
Streetwize
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Weddington, N.C.
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Thanks Cab, I'm going to set them at .008 and let them rip figuring I gat another .004-.006 for "growth' from the aluminum heads. I used to set them at .010 I and .012 E to get .016/.018 and I just feel that's too loose for a 59 degrees, but that's probably fine for a big block (or anything with straighter geometry).
Something else I do is I run a hollow pushrod and (I presume) they fill with oil as the motor is running....so I think they have a little hydraulic dampening (shock absorpsion)...even if they are a little bit heavier, also any degree of lubrication passing through the pushrod hopefully aids in reducing the wear. i only turn it maybe 7200 max and everything seems sweet up there.
Last edited by Streetwize; 11/14/23 11:10 AM.
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Re: Small block 59 Degree Racers - lash settings?
[Re: Streetwize]
#3190843
11/14/23 02:11 PM
11/14/23 02:11 PM
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Joined: Jan 2003
Posts: 8,035 Tulsa OK
Bad340fish
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Tulsa OK
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My current cam called for .014 and that is what I run it at, hadn't messed with tightening it up any. This is an all iron R1 W2 combo so I don't compensate for growth and just set them at .014 cold.
My cam is supposed to be .734 .747 at the valve with 1.6 rockers. What I measure at the valve is .645 and ,668, I do not believe this number includes lash. I measured lift at the retainer to set spring height and left a little wiggle room in case I wanted to tighten lash in the future. Pretty horrific loss that probably messes with timing a fair bit also.
Last edited by Bad340fish; 11/14/23 02:12 PM.
68 Barracuda Formula S 340
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Re: Small block 59 Degree Racers - lash settings?
[Re: Bad340fish]
#3190853
11/14/23 02:52 PM
11/14/23 02:52 PM
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Joined: Jan 2003
Posts: 9,888 Weddington, N.C.
Streetwize
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So you should have ~.458/.466 lobe lift on the cam card?
....so quick math you're losing about 10% or about 1.44:1 effective which I would think would be about right for a 1.5 but not a 1.6
and I would expect the intake would be worse than the exhaust because of the Offset.
I just think you can go tighter (and probably should) on a SBM to keep the slop (I liken it to "jiggle" or a Harmonic in the pushrod as the valves are seating) to a minimum. I kinda wish I didn't sell my 48 degree R3 9.2 deck now, lol
it's amazing SBM's run as hard as they do, imagine if they just fixed the lifter bore angle to begin with back in 64
Last edited by Streetwize; 11/14/23 05:03 PM.
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Re: Small block 59 Degree Racers - lash settings?
[Re: Streetwize]
#3190916
11/14/23 06:36 PM
11/14/23 06:36 PM
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Joined: Jan 2003
Posts: 6,149 Melbourne , Australia
LA360
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What do you consider as being "better" results?
Power wise, I will always try and lash loop any engine on the dyno. I've seen HP gains reducing it, and sometimes increasing it. Every engine was different.
A friend in the late 90's used to run up to 0.040-0.042" on his Comp Eliminator small block. Was hard on the valve train, but it was the nature of the beast back then.
Alan Jones
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Re: Small block 59 Degree Racers - lash settings?
[Re: Streetwize]
#3191554
11/17/23 09:24 AM
11/17/23 09:24 AM
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Joined: Jan 2003
Posts: 4,094 Shelby Twp. Mi
HardcoreB
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Th...
That brings us to the 59 degree which means the cams lift has to compensate for a 14 degree offset and this results in an oscillation of the pushrod as it doesn't move in anything close to a straight path from the lifter cup end or the rocker fulcrum. The loss of actual cam lift on say a gross 600" lift (1.5 rocker with a .400 lift base circle) looks to be in the .030" loss of lift...not even considering lash.
That's about what I measured the last time I looked at a 59* smallblock. No denying they generally run good!!!. But they are hard on valvetrain so of-course there is something to be gained in engineering as good a 59* SYSTEM as you can. And that'd start with a gentile cam profile, which is 'inefficient'. So like anything else you'd take into consideration the entire engine like CID and valvesizes and weight etc. The feedback you'd likely get is subjective because of all the variables like rockers used and even optimization of that rocker (B3R). Generally speaking I always error on running the lash on the tight side of recommended. Then you can experiment from there. Best regards.
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