First Dyno Complete
01-10-2023, 10:32 AM
#41
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Griff (01-10-2023), PQ290Enticer (01-10-2023)
01-10-2023, 01:16 PM
#42
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01-10-2023, 05:18 PM
#43
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Edit: i misread.
01-10-2023, 05:35 PM
#44
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“To calculate a valve spring rate, subtract the seat pressure from the open pressure, then divide by the lift.”
So, plugging in the provided #’s:
340lb (open) - 155 lbs (seat) = 185lbs
1.92” seat - 1.370” open = .550” lift
185lbs/.550in = 336.4 lbs/in spring rate
Did i do math right ? 336 rate is low. As example The popularly used Isky 8005A is 400lbs/in.
Last edited by SB; 01-10-2023 at 05:52 PM.
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01-10-2023, 07:34 PM
#45
540Fever, Yup. I missed almost 2 full season's working on these engines between cash flow and everything backordered. Now finally done and It seems everyone thinks I have 2 expensive grenades ready to go off at any time. Obviously it would be beyond terrible if they do grenade but I can't chase something based on opinions of people that had no hand in them at all. Ultimately I'm going with the guys that built and dyno'd these engines. Neither see's a problem with the printout's or the way they performed. If you boat on the Grand River or Lake Michigan and see me getting towed in, be sure to wave and tell me you told me so.
Sorry, couldn't help myself
01-10-2023, 08:30 PM
#46
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If you would like to have my head guy look at them for you just let me know. Valako just finished up my 302 and might have some time between the 496's he's rebuilding. He's local.
01-10-2023, 08:43 PM
#47
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His cam lift is just .550” vs the .610” to .632” or more we typically see on bbc builds. So maybe that makes the open look lower than normal ? Time for some math for a look see.
“To calculate a valve spring rate, subtract the seat pressure from the open pressure, then divide by the lift.”
OR JUST LOOK ON PAC's WEBSITE
So, plugging in the provided #’s:
340lb (open) - 155 lbs (seat) = 185lbs
1.92” seat - 1.370” open = .550” lift
185lbs/.550in = 336.4 lbs/in spring rate
Did i do math right ? 336 rate is low. As example The popularly used Isky 8005A is 400lbs/in.
“To calculate a valve spring rate, subtract the seat pressure from the open pressure, then divide by the lift.”
OR JUST LOOK ON PAC's WEBSITE
So, plugging in the provided #’s:
340lb (open) - 155 lbs (seat) = 185lbs
1.92” seat - 1.370” open = .550” lift
185lbs/.550in = 336.4 lbs/in spring rate
Did i do math right ? 336 rate is low. As example The popularly used Isky 8005A is 400lbs/in.
Install height = 194lb
Spring rate is 469lb/in (PAC website)
469*.550 = 258lb
258lb + 194lb = 452lbs open
Those are close to the Comp 933's I run.
Last edited by Rookie; 01-10-2023 at 08:47 PM.
01-10-2023, 08:55 PM
#48
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https://www.racingsprings.com/index....ing-11334.html
Install height = 194lb
Spring rate is 469lb/in (PAC website)
469*.550 = 258lb
258lb + 194lb = 452lbs open
Those are close to the Comp 933's I run.
Install height = 194lb
Spring rate is 469lb/in (PAC website)
469*.550 = 258lb
258lb + 194lb = 452lbs open
Those are close to the Comp 933's I run.
edit in: Okay, from your link PAC-1940.
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Rookie (01-10-2023)
01-10-2023, 09:21 PM
#50
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I thought someone talked to pac and they said not to use the hot rod series for marine endurance ?
