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Originally Posted by F-2 Speedy
(Post 4855458)
make sure you use the ARP assembly lube when reassembling the engine and proper torque sequence on the heads
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Originally Posted by PQ290Enticer
(Post 4855445)
Installed height for both are: 1.920 and 155lbs
Open ht is 1.370 and 340 lbs bind is 1.187 and 550lbs. I have no idea what this means. It's on the build sheet. |
Edit: i misread.
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Originally Posted by PQ290Enticer
(Post 4855445)
Installed height for both are: 1.920 and 155lbs
Open ht is 1.370 and 340 lbs bind is 1.187 and 550lbs. I have no idea what this means. It's on the build sheet.
Originally Posted by Unlimited jd
(Post 4855478)
in my opinion that’s a bit light for 5500+ rpm. Rather see at least 420-450 open.
“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. |
Originally Posted by PQ290Enticer
(Post 4855406)
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.
https://cimg2.ibsrv.net/gimg/www.off...d81ff0b4ec.jpg Sorry, couldn't help myself |
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.
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Originally Posted by SB
(Post 4855492)
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. 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. |
Originally Posted by Rookie
(Post 4855506)
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. edit in: Okay, from your link PAC-1940. |
Originally Posted by SB
(Post 4855509)
i missed the pac # then. What is it ?
edit in: Okay, from your link PAC-1940. "PAC Racing #1940 1.550” OD Hydraulic Roller Dual Valve Spring, 175 lbs. on seat, .725” maximum lift, Max RPM 6500-6700" |
I thought someone talked to pac and they said not to use the hot rod series for marine endurance ?
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