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#1
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Discolored rods
Are these rods fine or should i look for another set?
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#2
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That's from heating them to press the pin in and getting them hotter then needed to get that job done!
Now the Rods temper in that area has been changed and it's surface layer will be more proned to cracking. Is such a issue? I guess it depends on the motors stroke ( G force loads ) and intended rpm range. I myself would not chance using them in a motor of 4.210" stroke or greater at anything more then 6800 rpm.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#3
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They're junk, I'll give you $10 for them and you pay the shipping!
Seriously, I've seen that sort of thing many times, and to date haven't seen any break in that area..........
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
#4
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"At 480 degrees F., the steel turns brown, at 520 degrees, it turns purple, at 575 degrees, it turns blue and at 800 degrees, it turns grey. ... At 2000 degrees, the steel will be bright yellow."
I don't think 520-575 degrees will hurt them.
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
#5
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I've hung thousands of interference fit piston sets.
Coloring in that area seemed to vary on surface prep(shot peened or glass beaded) and how clean when hung. Yes temp also is surely a factor. NONE ever came back broken, many were budget circle track motors that got their neck twisted tight... for extended periods of time and comparably heavy slugs, longer strokes. Seems strange they are not bushed rods. I'd use them, glass bead if you don't like seeing the color! |
#6
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575 F is only 475 degrees away from the temperature that 4340 steel is tempered at, just sayin!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#7
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Quote:
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#8
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Unfortunately, this is the norm with most shops that do not first take the time to pin-fit the the rods to .001" interference fit. If they did, very little heat is required required to expand the small end of the rod. It's not going to hurt anything.
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Triple Black 1971 GTO |
#9
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You want them to be more brown than blue. A good weld is also brown with proper heat.
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#10
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I saw a set of used Eagle forged rods at a swap meet for sale once that were blued like this...ON THE BIG END !!!...some kid was looking at them and when the seller wasn't around I told the kid I wouldn't buy them, telling him they got very hot for some reason, most likely from improper clearances.
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Just a blind squirrel looking for a nut. |
The Following User Says Thank You to Brian Baker For This Useful Post: | ||
#11
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Quote:
I went with floating on my new set of eagle H-beam to avoid this type of situation myself Kenth. |
#12
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I'd have no problems running the rods as long as the pin moves freely in the pistons.
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62' Lemans, Nostalgia Super Stock, 541 CI, IA2 block, billet 4.5" crank, Ross, Wide port Edelbrocks, Gustram intake, 2 4150 style BLP carbs, 2.10 Turbo 400, 9" w/4:30 gears, 8.76 @153, 3100lbs |
#13
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LOL, no...but the guy selling the rods was well known in the Pontiac racing community in Maryland (and surrounding areas). His engines always ran like a scalded cat but for some reason the ones he built for others had a tendency for failure. And no, I'm not talking about JG.
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Just a blind squirrel looking for a nut. |
#14
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Even if the rod got to 1150F and air cooled, would it lose its temper? Just asking.
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
#15
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Quote:
Considering hardness is a good indicator of strength, here's a chart I found. Note this is probably for a 2-hr hold: If you want a deep dive, here is a good 4340 heat-treating summary a quick web search found: https://www.steelforge.com/alloy-steel-4340 I have no clue how 4340 rods are heat-treated but wouldn't be surprised if they were surface-hardened to improve fatigue life. If this is the case, the stress relief of the surface and reduction in fatigue life might be a bigger concern. |
#16
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If the rods are heat treated to the critical temperature (cherry red) for and hour per inch then quenched in an oil bath. They should be tempered at a temp of 450c- 600c then quenched. The tempering takes out some of the brittleness but builds toughness. Getting them to about 550 for a minute or two shouldn't affected them very much if at all.
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 Last edited by track73; 09-20-2020 at 12:18 PM. |
#17
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Thanks... this sounds reasonable. I don't know where 1150 F came from but that is way too hot for a tempering temperature. The OP's photo shows bands of oxide consistent with non-concerning temperatures but hard to tell how hot the small end got.
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#18
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Screen Shot 2020-09-20 at 12.36.22 PM.jpeg
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
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