Engine builders, got a question
#1
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Engine builders, got a question
I put a set of heads on a short block I've had for a while, torqued the bolts to 25 ft-lbs initially then 45 then 65. The next day I went back over them all and on the very last bolt, on the second head, I was easing on the torque wrench and heard the dreaded "pop" followed by an almost instantanious click from the wrench. I would estimate the bolt turned about 1/16 of a turn. After a couple of choice words I eased on it again and just got the click from the wrench with no turning. Did I crack the bolt hole? Is there a way to determine whether or not I did with out tearing it all the way back down and having it magnafluxed?
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Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
It *could* have possibly been just the head of the bolt spinning on the cyl head under pressure, i have had the same thing happen to me on different things. or maybe it snapped off the end of the bolt, pull it out and see if you still have the whole bolt.
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Car: 87 Berlinetta,work in progress
Engine: 468 BB,still in the build process
Transmission: TH350,3500 stall
Axle/Gears: 9" Ford,learning how to live under
You should be able to tell without a magnaflux.
If it were mine,I'd start by pulling that head bolt out completely,and seeing how the threads feel.If they are iffy,pull the head back off.I've found that usually if the threads are jacked,it's visually noticable.There are heli-coil kits available for head bolts,though they are not cheap,might still beat a complete rebuild.
Sounds like a 400SB,thy are known for weak threads.
If it were mine,I'd start by pulling that head bolt out completely,and seeing how the threads feel.If they are iffy,pull the head back off.I've found that usually if the threads are jacked,it's visually noticable.There are heli-coil kits available for head bolts,though they are not cheap,might still beat a complete rebuild.
Sounds like a 400SB,thy are known for weak threads.
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Well, I pulled the bolt out and its fine. Threads are all smooth. If the bolt hole cracked it would'nt necesarilly mess up the threads on the bolt would it? I guess I'll go ahead and pull the head back off anyway and see what I can see.
Man, this is a bummer......... This short block IS a new rebuild, block was decked, bored and align honed. All that machine work potentially down the drain, its just a 350 by the way.
Man, this is a bummer......... This short block IS a new rebuild, block was decked, bored and align honed. All that machine work potentially down the drain, its just a 350 by the way.
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
I just pulled the head off. I can't see a crack but I guess that does'nt mean one is'nt there. Has anyone else heard a pop like this while torqing heads down and not had the bolt hole crack? I've never heard the pop before, but have heard about it and have been told it usually means a cracked bolt hole. What do you think about getting a big magnet and some metal dust for a backyard type of magnaflux?
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Ohhhhhh, pressure test . Yeah I guess I could do that with it still on the stand. Though I wonder if it would leak with a micrscopic crack that has'nt had the chance to grow with heat and such.
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Car: '88 IROC-Z medium orange metallic
Engine: L98
Transmission: 700R4
Axle/Gears: 3.27
What kind of lube are you using on the threads? If you're using the wrong kind or not enough it'll cause the bolt to "jump" as you're torquing it. Stock head bolts you can use motor oil on the threads and under the head, and make sure to use sealant, and with ARP's you want to use their moly that they supply.
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Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Originally posted by gmgod
What is a penetrant test and how do you perform one?
What is a penetrant test and how do you perform one?
The noise could have just been from breaking stiction though.
#14
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Thanks Apeiron, I think I'm gonna go ahead with one of those tests, I've never heard a noise like that before with clean threads, new bolts and thread sealant.
#15
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Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Can anyone point me in the right direction to find a spotcheck jr kit. I just moved and no one local seems to carry it.
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Car: 1984 Z28 Hardtop
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Axle/Gears: 3.54 Dana 44
http://www.magnaflux.com/sales/sales.asp
Domestic Reps/Distributors: MO
B.C. MacDonald & Company Sales Team
1265 Research Blvd.
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phone: 314-993-2833
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Domestic Reps/Distributors: MO
B.C. MacDonald & Company Sales Team
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phone: 417-624-2150
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Domestic Reps/Distributors: MO
B.C. MacDonald & Company Sales Team
1265 Research Blvd.
St. Louis, MO 63132
Covering: mo
phone: 314-993-2833
fax: 314-993-0405
Domestic Reps/Distributors: MO
B.C. MacDonald & Company Sales Team
304 East 32nd Street
Joplin, MO 64801
Covering: mo
phone: 417-624-2150
fax: 417-624-4130
#17
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Car: 87 Berlinetta,work in progress
Engine: 468 BB,still in the build process
Transmission: TH350,3500 stall
Axle/Gears: 9" Ford,learning how to live under
GMGOD,PM me your phone #,I can hook you up with a dye/penetrant test.Lest ye forget,your living in the stainless steel capital of the US!
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