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So how did this happen? #1564911 01/18/14 12:33 AM 01/18/14 12:33 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	A couple of days ago I was preparing the car for the new season and discovered what I thought was a single crack in the block on the passenger side which runs from the top of the front freeze plug to beyond the top of the back freeze plug. Today while pulling the motor I discovered that the driver side is also cracked in the same place. Whoa!!!!! I consider myself lucky as the car was running fine last time out, and to think about what could have happened just sends chills down my spine. Details: 500 Wedge all motor, 625 HP, 727, No trans brake, motor plate with straps from the frame to the motor mount bosses on both sides. Any thoughts so I don't have the same thing happen again, if by chance I did something wrong that I don't know about. Thanks ole wise ones...... Last edited by Dart_racer; 01/18/14 03:07 AM.

Re: So how did this happen? [Re: Dart Racer] #1564912 01/18/14 12:35 AM 01/18/14 12:35 AM
Joined: Feb 2004 Posts: 34,927 S.E. South Dakota ! bigdad Still Posting A Lot
bigdad Still Posting A Lot Joined: Feb 2004 Posts: 34,927 S.E. South Dakota !	Did you have ani freeze and did it get cold enough ?

Re: So how did this happen? [Re: bigdad] #1564913 01/18/14 12:50 AM 01/18/14 12:50 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	Quote: Did you have ani freeze and did it get cold enough ? I am in California and the car is kept in a 72 degree temp controlled shop.....

Re: So how did this happen? [Re: Dart Racer] #1564914 01/18/14 01:01 AM 01/18/14 01:01 AM
A Anonymous Unregistered
Anonymous Unregistered A	Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ??

Re: So how did this happen? [Re: Dart Racer] #1564915 01/18/14 01:02 AM 01/18/14 01:02 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: Did you have ani freeze and did it get cold enough ? I am in California and the car is kept in a 72 degree temp controlled shop..... Do you have engine limiters on both sides(to each mount) and does the crack start near the mount ears

Re: So how did this happen? [Re: Dart Racer] #1564916 01/18/14 01:22 AM 01/18/14 01:22 AM
Joined: Oct 2006 Posts: 596 Mass. 8 80fbody mopar
80fbody mopar 8 Joined: Oct 2006 Posts: 596 Mass.	Is this a filled block?

Re: So how did this happen? [Re: 80fbody] #1564917 01/18/14 01:44 AM 01/18/14 01:44 AM
Joined: Apr 2007 Posts: 1,165 Central Ohio, USA Bigbeep super stock
Bigbeep super stock Joined: Apr 2007 Posts: 1,165 Central Ohio, USA	I feel your pain! What year block is it? I have since been told that the 66 and 67 blocks were the thinnest on the exterior casting walls. mine is a 66 casting and is filled and it is all cracked up. Beep

Re: So how did this happen? [Re: MR_P_BODY] #1564918 01/18/14 03:01 AM 01/18/14 03:01 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	[quote Do you have engine limiters on both sides(to each mount) and does the crack start near the mount ears Yes, engine limiters on both sides and attach to the motor mount attachment points. Crack starts right at top of freeze plug and runs horizontally past the rear freeze plug.

Re: So how did this happen? [Re: 80fbody] #1564919 01/18/14 03:03 AM 01/18/14 03:03 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	Quote: Is this a filled block? Yes, filled to the bottom of the freeze plugs

Re: So how did this happen? [Re: Bigbeep] #1564920 01/18/14 03:04 AM 01/18/14 03:04 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	Quote: I feel your pain! What year block is it? I have since been told that the 66 and 67 blocks were the thinnest on the exterior casting walls. mine is a 66 casting and is filled and it is all cracked up. Beep yes, it is a 67 block. Was your block filled? And did you have torque straps? Last edited by Dart_racer; 01/18/14 03:08 AM.

Re: So how did this happen? [Re: ] #1564921 01/18/14 03:06 AM 01/18/14 03:06 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	Quote: Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ?? Yes strap to each motor mount boss.

Re: So how did this happen? [Re: ] #1564922 01/18/14 03:11 AM 01/18/14 03:11 AM
Joined: Sep 2005 Posts: 570 Brea, Ca D Dart Racer OP mopar
Dart Racer OP mopar D Joined: Sep 2005 Posts: 570 Brea, Ca	Quote: Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ?? Where should they be attached? I never considered the motor mount boss wouldn't work given that's what point the factory used to hold the engine.

Re: So how did this happen? [Re: Dart Racer] #1564923 01/18/14 03:26 AM 01/18/14 03:26 AM
Joined: Feb 2003 Posts: 1,942 Metro Detroit OUTLAWD top fuel
OUTLAWD top fuel Joined: Feb 2003 Posts: 1,942 Metro Detroit	Had a 66 block that did the same thing. Rubber mounts, only 540 hp. Faster, Faster until the thrill of speed overcomes the fear of death... 71 Swinger - slowly collecting dust/parts 66 Belv. II - just a streetcar 88 Mustang - turbo LS beater

Re: So how did this happen? [Re: Dart Racer] #1564924 01/18/14 03:46 AM 01/18/14 03:46 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ?? Where should they be attached? I never considered the motor mount boss wouldn't work given that's what point the factory used to hold the engine. The original mounts were rubber so it didnt slam anything... I dont know the relationship between the freeze plug holes and the mount ears on a big block but if the ears are near the crank and a weak block then MAYBE thats your problem... I have limiters on both sides on my SB to the mount ears and havent hurt any block... a pic would really help

Re: So how did this happen? [Re: Dart Racer] #1564925 01/18/14 05:26 AM 01/18/14 05:26 AM
Joined: Aug 2003 Posts: 43,213 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,213 Bend,OR USA	Quote: Quote: Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ?? Where should they be attached? I never considered the motor mount boss wouldn't work given that's what point the factory used to hold the engine. I always use the power steering bolt hole on the water pump for my straps until I switched to elephant ears I also ran the stock motor mounts on both sides with the straps on the left(drivers) side I ended up with a 413 industrial block that had a crack in it, it wasn't found before all the machining was done for my 426 M.W. stocker back in the early 1980s, I ended up running that motor foor the whole year, I took the radiator cap apart so it wouldn't hold any pressure at all and drian the block bewteen races The machine shop had found a crack cylinder beside the crack in the block but I didn't find the exterior crack before it starting leaking at the first race of the year Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: So how did this happen? [Re: Cab_Burge] #1564926 01/18/14 06:23 AM 01/18/14 06:23 AM
Joined: Jul 2009 Posts: 413 Norway (old world) Oyvind Mopar mopar
Oyvind Mopar mopar Joined: Jul 2009 Posts: 413 Norway (old world)	They are stress cracks due to the design. I read about the development of the Hemi that they had to stress-relieve the blocks (heat treat them) after casting was done to avoid this from happening when raced. A socalled seasoned (used) block is supposed to have been stress relieved due to the heat cycles. Maybe the factory solved it with adding goods on later blocks?..

Re: So how did this happen? [Re: Dart Racer] #1564927 01/18/14 10:47 AM 01/18/14 10:47 AM
Joined: Jan 2008 Posts: 1,213 Minn S SportF pro stock
SportF pro stock S Joined: Jan 2008 Posts: 1,213 Minn	Well, if you are making 700 foot pounds of torque, that means a foot away from the damper, you have 700 foot pounds of rotation. I am pretty sure those motor mounts will take that. Also, a block "seasons" itself after time and that stress goes away. From here I would guess the block was froze at one time and cracked it. I have seen a few blocks crack around here and that is the way it turns out. I know a lot of folks think the ice will extrude through the "frost plug" holes but that ice expands equally in every direction, restrained or not. That is my guess, and this crack worked its way out with the power you are making. An interesting experiment is to try and hammer up an old block and knock some cast iron off of it. It will surprise you how much effort that takes, IF you can do it at all. Better luck to ya in the future.

Re: So how did this happen? [Re: Oyvind Mopar] #1564928 01/18/14 10:49 AM 01/18/14 10:49 AM
Joined: Jan 2003 Posts: 21,074 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,074 Niles , Ohio	My 65 casting 440 block cracked between the soft plugs also.It was in for 30 years.Never dripped and never froze.At the machine shop they found the crack.Now I run my 70 block.It ran on OE mounts and wasnt making a ton of HP.Rocky Chrysler Firepower

Re: So how did this happen? [Re: therocks] #1564929 01/18/14 11:26 AM 01/18/14 11:26 AM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	Dudes, you haven't lived enough. Those are VERY COMMON cracks. They aren't from freezing. They happened even at stock hp levels. They can be pinned. Later blocks had more material added there. R.

Re: So how did this happen? [Re: Dart Racer] #1564930 01/18/14 11:34 AM 01/18/14 11:34 AM
A Anonymous Unregistered
Anonymous Unregistered A	Quote: Quote: Don't know your setup, but torque straps to one of the mounting bosses is never a good idea....... I don't get why the passenger side would be cracked also though....unless....do you have rigid straps on both sides ?? Where should they be attached? I never considered the motor mount boss wouldn't work given that's what point the factory used to hold the engine. The original mounts were bolted to 3 points on each side....if u have rigid straps going to only one of the bosses.....that's where the problem lies imho

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