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Where do RB bores split / crack typically? #1417363 04/09/13 02:27 PM 04/09/13 02:27 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Is there a common pattern of where RB block cylinders split or crack when they fail? Does it tend towards being on the thrust sides vs. non-thrust? Is it more likely when they fail it's toward the top of the bore where the pressure is the highest under combustion, or more towards the bottom of the stroke? Any real-world experience is of interest... Thanks.

Re: Where do RB bores split / crack typically? [Re: BradH] #1417364 04/09/13 02:33 PM 04/09/13 02:33 PM
Joined: Aug 2003 Posts: 43,141 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,141 Bend,OR USA	All the Mopar, not just RB and B motors that split cylinders split them on the drivers side cam side, same thnig on the passenger side I have seen more RB blocks crack the main webs than the cylinder walls IHTHs Race block for HP application Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Where do RB bores split / crack typically? [Re: Cab_Burge] #1417365 04/09/13 02:40 PM 04/09/13 02:40 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Are you saying what you've seen is the driver's side bore failures tend to occur on the major thrust side, but the passenger side failures are on the minor thrust side?

Re: Where do RB bores split / crack typically? [Re: BradH] #1417366 04/09/13 02:52 PM 04/09/13 02:52 PM
Joined: Aug 2003 Posts: 43,141 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,141 Bend,OR USA	Quote: Are you saying what you've seen is the driver's side bore failures tend to occur on the major thrust side, but the passenger side failures are on the minor thrust side? If that is what thier called, yes It is what it was I may have seen one 400 block split the passenger side cylinder split the outside (block side) CRS The same 400 block split the number two cylinder and had the #4 main cap broken after the same race (half filled) That racer was running it in S/G on a low budget, probally got the motor into detonation Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Where do RB bores split / crack typically? [Re: BradH] #1417367 04/09/13 06:04 PM 04/09/13 06:04 PM
Joined: Jan 2003 Posts: 74,992 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 74,992 U.S.S.A.	Brad you need to just get it over with and buy a siamese bore block ...

Re: Where do RB bores split / crack typically? [Re: JohnRR] #1417368 04/10/13 03:36 PM 04/10/13 03:36 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: Brad you need to just get it over with and buy a siamese bore block ... How about you buy the block and I'll pay for the final machine work that it will need to make it usable?

Re: Where do RB bores split / crack typically? [Re: Cab_Burge] #1417369 04/10/13 04:12 PM 04/10/13 04:12 PM
Joined: Feb 2005 Posts: 20,169 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,169 PA.	Quote: All the Mopar, not just RB and B motors that split cylinders split them on the drivers side cam side, same thnig on the passenger side I have seen more RB blocks crack the main webs than the cylinder walls IHTHs Race block for HP application BINGO. I have never seen such a group of paranoid racers in all my life. Mopar guys over-think things so bad it isn't funny. I swear guys build stuff, sell it, and build something else just so they never have to take it to the track. Build it, take it to the track and beat the snot out of it. You may have a GREAT time. 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27 Livin and lovin life one day at a time

Re: Where do RB bores split / crack typically? [Re: pittsburghracer] #1417370 04/10/13 04:50 PM 04/10/13 04:50 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: ... I have never seen such a group of paranoid racers in all my life. Mopar guys over-think things so bad it isn't funny. I swear guys build stuff, sell it, and build something else just so they never have to take it to the track. Build it, take it to the track and beat the snot out of it. You may have a GREAT time. Guilty! And, regardless of my paranoid posts as of late, I WILL be putting the car back on the street & track w/ the 4.380" short block I'm already in the process of reassembling. And when THAT one breaks, I WILL be putting in the 4.375" block that I've posted the sonic test results about, thin non-thrust walls or not. But if/when they do blow, I'd rather have a good idea of what the problem was than to be totally blind-sided by ignorance. Such is the price of paranoia...

Re: Where do RB bores split / crack typically? [Re: BradH] #1417371 04/10/13 10:37 PM 04/10/13 10:37 PM
Joined: Jan 2003 Posts: 4,448 Phoenix, AZ M MoparBilly master
MoparBilly master M Joined: Jan 2003 Posts: 4,448 Phoenix, AZ	Brad, My 440 cracked the 2 middle bores just off center of the thrust. 4.350 bore, tall fill. Pic below. If you remember, this engine saw heavy loads of nitrous occasionally. So occasionally that I sometimes lost track of my tune-up! Thought I was on 175 1st stage, then 225 2nd stage. Nope, I had 250 in the first hit, because I had agreed to race a guy on one stage, 3 or 4 months earlier. I was on marginal fuel for that much spray, so things got unhappy about 1000 ft. out. I sleeved those 2 holes and replaced those 2 pistons and continued to run it. 7663213-100_0583-Copy.JPG (75 downloads) "Livin' in a powder keg and givin' off sparks" 4 Street cars, 5 Race engines

Re: Where do RB bores split / crack typically? [Re: MoparBilly] #1417372 04/11/13 11:03 AM 04/11/13 11:03 AM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	/

Re: Where do RB bores split / crack typically? [Re: BradH] #1417373 04/11/13 04:53 PM 04/11/13 04:53 PM
Joined: Jun 2009 Posts: 1,186 OHIO T THE GLASS MAN super stock
THE GLASS MAN super stock T Joined: Jun 2009 Posts: 1,186 OHIO	I was told by a good source and a long term record holder and engine builder that my #1 cyl. cracking problem was due to the fact that I was using a stock mount that had been welded solid and I was actually stretching the block in that area. I went with a plate and never had a problem after that.

Re: Where do RB bores split / crack typically? [Re: THE GLASS MAN] #1417374 04/11/13 05:18 PM 04/11/13 05:18 PM
Joined: Jan 2010 Posts: 1,088 st.cloud fl D d-150 Smarter than a 5th grader?
d-150 Smarter than a 5th grader? D Joined: Jan 2010 Posts: 1,088 st.cloud fl	not going against anybodys machine work, just a question.could the cracking be caused by boring honing cylinders to tight for pistons?

Re: Where do RB bores split / crack typically? [Re: d-150] #1417375 04/11/13 06:49 PM 04/11/13 06:49 PM
Joined: Feb 2005 Posts: 20,169 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,169 PA.	Quote: not going against anybodys machine work, just a question.could the cracking be caused by boring honing cylinders to tight for pistons? These are the kind of questions I have too. The engine plate suggestion above could be question mark. Every big block race car I ever had used a motor plate. Why do some shops see more problems than others? I have seen some awful crappy machine work performed over the years and I know 2 shops locally that I wouldn't let them change the spark plug in my lawnmower. If you guys are gonna scrap those THIN blocks I will take them off your hands to free up some room for you in your shop. 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27 Livin and lovin life one day at a time

Re: Where do RB bores split / crack typically? [Re: pittsburghracer] #1417376 04/11/13 07:14 PM 04/11/13 07:14 PM
Joined: Jan 2010 Posts: 1,088 st.cloud fl D d-150 Smarter than a 5th grader?
d-150 Smarter than a 5th grader? D Joined: Jan 2010 Posts: 1,088 st.cloud fl	or another possibility ring gap set to tight?

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