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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: AndyF]
#1409836
03/27/13 07:07 PM
03/27/13 07:07 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
I've sonic tested a lot of Mopar blocks and 0.060 over is pushing the limit a fair amount of the time. To have two blocks that are both good to 0.060 without the benefit of any sonic checking would be a stroke of luck.
Uuuuuuugggggghhhhh.... 
I may have located a close(r) shop w/ a tester (Seriously Phord people, unfortunately) and would like to have them check both the "done" .055" block and the one remaining standard core I have. The .060" block is already an assembled short block and it's not worth pulling it down for this, given it's intended to be an interim solution while I finish a fresh build.
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: BSB67]
#1409843
03/27/13 10:25 PM
03/27/13 10:25 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Too thin is whatever breaks on you. It's all opinions on what is thick enough to live. I own a good tester and it's debunked everything that the "bibles" preached about factory blocks. In terms of "thick enough" for me - it's a minimum of .225 on the major thrusts, .175 on the minor, and .100 on the pin axis. Thicker IS better but trying to find everything at .250 or larger in every hole you better have a big pile of blocks to test. It may be better in the long run to use a milder rod/stroke ratio or shorter stroke and get a taller & more stable piston that loads the walls less too.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: evenflow]
#1409844
03/27/13 10:30 PM
03/27/13 10:30 PM
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Joined: Jan 2003
Posts: 31,060
Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,060
Oregon
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Quote:
Google mopar myths thin wall blocks
Nice to see one of my old articles still floating around the web.
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: loaderpro]
#1409846
03/28/13 05:02 AM
03/28/13 05:02 AM
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Joined: Jan 2003
Posts: 2,933
Finalnd, Perkele
jyrki
master
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master
Joined: Jan 2003
Posts: 2,933
Finalnd, Perkele
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I think it's nice that people recommend sonic checking, but when you ask what is the limit when you should discard a block, it becomes much more quiet. I have never sonic checked a block before, but now have a 4.375" bore 400 that cracked one cylinder. There is about a two inch long crack in one wall next to the pin, I believe water entered the cylinder and broke the connecting rod. The block is fully race machined with aluminum caps etc., so if possible I would like to save it if it only requires one or two sleeves. But what is an accepted wall thickness? I think the engine will make about 700 hp when ready, it's a roots blown 400.
Plynouth VIP '67 TT IC EFI
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: jyrki]
#1409847
03/28/13 08:50 AM
03/28/13 08:50 AM
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Joined: Jan 2003
Posts: 3,103
Phila Pa
scatpacktom
master
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master
Joined: Jan 2003
Posts: 3,103
Phila Pa
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Quote:
I think it's nice that people recommend sonic checking, but when you ask what is the limit when you should discard a block, it becomes much more quiet. I have never sonic checked a block before, but now have a 4.375" bore 400 that cracked one cylinder. There is about a two inch long crack in one wall next to the pin, I believe water entered the cylinder and broke the connecting rod. The block is fully race machined with aluminum caps etc., so if possible I would like to save it if it only requires one or two sleeves. But what is an accepted wall thickness? I think the engine will make about 700 hp when ready, it's a roots blown 400.
Why don't you sonic test your busted cylinder and share the results with us? That way we will know what not to do.
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: scatpacktom]
#1409848
03/28/13 09:31 AM
03/28/13 09:31 AM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
Quote:
I think it's nice that people recommend sonic checking, but when you ask what is the limit when you should discard a block, it becomes much more quiet. I have never sonic checked a block before, but now have a 4.375" bore 400 that cracked one cylinder. There is about a two inch long crack in one wall next to the pin, I believe water entered the cylinder and broke the connecting rod. The block is fully race machined with aluminum caps etc., so if possible I would like to save it if it only requires one or two sleeves. But what is an accepted wall thickness? I think the engine will make about 700 hp when ready, it's a roots blown 400.
Why don't you sonic test your busted cylinder and share the results with us? That way we will know what not to do.
X2. Some empirical data would be swell...
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: Cab_Burge]
#1409850
03/28/13 05:20 PM
03/28/13 05:20 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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I did a lot of Googling late yesterday searching for functional, yet "budget priced", sonic thickness testers and came away w/ mixed results. The same stuff you can eBarf from China directly for under $200 can sell for about twice that much if you purchase it from a U.S. or Canadian vendor, yet I'm not giving anyone in China my credit card info... Apparently the cheaper offshore testers can actually read fairly accurately on flat surfaces, but the issue is the probes they come with don't read curved surfaces accurately. And either there is no appropriate curved-surface probe available for those cheaper testers, or the cost for a probe that should work from a US supplier is more than the tester itself costs. Some folks have been able to self-modify the supplied budget probes to read a curved surface, but others attempting to perform the same modification have said it simply effed up the ability to take an accurate and consistent reading. Anything that's a known-to-be-good unit available from a US supplier is pushing (or exceeding) the $1K mark, which simply doesn't fit my budget. 
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: BradH]
#1409851
03/28/13 06:01 PM
03/28/13 06:01 PM
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Joined: Oct 2005
Posts: 8,902
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,902
Ontario, Canada
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Quote:
but the issue is the probes they come with don't read curved surfaces accurately.
I know very little about these sonic testers BUT ...
I understand that a bore is round but it is straight up and down so read it that way.
Just how wide does that probe actually read ... it seems to me that it would only read an area the size of the probe itself, which isn't very large. So despite it being a curved surface the variance from that curve should be minimal. Hell, there's probably more variance from the courseness of the casting sand!
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: Stanton]
#1409852
03/28/13 06:03 PM
03/28/13 06:03 PM
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Joined: Oct 2005
Posts: 8,902
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,902
Ontario, Canada
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Quote:
Loc: La Casa de Chaos!
Where the F&#@ is that? If we had an idea of where you live we might be able to offer a couple of alternative suggestions!
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Re: How common is a .055" OS 440 cylinder really too thin?
[Re: BradH]
#1409855
03/28/13 10:08 PM
03/28/13 10:08 PM
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Joined: Oct 2005
Posts: 8,902
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,902
Ontario, Canada
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Quote:
Quote:
Quote:
Loc: La Casa de Chaos!
Where the F&#@ is that?
According to MapQuest, I'm 24 miles northwest of the official residence of the President of the United States of America.
Ok, great! Sorry, can't help ya.
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I had a block tested to see if it was safe to go .090 (very early 318 block) and they told me it was over .250 at the thinnest spot they could find, of course it cracked and was no where near that thick in a lot of places when measured with calipers 
I had one 400 block that had massive core shift on the drivers side cam side of the block, it was right at .060 before boring is what we determined after having it crack # 1 cylinder on the dyno 
Shame on me, my sonic tester battery was low and I didn't realise what it was telling me when it would flash and turn off 
That`s why I asked earlier......... 
