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283 Crank id issues!

7K views 23 replies 8 participants last post by  V8CarreraGTS 
#1 ·
So I have a 283 crank it reads GM-11 3849847 cast number and have searched forums up and down and can't really figure it out so forums say its forged some say cast. the center line points to cast being a thin line but when you hit it with a hammer it rings like a bell I have read on another forum that sometimes cast and forged will make different sounds IDK. Any ideas out there is there anyway for it to be forged with the thin center cast line? is there any other id number that might help I know there's the date code on it but didn't think that would help much I know by the cast number its a 1963-67 crank just at a total loss here any help would be appreciated. thanks guys!
 
#2 ·
The sound isn't indicative of cast or forged. The DO make a different sound when hit, but unless you have both cast and forged side by side, the comparison really cannot be made difinatively IMO.

Thin line should be cast. But a 3" stroke factory SBC crank is going to be forged.
 
#3 ·
i had a steel crank and block, 283. i couldnt tell from just lookin. the guy that gave it to me showed me the ping thing. i couldnt really do that either. even side by side with a cast crank. hahaha. he also said he can find a crack in a crank by that ping test. is he b s'n me or do you guys know anything about that. i dont know much about engines. just piddle with em.
 
#4 ·
Some cracks at the earliest stages are barely visible even w/penetrant or magnaflux, but the different sound w/a cracked crank crack is legit. The sound is very different w/a significantly cracked crank and to someone who deals w/them on a regular basis its a no brainer. Not so much to someone like us who don't handle cranks a hundred times a day unless the crack is bad or you have a good one to compare it to.
 
#5 ·
My grandad was an old school welder; he was born in 1918 and learned things like hammer welding, cast iron repair and gas aluminum welding and used them every single day. He had 2 big anvils in the shop; a cast one and a forged one. Yes there is a difference, no its not easy to tell and I have a feeling the larger the object, the easier it is to hear the difference.

There was a cast 262 (yeah I said it 262) crank; I think its actually 3.10" stroke, but its a large journal crank if Im not mistaken. I heard of guys using them in a 283 block (why not just blueprint a 307 I dunno).

Now; chevelles.com list that as a 1964 crank and is labeled as cast or forged???
http://www.chevelles.com/ref/64f.html

interesting... Over the counter service replacement?
 
#7 ·
To the OP:

If you are in dire need of a 283 crank and its free; or you're building a numbers matching 283 from 1964, use it. If you just need a crank for a 283, find an earlier one that is confirmed as steel. I've been given 283 parts and if its a GOOD crank I could see paying $50-75 for a non-corvette piece.

Nothing wrong with a 283; get a rebuild kit from Northern, some moly rings, a 260H cam, a small aluminum intake manifold with a 600cfm carb and you've got a nice piece
 
#10 ·
So I am going to take it to a machinist that specializes in cranks today and see what he has to say. ill try to get some pics up of it here soon and let you all know the results. and for its purpose I am building a 302 yaya i know lol I did happen to stumble upon an original 302 DZ engine with original crank waiting to see if its for sale was left a my machinist shop for over 2yrs so i might have a chance at getting it ya y1:mwink:a
 
#11 ·
so the machinist has verified it is a cast crank so it looks like i am buying one from him. grrrr heres a question for you guys that he mentioned to me about making a 302 is the pistons height is like 1.8 and a 350 piston height is 1.5 so couldn't I just use a 350 piston 5.7 on a 6" rod to make up the difference? so the piston height would be back up to stock 1.8???
 
#14 ·
The 350 piston has a compression height (CH) of 1.56" stock or 1.54" if they're "rebuilder" pistons.

So the stack would look like:

deck height (9.025" to 9.00") minus 1/2 stroke (1.5") minus rod (6") = 1.525" CH, or 1.50" CH if zero deck (9.00") block.


Using a rebuilder piston this puts the top of the piston out of the cylinder at TDC by 0.015" if the block is uncut, or 0.035" using stock CH piston.

Using a zero deck block, the 1.54" piston is 0.040" out; 0.060" out if using stock CH pistons.
 
#13 ·
first,just buy 302 pistons,use 283 rods and a small journal 327 block.

Problems: 283 uses a small pressed on ,one piece balancer,many prefer to use the bigger 2 piece balancer. If you have a 350 block,then buy a large journal 302 crank. then its worth upgrading the rods.large journal rods are more common so price is fair.
If you have a 283 block then consider building a 292 (060 over 283) you only lose 13 inches.
Depending on how much horse power you want? its easy to get too much cylinder head on that little engine. A small runner 2.02 head will make lots of power. I wouldnt build much more than 425 horse power for a normally aspirated 5 liter
 
#15 ·
Thank you so much cobalt327 Now it makes sense to me! :) I would buy 302 pistons if they weren't 500+ dollars a set with out rings! also on that note its hard to find a 302 dish piston for running forced induction. my goal is 8.5-9CR The other huge problem with 302 piston is most of them are around 11-1CR and while I love a nasty N/A V-8 I can't see using race gas to just play around cause that's what I will mostly be doing don't get me wrong I will be going to the drag strip and autocross.
 
#23 ·
You are welcome, Rick. You may be surprised to hear how many guys ask about building a clone of the 'mighty Z28 302'- there's at least one a month here alone. Times that by all the sites and all the other people who never post about it and that extrapolates out to a surprisingly large number of people who might build one if the pistons were priced like a 283 piston (which it essentially is). This makes me wonder why one of the companies doesn't tool up for a run of them.:confused:

In your case (using boost), you'd want forged. But for the majority of builds, a good cast piston would be just fine.

FWIW, there is a franken-build you could do using the crank and rods from the Gen 2 L99 engine. The rods from the L99 are 5.94", this will allow you to run off the shelf 350 pistons with the L99 3.00" stroke crank. Takes a 1-piece rear main seal block.

Or use spacer bearings to put the SJ 283 crank in a 4" bore block. Use the L99 rods to run stock CH 350 slugs.

BTW, the rear seal area of the 283 crank has to be inspected to see if it originally used a rope seal or 2-piece rear main seal.
 
#17 ·
well for me there is a multitude of reasons and I'm going turbo charged, more efficient hp than super or blown and when it comes to forced vs. HIGH C.R. N/A. There is very small price difference in the over all build either way I'm spending good amount of money on Ignition and Fuel system so why not. I'm not looking to break records or be the biggest guy out there or anything, I just want to have fun and doing this kind of build is a part of it for me. If i wanted to go fast for cheap I would just do what everyone does and get a 454 and slap boost or nos to it till i blows up and get another one! Plus its for my 69 Nova so I'm looking for handling, power, and engine response.
 
#20 ·
I totally agree that there are more suitable and practical ways to go. However the reason for this build is for nostalgia with a modern twist but is mostly for a family member that has recently been diagnosed with cancer and is my inspiration for the engine. He had the 302 Camaro in his youth and it later became his speed boat engine after totaling his Camaro. When he put it in his boat he painted the engine pink and once I have mine together I will also follow suit and pay homage to this man who has helped shape my life. Most likely more than most of you wanted to know but that's my reasoning behind this build.
 
#21 ·
As far as the crank goes I think it is a cast steel I recently bought a forged steel crank and have them side by side and you can see the difference and even hear the difference when you tap the counter weight with a hammer. I'll try to post some pics up once I get the photos up online.
 
#24 ·
I have a set of new reconditioned 5.94 rods and a set of std. flat top forged pistons on E-bay right now for a really good price.

I ended up buying a set of I-con forged hollow dome pistons ($400) and forged lightweight rods for mine. I did this because I got a deal on some aluminum heads with 64cc combustion chambers. I sold the LT1 heads I had.

And yes, there are forged and cast 283 cranks. I have both. The cast has the same casting as one one posted above.
 
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