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Author Topic: connecting rod reconditioning  (Read 1093 times)
mainmansam
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« on: February 27, 2014, 09:47:22 AM »

Hi I have a shot at a set of 67 SS350 dimple rods at a decent price.  They are reconditioned and my question is if rods can be over-reconditioned?  Is my best course of action to take them to a shop have them measured and magnefluxed then make my decision?  I don't want to have a bunch of money in a set of rods I can't end up using.  Thanks.
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CNorton
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« Reply #1 on: February 27, 2014, 10:12:44 AM »

There are a few considerations when using re-conditioned rods.  The first is a slam-dunk:  make sure that new rod bolts, preferably ARP or some other recognized fastener, are included.  Rods should be re-sized any time the bolts are changed.

Second, double-check the center-to-center dimension.  A sloppy job of re-conditioning can result in variations in length if too much metal is removed from the rod.  Shortening the rod lowers compression slightly because the piston does not sit as high in the cylinder.  Of course, that difference can be compensated for during block prep but the center-to-center dimension should not vary more than a .001" if the job was done correctly.

Visually inspect the rods for nicks or grinding marks that could become stress risers and eventually result in cracks leading to rod failure.  This is a less common problem but it's always worth the time to hold the rods in your hand and visually inspect them for visible flaws.

If you're particularly concerned, you might ask to have them magna-fluxed.
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ko-lek-tor
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« Reply #2 on: February 27, 2014, 10:13:10 AM »

Hi I have a shot at a set of 67 SS350 dimple rods at a decent price.  They are reconditioned and my question is if rods can be over-reconditioned?  Is my best course of action to take them to a shop have them measured and magnefluxed then make my decision?  I don't want to have a bunch of money in a set of rods I can't end up using.  Thanks.

Several statements you make I do not quite understand. I am not aware of any 350 rods referred to as a "dimple" rod. If you have them "checked out" and are getting them at a "decent price", how can you have too much in them? If they are bad, a decision will be made at that point whether to spend extra to make usable or pitch them. If you have a concern about the quality and do not have the tools to measure them yourself, perhaps you should just get a used set of small journal (1967 and earlier) rods and have them re-conditioned at the shop you would have these rods you are considering checked out. SB Rods are generally plentiful and rod machine work for stock rebuild is generally not a bank breaker. Over re-conditioned? Not sure what that means-the rod is either good or it is not. Now, other modifications are possible such as "floating" or "bushing" the small end, indexing, balancing, stress relieving, side beam polished, lightened, etc...A basic rebuild, I would have the rods checked for bent/twisting, magnafliuxed, big end resized, and new rod boltsd, if money holds out have reciprocating assembly balanced.
A note:
    small journal, 11/32 rod bolts in 1967
    large journal, 3/8 rod bolts 1968, 1969
    forged steel
    pressed pin
    small rod beam
    a Chevrolet Engineering Servce Letter, dated November 1, 1967, read in part:
    "In order to use up a surplus of 45,000 1967 350 cu. in. Connecting Rod Assemblies (incorporating the 11/32" rod bolts and nuts), approximately 5,600 1968 RPO L30 (327 Cu. In.) engines with Powerglide Transmissions were built from 10-11-67 through 10-13-67 with the 1967 Connecting Rod Assemblies."
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mainmansam
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« Reply #3 on: February 27, 2014, 11:26:25 PM »

these rods are from a 67 SS350 engine with a dimple up by the piston pin.  11/16 bolts   They were reconditioned and I'm wondering  if it is possible to take too much material off while reconning them.  I could easily use any 350 rod but with my SS350 engine but I have a thing about originality.  Maybe somebody could tell me if a rod can be reconditioned more than once.  My instints tell me if too much material is taken off with a loose fit that I could spin a bearing more easily.

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CNorton
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« Reply #4 on: February 28, 2014, 10:36:05 AM »

these rods are from a 67 SS350 engine with a dimple up by the piston pin.  11/16 bolts   They were reconditioned and I'm wondering  if it is possible to take too much material off while reconning them...  Maybe somebody could tell me if a rod can be reconditioned more than once.  My instints tell me if too much material is taken off with a loose fit that I could spin a bearing more easily.

 I hope you'll pardon me but in fifty years of working with small block Chevrolet motors, I've never encountered a set of rods with 11/16" bolts.  I think that dimension should be carefully re-measured. 

To answer your direct question, a connecting rod could conceivably undergo the reconditioning process more than once and, if the procedure is done correctly, wouldn't be necessarily at risk of spinning a bearing.  Personally, I would not want to use such a rod because of the odds that the center-to-center length could be compromised or inconsistent across the set.
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69Z28-RS
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« Reply #5 on: February 28, 2014, 10:43:37 AM »

I think his  '11/16"' measure has to be a typo... Smiley
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rszmjt
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« Reply #6 on: February 28, 2014, 11:16:52 AM »

"Dimple" rods weren't used on the 67 350, but to answer your question, yes you can overdo anything.

Ed


Sorry Ed but 1967 Camaro 350 rods WERE Dimple, they are very unique in that they used the 11/32 bolt same as the small journal rod, and to clarify they had a raised dimple just under the wristpin area on both side, same as a L78 rod. in the last 40 years I have taken apart and overhauled 3 known original SS350 Camaro engines and they all had them. Very hard to find rods and only used in 1967.
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Ed Bertrand
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« Reply #7 on: February 28, 2014, 11:37:04 AM »

Yeah, I looked it up in the P&A and the 67 350 DID use dimple rods! I didn't realize that. I thought they were like 68 and 69 which DIDN'T use dimple rods. I've deleted my original post.

Ed
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rszmjt
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« Reply #8 on: February 28, 2014, 11:41:12 AM »

Yeah, I looked it up in the P&A and the 67 350 DID use dimple rods! I didn't realize that. I thought they were like 68 and 69 which DIDN'T use dimple rods. I've deleted my original post.

Ed


Yes they sure puzzled me the first time I saw a set, VERY Rare. I personally would use the later 3/8" bolt "pink" rod to gain bolt strength and better rod material, especially if it is a original stamp block.
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mainmansam
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« Reply #9 on: February 28, 2014, 03:06:59 PM »

thanks rszmjt  I will take your advice.  Its funny  I've owned half a dozen 67's and still see posts debating medium journal vs small journal and dimple or not dimple rods in SS350's.  I do feel I know my 67s and would never chime in on a conversation I'm not 100% confident that  I know the answer to.  It waters down the credibility of the advice when a person is criticized for a typo or how he words his post.   Some birds chirp just to hear themselves.  Maybe a self confidence issue   Sorry in advance to those I've offended
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Ed Bertrand
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« Reply #10 on: February 28, 2014, 03:12:24 PM »

Quote
Some birds chirp just to hear themselves.  Maybe a self confidence issue

Since your reply is obviously aimed at me, I'll just say "chirp chirp".

Sorry to reply to your thread. Don't worry. It'll never happen again.

Ed
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z28z11
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« Reply #11 on: February 28, 2014, 05:19:43 PM »

Yeah, I looked it up in the P&A and the 67 350 DID use dimple rods! I didn't realize that. I thought they were like 68 and 69 which DIDN'T use dimple rods. I've deleted my original post.

Ed


Yes they sure puzzled me the first time I saw a set, VERY Rare. I personally would use the later 3/8" bolt "pink" rod to gain bolt strength and better rod material, especially if it is a original stamp block.

Then again, the '67's are small journal, no "pinks" until medium journal '68-9, right ?

Regards,
Steve
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1969 X66 L78 Cortez/BVT
1969 Z11 L48
rszmjt
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« Reply #12 on: March 01, 2014, 01:50:03 AM »

Yeah, I looked it up in the P&A and the 67 350 DID use dimple rods! I didn't realize that. I thought they were like 68 and 69 which DIDN'T use dimple rods. I've deleted my original post.

Ed


Yes they sure puzzled me the first time I saw a set, VERY Rare. I personally would use the later 3/8" bolt "pink" rod to gain bolt strength and better rod material, especially if it is a original stamp block.

Then again, the '67's are small journal, no "pinks" until medium journal '68-9, right ?

Regards,
Steve

No, All 1967 SS350,s are Large journal with 11/32 bolt large journal rods, the 327 was a small journal engine, same as the 302 for that year. Early 68 Z28 used the non shotpeened rod pressed pin, later production 68 used the shotpeened rod with floating pin same as all 69 302DZ.
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Buzz1967
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« Reply #13 on: March 01, 2014, 09:25:28 AM »

Greetings members,

I'm new to the forum. This "dimple" rod thing is new to me. Are we referring to the reinforcing gusset that bridges up from the I beam to the wrist pin? Is that the "dimple" that the name refers to? 
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zman1969
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« Reply #14 on: March 11, 2014, 11:38:11 AM »

"Dimple" rods weren't used on the 67 350, but to answer your question, yes you can overdo anything.

Ed


Sorry Ed but 1967 Camaro 350 rods WERE Dimple, they are very unique in that they used the 11/32 bolt same as the small journal rod, and to clarify they had a raised dimple just under the wristpin area on both side, same as a L78 rod. in the last 40 years I have taken apart and overhauled 3 known original SS350 Camaro engines and they all had them. Very hard to find rods and only used in 1967.
Very interesting - does anyone have some pics of these? I've been playing with camaros since late 70's and I'm still getting educated
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Rich

69 RS/Z DZ302 Daytona bumble bee
69 T/A clone LS6/6sp
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