In a post some ways down the thread list and titled "Unhappy 1957 Fuelie", Duke Wiiliams provided some photos of Chevrolet connecting rods and these were posted by Tracy Crisler. I provided some additional information regarding the pictured and other connecting rods used in PRODUCTION for Chevrolet small blocks during the 1955 through 1982 period. If you're interested in some pretty extensive information on connecting rods, you may want to check out the posted photos and the comments by Duke and myself.
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In Appreciation of John Hinckley -
Absolute gold mine of info...now the $50 question
My engine in still on the stand and my rebuilder doesn't seem to remember which style of rods I have.. Beings it's a July 63 build and the odds are pretty high that the rods are still the original ones, I'm going to roll the engine over and pop the pan for a look.
Assuming they are originals, how big of task is it to swap the rods out once they are on the bench? -
Re: Absolute gold mine of info...now the $50 quest
If you install new rods, the bottom end should be rebalanced, but everything can be reassembled with the same new rings and bearings.
What if any prep did you have done to the old rods?
Is your engine medium performance or SHP/FI?
Being as how it's a '63 the original rods would definitely be the weak "early 327" type without the extra hump of metal adjacent to the bolt seats.
DukeComment
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Re: Absolute gold mine of info...now the $50 quest
Duke,
This is a SHP engine. The rebuild was done about 8 years ago and I don't have any idea what was done to prep the rods.
Are the wrist pins a press fit deal? I seem to remember the pistons installed are a forged TRW piece. 'Splain the rebalancing of the bottom end. Can I do this at home?
Forgive my questions here, but the last engine rebuild I did personally was in high school shop class in 1976... No performance tricks, just basics.
tcComment
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Looks likes I lost the connecting rod lotto....
The picture is pretty crummy, but these appear to be the original style rods.
wonderful...
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Re: Absolute gold mine of info...now the $50 quest
Yes the OE type replacment pistons have pressed pins, unless they were modified. The bottom end should be rebalanced because the big and small end weights of a different rod would likely be slightly different than the original type. It requires special equipment that a high end engine machine shop or specialist would have.
DukeComment
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Re: Absolute gold mine of info...now the $50 quest
Tracy,
My observations of the lower end of your engine lead me to the following conclusions.
1. Your engine has the stock earlier rods.
2. Your rods have new rod bolts.
3. Your engine has been bored and has new pistons.
4. Your engine has never been rebalanced since the rebuild.
5. Your rods have been rebuilt and probably magnafluxed.
This engine rebuild is very common to production engine rebuilders and will last as long as your 1963 SHP is not used for a special high performance application. In other words, if you are building a trailer queen this motor will probably last for a lifetime. If you are building a 1963 that your want to autocross, drag or occasionally want to run her up to 6000RPM you should consider consulting a shop that will change those rods and rebalance the lower end.
I'm not an expert by any means on engine rebuilds but like to have a dependable SB that won't let me down when my right foot tells me to go and my brain agrees.
Regards,
JRComment
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those are newer style conn rod bolts
you can tell by the dimple in the ends as these are there to use a "stretch" gauge on the bolts. no GM bolts ever had them. when you get items magnafluxed they always come back with a tag saying "no cracks showing" but there still can be internal cracks. any part of a rotating assy has a certain life and if your orignal engine add great value to your corvette i would change the rods.Comment
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Re: Absolute gold mine of info...now the $50 quest
Pressing out the pins without damaging the rods and pistons is difficult without the proper equipment, as the end of the rod (buried between the pin bosses up inside the piston) has to be heated without damaging the piston, and the piston has to be properly supported in the press to avoid damage, especially if they press the pins out "cold". This doesn't matter much in a normal rebuild, as they trash the old pistons anyway and don't care if they're damaged when they press the pins out.Comment
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i have pressed out pins and reused the pistons
you just have to have the proper fixture and you must rehone the pin hole in the piston.Comment
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Re: those are newer style conn rod bolts
clem-----
Yes, the rod bolts have definitely been changed to non-GM aftermarket type bolts. However, the rods, themselves, look like GM rods. From the photos I can't tell if they're the early or late style 327 rods.In Appreciation of John HinckleyComment
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