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Someone just brought to my attention that there is a defect in the 62-65 327 connecting rods. Can anyone confirm or deny this? I've never had an issue using rebuilt 327 rods in these year models. I googled the subject, but not a single page came back with any info on defects in the 327 rods.
I've never heard of a "defect" in those motors' connecting rods. I didn't drive Corvettes for those years "back in the day", but I thrashed the snot out of plenty of Impalas and other GM products off my Dad's used car lot and never had rod problems...
There isn't so much a defect as the pre-66 rods just aren't as strong as 66 and later rods.
Metal fatigue, as Mike mentions, can limit the remaining useful life of the rods.
If I were re-building an engine, regardless of whether it had the early or the late rods, I'd buy all new rods. That would eliminate the relative weakness of the early rods and also remove the issue of possible metal fatigue from the reliability equation.
Jim
Last edited by jim lockwood; 10-30-2014 at 09:37 AM.
As mentioned, the 66-later 327 rods are better/stronger-----------------only 2yrs for the 'better rods. ALLLLLLLLLLLLLLLLLLLL 1955-1967 SB rods are 100% interchangeable. So, when building and SMALL JOURNAL SB, and using factory rods, the 66-7 variety are the most desirable.
I have zero disagreement with buying new, aftermarket rods for an engine build. But for a regular rebuild of a small journal SB, it's hard to beat using the 66-7 rods. When I build any of my engines with used rods, I seperate the cap and bolts and use a die grinder with a sanding drum and lightly clean up the beams all the way to the recessed area for the head of the rod bolt. Then I thoroughly blast them with VERY FINE media (the purpose of blasting is to relieve stresses). I install new ARP Wavloc bolts and have my machinist resize them. I've never had a rod failure by doing this on the workbench at home.
EVERYTHING I do is on a thin budget, I do not have unlimited funds. So, money IS an object for me. I do anything and everything that I can do on the workbench BEFORE taking an engine to the machine shop to save whatever I can. As a result, I pay a lot of attention to detail and I feel that the engines I build are comparable to what would be paid to a machine shop for total machine work and complete assembly.
BUILDING AN ENGINE IS NOT ROCKET SCIENCE! Patience and attention to detail is the key. Decide what you want from an engine, SHOP AROUND for prices on parts and only have REQUIRED machine work performed. For example, MOST machine shops will try to convince you that the heads and cylinder decks should be surfaced. If a head and cylinder deck were flat when disassembled, THEY WILL STILL BE FLAT!!!! I don't fault a machinist for wanting to resurface a set of heads (it's extra income for him), but if they really don't need it, why pay for unnecessary work?
Anyway, back to the rods. Below is a picture comparing two stock rods. The right is an as forged and installed rod and the left is how the rod looks after I have smoothed the beam. Anyone can do a lot of small things such as this so that the machine shop doesn't nickel and dime your budget.
Low horsepower hyd lifter engines I think will be fine with the early rod. The solid lifter, SHP engines put too much stress /RPM on the early small rod. Thats why GM made them thicker for 66. I've only built a few of small journal blocks, but every one of them had at least one early rod that did not pass mag due to cracks.
Boyan
Low horsepower hyd lifter engines I think will be fine with the early rod. The solid lifter, SHP engines put too much stress /RPM on the early small rod. Thats why GM made them thicker for 66. I've only built a few of small journal blocks, but every one of them had at least one early rod that did not pass mag due to cracks.
Boyan
????? Hmmm, so what small block "solid lifter SHP engine" did GM make in 1966 ? IIRC that's the year they dropped the solid lifter sb engines. The 327/350 L79 was the highest preforming SBC that year. The BBC did come in a solid lifter versions, but the OP was about small block (327) rods?
I went with Crower rods when rebuilding a generic 327. Bored .060, the motor was built using Crower rods, '70 LT-1 cam, lifters and intake, stock forged crank, 1.5 GM stamped steel rockers with screw in studs and used the 585 cfm stock Holley offered for the '64/'65 solid lifter motors.
Here's a a couple of pics of these rods purchased as a group buy through this forum back then.
No SHP in 66, obviously. If you are building one, in my opionion, regardless of what year you call it, you should use the larger or aftermarket rod. I use Crower.
Boyan
There was a defect (weak rods) in the connecting rods in the 65 - 396 that is one of the reason's so few exist today. I never heard that in small blocks.
Originally Posted by 65silververt
Someone just brought to my attention that there is a defect in the 62-65 327 connecting rods. Can anyone confirm or deny this? I've never had an issue using rebuilt 327 rods in these year models. I googled the subject, but not a single page came back with any info on defects in the 327 rods.
@ $630.00 for a set of the crower i beam rods, they are out of the picture. This engine is going to produce below 400hp at the flywheel, so I doubt super high end rods are really necessary. I see scat and eagle offer i beam rods with arp bolts for under 300. They are rated to 500hp. Surely one of those brands will be sufficient for a little naturally aspirated 327 with a cam upgrade
@ $630.00 for a set of the crower i beam rods, they are out of the picture. This engine is going to produce below 400hp at the flywheel, so I doubt super high end rods are really necessary. I see scat and eagle offer i beam rods with arp bolts for under 300. They are rated to 500hp. Surely one of those brands will be sufficient for a little naturally aspirated 327 with a cam upgrade
Amen..
Why get ridiculous when it is not required.
10-30-2014, 08:39 AM
62-65 327 Connecting Rod Defect???
