Should piston gudgeon pin retainers be replaced at rebuild?

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70Hardtop

70Hardtop

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What is the consensus from experienced engine builders on replacing the retainers of the piston gudgeon pins (wrist pins I think you call them ?). I am doing a budget rebuild on a 1967 273 with full floating rods. It will be a mild performance rebuild with mild solid cam, Weiand intake, headers etc, expecting about 290-300 HP. I am reusing the original pistons (using new rings/bearings of course) because not only are new ones hard to source now but the engine was in such amazing original condition when I disassembled it, pistons hardly worn and I got a hone on the bores and using some nice worked over conrods which have been sitting around for many years, been weight matched and shot peened and resized + ARP bolts.

The wrist pin retainers have been there nearly 50 years, they are just wire spring clips. They don't do much work but can they be a point of failure after a lot of miles and heat cycles?

I can just buy some new circlips but is it a good idea?, or necessary on a mild street driven engine?

thanks
 
You're rebuilding the engine, those clips are inexpensive buy new one's! 65'
 
Yes I know I more or less answered my own post in the dialogue and it's so easy to say, "yeah just go and buy new ones", doesn't take much brainpower to say that. As I am not an experienced engine builder, what I was hoping for was some reason why and why not from someone who had built lots of engines and SEEN lots of things. Are they a point of failure? New performance pistons should have them included, but that doesn't mean they are a weak point. I was just looking for a person who really knows the answer, not armchair experts giving an easy opinion. Thank you!
 
easy:poke:, I love watching experienced engine builders grenading $40,000 dollar boss 429's !!!!

lets just stick to "no such thing as a stupid question"
 
70Hardtop said:
Yes I know I more or less answered my own post in the dialogue and it's so easy to say, "yeah just go and buy new ones", doesn't take much brainpower to say that. As I am not an experienced engine builder, what I was hoping for was some reason why and why not from someone who had built lots of engines and SEEN lots of things. Are they a point of failure? New performance pistons should have them included, but that doesn't mean they are a weak point. I was just looking for a person who really knows the answer, not armchair experts giving an easy opinion. Thank you!
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Cheap insurance.
 
You called them circlips. Pic?
If there is a flat side make sure its' facing out.
Coming from an armchair engine builder.
Good luck
 
4spdragtop said:
If there is a flat side make sure its' facing out.
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If you are not removing the pin from the pistons, leave them alone, if removing the piston pin........?!?
Yes, replace them cheap insurance, open end of the criclip up toward the top of the piston. Try to only use your fingers to install or a wooden dowel, no screwdrivers, no metal scribe, or awl.
 
Depending on clip type, there is a true flat side and opposite side is somewhat "rounded". Rounded side facing out would be asking for trouble.
You came as far as removing pistons in disassembly, so why not remove clips and inspect?
I installed one clip at 12 o'clock and one at 6 o'clock. Offset so to speak. Not sure if correct but in my warped mind it is.
Dicer said:
If you are not removing the pin from the pistons, leave them alone, if removing the piston pin........?!?
Yes, replace them cheap insurance, open end of the criclip up toward the top of the piston. Try to only use your fingers to install or a wooden dowel, no screwdrivers, no metal scribe, or awl.
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Those clips in the pics, you should replace with spiral locks. If you have spiral locks to begin with and you haven't removed them...and this is a refresh deal. Leave them in and alone.
 
locks.jpg
I like the spiral locks over the snap rings myself. Don't the snap ring style locks require 2 with the flat faces against each other? I'm sure it makes a difference what the snap ring grooves were machined for.
 
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The old 273 and 318 pistons are machined for a round wire spring clip retainer only. Probably difficult to find new ones. If they did not get overheated, and u remove only 1 per piston gently, compressing as little as possible, I would not worry about reusing for a street engine
 
I never had one fail....there is so little load on them unless the rod is bent. I pulled a 310k 318 motor and the floaters were fine. These are made of spring steel and you compress the ends maybe .1 to install? I wouldnt call that stressing, but if you can get new ones and you got the time and money, you may sleep better. Floaters have 2 rotational surfaces while pressed only have 1: you overheat a pressed fit rod and you may gall the pin but the floater has another bearing surface to take the torque. Think about how a pressed pin could even move in a piston after you try and remove one of those! ? Only way would be to seize the small end and turn it out, to me at least.
 
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MOPAROFFICIAL said:
Those clips in the pics, you should replace with spiral locks. If you have spiral locks to begin with and you haven't removed them...and this is a refresh deal. Leave them in and alone.
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You can't replace one style with another as the grooves are likely a different width. Circlips and spiral locks have the pins machined flat... wire locks have a pin that has a bevel on each end to help seat the lock. If the lock groove is the same size he's OK... but I doubt replacing those OE locks with spiros will do anything except put little holes in his fingers when installing those little b*stards.
 
MOPAROFFICIAL said:
Those clips in the pics, you should replace with spiral locks. If you have spiral locks to begin with and you haven't removed them...and this is a refresh deal. Leave them in and alone.
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the picks u are referring to not posted by the O.P. and he is replacing the connecting rods. I have used tru arcs in pistons machined for tru arcs for 40 years without a single problem-like chrysler used in the 340 and hemi
 
Marcohotrod said:
the picks u are referring to not posted by the O.P. and he is replacing the connecting rods. I have used tru arcs in pistons machined for tru arcs for 40 years without a single problem-like chrysler used in the 340 and hemi
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I haven't personally, others have, had any problems with the classic tru arcs either, but I know a better design when I see one and have used spiral locks for 20+ years without a failure.
 
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