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Connecting Rod Fastener Question

Jaybey

Contributing Member
I'm getting closer to reassembly on my '69 1000ss, installing new roller bearings all around but.. For obvious reasons I don't want to reuse the original nylon locknuts, however I can't seem to find new ones as they are NLA (dear God). Any suggestions on a suitable replacement? They'll be going everywhere from the con rods to the reed blocks and center main bearings.
 
Once again folks need to look and don't give up.------Those nuts are available right here on this site ( NOS I believe )-----At $2.00 each
 
Time to start calling some dealers to see if anyone has some hidden.----But there are not many dealer who tear down and rebuild those wonderful motors.
 
This is the trouble.. some places (not dealers) have recommended stover nuts but, I don't know.. that's a lot of centrifugal force...
 
???-----No idea what a " stover nut " is.------These bolts / nuts are usually made with " high tensile " alloy steel.------You might as well re-use them instead of using something that you do not know the specs on ------Just my opinion.----For the pennies that it is worth.
 
???-----No idea what a " stover nut " is.------These bolts / nuts are usually made with " high tensile " alloy steel.------You might as well re-use them instead of using something that you do not know the specs on ------Just my opinion.----For the pennies that it is worth.

If you're referring to your opinion, I'd say you're undervaluing yourself :)

Stover nuts are crimp nuts (from what I can gather), what's on there now is the merc red nylon lock nuts...
 
Ever set foot in the speanaur industrial supply store / catalogue.--I have.----They list all kinds of grade 8 locknuts.----Cheap to order a package of 50.----Some folks have absolutely no idea what my " work experience / resume " look like.
 
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racerone, you've chimed in on just about every question/post I've put forward on here... just wanted to say thanks a bunch. I have limited experience in the outboard world, though not totally green I rely on fellas like yourself to get me through the things I've never touched on before. A lot of guys do. Whatever your resume may be, compared to me or the average Joe you're a professor and we're the eager students..

What I'm not sure of is whether the standard nyloc nuts will stand the test of time being subjected to fuel mixture for many seasons to come. Did Merc used special nylon in their nuts that were impervious to fuel? Or was it just standard..? Because boy haha, if they ever let go.. it'd be the end of it all. I'd be left with a great looking custom mailbox :cool:
 
20191127_195928_resize_8.jpg

Comparison of original roller bearings (piston pin) on the left and n.o.s. on the right.. can't see much difference other than color

Can someone school me on how to link up some of my previous threads?
I've started many involving my inline, I'd like to connect them if possible...
 
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Stover nuts have great holding power, actually better than a nylock in my opinion. If in doubt, clean up the threads and add a drop of red Loctite and with the Stover or Nylock you’ll be in good shape.
 
You know, after thinking about this, the stover may be too “aggressive” on stainless fasteners (not sure if you can even get SS stover nuts?). Most of my experience using these has been with mild or hardened steel fasteners. Maybe best to stick with nylocks then. Still no harm using some form of thread locking liquid like Loctite for insurance though.
 
Why did Merc use locking nuts in this case? None of the other Mercs I've worked on use locking nuts. nor is that standard automotive or racing practice.

Just had to toss that out there.

Jeff
 
Every BBC that I built used aftermarket rods that used bolts on rod ..no nuts as weak link at 7K+ RPM. Standard automotive practice nuts are OK as engine never runs above 2K as tranny downshifts. And smart old racers never use stock rods unless heavily worked and treated but then its cheaper to buy aftermarket. I had over 4K in the rotating assembly in my last BBC..had around 11K in a motor in a 4K boat.....quick ride in a 16ft tunnelboat. Every I-line Merc I have every repaired has had lock nuts except the newer cracked rod style that use bolts
 
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Just checked a rod from a 1961 Merc 500 - Nylock nuts; maybe no one is paying attention to them when they work on them, my 1975 850 has them of course.
 
Sure ----Karl used what was available to him by the suppliers of the day.---Local suppliers too I think.-----If he said use these lock nuts then that was it.------It was not a global economy with overnight shipping back then.
 
The threads and the tork setting determine the holding power of the bolt, I'm sure they tested them to see if the nylon was able to hold them; they work - what else do you want.
 
What do I want?

Well, for starters, the OEMs are $2 US, the hardware store has different ones (white nylon) for much less.. I'd like to know whether the merc ones had special attributes that made them worth spending the money on. Or am I buying the brand with that extra money...,
 
For me I never cut corners to save a couple of bucks for anything that’s in the engine’s internals. Maybe the white nylocks are the same but I wouldn’t risk it just in case Mercury has a special plastic that they use on the nuts to withstand heat, fuel and oil. I also found that some less expensive nylocks are close to one time use, meaning once they have been threaded onto a fastener and removed, if reinstalled they have much less holding power the second time around.
 
This is an interesting thread so I figured I better chime in, and add my two pennies. I have built several Mercury's that use the aforementioned connecting rod nuts. Granted I am not building them for racing but for everyday use. If the original fasteners come out nicely and are in good shape I use a Loctite 243 for use in oil. This is a medium strength which I often use when assembling racing rear ends fastening the ring gear. Just talked to my friend in the Black hills of South Dakota and asked him about a few axles that I did for him and his friends. So far no problem with any of the rear ends and that was over 20 years ago. Granted this is a completely different application but it shows the ability of the Loctite 243 to hold in severe conditions. I also have assembled ring gears on several loaders including the very popular Case 580 which often have ring gear bolts come loose. This is a great compound when exposed to petroleum products and even synyhetics. Might argue that it's not the same as gasoline with all it's additives, but then again maybe nobody feels like a dispute right now.
 
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