I was working on a car with no compression in four holes and did an "adjust as solids" procedure and got those four back working. I noticed all 12 adjusting nuts (first because the 5/8" socket slipped ) had been replaced earlier with Nylocks.

Should I tell the owner they need to be replaced with stock like distorted thread (top lock) nuts? Or have people successfully used Nylocks?

Frank DuVal

Fredericksburg, VA

I wouldn't think that Nylocs would be a good application for rocker arm nuts because of how hot those studs can get. Even if the nylocs are tight when first installed, it's possible for the nylon to lose its grip on the threads from heat over a long enough time. It isn't a max temperature rating, it's the fact that the nylon will soften well before its max temperature, and slowly lose its grip. Kind of like aluminum heads and valve seats when the heads get too hot!

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Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
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My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]

Yes, a good locknut, Phil, those are center lock distorted lock nuts. They can be threaded on the bolt/stud from either direction.

Kevin, I agree hot is not a good use of Nylon. Some specs I read say 250°F. Seems like these studs can get hotter. I did think these Nylocks were much "looser" than the top locks GM used.

Frank DuVal

Fredericksburg, VA

Frank DuVal Wrote:
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> Yes, a good locknut, Phil, those are center lock distorted lock nuts. They can be threaded on the bolt/stud from either direction.
>
> Kevin, I agree hot is not a good use of Nylon. Some specs I read say 250°F. Seems like these studs can get hotter. I did think these Nylocks were much "looser" than the top locks GM used.




1964 Monza Coupe
1965 Corsa 140
1967 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

I've had the stock type loosen up so I vote no on the nylon.

Joel
Northlake, TX
5 Ultravans, 145 Corvairs and counting...

I worked on a Corvair once where the guy had the head nuts on the rocker arms, free to loosen for sure.

He put the rocker arm nuts on the upper stud nuts with the rounded end in, it must have taken patience and persistence to get them started. The rounded head dug into the aluminum causing it to tightly surround the crankcase studs. It was very difficult to get the heads off and I had to buy a counter-sink tool to repair the surfaces. I suppose I had to use thick washers too but I don't remember.

I don't think he ever got it started. Another interesting thing was the carburetor base spacers installed backwards so they were blocking the center hole.

It started out that they wanted the carburetors adjusted.

Jim Brandberg
Isanti, MN
CorvairRepair.com