Engine Bearing Cap Lock Method Question
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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=145381
Printed Date: 31 Aug 2025 at 3:13am
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Topic: Engine Bearing Cap Lock Method Question
Posted By: CrestonM
Subject: Engine Bearing Cap Lock Method Question
Date Posted: 12 Dec 2017 at 12:31pm
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This may be a dumb question, but how necessary are things like cotter pins/wire/lock nuts for an engine's bearing caps? For instance, on my 8N, all the bearing cap bolts have wire running through them, I guess as a safety measure to keep them from loosening? My B has nothing on the main bolts, but has cotter pins through castle nuts on the rod bolts. My 1951 Chevy has nothing on the main bolts, but has these flimsy stamped steel lock nuts on the rods. In fact, some were missing when I took the engine apart, and they weren't in the oil pan. I also found out, just barely tighten them, or they crush/strip out. Maybe these things are more important than I'm thinking they are, but is a piece of wire or a flimsy stamped nut with no true threads going to really keep a bearing cap from coming loose? Is that their real purpose? Either way, I always put everything back like it was. Figure the engineers had something in mind. Thanks
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Replies:
Posted By: Dick L
Date Posted: 12 Dec 2017 at 1:20pm
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I have taken a bunch of these engines apart and most but not all have the main cap bolts wired. I have never found any main cap bolts that were loose. I have always found the cotter keys in the rod cap nuts. I wouldn't put one back together without them. The stamped spring steel safety locks do work. The way I have always done the B and C engine rod caps was to torque to 35 foot pounds and tighten only as much more it takes to get the cotter key in if necessary. I never had a loose nut failure this way. |
Posted By: CrestonM
Date Posted: 12 Dec 2017 at 2:18pm
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Thanks, Dick! These are the stamped nuts I was talking about. Is that what you meant by the spring steel safety locks?
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Posted By: Dick L
Date Posted: 12 Dec 2017 at 4:55pm
Yes.
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Posted By: DMiller
Date Posted: 12 Dec 2017 at 4:59pm
| They are called "Pal Nuts" and are far from a locking device but were used for such on early engines where many of them ended up drained with oil changes. A LITTLE red or even LESS blue Loctite will hold as well if not better on the cap nuts. |
Posted By: CTuckerNWIL
Date Posted: 12 Dec 2017 at 6:38pm
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Working on machine tools for most of 15 years I always carried a roll of safety wire and the pliers for twisting it up. It came in real handy when putting my WC back together. I would never put a pan back on without something on each nut!  ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: CrestonM
Date Posted: 12 Dec 2017 at 6:44pm
| I've always put the correct wire/pin/pal nut wherever they are supposed to be, it's just a curiosity I've had, ever since I opened up my 1st engine project in 2014. |
Posted By: ALLISMAN32
Date Posted: 12 Dec 2017 at 7:20pm
| I was wondering the same thing saturday evening assembling a continental n62 engine Creston! The mains bolts on it had the holes for lock wire. I went ahead and put the wire on them but I think if they were properly torqued they would never back out. Many of the other bolts on those older engines have no retainment device on them, i cant think of any automotive or agricultural engine that uses a locking wire or cotter pins In the last 50 years. |
Posted By: Hubert (Ga)engine7
Date Posted: 12 Dec 2017 at 8:32pm
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[QUOTE=CTuckerNWIL]Working on machine tools for most of 15 years I always carried a roll of safety wire and the pliers for twisting it up. It came in real handy when putting my WC back together. I would never put a pan back on without something on each nut! [/QUOTEX2! After working on military aircraft for over 36 years I have used miles of lock (safety) wire and it is essential as are cotter pins for castellated nuts and there is a right way and wrong way to install the wire. The wire twister pliers Charlie pictured come in very handy but you can do the job with a good pair of duckbills and diagonal cutters. Good wire twisters are expensive (around $90) but the cheap ones from HF are junk and a waste of your money. Safety wire is s/s and comes in .020", .032", and .041" plus copper in .020". ------------- Just an old country boy saved by the grace of God. |
Posted By: MACK
Date Posted: 12 Dec 2017 at 9:04pm
| If the bolt is properly tightened it will stay. If it is left loose, it will ware the safety wire out and come loose anyway. Old technology. MACK |
Posted By: LeonR2013
Date Posted: 12 Dec 2017 at 11:39pm
| Had you ever thought that these bolts are not torque to yield bolts? That's why some bolts torque to a certain point, and then you turn them the so many degrees. It also prevents a false torque. |
Posted By: B26240
Date Posted: 13 Dec 2017 at 6:20am
| Some years ago I overhauled a WC and found one of the nuts on a rod bolt split (cracked) I think it happened when someone over tightened it to get it to the next wire slot to put safety wire in. That made me question tourquing to a certain spec but then going more if nessesary to get safety wire in. i still do it though as who knows how many times that nut had been off and reinstalled over the years. |
Posted By: Allis dave
Date Posted: 13 Dec 2017 at 7:01am
| Far from an expert, but the reason you don't see safety wire and cotter pins on todays engines, is new technology like MACK said. Now you have all sorts of lock nuts. Even the WD45 had a sort of lock nut instead of wire. |