AC engine assembly problem
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=194921
Printed Date: 23 Aug 2025 at 12:15am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: AC engine assembly problem
Posted By: WF owner
Subject: AC engine assembly problem
Date Posted: 01 May 2023 at 2:22pm
|
I am assembling an engine with a 201 (WF) block with a 4.5" (WD45) crankshaft, WD45 connecting rods and (D-17) 7.5/1 pistons. The mains are -.030 and the rods are -.020. I have checked and all (new) main and rod bearings are the correct size. I shimmed the mains and have everything in spec and it turns nice; easy and smooth. Since I am using WD45 rods, they don't need shimming, but I have checked the clearances and all are correct. I have castellated nuts, so the book says rod bearings should be torqued to 70 ft. lbs. I tightened the rod bearings at 20 ft. lbs. and it turns nice. Increased to 40 ft. lbs. and still turned nice. When I increase to 50 ft. lbs., it starts to turn harder than I think it should and at 60 ft. lbs., I can barely turn it. I find it odd that lock nuts (which have more resistance to turn) torque spec is only 40 ft. lbs. and castellated nuts torque to 70 ft. lbs. I have checked the bearing caps and all are oriented correctly. Suggestions? |
Replies:
Posted By: steve(ill)
Date Posted: 01 May 2023 at 5:31pm
|
thats what the book says... but i would have thought just the opposite.. the LOCK NUTS have some torque resistance to get them to turn... you add that to the REQUIRED TORQUE and get the total.... Normally a LOCK NUT has a higher torque value than a standard nut.. What is the diameter of the bolts ? 3/8 or 7/16 ? ------------- Like them all, but love the "B"s. |
Posted By: WF owner
Date Posted: 01 May 2023 at 5:37pm
I thought the same thing. The castellated nuts have no resistance when torquing them, plus they are wired to keep them from loosening. The rod nuts take a 5/8" wrench, so I assume the bolts are 7/16".
|
steve(ill) wrote:Posted By: steve(ill)
Date Posted: 01 May 2023 at 5:48pm
|
yea, something seems wrong.. Maybe Dr or someone with more background knowledge will jump in......... 70 is too high for a 7/16 bolt in my opinion.. note the torque on the smaller B-C motor ... not depending on nut style.  ------------- Like them all, but love the "B"s. |
Posted By: plummerscarin
Date Posted: 01 May 2023 at 6:49pm
| Just throwing this out there but is this a case of an offset rod or piston and when torqued to spec is when binding occurs? |
Posted By: WF owner
Date Posted: 01 May 2023 at 6:52pm
| uploads/9389/SCN_0025_2023-05-01_18-51-55.pdf" rel="nofollow - uploads/9389/SCN_0025_2023-05-01_18-51-55.pdf |
Posted By: WF owner
Date Posted: 01 May 2023 at 6:57pm
I was pretty careful to follow the instructions in the service manual when I was putting them together. Everything rotates fine when torqued to 40 ft. lbs., starts to bind at 50 ft. lbs. and turns very hard at 60. |
Posted By: WF owner
Date Posted: 01 May 2023 at 7:49pm
| I have been using an AC Service Manual for my specs. I just checked an IT manual and it says exactly the same. |
Posted By: Acdiesel
Date Posted: 01 May 2023 at 8:18pm
|
I WOULD TRY THE SELF-LOCKING NUTS AND TORQUE THEM TO THE 40 LBS. AND SEE HOW SHE TURNS OVER. ------------- D19 Diesel,D17 Diesel SER.3 2-D14, 2-D15 SER.II WF/NF D15 SER.2 DIESEL D12 SER.I, D10 Ser.II 2-720'S D21 Ser. II Gmc,caterpillar I'm a pharmacist (farm assist) with a PHD (post hole digger) |
Posted By: Rod in MN
Date Posted: 01 May 2023 at 8:37pm
|
What I would try is to tighten one rod and check for the rod to have side play . Same with the wrist pin that it is not pushing on one side of the piston. Do that to each rod one at a time. Back the of the one you did first. And when you torquing the nuts if torque is 70ft lbs. first torque the nut to 40 . Then on your final torque go to 70 ft lbs but do that final one with out stoping from 40 to 70 . If you don’t your final torque will be off. Good luck |