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WF owner 
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Joined: 12 May 2013
Location: Bombay NY
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 Topic: AC engine assembly problem
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?
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steve(ill)
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Joined: 11 Sep 2009
Location: illinois
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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 ?
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Like them all, but love the "B"s.
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WF owner
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Location: Bombay NY
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Posted: 01 May 2023 at 5:37pm |
 steve(ill) wrote:
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 ? |
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".
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steve(ill)
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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.
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Like them all, but love the "B"s.
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plummerscarin
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Posted: 01 May 2023 at 6:49pm |
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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?
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WF owner
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Posted: 01 May 2023 at 6:52pm |
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WF owner
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Posted: 01 May 2023 at 6:57pm |
plummerscarin wrote:
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? |
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.
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WF owner
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Posted: 01 May 2023 at 7:49pm |
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I have been using an AC Service Manual for my specs. I just checked an IT manual and it says exactly the same.
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Acdiesel
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Posted: 01 May 2023 at 8:18pm |
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I WOULD TRY THE SELF-LOCKING NUTS AND TORQUE THEM TO THE 40 LBS. AND SEE HOW SHE TURNS OVER.
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Rod in MN
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Posted: 01 May 2023 at 8:37pm |
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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
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