Shims under main cap and Rod caps ?
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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=128291
Printed Date: 27 Sep 2024 at 10:24pm
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Topic: Shims under main cap and Rod caps ?
Posted By: Whtbuch
Subject: Shims under main cap and Rod caps ?
Date Posted: 04 Sep 2016 at 4:09pm
| I have never seen these before working on car engines. Can someone inlite me to how these are used correctly in reassembling the rotating assembly thanks William |
Replies:
Posted By: Gerald J.
Date Posted: 04 Sep 2016 at 5:52pm
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Add shims until the Plastigage shows .003" clearance. The shims allow for adjusting the clearance without needing new bearing inserts as the original soft babbit lined inserts wore fairly rapidly. Modern inserts can be made to not need the shims. Gerald J. |
Posted By: DrAllis
Date Posted: 04 Sep 2016 at 7:09pm
| I'll address the WC-WD-WD45 4 cylinder engines, as I'm used to them. Any other AC engine someone else will have to tell you, such as the B-C-CA-IB engines. The WC-WD engines had shims on the main caps and rod caps. The WD45 only on the mains. Pay close attention when disassembling any engine !! That engine might have a WD-45 rod in it or maybe all the rods, so pay attention and lay everything out like it came apart. The shims used in these engines (mains or rods) were .010" thick when new. They consist of four- .0025" shims glued/laminated together for a total of .010" thickness. When you have a freshly reground crankshaft and new bearing inserts, you should have to use .010" at every location. That is the way they were designed. Everything new and straight bores will REQUIRE .010" shims to make the bearing crush correct. |
Posted By: WF owner
Date Posted: 05 Sep 2016 at 6:04am
Actually, you should REMOVE shims until the Plastigage shows ~.003 clearance. You should always start with the full shim pack and remove shims if necessary. You may also have to file the end of the bearings if you have to remove shims. Starting with too few shims can (over) crush the bearing mating surfaces. Read the service manual. It details the process, step by step. |
Gerald J. wrote:Posted By: Whtbuch
Date Posted: 05 Sep 2016 at 3:29pm
| Thanks guys . I will be dropping of the crank to have turned down and then will put back together.. p.s would any one know where to get a oil pump spring? . Many thanks william |
Posted By: wbecker
Date Posted: 05 Sep 2016 at 4:15pm
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When doing an overhaul I have the engine line bored and rods machined so that they do not require shims, like other engines. Easier to assemble, more accurate.
------------- Allis B, IB, Low B, G, D10, JD M, 8KCAB, C152 |
Posted By: DrAllis
Date Posted: 05 Sep 2016 at 4:15pm
| I've always been able to buy a complete engine shim kit from my crank grinder machine shop. |
Posted By: Dick L
Date Posted: 05 Sep 2016 at 4:17pm
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Here is a sheet showing the clearances. I have always used as close to .002 I could get with plastigage. Just remember that you need to have the exact thickness of shim under both sides. The rods and mains were bored with .010 shims under the bolts which when done let the caps shallow from half round. That was done so shims could be removed in the back yard or barn to bring the clearances back into spec. I had the rods bored to eliminate the shims on my pulling C. When assembled on a fresh ground crankshaft the plastigage showed a clearance of .0015. 
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Posted By: WF owner
Date Posted: 05 Sep 2016 at 7:02pm
| Although it's been about a year since I ordered any, one of my suppliers had shim packs (for both rod and main bearings) available. If you can't find them, send me a PM and I will check to see if they are still available. |
Posted By: Whtbuch
Date Posted: 25 Oct 2016 at 1:02pm
| Okay guys I have a question if I have my connecting rods resize do I still have to use shims? |
Posted By: wbecker
Date Posted: 25 Oct 2016 at 1:15pm
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No, the machine shop can machine the rods, and line bore the crank bores so they will fit your new bearings perfectly with no shims, just like other engines. Bill B ------------- Allis B, IB, Low B, G, D10, JD M, 8KCAB, C152 |
Posted By: WF owner
Date Posted: 26 Oct 2016 at 10:45am
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Line boring is very costly. If you're going to build a stock engine, it's hard to justify the cost. These engines ran well for years with shims. It's your money, but the couple hours spent adjusting the shims is a lot cheaper than line boring. |
Posted By: Allis dave
Date Posted: 26 Oct 2016 at 11:09am
| I would be very tempted though to have the rods cut to eliminate shims. That's a lot of shimming. Depends on cost I suppose. |
Posted By: Gerald J.
Date Posted: 26 Oct 2016 at 11:15am
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The beauty of shimming is that as the bearings and crankshaft wears you can take out shims to restore the clearance and get many more thousands of operating hours before new bearings are required. Gerald J. |
Posted By: Whtbuch
Date Posted: 26 Oct 2016 at 2:13pm
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Thanks guys for the information very helpful!!!! I have decided to have the rods cut since it's very cheap to do so and we'll be using the shims for the main caps as stated above very expensive to have line board. And again thanks very much William |
Posted By: Allis dave
Date Posted: 26 Oct 2016 at 2:27pm
| When the WD's switched to WD45's they switched to shimmed mains and non-shimmed rods. I was a little nervous about shimming my mains, but once I understood it, it wasn't hard at all. |
Posted By: WF owner
Date Posted: 26 Oct 2016 at 4:26pm
| I have a bunch of old used engine parts, including connecting rods. How do I tell if they are from a 201 (and need to be shimmed) or from a 226 (that doesn't need shimming)? Are they different part numbers? |
Posted By: Brian Jasper co. Ia
Date Posted: 26 Oct 2016 at 4:53pm
------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: Brian Jasper co. Ia
Date Posted: 26 Oct 2016 at 4:58pm
------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: CTuckerNWIL
Date Posted: 26 Oct 2016 at 5:30pm
|
AND, I might add that over time, the bores may not be round anymore with a new shim pack in place. I had nearly .003 bigger vertically than horizontally on my old WC, when I started re-assembly. What I did was put .006 shim in and hone the bore round to size. It worked great and the crank rolled like a dream, ending up with .0022 to .0025 clearance. If I had assembled it with a new shim pack, I would have had about .001 horizontally and .004 vertically and I didn't want that, nor did I want to pay for line boring. I just didn't have the shop time available to line bore it at work. ------------- 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: SteveM C/IL
Date Posted: 26 Oct 2016 at 8:24pm
| Sunken center mains and shrunk bore sides can develop after 60 yrs. |
Posted By: Whtbuch
Date Posted: 12 Dec 2016 at 3:22pm
| Hi guys so if I have this thing line board and the rods resize I can use their original bearings without having used the ship's or anything am I correct about this thanks |
Posted By: Whtbuch
Date Posted: 12 Dec 2016 at 4:43pm
| Hi I was wondering if the CA is the exact same as the C ? I'm trying to help my machine guy to find specs so he can line board it for me. P. S. Main Journal sizes and Rod Journal sizes |
Posted By: Dick L
Date Posted: 12 Dec 2016 at 6:36pm
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They are the same!
The dimensions you need are on the sheet I posted above.
|
Posted By: CTuckerNWIL
Date Posted: 13 Dec 2016 at 1:21pm
I don't see any dimensions for main bearing bore or rod bearing bore. SO, how do you come up with the right size to bore them too other than mic a new bearing using a ball and adding twice the thickness of the bearing plus needed clearance? ------------- 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: Whtbuch
Date Posted: 13 Dec 2016 at 1:37pm
| If I'm not mistaken how I understand the paperwork the main would be 2.250 in . With a .002 oil Clarence. But that is how I understand it I could be wrong? But I did not see A Rod bore diameter. |
Posted By: Whtbuch
Date Posted: 13 Dec 2016 at 1:42pm
| Mr Gerald do I have to buy a new style main bearing when I have this thing line bored |
Posted By: Dick L
Date Posted: 13 Dec 2016 at 2:40pm
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When in doubt measure! Placing the two shell together and measuring the outside with a mic will give you the diameter then less crush for the bore diameter. Unless your buying the line bore machine to do it yourself it would not something to be concerned about. If your machine shop has questions as to what to line bore the inside diameter to, you need to find a different machine shop. The outside of the bearing shells for that engine will all be the same diameter even when the inside changes as it is fit to the new ground journals. The chart I posted only gives the standard bearing journal diameters which is the size of standard bearings you would buy. I miss understood your question.
---------------------------------------------------------------------------------------------------- Actually if you would measure the rod at the position I was measuring the bearing in the picture without the bearing you would have the proper diameter. When the rod is recut you only need to cut the cap. You would not dare cut the width or the hole would be to large. 
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Posted By: Dick L
Date Posted: 13 Dec 2016 at 2:55pm
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You are welcome to look thru the pictures at the link. Some might help! http://public.fotki.com/DickL/allis_chalmers_engi/" rel="nofollow - http://public.fotki.com/DickL/allis_chalmers_engi/
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Posted By: wbecker
Date Posted: 13 Dec 2016 at 6:26pm
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Mr Gerald do I have to buy a new style main bearing when I have this thing line bored No. The bearings are the same, because originally it was bored WITH the shims, now it is bored the same dimension WITHOUT the shims. Bill B ------------- Allis B, IB, Low B, G, D10, JD M, 8KCAB, C152 |
Posted By: CTuckerNWIL
Date Posted: 14 Dec 2016 at 5:20pm
That is the JOURNAL diameter. You have to add clearance and twice the thickness of the shell bearing to get close to the actual bore size. If you could mic across the shell insert, the bore should be about .002 smaller than the OD of the bearing. ------------- 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 |