Farm Equipment - D17 rod bearings

D17 rod bearings

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=172279
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Topic: D17 rod bearings

Posted By: Doobletango
Subject: D17 rod bearings
Date Posted: 23 Jun 2020 at 7:09pm

I have a series 1 D17 that develop a knocking sound 2 weeks ago. After a lot of digging to get the oil pan off, I found the #3 rod loose on the crankshaft. Upon removing it the upper bearing is completely gone and the lower bearing is partially there. I’ve been carefully cleaning the the rod journal.
My IT manual says the rod journal should 2.995”. I have 2.365”ish. I pulled a good rod cap and checked it. The measurements are relatively the same. After measuring further (just with dial calipers to see roughly where I am at) I’m showing .0015” taper from ones side to the other. I have yet to polish the journal and actually use a mic on this to see where I’m actually at.
1. I’m guessing this engine has .030” bearings. Does this sound right?
2. Can anyone edify how much out of round, etc I have for play on this journal. I was really hoping this would be a quick/easy fix but it’s becoming more and more of a project.

Replies:

Posted By: Boss Man
Date Posted: 23 Jun 2020 at 9:37pm

Double check your measurement or typing. According to my math you have 5/8 of an inch clearance. Thats not possible. If this is a non diesel the rod journal is 2.374. That would mean your crank is .010 under. That amount of taper shouldn't be a huge concern as your clearance is .001-.003. Unless of course your running full load most of the time. Then I would consider pulling the crank and having it machined.

Posted By: Doobletango
Date Posted: 25 Jun 2020 at 12:33pm

I’ll recheck my measurements. Maybe I was looking at the wrong specs in my manual because what you’re saying sounds right.

Posted By: d17brown
Date Posted: 25 Jun 2020 at 9:24pm

You were looking t main bearing size. 2.99

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phil

Posted By: Doobletango
Date Posted: 17 Jul 2020 at 5:42pm

Yeah, after looking closer I see that. Lol
So here’s what I’ve got...
I double checked with one of the good journals.
Good journal: 2.3645”
Questionable journal: 2.3505”
Unless my math is wrong, I’m showing .014” wear. My manual says .001”-.003” so I’m WAY out of specs on this.
So here’s my next question: am I better off buying a crankshaft with standard size journals, or waiting for a shop to grind this one down after I get the time to take it out? I’d one option better than another?

Posted By: DrAllis
Date Posted: 17 Jul 2020 at 6:53pm

Ask your machine shop to give you a quote on clean, magnaflux and regrind your mains and rods. The rod journals might have to go minus .030" to be true again. Then, have him price you a set of bearings. Now you can compare that total price to a different crank plus bearings for it.

Posted By: Doobletango
Date Posted: 17 Jul 2020 at 7:14pm

I’ve never done work on a setup this large-I’m used to small engines where you simply replace the whole connecting rod. Can I re-use the rod with an undersized bearing, assuming there’s no damage to the rod bearing surface?

Posted By: Boss Man
Date Posted: 17 Jul 2020 at 7:22pm

Unless the rod is twisted, install the under sized bearing and your good to go.

Posted By: DrAllis
Date Posted: 17 Jul 2020 at 7:30pm

Not if the old bearing shell has turned or damaged it. Resizing that rods big end would be in order.

Posted By: Doobletango
Date Posted: 17 Jul 2020 at 7:42pm

Thanks guys. I thought that was the case.
Can the rod be removed from the bottom end without pulling the piston if need be?

Posted By: DrAllis
Date Posted: 17 Jul 2020 at 7:51pm

NO.

Posted By: DSeries4
Date Posted: 18 Jul 2020 at 8:50pm

No such thing as a quick and easy fix when you get a knock in an engine.

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'49 G, '54 WD45, '55 CA, '56 WD45D, '57 WD45, '58 D14, '59 D14, '60 D14, '61 D15D, '66 D15II, '66 D21II, '67 D17IV, '67 D17IVD, '67 190XTD, '73 620, '76 185, '77 175, '84 8030, '85 6080

Posted By: SteveM C/IL
Date Posted: 18 Jul 2020 at 11:10pm

Do what it takes to fix it right and be done. Cutting corners there could end up with junk.

Posted By: DaveKamp
Date Posted: 19 Jul 2020 at 12:24am

Unfortunately, piston needs to go out the top in order to remove the wrist pin.

Take your mic to that journal again, and check it in the vertical plane, and at 90 degrees to vertical... is the journal round, or out-of-round?

Pulling it all down to go through it right would be the 'company line' way to solve it... but if the journal IS still round, and you don't have a bent rod, and you're not expecting brutal service out of it, an undersize bearing insert for an in-situ swap, carefully done, could buy you several years, perhaps more, before having to yank the engine for a full job. IF the big-end needs doctored, you'd hafta lift the piston out of the top anyway, but I know guys that would do some amazingly bold things with very little resources... I won't recommend, but I cannot deny that such things DID work...

Realize that way-prior to the D, was the WC, WD, and WD45... the early WCs had shims, and when there was slack, one would simply remove a thin shim. That technology has passed onward with the appearance of replaceable inserts, but there's still validity in the concept.

How hard are you gonna work it?

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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

Posted By: Doobletango
Date Posted: 23 Jul 2020 at 9:27pm

Well, I want to be able to run this tractor full throttle so I can mow with it.

Posted By: frnkeore
Date Posted: 24 Jul 2020 at 2:19am

If this happened, as you state:

Upon removing it the upper bearing is completely gone and the lower bearing is partially there. I’ve been carefully cleaning the the rod journal.

I would buy a good used rod to replace it. When that happens, the rod is usually scored, pretty good, it might not be resizable and when they do resized, enough rod material has to taken of to allow it to be resized round. That gives you a little shorter rod and less compression. Personally, I don't like to do that and a used rod might be had for less than resizing.

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Frank
1959 D17 Series I #24001+, '59 D14
'55 & '59 Ford 850 & 861
Ferguson TO 35 Deluxe, Oliver 70 and 5 more.

Posted By: DrAllis
Date Posted: 24 Jul 2020 at 6:42am

BUT, I have seen rods from a different generation engine (remember 1953 thru 1975) weigh considerably more or less than the rod that is already in the engine. Resize if it all possible.