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Bent connecting rod!

Bent connecting rod!

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Pillarman
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Was able to get 2 pistons free from my seized D2 last night. After a few minuites of swearing and head scratching, realized they come out the bottom rather than the top of the engine. Anyhow, number 4 con rod has a nice gentle bend in it. Bent enough that it has run for a while slightly rubbing on the bottom of the liner!! Probably why it got parked.

Has anyone every had luck straightening a con rod? If so, how did you go about it? I have access to heat/stress relieving facilities.
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Thu, Jan 31, 2008 11:16 PM
SJ
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I never in all my engine experience heard of trying to correct a bent rod but if you post the serial number of your tractor I,m sure someone out there has one to sell which would be the way I,d go and discard that old one.It,s a gamble to try to correct the bend and get it perfect again and if it was straightened then down the road it could fail due to a minor stress crack not visible to the eye.If your tractor is a 4U or 5U D2 I know of a place that sells Cat used parts but not sure if it,s an older model if they,d have parts that old.
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Thu, Jan 31, 2008 11:34 PM
gemdozer
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Reply to SJ:
I never in all my engine experience heard of trying to correct a bent rod but if you post the serial number of your tractor I,m sure someone out there has one to sell which would be the way I,d go and discard that old one.It,s a gamble to try to correct the bend and get it perfect again and if it was straightened then down the road it could fail due to a minor stress crack not visible to the eye.If your tractor is a 4U or 5U D2 I know of a place that sells Cat used parts but not sure if it,s an older model if they,d have parts that old.
I Dismantle 3 D2 Motor For Parts And Should Have Some Rod But Need The Parts Number On.
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Fri, Feb 1, 2008 1:05 AM
SJ
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Reply to gemdozer:
I Dismantle 3 D2 Motor For Parts And Should Have Some Rod But Need The Parts Number On.
Pillarman as Gemdozer said, get the casting part number off the rod then you,ll get the correct one as I didn,t think of that but only the SN. If you can, then get the other rod numbers to be sure they all are the same.
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Fri, Feb 1, 2008 2:01 AM
Pillarman
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Reply to SJ:
Pillarman as Gemdozer said, get the casting part number off the rod then you,ll get the correct one as I didn,t think of that but only the SN. If you can, then get the other rod numbers to be sure they all are the same.
Serial Number is 3J 3221 SP. I will get the casting numbers tonight.
Thanks.
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Fri, Feb 1, 2008 2:35 AM
Pillarman
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Reply to Pillarman:
Serial Number is 3J 3221 SP. I will get the casting numbers tonight.
Thanks.
The number cast into the rods is "4B8435". Can't see the 2 still stuck in the engine. On the other side of the rod is cast "UNAA".

If anyone has one to match I would be interested. Thanks.
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Fri, Feb 1, 2008 8:03 AM
gemdozer
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Reply to Pillarman:
The number cast into the rods is "4B8435". Can't see the 2 still stuck in the engine. On the other side of the rod is cast "UNAA".

If anyone has one to match I would be interested. Thanks.
I have some 4b8435 rod. [email protected]
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Sat, Feb 2, 2008 12:06 AM
Pillarman
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Reply to gemdozer:
I have some 4b8435 rod. [email protected]
Recieved my replacement rod from Gemdozer the other day. Thanks. Isn't the internet amazing!! Anyhow, got it cleaned up and measured up last night, measured up good but, the beam of the rod is beefier than the one pulled out of my D2. Same casting number. Is this common? I can only assume that they must have had some bending issues (as mine did) and beefed up the beam.
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Wed, Feb 13, 2008 1:03 AM
Old Magnet
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Reply to Pillarman:
Recieved my replacement rod from Gemdozer the other day. Thanks. Isn't the internet amazing!! Anyhow, got it cleaned up and measured up last night, measured up good but, the beam of the rod is beefier than the one pulled out of my D2. Same casting number. Is this common? I can only assume that they must have had some bending issues (as mine did) and beefed up the beam.
That's unfortunate🙄 🙄
I think I'd try to come up with a matched set or possibly risk balancing problems or at least compare weights with what you have.
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Wed, Feb 13, 2008 3:59 AM
Frank Fox
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Reply to Old Magnet:
That's unfortunate🙄 🙄
I think I'd try to come up with a matched set or possibly risk balancing problems or at least compare weights with what you have.
All rods should be the same weight, other wise it will be out of balance and that will effect engine life and HP. When one has the rods out of almost any engine it is good practice to have the rods check for alignment (straightness) Most engine shops have a special tool to check the alignment of the rod and can straighten them, if---if they are not bent to badly. Sounds like I would replace the bent rod in your engine, just make sure that all rods are of the same weight and if you get used rods have them checked for alignment. You will be glad you did.
Just my two cents worth
Frank
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Wed, Feb 13, 2008 10:07 AM
neil
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Reply to Frank Fox:
All rods should be the same weight, other wise it will be out of balance and that will effect engine life and HP. When one has the rods out of almost any engine it is good practice to have the rods check for alignment (straightness) Most engine shops have a special tool to check the alignment of the rod and can straighten them, if---if they are not bent to badly. Sounds like I would replace the bent rod in your engine, just make sure that all rods are of the same weight and if you get used rods have them checked for alignment. You will be glad you did.
Just my two cents worth
Frank
Kind of related - my father was a topdressing pilot in NZ (cropduster) flying Agwagons and such. Anyway, he bent a prop once, and being way out in the wops, he got the crescent (adjustable wrench) out, swung on the prop blade til it was "about right", and flew home. His engineer tore strips off him and threatened to remove the seat and controls from the aircraft if he ever ran the engine with a bent prop again : )
Moral of the story is don't try to run stuff you know is not in good shape IF you don't want to buy more problems....

Cheers,
Neil.
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Fri, Feb 15, 2008 10:09 AM
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