301CI allis motor model 649T

Hello everyone. I have a 301ci 649T allis motor and was wondering if these are good motors or what you guys think of them. I havent had it that long but learning quick about it being ive had some issues to say the least! Its in a Hood slasher for logging I recently purchased and just last week had to buy a used motor as mine took a puke but no idea how many hours were on the one that was in it due to no hour meter.... I will be installing a hour meter now before i put it back to work. I just put rod bearings in this motor 3 weeks ago and things seemed good again(lost oil pressure prior to the bearings) but last week i started the motor up and ran for about 3 hours and something went terribly wrong. I knew by the sounds of it that i would have to rebuild it or find a different one so bought one out of a gleaner and am fitting that to my slasher. My original motor come to find out broke the crank! bearings are 20 over so assuming that maybe this couldve been from the last time the motor was rebuilt maybe the rod bearings were real bad and had weakened the crank? So with this knowledge as i was changing the front plate and cover over to the new to me motor i checked the rod bearings in it (so this is the motor out of the combine with a guess of 2500 to 3500hrs on it) and the rod bearings were wore... into the copper but no damage to any hard parts....main bearings are fine with little to no wear... is this common for this motor to have wore rod bearings at approx 3000 hrs? Thanks in advance for any input.

Edited by pigpenH - 25 Feb 2015 at 10:57am

Thanks Neil... wasnt sure if that was a norm for this motor or what. Appreciate the info! Have a good day!

Crank could have broke from poor machining, if the journals weren't radiused, at the corners...

• Bulletin:  Connecting Rod Bolt Torque Caution For Allis Chalmers 201, 301 & 426 Cubic Inch Engines

The AERA Technical Committee offers the following information on connecting rod bolt torque specifications for Allis-Chalmers engines.
This information applies to both early and late style engines, as several different hardware combinations have been used. 

Two different connecting rod and cap mating surface finishes were used and identification can be made by visual inspection. Early style
connecting rods have a serrated mating surface between the cap and the rod. Middle and Late style connecting rods can be identified
by smooth/machined surfaces between the cap and the rod.

ALL MODELS

When installing, use a light amount of engine oil on capscrew threads and on the underside of the capscrew head at the mating surface. Tighten
hardware using a minimum of two incremental torque steps, three on higher torque hardware (7.0L). Non-serrated connecting rod caps MUST
be aligned with the rod during installation. To do so, install hardware finger tight, use two feeler gauges between the rod/cap assembly and the
side of journal to hold assembly snug to one side of journal. Tighten hardware in multiple steps and then remove feeler gauges.

Allis-Chalmers engine models: 2000 series, 3.3 and 4.9-liter series (2200, 2800, 2900, 433 & 649 types, etc.)

Early style rods use hex-head capscrew with washer. The rod cap bolt holes have a 30° degree chamfer. Capscrew size used is .375" 24 x 2.00"
long, grade 8, tighten those capscrews to 50 ft/lbs.

Later style rods have the rod cap chamfer deleted and a new 12-point capscrew introduced. Capscrew size used is .375" - 24 x 2.00" long, grade
100, tighten those capscrews to 45 ft/lbs.

Note: Do not use later 12-point capscrews in early-serrated rods with chamfered holes or loosening of capscrews will occur. Early rods may be
machined and balanced to accept later capscrews.

Allis-Chalmers engine models: 3000 Series, 7.0 liter series (3400, 3500, 3700, 3750 & 670 types, etc.)
Early style rods use serrated rod caps with hexhead capscrews and washers. Capscrew size .437" 20 x 2.25" grade 8, tighten those capscrews to
85 ft/lbs.

Middle style rods use smooth machined rod and cap mating surfaces. Socket head capscrew size .437" 20 x 2.156" long, grade 100, tighten
those capscrews to 70 ft/lbs.

Later style rods use smooth machined rod and cap mating surfaces. 12-point capscrew size .437" 20 x 2.156" long, grade 100, tighten
those capscrews to 70 ft/lbs.

Note: Do not use middle or later type hardware in early-serrated connecting rods.

*Agkits.com cannot be held responsible for the accuracy of this data.

HTH      B:-)     Dnoym


ps  http://www.agkits.com/allis-chalmers-7000-7010-and-7020-tractor-data-sheet.aspx


HOT: .015

Edited by Dnoym N. S. Can. - 26 Feb 2015 at 8:08am

pigpen you are having some really bad luck. However your at the right site for info to fix your problems.  I'm sure that someone will be along to help you out, I wish I knew more I sure would like to help.  

Maybe try asking on the farm equipment page.  You might get a better response from guys in the know.

Well guys I figured it out... took the fan belt off this am and everything smoothed out... put different fan on(a little smaller and aluminium) and it smooth as silk now... cannot find anything visually wrong with the old one but im back to work so oh well. My old fan was much heavier and 22inch diameter amd this one is 20inch diameter and aluminium... dont know... but thanks for all the help!!!