1206 with a miss

[IA1456]

Ok for those who have experience in the 361-407 world I have a delimia. To start from the beginning my son and I bought a 1206 as a project in pretty wrough condition. We done a dozen or so of these so the condition really didn't scare me. So we overhauled the engine by that I mean piston sleeves .honed to 005 of a fit with a ridged home So no hour glassing.new valves ,guides, and seats. Had pump and injectors throu the shop . now this tractor still has a miss or flutter to it. Any body got a idea where to go from here like I said not my first go around but I'm kinda stumped. When I bought it the turbo was from a 1066 the guy said does anybody know could that different turbo be causing my problem. Im open to suggestions . hold your criticism I realize I'm not an expert just somebody with a big I treat in the ih muscle tractor era that wants to learn. Thanks

 

[caterpillar guy]

If the air is all out of the system, and new filters with good lines and hoses. I would have to say sounds like you need to have the governor looked at in the pump and the low pressure side, to see that it is getting the fuel evenly and weights are working properly in the pump. The place that did the pump work should be willing to look at it for you for free or a very reasonable fee. Have you loosened the lines at the injectors to see if it changes like was mentioned in your previous post about this. If a bad injector it will be like a spark plug no change and if they all change then I would look to the pump at that time. I would not expect the turbo to affect that since all it is is an air pump of sorts. After all if it is missing at idle the turbo is not really doing anything to effect the running like it would at half throttle or pulling a load. Even off a wee bit on the timing I would not think would make a miss. looking more to injectors or pump to me.

 

[the tractor vet]

Well Pete and i and Owen are the ones that worked on them for a living , Pete touched on some things i never gave tough to Owen has not been on for a good while . also really with out standing there and hearing it we are all shooting in the dark with ideas Thy can be vary temperamental . and in my almost 60 years of wrenchen only two engines worry me when working on them , one is ANY two stroke Detroit and the other is the 361 -407 . They are extremely fuss on valve height , they are extremely fussy on piston fit . As for the turbo your usen i do not know off hand the CFM and boost pressure between the two is , could it be adding just enough to aid in popping and intake off it's seat ???? as the valve springs are not that heavy , were the springs tested ??? , Do you have maybe a couple can lobes that are NOT opening the valves all the way of holding them open longer from being wore down??? , Do you have excess gear clearance as in back lash on the gear train that is causing pump flutter and cam flutter ????? Could you have one slightly bent connection rod that is letting one piton set lower in the bore ????? One piston that is NOT wright ????? and then back to the injection system . The person i use on my injection system work was and OLD I H mechanic and has been bringing his boy in to the field . He does great work and yep he even messes up once in awhile . HE messed up on a 1256 pump once some 30 years back . That tractor was two and a half hours one way south of me and Harry's is over and hour north of me . Harry wanted to hear it run on the tractor SO to save time to get to the tractor I dove up to Harry's threw a hand full of tools to pull the pump if need be in a small tote and Harry and i went down to the Airport and pushed out his Beechcraft Turbo Baron and flew down as this farmers place was at the end of the run way of the county airport . We flew over the farm and saw they were just going in the house for lunch , Harry called on the radio and had the person at the air port call the farm and the wife came over and picked us up . all it was on that was Harry miss set the timing advance . I could have done that but no he had to see what he messed up . Plus i just think he wanted out of the shop and log up somemore flight time.

 

[fastfarmall]

All i can tell you is a friend of mine bought a new 1256,of the lot, his son drove it most of the time, he plowed with it after school,anyway that had a miss in it too, the dealer that he bought it from, Found it had a 806 injector line on it, changed that it fixed the miss, both the mechanic and owner told me the same story, but i would of thought they had they had the same lines !

 

[the tractor vet]

Ya know you could be on to something here , if it has just one fuel line that is say smaller or BIGGER this will cause a some what a miss if one line is shorter this will also screw with it . Just like a plug wire that on a nice dry day everything runs fine but throw in a damp day and it starts to miss or jumps between two wires at the cap . Like the nobody could find the miss on our 03 Dodge Durango when it was new i had to do it myself .