IH B-265 tractor - timing

First off, you have to remove the timing gear cover. I have done this on my B414 without taking off the radiator, belts and other stuff, so I think that it can be done without doing that on a B275.

The gears that are under this plate have punch marks on them that line up with punch marks on the other gears. According to the illustration, the line ups are obvious.

The engine on a B275 is timed at 20 degrees before top dead center, BTDC, which is indicated on the injector pump gear, if the illustration is accurate. If not:

In the case of a pneumatic governor, and having the #1 cylinder at top dead center, TDC, measure from the marker in the cranshaft pulley to the timing marker. The distance should be 1 and 1/8 inches around the circumference, which is 20 degrees BTDC.

In the case of a mechanical governor, with the flywheel TDC mark aligned with the scrib mark located on the left fornt flange of the clutch housing, you will have to remove the dust cover on the clutch housing to find this.

Shut off the fuel and remove tht injection pump timing window. If the mark "E" os aligned with the scribed lines at the lower hole of the pump snap ring, that is 20 degrees BTDC. This can be adjusted by loosening the nuts on the pump mounting studs and moving the pump between the two marks on the engine front end plate and retightening the nuts. These scribe marks are a variation of about 3 degrees.

The engine can be timed 22 to 16 degrees BTDC as it suits your needs. 16 is quieter but less powerful, 22 is full power but noisy and will reduce engine life.

Hope this helps, let us know how it works out.

UFO Man

Does it have a CAV injection pump??

Look for two scribe marks on the timinig gear cover that the inject pump mounts on. It is by the mounting bolt farthest away from the engine block. Install the injection pump and with the 3 mounting nuts loose rotate the injection pump until the center of the slotted mounting hole on the injecton pump is midway between the timing marks on the timing gear cover. Then tighten the mounting bolts nuts.

Now bleed the fuel lines and start the tractor. Let it warm up. Now stop it and try starting it again. If it is difficult to start and blows a lot of smoke then it is timed to slow. If it kicks back on the starter then it is timed to fast.

To adjust, stop tractor, put a scribe mark at the present location, then loosen injection pump mounting nuts and rotate injection pump slightly in one direction, tighten nuts and try starting test. If it is worse repeat above adjustment but rotate in other direction.

Mechanics that worked on these tractors a lot would just time them by listening to the clatter of the engine.

Good luck
JB