D4 7U Exhaust noise and lack of power

Check valve lash first.
Could be the #3 injector is not functioning properly. Try moving it to another cylinder and see if the same results occur.
If nothing changes then it's head pulling time.

Check the injection pump lifter heights. They should be 1.736" at TDC Have to remove pumps and use a depth micrometer. Clean area around pumps very good before removal. Engine service manual shows the procedure for setting lifters.

So I pulled the valve cover and adjusted the valves with it hot, it does sounds better but still has a slight noise from the exhaust, I think I might pull the exhaust manifold to look at the valves/cylinders with my borescope. Any other thoughts on the lack of power, it hardly smokes at all when lugged down in 5th gear. I saw the post about checking the injector pump heights and possibly fuel filters, I have not had time to check those yet. I'm just wondering if I should check anything else while it is apart. I have ordered an engine/tractor manual and parts manuals, they just haven't arrived yet, thanks for the input.

Check the injection pump lifter heights. They should be 1.736" at TDC Have to remove pumps and use a depth micrometer. Clean area around pumps very good before removal. Engine service manual shows the procedure for setting lifters.

I agree with this advice. I had the same problem and adjusted the lift height on No3 which was slightly out and the exhaust beat improved. Mind you I think these engine can produce a slight off beat when idling anyway - perhaps something to do with harmonics. After adjusting the pump lifter it was better and reassuringly a person assisting the 'new' owner said he had a D4 7U from new back in the day, and he said that's how they sounded at idle. The new owner had no idea what we were talking about😊

Get a depth micrometer and adjust lifters as noted previously. Then evaluate the noise. You may also want to replace or check the injectors since the pressure they crack at affects the timing like the lifter setting, just not as dramatically. Also the spray pattern and quality of the spray will affect the burn in the PC chamber, so again, the injector can easily affect the sound and the performance of the engine.

Note that the lifter you are checking should begin to rise at TDC when you are checking/adjusting it. The flywheel can be installed incorrectly on the crankshaft flange, so it's always possible that the cylinder markings on the flywheel do not correspond to the crankshaft and camshaft timing. Best to make sure that the lifter is the one that's moving before you adjust it. If you go past the TDC mark on the flywheel to confirm the lifter movement, you should back up a good 1//6 turn of the crankshaft and then bring it back to the mark, stopping exactly on it.

Measure twice.........adjust once! If your check doesn't yield a measurement close to what you expect, stop and re-evaluate your procedure. As I said, the flywheel has 6 equally spaced holes, so on a 4 cylinder engine, there are only 2 positions out of 6 possible that will put the flywheel TDC marks in the correct relation to the crankshaft and pistons. And one of the two will have the cylinder numbers wrong!

I believe SJ used to recommend setting the lifter height high to compensate for pump plunger and lifter yoke wear, so you might want to consider that after you look those parts over carefully.

Thanks for the input, I'll report back as soon as I can get back to work on it.

Hi Team,
Spec. length for pump plunger is 2.6575"-2.6577" (Cat recommend to replace at 0.005" worn) when measured for overall length with an accurate micrometer.

Any wear measured on the plunger length can be taken off the lifter setting to raise the lifter yoke to compensate for the wear on the plunger end where it contacts the lifter yoke.

For example, the lifter setting on engine is 1.736" at Top Dead Centre on the respective cylinders firing stroke.
If your plunger measured 0.002" worn then the lifter setting can now be adjusted to 1.734" This new measurement is determined by :- 1.736" minus the 0.002" wear on the Plunger.

If you were to check the Injection Timing, by the Spill Timing method, your actual injection timing should now be back at the Spec. 15 Deg. Before Top Dead Centre.
Hope this helps,
Cheers,
Eddie B.