My 83 SD has had injectors rebuilt with new nozzles, injection timing, rack damper replaced and valves adjusted recently. Fuels mileage has gone from 23 mpg to 27 mpg. I noticed this weekend what sounds like valve clatter while accelerating between 1100 - 1600 rpm through every gear. The noise started after the injectors and injection pump timing. Any ideas on what it could be?

I would double check the valve clearances. They may need to be adjusted again if it had been a long time since the last service.

It's not uncommon for new, or newly rebuilt, injectors to be noisy for a short break in period. It is a good idea to do a followup valve adjustment if the car has not been getting regular maintenance, but it won't hurt to wait to see what happens after a few hundred miles of driving.

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'79 240D

The valve adjustment and injectors have about a thousand miles. I'll check the valves and see if an adjustment is out of whack. The 440 in my 67 Chrysler makes a similar noise on cheap regular unleaded.

I agree to give the injectors time to break in for perhaps another couple of thousand miles. Then check the injection pump timing again if the noise is still present.

I think that if the valves where reducing carbon they would become quieter not louder. You might want to add some form of celane booster to the fuel as there is a chance the local fuel is just poor.

Or just mark the current injection pump position and pull it a fraction back from the engine to retard the timing a little from it's present setting. Your fuel milage again sounds like you may be a little too far advanced.

First though give those injectors some more time to settle in.

I am curious what Injector Nozzles you are using and were the Injectors completely rebuilt with the normal Pop Pressure?

When I timed My Fuel Injection Pump to more advanced timing it ran a little peppier but nailed on acceleration.

In My case I had marked the IP and Engine Block where I started from with the Timing and where I ended up when I advanced the Timing. So I split the difference and ratated the Fuel Injection Pump back in between the marks and drove it like that and that relieved the nailing issue.

Later when I removed the Fuel Injection Pump I installed it with a Timing/Locking Pin and left it like that with no nailing issues.

I don't know if they have Winter Fuel in My area or not so I don't know if Winter Fuel can increase the chance of Nailing or not.

No one has mentioned a change in the Engine Camshaft Timing due to Timing Chain Stretch and Timing Gear Wear.
If you do the Valve adjustment recheck as precision as possible line up the Timing Chain Gear with the Camshaft Bearing Tower mark and look down and see what degrees on the Crankshaft Damper your pointer points to. That gives a ballpark idea how much you Camshaft Timing is off.

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84 300D, 82 Volvo 244Gl Diesel

The 440 is exploding the fuel instead of a combustion.
CAREFUL, exploding fuel can burn holes into your piston head! The leaded fuel was supposed to prevent this from happening in the older days/

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Mostly, I don't know notin, I just know where to look.
I am looking back, to over 30 years in Electronics Design.
Electrons don't care if they move in a car, computer or relay!

95 W124 E320 M104.992 - Because, I love to repair, naaaah!
Over 221,000 Miles
Cheers,
Norbert

I started the car today to see if the noise was still there and it was. I went ahead and pulled the valve cover to check the valve clearance and all was fine. I went ahead and checked the drip timing and still had a 1 second drip at 24 degrees. Put everything back together and took it for a ride and the sound is gone. I do have some nailing on # 1 injector but the noise which I thought was valve clatter was gone. I can only assume that the injector line wasn't seating correctly which somehow caused the noise. Diesels are new to me. I'm an International SV and Mopar guy.