D24 na problematic everything

[RedArrow]

This is great progress.
It`s very late there now in Belgrade so I`ll shorten my answer so it reaches you before you sign off.

Good job setting the timing! If I were you, I`d go back and reconfirm the timing at least a few times (spinning the engine multiple times or by driving it for a little while).

When you said, I quote, "higher speeds", there was a sarcastic smile on my face. I know these cars run quite slow and reach top speed damn slowly but we have torque. The person reading this, if you never owned a d24 car, you dont exactly know the feeling of holding steering wheel on top with two hands and waiting for your car to kill the hill before the hill kills the car... we still like our slow d24 Volvos.
Here I`d mention that you should be able to climb hills better, maybe* faster and stronger than what you are describing. But you have a really good start at fixing up all your troubles. It already runs much better and we knew it will.
Maybe consider a brand new fuel filter (best time is now, you need adequate feedback on how it runs and not some partially clogged filter situation), perhaps and air filter too and some really good checkup on the entire fuel system. Get a clear hose for between the filter and the IP too and do use clamps.

The smoke

It is probably not from readjusting (or misadjusting) your timing but from other maybe typical factors, such as
-recent years` driving style was too `slow`
-etc, look for car-smoke causes in `Sticky` of this forum
-and consider having your injectors checked, rebuilt etc or you could do it on your own one day in the future
-your car may start clearing up internally and lose some of the smoking you described having

120kph top speed isn`t super maxxed out, it should be able to do 135-140 maybe but again, there are a ton of factors for that to happen, too... tires including pressure of tires, fuel quality, injectors` condition, road surface types etc, weather, etc and much much more.

No worries about your top speed for now and do not push it much until you set things really well and keep testing car on local roads and shorter trips in town.
I`m not saying you have to fold side mirrors for a higher top speed but certainly you have many things to do before attempting to keep breaking your own topspeed records. I think of thermostat, condition of cooling hoses, injectors, setting fuel quantity right, maybe adjusting the pump linkages if misadjusted by someone, take a look at max rev stopper alignments etc, could use a fuel octane booster (dont overdo it), diesel additive, flush the IP using low pressure pump or vacuum, reseal manifolds and check exhaust etc. Especially bc this car is just a setup experiment vehicle currently. You want it to run as well as possible.
I highly suggest you do only 1 fix at a time so when/if it goes wrong, you know what to reset... and to where it was set. That`s my advice and some will think it is bad advice but it works best for me. Originated here on this forum.

My d24t doesnt have the IP timing hole copper washer either but it doesnt leak at all despite I did not overtighten it. It`s good to have but isn`t a must. Some pumps I opened didn`t have it.

A note. If your cars starts `excellent` when warm, you perhaps have no badly low compression. Do you mean warm as warm weather or warm as warm engine?
If warm engine starts really well or excellent, you prob dont have horrible compression. Do you energize glowplugs manually??

Good job on starting with the IP stuff bc that maybe means the most and contributes the most in how these cars run. By planning to redo the too tight rear belt loosening repair you are protecting the injection pump shaft seal from wearing out too early which can cause developing a fuel leak. I`ve seen a d24 run with that belt installed so tightly that you could hear the grinding.
Do follow torque specs on the cam bolt and the ip bolt as well.