You're compression is exceedingly low. Either you did it on a cold engine or the gauge is wrong. A TDI even with 200K will pull 480-510 psi when warm. Your smoke is due to either low compression (likely) and or a bent rod on the #4 as seen by your compression test. Sorry....And I'd have sued the first mechanic for an engine. He botched it.

 

i wont say he botched it.. crap happens... but cannot trust 7mm valve stems like he did and it dropped a valve.. the bew car i swapped drivelines in, was cause the tensoner stud snapped at the 8mm to 10mm step.. the saddest part you all do not know.. back in 75/76 they had 8mm studs for the t belt.. then went to a 10mm stud as the 8mm ones broke often!! so its funny that they went back to a crappy design that had proven itself bad... and installed them into interfearance engines at that..

id say bent rod too.. but you got screwed as you knew it had a missfire/smoke before buyng...

 

@jasonTDI
Thanks for the quick reply.
These are cold compression readings as I did not have the most stable conditions to be able to warm up the engine at the time. I will try to gather warm compression readings and see what I get.
Do you know what would be required to measure and replace the bent rod if it I find that it is in fact bent? Would it be worth it to replace all at the same time along with any other parts?

 

Update:
Just performed a warm compression test. Readings are:
[405, 340, 360, 310] again, for cylinders [1, 2, 3, 4]. Cold readings were [350, 325, 335, 300] looks like all pistons will need new rings. I'm going to pull the head and see what else I'm dealing with. Checking piston protrusion, valves, lifter height, and cylinder walls. Any helpful tips?

Sent from mTalk

 

#4 rod was bent and protrude 54 thousands lower than #1. #3 piston was also very slightly bent. Swapping two rods and pistons from old engine and balancing them to match the whole set. Replacing all valves, guides, and lifters as I do not know what damage may have occurred if something caused the rods to bend. Also doing bottom end bearings to eliminate whatever is knocking. Ordered everything including Goetze rings, head bolts, downpipe studs, gaskets, seals, valve guide reamer and remover/installer air gun tool. Ready for the rebuild next weekend. sliced my index finger through tendon and nerve with the top layer of head gasket during head removal so had some delays for surgery etc.

 

dont forget new rod bolts... not in your list

turbo oil leak
water sucked in thru air filter
starting fluid
using diesel kleen as or in a alternative fuel source, injectors stick open and hydro lock on fuel

all bends rods....

 

Oh yeah, have all the new bolts as well for rods and crank.

 

Are you sure that the 54/1000 (mm ?) less protrusion indicates a bent rod?
The protrusions should be in a tolerance band (which is e.g. for the 1Z engine 0,09mm wide, ALH seems similar), to fit for a certain head gasket thickness.
Cheers

 

0.054 inches lower piston protrusion at tdc. It's a visible difference between the two (#1&#4) pistons. Without the gasket on, #1 cylinder protrudes from the block and #4 cylinder recesses into the block. But thanks for that call out! I'll check the factory tolerances in inches just to make sure because any less bad news to me would be welcomed but I think that this one's bent.

Sent from mTalk

 

Thanks @audi1z.

@crsmp5
I did experience a leaky injector for cylinder #3, because when I had swapped my new injectors from my old engine, I failed to notice the damage from piston related contact (in the old engine)that the nozzle had received. This was causing diesel to drip out of my tailpipe in a steady stream after it had accumulated in the exhaust system from idling for a while. I was very quick to replace that individual nozzle and checked for damage to the cylinder (from possible fluid accumulation) but nothing was obvious at the time without removing the head. Cylinder #4 was not firing from the first turn of the key, however, and was also accumulating to unburnt diesel fuel entering the exhaust system. I never got positive results that #3 cylinder was indeed leaking, because it was mushroomed on the tip in a very unnoticeable fashion and could have just disturbed the spray pattern.

Sent from mTalk

 

Well everything is good again. Taking apart the engine resulted in FOUR bent connecting rods with slight valve indentations on the face of each piston. Crank position sensor plate on the end of the crankshaft was also broken so the engine was running solely on the backup position data, relayed from the needle lift sensor in injector 3. Was planning on swapping crankshaft position sensor plates between my old engine and the one in the car but that would involve dropping the entire crankshaft. going back to the old block, even with the heavily damaged piston from the dropped valve, the cylinders were all in great shape and a simple honing restored the walls to excellent condition. I used the head from the current engine and swapped it onto the old block, taking careful time to replace all lifters, valves, valve guides, seals, as well as reaming the guides and hand lapping the valves. Then I replaced all of the bearings and bolts in the block along with a matching new(used) pair of connecting rods to replace the single damaged one, all new piston rings, and plenty of assembly lube and put everything back together and into the vehicle. 700 miles down the road from the first startup after rebuild, everything is running exceptionally well and the break in process went smoothly. Tdi found its legs again! Still burns tires into 3rd gear while achieving 48mpg!