1.6 TD reliable performance build

[745 turbogreasel]

I  am not sure why they fail, but it may be worth noting their longest lasting engines are made by another company

[mcpook]

Got my hone pics.  #1 and #4 were wiped down before shooting.  2 and 3 au naturel.  The crosshatch/hone looks fine to me.  Will still have my machinist check for round.

[Toby]

I suspect you are hosed. Whoever honed the block did not know what they were doing and did not have the correct tools.

Clearancing German pistons is unlike other engines. The numbers on top of the pistons tell you what the clearances should be. These piston tops DO NOT have all of the numbers. Any chance these are from Prothe? At any rate the piston to wall clearance is measured in a different spot on kraut pistons than others, so a guy who does lots of Chevies and Toyotas will louse up a German bore job. It is not uncommon to have a rebuilt MB motor make make more noise than before it was rebuilt.

That being said, your best bet is to rehone the bores to give you a good crosshatch (45*) and take you chances. The bores are likely already too big so the tiny amount of material that you can take off with a ball hone won't be noticeable. Maybe not even measurable with typical tools. You also have no guaranty that the bores do not contain lots of honing grit. You will need to scrub them with lots of hot soapy water to be sure.

IIWY, I would also break/grind off the cast flash in the crankcase. I would also break all of the sharp edges in there as well with a file or a Dremel tool. The casting flash could break off of its own accord and rattle around in the motor. Breaking the sharp edges reduces the amount of lint that is still in the motor on start up. Lots of flotsom and jetsom is visible in your first photos.

[TylerDurden]

Ya, good old Chrysler.  Single-handedly keeping the towing industry out of default for decades. You prove your own weak points when given enough rope.

I gotta 1998 3.8 with 367K on the odo. Daily beater, engine all original, burns zero oil, starts first crank even at at subzero (F) temps.

[TylerDurden]

Whoever honed the block did not know what they were doing and did not have the correct tools.

Looks like they were honed with the pistons in? Bores #2 & #3 seem very shiny at the bottom.

[RabbitJockey]

probably just the oil down there.

[mcpook]

So I took my block into my machinist to measure the bores and his measurements indicated that the pistons were too tight.  Pistons are stamped 76.98 on top which equates to a bore of 77.01 (.03mm clearance).  His measurements indicated I had about half that. 

So I disassembled the block and delivered to him:
1)   the block so the cylinders can be honed to the proper clearance
2)   the de-ringed pistons so that he can measure the pistons rather than relying on the numbers stamped on the tops
3)   the crankshaft to check journal measurements (which should be fine as I plastigauged them)
4)   the rods to check length/straightness
5)   the IM shaft to check bearing to IM journal clearance.
6)   The oil pump to check oil pump shaft to bearing clearance. 

I’ll supply him with the tolerances from the Bentley regarding the cylinder bores, crankshaft journal wear.  Highlighted sections from pgs 59-61, 63 and 73 from the manual.

I don’t see any specs in the Bentley for the IM shaft or oil pump shaft bearing clearances.  Does anybody know what these numbers should be? 

Hopefully him removing .015mm from the cylinder bores doesn’t throw the piston ring gaps out of spec. 

Sounds like in another week, the assumptions will be replaced with knowledge and worse case scenario, I’ll need new piston rings if the gaps are too big.

[mcpook]

Here’s a mock up using an old head with the new manifolds and turbo. Looks like a ½” thick inlet flange welded to the ex. mani should fix the clearance issues.  The hot side clears, but the cold touches.  Should take some measurements to make sure I’m not creating firewall clearance issues though.  I ordered a T3 inlet flange off ebay today that was pre-drilled for M10 x 1.5 bolts.  I’ll chase those through the ex. mani as those threads are currently 3/8” 16.  I had to hack off some intake mani brackets, but still couldn’t attain the necessary clearance.

[theman53]

It is tough to weld cast, I would just bolt it together and maybe run a gasket on the turbo and exhaust mani side. I think crazy andy used 3/8" but 1/2" would work too right in between the turbo and mani and it shouldn't get you into trouble on the firewall at all.

[RabbitJockey]

could also flip the turbo, using a spacer is probably easiest tho, especially if you like how the turbo is oriented already.

[mcpook]

could also flip the turbo, using a spacer is probably easiest tho, especially if you like how the turbo is oriented already.

What do you mean by flip the turbo?  Just flip it on end 180* so that you effectively reverse the hot and cold sides?  That would put the air filter/intake on the driver's side which may work better and uncramp the timing belt fuel filter area.  I like .   Only wild card is getting the exhaust past the shift linkage if it's on the passenger side.

Anybody done this and have pics/thread?   

[RabbitJockey]

yeah thats what i meant, check 8v turbo threads in the mk1 forum on vwvortex.com  it's definitely been done many times.  and most aftermarket kits like callaway had the turbo fitted this way.

[Dakotakid]

Trying to get some info on that intermediate shaft. I didn't realize the axial measurement is the only one offered.
When I have pressed in new inter bearings with my tool, I always used some assembly grease and worked to establish some spin with the aluminum pulley and end cap on the shaft. Couple times, they were a little tight. I just keep turning them and pretty soon, things improved. Make sure the installer got those oil holes lined up!

I would suspect a measurement of 0.002 to 0.005 inch. clearance. On one hand, there is some heat swell.....on the other hand, the rear sees oil immediately and the front a bit delayed (once running).

Does your shaft feel nice and pretty tight as far as fitting it in the bearings?....probably not that far.

The bore measurement is a bit "intriguing." Is this new guy using a digital bore guage? As annoyed as I sometimes get with driving these old cars....I always get a little excited when I see a brand new piston peeking through a fresh bore. Just something about it.

[theman53]

Yeah I am with Dakotakid on this. If you have new IM bearings in your hand and the block isn't in the car, I would put them in. Unless you know 100% that the old ones are fresh. I would suspect the #1 oil pressure problems are directly related to these bearings. It is worlds easier to do with the engine out of the car.

[mcpook]

Found an old e-mail from the previous block owner stating that he did replace the IM bearings with new.  Machinist thought they looked new as well.  I'll sleep soundly tonight.  Machinst did say a good rule of thumb as far as bearing clearances go is .001" for every inch diameter in journal size.  That seems to land within the range that Dakotakid posted.  He hasn't thoroughly measured pistons or cylinders yet.  Next week.  

While the block is away, I worked on the radiator fan assembly.  I think this is off an MKIII Passat.  Hacked a few inches off the bottom and then scabbed it back on.  Not great welds, but every bit of practice helps.  Two inch passes to try to minimize warpage.  I liked that the assembly was slim toward the alternator, but in looking at my engine compartment, it looks impossible. Maybe an a/c alt bracket is the trick?  I've read the 675mm radiator swap is doable in an MKI.  I think the radiator will fit, just not the fan assembly.  I'll e-mail GEE-BEE as I read he did the swap, but I never saw pics of how his fan assembly cleared.  Hopefully the 675 also leaves room to pass 2" pipes for a FMIC.  

Also worked on the crankcase breather system.  Hopefully no more gunk in the intake and turbo.  I didn't weld the 1/2" 90* barb to the block off plate yet as I want to make sure the barb is directing the hose on a clear path.