Builds Another Prado in Montana (9 Viewers)

[AirheadNut]

Spent a little time playing around with various manifolds and positioning for the turbo, at first I thought I might be better off using the 1Y manifold but that pushes the turbo too far away from the engine (runs into the clutch and brake MC heat shield). The JX manifold puts the compressor inlet quite far forward, but I think it will still be workable with a custom air filter box. I won't be able to weld the turbo directly to the manifold since it would sit too low and the actuator would run into the inner fender, so its back to Plan A: weld on a stainless v-band flange and make a short riser/adapter from the manifold.

It will still be a bit tight getting a 3" downpipe off there, but it's way better than before. I'll have to get an extension on the oil drain line, since it is too short to reach the drain port in the block now.

 

[AirheadNut]

I stopped by the local machine shop to discuss a cylinder head rebuild. The guy seemed to think it would probably run around $500 plus parts, but he is booked out for the next two months. Indicates a good shop, but I need the Prado back on the road before snow flies and that would be pushing it.

He also seemed to think it would be very unusual for one of these engines to consume oil via the valve guides and seals. Once I got home I looked over everything again to reconsider where the oil might be coming from. I pulled the old turbo apart to see if it could have leaked into the exhaust manifold, it didn't look terrible inside, and the oil in the manifold showed very clearly all along the path from #4. It would have had to run uphill to drain back into the exhaust port.

I pulled the glow plugs just to see what they looked like, nothing unusual to my eye:

Reaching up the exhaust ports with a finger I can feel the oil on each exhaust valve stem, this is what I get just touching each valve stem:

Just to satisfy my curiosity I popped the valve cover off, things looked pretty normal under there, cam lobes still look nice and crisp, nothing untoward on the lifter surfaces:

It is looking like just getting a new head will be the best option for getting this on the road before winter. I don't see where else oil could be coming from; the machinist seemed to think rings would better explain oil consumption but that wouldn't spray oil out the exhaust on a cold start unless something was seriously wrong, like a hole in a piston.

 

[AirheadNut]

I've gotten some input from a TDI expert and cylinder head/engine rebuilder, he seems to think that all my symptoms point toward oil control rings rather than valve stem seals. He also noticed that there are some wear and heat marks on my cam, indicating it has suffered some in the past. Going to attempt to get a compression with my cheap Harbor Freight compression tester, but it is looking like I'm going to be needing a replacement engine soon. Swapping engines will be cheaper and easier than rebuilding mine right now.

 

[AirheadNut]

I put my engine back together yesterday since it will be a while until I get around to properly fixing it. Once together the engine fired right up with a bit of smoke, similar to what I've seen earlier this year. Runs pretty smooth, but there is definitely a little stumble when holding the throttle partly down. Fresh composite exhaust manifold gaskets seem to have taken care of leaks there, but now there is a leak between the turbo and the manifold adapter. The turbo and manifold never had a gasket there from the factory, but probably under the increased load and with my less than perfect turbo adapter surface it has started leaking. Luckily I have a gasket for it that came with a set of gaskets I got earlier, so I'll tear the whole thing apart again and try that.

 

[AirheadNut]

A little tidbit I found when the exhaust manifold was off:

Looks like the gasket wore a groove into the aluminum head when the manifold had loosened up. If I end up keeping this engine it will definitely need a head rebuild and to get that either filled and machined or simply skim the side of the head.

 

[AirheadNut]

Got the turbo reinstalled and went for a short test drive. There was an exhaust from the turbo/manifold adapter interface, so I tore everything back apart. Getting quicker at this, only took my about 45 minutes to get the turbo off the manifold this time around.

I added a new gasket between the turbo and the adapter, cleaned up the copper gasket and its mating surfaces, and stuck everything back together.

Unfortunately it now leaks much worse than before, won't build more than about 4-5psi of boost. In addition, the turbo drain line is now leaking oil at both ends, despite a new gasket and some sealant. At this point I'm done putting effort into this turbo setup, I need to decide how to deal with the new turbo from Poland. There are a few ways I could do this:

- Cut the turbo off its manifold, weld a v-band on it, mount it to the Vanagon JX manifold like I originally intended.

- Get a new, 0º tilt adapter plate and mount the engine upright, this would allow enough clearance for the turbo as-is, but would require new motor mounts and cooling lines, among other modifications.

Both of the above options are contingent on this engine still being sound; a cylinder head rebuild will be necessary, and possibly a hone and re-ring of the block.

- Replace the whole ALH engine with a 2.0L BHW TDI that I have available to me. This would require a new adapter plate, motor mounts, cooling and charge pipes, wiring, tune, etc. Basically another complete swap. This engine is more powerful and has a stronger bottom end than the ALH, but would definitely require the most work and cost to implement. On the other hand, it would allow me to start with essentially a clean slate and fix/avoid the mistakes I made the first time around.

 

[rkymtnflyfisher]

Sometimes it is a better option to tear everything back out and start with a clean-ish slate. The current engine has been beating you up for a while now!

 

[AirheadNut]

Sometimes it is a better option to tear everything back out and start with a clean-ish slate. The current engine has been beating you up for a while now!

That is the direction I'm leaning, whether it be with a new engine or my current one after a light rebuild. Either way I plan to accumulate parts and information over the next few months and tackle the project sometime early next year.

 

[FJBen]

Sadly I would lean towards pulling it all out and starting again unless you really need it in a day or 2.

I love the ALH, but sometimes you just get a problem child. Can you reuse your tune or im
Guessing not compatible and need a new ecu?

 

[AirheadNut]

Sadly I would lean towards pulling it all out and starting again unless you really need it in a day or 2.

I love the ALH, but sometimes you just get a problem child. Can you reuse your tune or im
Guessing not compatible and need a new ecu?

I am inclined to agree. A BHW would require a new wiring harness and a new tune, and the 0.260 injectors I got for the ALH wouldn't work. That said, when compared with a cylinder head rebuild and possible hone and re-ring on the ALH I would probably come close to breaking even on cost and effort. With a 0º or maybe 10º tilt adapter plate the GTD2060zv could be used on the BHW without modification, the stock injectors should be good for at least 160hp/300ft-lbs.

A friend has a complete Passat sedan as a parts car, the engine is in good shape but the transmission is dead. He doesn't need the drivetrain, got it for interior and cosmetic parts for his manual swapped Passat wagon. He has offered me the engine and harness, I need to figure out the details but I think that would be the ideal solution.

Fortunately @SnowVersion snagged a 2003 Jetta TDI sedan for me a couple of weeks ago, its only got 167k on the clock and was for sale by the original owner. Planning to put a new timing belt and a skid plate on it next weekend, that will take the pressure off getting the Prado running for a winter vehicle. The old 450SEL would not cope well with the terrible snow plowing they do here in Bozeman. I may end up sticking the DLC1019 injectors from the Prado in it sometime in the future...

 

[FJBen]

I am inclined to agree. A BHW would require a new wiring harness and a new tune, and the 0.260 injectors I got for the ALH wouldn't work. That said, when compared with a cylinder head rebuild and possible hone and re-ring on the ALH I would probably come close to breaking even on cost and effort. With a 0º or maybe 10º tilt adapter plate the GTD2060zv could be used on the BHW without modification, the stock injectors should be good for at least 160hp/300ft-lbs.

A friend has a complete Passat sedan as a parts car, the engine is in good shape but the transmission is dead. He doesn't need the drivetrain, got it for interior and cosmetic parts for his manual swapped Passat wagon. He has offered me the engine and harness, I need to figure out the details but I think that would be the ideal solution.

Fortunately @SnowVersion snagged a 2003 Jetta TDI sedan for me a couple of weeks ago, its only got 167k on the clock and was for sale by the original owner. Planning to put a new timing belt and a skid plate on it next weekend, that will take the pressure off getting the Prado running for a winter vehicle. The old 450SEL would not cope well with the terrible snow plowing they do here in Bozeman. I may end up sticking the DLC1019 injectors from the Prado in it sometime in the future...

Nice score on the 03! Low miles for sure on that year.

I just put my skid plate on a couple weeks ago and feel a little better about it now. Dlc1019 were great on my Jetta, I’m thinking about those or pp764, not sure yet.

160/300 would feel good in the Prado and plenty of room to grow.


Is the wire harness easy to diy or just better to have a custom made? I know VW you could just swap partial harness, is that bhw the same?

 

[coldtaco]

I love your stick-to-it attitude.

 

[AirheadNut]

Nice score on the 03! Low miles for sure on that year.

I just put my skid plate on a couple weeks ago and feel a little better about it now. Dlc1019 were great on my Jetta, I’m thinking about those or pp764, not sure yet.

160/300 would feel good in the Prado and plenty of room to grow.


Is the wire harness easy to diy or just better to have a custom made? I know VW you could just swap partial harness, is that bhw the same?

The harness should be pretty straightforward to build, I'll get the complete harness from the Passat and pare it down to the essentials. Building a fresh harness specific to this application would allow me to get all the lengths and routing correct, my current harness was originally from a TDI-swapped Toyota Pickup, so there is some extra harness in some places and the relays are just floating around behind the dash.

I'm super stoked about the Jetta, haven't actually laid eyes on it yet but my brother says it is the tightest, least squeaky/rattly MK4 he's ever driven. I'll keep it stock for now until the Prado is reliably back on the road, then I'll probably look into doing a mild tune with injectors and possibly an upgraded turbo.

 

[AirheadNut]

I love your stick-to-it attitude.

Thanks! I just want so badly to be able to drive the thing, it doesn't really occur to me to consider any alternative to fixing what breaks. A trip to AK is high on the bucket list someday once things are back together (and I can get enough time off), would love to meet up with you when that happens.

 

[Rigster]

Ok, so if I read this correct.... you are going to keep the 2003 intact and drive it while you work on the Prado with a 2.0L donor engine from the passat?

That sounds like a solid plan, as trying to find a good low miles ALH to match what you have done so far is getting harder all the time.

I just finished the BEW engine swap for my son on the weekend, and after troubleshooting an ignition switch issue (new ignition switch) it fired right up without even stalling, new flywheel and clutch worked without any issue and drives nicely. Hoping for a similar positive experience for you on this Prado! Hang in there, it will be worth it!

 

[AirheadNut]

Ok, so if I read this correct.... you are going to keep the 2003 intact and drive it while you work on the Prado with a 2.0L donor engine from the passat?

That sounds like a solid plan, as trying to find a good low miles ALH to match what you have done so far is getting harder all the time.

I just finished the BEW engine swap for my son on the weekend, and after troubleshooting an ignition switch issue (new ignition switch) it fired right up without even stalling, new flywheel and clutch worked without any issue and drives nicely. Hoping for a similar positive experience for you on this Prado! Hang in there, it will be worth it!

Yep, that is exactly the plan. I've been on the lookout for a decent MK4 for a while, the Prado is fun to drive (when it works) and the Mercedes is fabulous on the highway but gets terrible mileage. Neither one makes a good, reliable daily/road trip car. I also really don't want to be stuck with a 48-year-old, RWD V8 Mercedes during the winter.