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  #31  
Old 05-22-2020, 09:16 PM
Nevadan Nevadan is offline
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End of day 2, a little sunset through the shop window highlighting the soon to be awesome engine, car anxiously waiting it.
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1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
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  #32  
Old 05-22-2020, 09:19 PM
Nevadan Nevadan is offline
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Every gasket I've seen: oil pump, rear main, turbo supply and return, etc. looks quite new so although the engine looks ancient on the outside it's in very good shape. I'm quite happy.

Any input on routing coolant from the back of the head/block?
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J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
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  #33  
Old 05-23-2020, 07:34 AM
v8volvo v8volvo is offline
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Looks great so far. What size are the pistons stamped? Sounds like they might have been oversized if it was rebuilt before, may want to double check the size for ordering new rings. Pretty clean inside overall!

One time I took the pan off a D24T and saw that it had several squirters broken off. When I got the engine the rest of the way apart, I discovered the reason for the broken squirters was that someone had attempted to use non-turbo oversize pistons during a rebuild, which do not have notched skirts to clear the squirter nozzles. Once the engine "rebuilder" figured out that this would be a problem, they took an angle grinder to the NA pistons and cut notches in the skirts by hand, rather than ordering the correct pistons! Some of their hand cut notches were not deep enough and they chopped the nozzles off. The ones that hadn't been broken had dents from getting kissed.

Anyway, now I think of a broken squirter as a warning sign, might want to confirm you have correct TD pistons in here.

Sharp looking wagon, white is a good color on these. Did the vinegar get the block that clean?? That's a new method to me, sure would be nicer than using solvent.

Nice well lit and spacious work space you have there too, sure beats mine.
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86 745 D24T/ZF 340k lifted 2.5"
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  #34  
Old 05-23-2020, 08:18 AM
v8volvo v8volvo is offline
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Regarding your questions about coolant flow:

How is the current engine in the QSW set up? Does it have a method for continuous recirculation? Or does it use a heater control valve? Since the 2.2 gasser is the same fundamental cooling system design, maybe whatever they did to integrate that engine in the car could be done the same way for the diesel?

And what about in an old 5000TD like what this 2.0 presumably came out of? Do they have a heater control valve or does the heater circuit run continuously? And how does the oil cooler circuit work on the 2.0TD? Is it like the D24T where it's fed from the back of the head?

It's an interesting problem to try to solve, but one assumes the original designers must have thought about it too, so maybe their solutions are a starting point at least.

Here are my thoughts: the non-turbo D24 engines look the same as the back of your 2.0TD, with no outlet from the back of the head. There is an outlet from the back of the block for the heater circuit, but that circuit is designed to be able to be closed some of the time (heater output on a Volvo 240 with a D24 is controlled by a heater control valve). So, as produced from the factory, there has to be an accommodation for there being no coolant outlet from anywhere on the backside of the engine, either the head or the block, yet for the engine still to maintain temperature and balanced coolant flow. I think they therefore accomplished balanced coolant flow throughout the engine in the usual way, by using precisely calibrated, and varying, orifice sizes for the "steam holes" (i.e. coolant passages) in the headgasket.

If you examine the headgasket you'll notice that the coolant passage holes towards the front of the engine, closer to the water pump, are very small, practically pinhole size. As you work back towards the rear of the engine, you see the holes get progressively larger. The holes surrounding the rearmost cylinder, and especially behind it at the very rear of the engine, are by far the largest of all. This I think is intended to prevent the problem you describe, of the front two or three cylinders near the WP getting all the coolant flow while the rear ones get nothing. Instead it regulates the flow through the front cylinders and forces much (or presumably an equal) amount of flow to run back to the rear of the engine, through the back of the head, then back around through the head to the upper radiator hose outlet, or the internal return through the block, depending on what the thermostat is doing at that moment. I assume the exact size of these holes in the headgasket is the result of a very careful fluid flow engineering calculation and probably lots of testing. It probably also takes into account the design of the cooling and HVAC systems of the vehicle applications the engines were meant to be used in, and accommodates the possibility that a heater control valve could be closed.

I have an old D24T headgasket floating around that I'll take some pictures of later to show what I'm describing.

So, all that said, I think the question of coolant flow through the rear of the engine probably won't be a problem in this setup, regardless of how you build it. This coolant distribution question is really a challenge that has to be solved in any inline engine, and the longer the engine the greater challenge, since the water pump is way up at the front and there's a long distance to the back of the motor. But obviously there must be good and well proven solutions for it, otherwise long inline engine designs would be considered troublesome, which is the opposite of the real world situation (I-6 is dominant in every heavy duty application, etc). My belief is that the headgasket's careful design is what does it. Bottom line is I think you won't have to do anything for it to work as it should, unless you actually observe a cooling difficulty once it's in the car.

Beyond coolant circulation within the engine, though, there's one other issue that is relevant to reliable cooling performance with this design, and this is the one that has been of greater concern to me. It's the ability of the wax pellet in the thermostat to "read" the engine's temperature. I think that can be problematic due to the way this engine is configured, since the tstat is positioned at the inlet of the water pump, rather than the outlet from the head like in some designs. The WP draws coolant past the tstat from multiple sources, including the heater return. The coolant that flows past it therefore could include some coolant that has passed through a heater core and has been cooled down significantly in the process, thus causing the tstat to "think" the coolant in the engine is colder than it actually is and begin to partially close, even if the real cooling demand is still very high. One of my old goals that I have never really figured out is how to return the heater circuit somewhere else rather than the tstat housing to avoid this. But this is only a real problem in the bitterest cold weather. Not so much if the heater is not in use. Anecdotally, all the headgaskets I have ever blown in D24T engines have been while climbing mountain passes in subzero weather, which is why this issue interests me. It's a bit of a paradox that *cold* weather is a threat to effective engine cooling with this particular design, more than hot weather even. Still want to work more on it, someday.

But that's not really the question you're asking, so maybe it's a separate discussion for another place and time, rather than in your build thread...

Look forward to seeing the next phases of the project, looks like you have it moving along at an efficient pace.
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86 745 D24T/ZF 340k lifted 2.5"
83 764 D24T/M46 145k
93 Toyota 4x4 pickup 1.9 TDI swapped
04 Audi Allroad 2.0 TDI swap in progress
02 F250 SD 5.4/4R100
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  #35  
Old 05-23-2020, 09:28 AM
ngoma ngoma is offline
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Quote:
Originally Posted by v8volvo View Post
It's a bit of a paradox that *cold* weather is a threat to effective engine cooling with this particular design, more than hot weather even.
Especially considering its Swedish/Germanic roots.
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  #36  
Old 05-23-2020, 09:55 AM
Nevadan Nevadan is offline
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Damn! I need an oil squirter, the ones I have are for a 1.6, a different design. Does anyone have one? Iíll pm Anders since I got one from him before. All the pistons have the notch cast in the skirt so no telling why the tube came out of the base.
Iíll reply to v8volvoís cooling summary when Iím at a keyboard tonight.
This is a nice shop, cement floor and a forklift!!
__________________
J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
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  #37  
Old 05-23-2020, 10:06 AM
Nevadan Nevadan is offline
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Just found two squirters Anders sent me years ago!!!
Thanks again!!!!!
__________________
J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
Reply With Quote
  #38  
Old 05-23-2020, 09:10 PM
Nevadan Nevadan is offline
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Quote:
Originally Posted by v8volvo View Post
Looks great so far. What size are the pistons stamped? Sounds like they might have been oversized if it was rebuilt before, may want to double check the size for ordering new rings. Pretty clean inside overall!

One time I took the pan off a D24T and saw that it had several squirters broken off. When I got the engine the rest of the way apart, I discovered the reason for the broken squirters was that someone had attempted to use non-turbo oversize pistons during a rebuild, which do not have notched skirts to clear the squirter nozzles. Once the engine "rebuilder" figured out that this would be a problem, they took an angle grinder to the NA pistons and cut notches in the skirts by hand, rather than ordering the correct pistons! Some of their hand cut notches were not deep enough and they chopped the nozzles off. The ones that hadn't been broken had dents from getting kissed.

Anyway, now I think of a broken squirter as a warning sign, might want to confirm you have correct TD pistons in here.

Sharp looking wagon, white is a good color on these. Did the vinegar get the block that clean?? That's a new method to me, sure would be nicer than using solvent.

Nice well lit and spacious work space you have there too, sure beats mine.
The pistons are stock, I think 76.48 is what was stamped on them. The rings were in pretty good shape so I think they were new, although they weren't lined up correctly, some of the gaps were in the same location. You'll see in the following pictures the cylinders should have been bored but I just don't want to do that right now for lack of time. When the engine is installed and if I like the way it works and drives I'll have no problem taking it out again for some machine work. It's taken so much time removing frozen bolts, cleaning, wire wheeling, etc., that it will be much quicker next time. Plus I'm going to cut the grill metal, the front end of the car, so I can just remove that for a simple engine extraction. I've put rings in a far worse 1.6 and it ran pretty good so I'm not concerned right now.

I don't know why the squirter was broke off, some of them are pretty close to the very top of the piston rod, so maybe that's what happened.

I had to make a turbo piston for my 1.6 and I just hand filed the slot from an NA piston, it ran that way for about 50,000 miles just fine. That's the engine that was completely wore out as well.
__________________
J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
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  #39  
Old 05-23-2020, 09:15 PM
Nevadan Nevadan is offline
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[QUOTE=v8volvo;13706]Regarding your questions about coolant flow:

How is the current engine in the QSW set up? Does it have a method for continuous recirculation? Or does it use a heater control valve? Since the 2.2 gasser is the same fundamental cooling system design, maybe whatever they did to integrate that engine in the car could be done the same way for the diesel?

/QUOTE]

The current QSW does have a heater control valve so it's set up to accept this engine as is. It's a cable operated "ball valve" of some sort.
__________________
J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
Reply With Quote
  #40  
Old 05-23-2020, 09:24 PM
Nevadan Nevadan is offline
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Join Date: Jan 2013
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Quote:
Originally Posted by v8volvo View Post
Regarding your questions about coolant flow:

How is the current engine in the QSW set up? Does it have a method for continuous recirculation? Or does it use a heater control valve? Since the 2.2 gasser is the same fundamental cooling system design, maybe whatever they did to integrate that engine in the car could be done the same way for the diesel?

And what about in an old 5000TD like what this 2.0 presumably came out of? Do they have a heater control valve or does the heater circuit run continuously? And how does the oil cooler circuit work on the 2.0TD? Is it like the D24T where it's fed from the back of the head?

It's an interesting problem to try to solve, but one assumes the original designers must have thought about it too, so maybe their solutions are a starting point at least.
The QSW does have a heater valve, some type of ball valve, cable operated just down-flow from the back of the block/head.

I'm not sure about the AUDI 5000 or 100, whatever this came out of. Since it's a VAG vehicle it may be similar. My 1985 Jetta is just the opposite, there's always flow going through the heater core.
__________________
J.D. in Reno
1958 Mercedes 180D (rebuilding now)
1985 VW Jetta 1.6TD
1985 Volvo 745 Wagon 2.4TD (sold but still maintain it)
1987 VW Quantum Syncro 2.2 (converting to 2.0TD)
1996 TDI Passat
1997 Chevy 3/4 ton 6.5TD
2006 V10 TDI Touareg
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