Can the 1.8t run backward?

[vanagonjr]

Here's my Flint European Reversed 1.8T engine.

_________________
John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
LiMBO (late model bus club) www.limbobus.org
LiMBO is on Facebook too! https://www.facebook.com/groups/
FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798

[levi]

Look at that.
A thing of beauty.
Elegant rerouting.
_________________
One of these days I'm gonna settle down,
but till I do I won't be hangin round.
Going down that long lonesome highway,
gonna see life my way

https://youtu.be/cSrL0BXsO40

[xoo00oox]

Hey guys, John alerted me to the recent activity on this thread. There is some confusion being caused by my early and later designs. Wellington, Levi, t8.1, and a couple others have the AEB that I built along with Tristessa who built his own.

I did put AC on a few of those using the Compresor used on the MK 4 cars and a custom bracket I made. This compressor is made to run CCW. Here’s a picture of one on an AEB although it’s hard to see.

The picture John showed of his engine is one built using the later 1.8t engine, the much more common one typically referred to as the O6A 1.8t. This on has no intermediate shaft and has a chain driven oil pump and a water pump driven by the timing belt. This engine is much easier to work with to make run CCW, no more searching for old 1.6 diesel parts.
With the late style engine I use the accessories bracket from the MK4 2.0 or 1.8t. As you can see in Johns picture it is very compact and only requires a idler pulley to correct the rotation of the alternator, PS pump, and AC compressor.



Hope this helps clear things up a bit!


Andrew-

[tristessa]

Ah!

Now I see where the confusion stems from -- you've got one of the "second generation" reversed 1.8t engines with the internal water pump, based on the later 06A block. I knew Andrew had figured out how to make that happen but didn't realize he'd done any production with them.

My engine is the "first generation" style reversed, based on the earlier 058 block with an external water pump, and while I built it myself it's very much taken from Flint's build documentation here.

The accessory brackets and belt routing are entirely different between the two engines.

Wonder if the AAZ/1Z serpentine stuff can be used on the AEB. If I ever build another engine I'll have to play with that...

edit: I see Andrew chimed in in the time it took me to punch out my reply. Am I seeing things right in that picture of the AEB SD7v16? It sure looks like the compressor's oil plug is on the bottom, which is a no-no from what I've read on Sanden's website.

[xoo00oox]

I’m not sure what number it is Tristessa, do you know why they don’t want the plug on the bottom? It seemed to work fine.

[Zeitgeist 13]

Probably because you can't gravity drain the oil with the compressor in situ. Pretty much a non issue out here in the real world.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[tristessa]

SD7V16 is the MK4 compressor. I don't know their reasoning, but everything I've seen on the SD5/SD7 compressor series says the plug should be no more than 90*degrees from vertical. They also show what the oil dip stick should read for various amounts of oil at various degrees from vertical, and the dip stick is inserted through the oil plug hole so it might just be that and nothing more. Not everything I've found on Sanden's site is correct -- I kept seeing that SD7 compressors are CW only, but we KNOW that's wrong because VW shipped millions of CCW compressors in their cars for years and years...

[Abscate]

Does oil plug orientation on an AC compressor matter? You sure as hell don’t what any liquid in that thing, you want it dispersed and then reserve in the accumulator....right?
_________________
.ssS!

[Zeitgeist 13]

I just installed a brand new compressor on my ALH, and had to drain the PAG out prior to installation. I think it had something like half a cup. I reinstalled it with mineral oil. The drain plug is situated on the side of the compressor on the ALH, so draining in situ isn't relevant.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[xoo00oox]

So is it a drain plug or a fill plug? I guess it’s both, I’m guessing Sandin recommended keeping it on the up side is so it can be used as a dipstick hole. Looking at the internals of these compressors I don’t think it really matters where that plug is when it’s in service. As Abscate pointed out you don’t want it to be able to pull oil into the cylinders and try to compress it, this doesn’t look like that would happen by positioning it with the plug on the bottom side.

[tencentlife]

Haven't looked at this thread for a long while but still amazed at Andrew's ingenuity and persistence, what a fantastic and totally "out of the box" project!

But on the question of running some of the ancillaries in the opposite direction than they did originally, here are some relevant observations:

Alternators don't care which way they turn, efficiency will be identical in either direction.

Most water pumps are centrifugal and as such would pump liquid in the same flow direction whichever way they turned, but in most models volute shape and impeller vane bias would result in reduced efficacy if reverse-rotated. This is going to vary between different pump models, but some may perform more than adequately reverse-rotated, especially since an engine cooling system is closed-loop dynamic-pressure, so the pump merely acts as a circulator. The amount of dynamic head it needs to generate is simply the total fluid drag within the system created by piping and heat exchanger friction, which isn't much.

The type of PS pump in Vanagons will unfortunately pump backwards if spun backwards, and the output is pressure regulated so you don't want to reverse flow thru the back cover. But it is easily modified by drilling new dowel holes in the shaft housing and the "butterfly" internal impeller port cover at 90º from the existing locations, then turning the steel volute 90º, which will make it pump forward when turned CCW. You have to hold center on this pretty well but the flying-vane impeller allows for some leeway.

The internals of a Sanden 5-cylinder axial-piston compressor show that it will pump the same when spun in either direction. The 7-cylinder is not substantially different. The pistons are reciprocated by a wobble-plate drive and all refrigerant gas flow is thru passive reed valves that admit gas from the inlet manifold when the piston goes down and eject gas into the outlet manifold when it goes up. The mechanicals inside the crankcase are splash-lubed by the wobble-plate spinning thru the oil bath, which will also throw up an oil mist within the casing. The plug is just closing a hole in the side of the casing where oil can be drained and added, but its orientation is important. It can be in any position above a horizontal centerline when the compressor is installed (Sanden's literature confirms this). The orientation is important because the plug location indicates the locations of two oiling features. The first is a small orifice that draws some oil mist into the suction manifold to lube the pistons and valves. The second is a small straight tube that is also ported into the suction manifold and runs to the other end of the compressor casing to a port in the bearing endplate that communicates with the main needle bearing housing. This creates a lowered pressure within the bearing housing, so oil mist from inside the casing will be drawn into the main shaft needle bearing. As long as the first orifice is always above the level of any liquid oil in the bottom of the sump it will only draw oil mist. If it were below the oil level, though, it could draw up liquid oil and potentially hydro-lock one of more cylinders, which would probably destroy the compressor.

The odd thing is there is no obvious pathway for oil to return to the sump, but the piston rings don't make a perfect seal so blowby will carry oil past, and the suction side goes from suction to a low positive pressure between cycles, so I suppose there is opportunity for oil to return. Or perhaps it's scavenged off the refrigerant flow by an imbalance of pressures between the two orifices.
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Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[tristessa]

Progress.

I went with the '01-'03 Eurovan VR6 compressor, which is built for CCW operation and has "extra" mounting ears. Mine is a Universal Air Conditioner p/n CO 1222DC, Hecho en China like everything these days. This compressor, when used with the bracket I'd modified earlier, puts the oil plug at 90*deg from vertical aimed at the block. I did have to relocate the connector for the clutch because the original placement would have interfered with the mounting bracket. Interestingly, the manufacturer achieved the EV's oddball 6-ear configuration by using an 8-ear compressor housing and cutting two off.

New compressor next to the SD508 I'd been using for mockup:

Tapping the new screw hole for the electrical plug:

New plug position. Had to tweak the mounting clip to keep the plug from hitting the compressor body:

Mounted up, everything clears despite how it looks. You can see where "extra" ears were cut off by the mfg:

Had to knock the threaded inserts out of the rear mounting ears to fit the bracket, need to replace them with non-threaded bushings because now the hole's too big for the bolts:

Compressor box:

Now to measure for the belt and track down fittings for the compressor end of the hoses. Will probably need to build a heat shield to protect the belt/idler/compressor from heat off the catalytic converter as well.

[tristessa]

Belt to use with this combo of parts is 373K4 aka 4PK0945. Sits in the middle of the grooves on the compressor pulley, which is a 7-groove:

Pardon the layer of dust on things, I was down several miles of gravel logging road on Mt. Hood a few weeks ago and haven't cleaned the engine bay since...

[Vanagon Nut]

Thats really cool, no pun intended.

Useful info! Thanks!

Neil.
_________________
1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[levi]

Nice setup tristessa
My van never had AC and I live in vegas so I don't really need it.
In the above pic is it making contact on the left side?
...not that I would even know if that matters...
_________________
One of these days I'm gonna settle down,
but till I do I won't be hangin round.
Going down that long lonesome highway,
gonna see life my way

https://youtu.be/cSrL0BXsO40

[tristessa]

The angle makes it look like things are touching but there's easily 3/8" of clearance between the compressor and the boost plumbing. I thought about making a bracket to attach the metal tube to the compressor for about two seconds but it's not necessary, the stuff doesn't move.

I went to the local pick & pull and grabbed some different #8 & #10 compressor end fittings to see if I can get something to work, else I'll be going with adapter fittings...

[Abscate]

That T4 ACcompressor is a thing of beauty. It’s a variable displacement comp which keeps the big box of kids cool even at idle in city traffic.
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.ssS!

[bobbyblack]

But, we CAN talk all about it here

Way to go on the new thread, thanks so much!!!


_________________
'87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch

[kamzcab86]

[bobbyblack]

I think hdenter is on to something regarding the idler not having teeth, but I am scratching my head over it. While the chain obviously hasn't just fallen off, aren't the 'bearing' surfaces of the chain the rollers? I'm sure there will be one found by a dedicated fan of the thread soon. Can't just throw a toothed replacement in later tho, either. The teeth and chain wear together.

Is it painless enough to get a look at the chain and idler roller every so often?
_________________
'87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch