Introduction / 2.6L I5 engine build

[nmerrill]

Hey folks.
Long time Lurker (actually joined in '05 under different name) but mostly spent my youth lurking on the Vanagon, and then Syncro list.

I've had my Syncro Westy since '98

Several years ago I had a 5 cylinder (audi NF - 2.3L) installed using a "kit" from a fellow named Detlev, whom I believe is still active in the community.

I've put about 50K miles on that engine mostly trouble free. Well, I suspect my wife might point out the blown out exhaust down pipe, and failed (new rebuilt Bosch) alternator that, ah, interrupted our Honeymoon... but who is nit pickin?

That engine's performance was "fine", like the weather.

When I found a eurospec 2.6 L 5 cylinder with low miles locally, I decided I needed it! I've already got everything in there for the 5 cylinder, why not a 2.6 L stroker! How hard could it be...?

OOPS!

So, enough BS, let's get to it!

This is my first Auto engine build and I've been trolling for help over on Motorgeek, but thought see if there are any VW specialists over here

So let me plagiarize my self a little...

This Eurospec built block is *supposedly* built on the VW block from the South African 2.6L transporters. It is a 95.5 mm stroke, and supposed to be a block height of 221.35 mm compared to the "standard" 220mm (7A, NF, 3B...)

My intentions are to put a 20V (7A) head on it, and run VW 9A pistons in it. An AAN intake, 7A bag-o-snakes, and 034efi round out the package.

Next post, compression ratio calculations etc..

As I said, this is a new adventure for me, and I've got questions! Hope someone here can help.

Nat
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[rubbachicken]

wow, very interesting

keep the pictures coming
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lucy our westy

lucy's BIG adventure

meet 'burni'


markswagen {mobile mechanic} san diego area all early VW's cared for.

619 201 0310 or 617 935 4182

[Zeitgeist 13]

Looking forward to seeing your progress. I've long contended that these are the engines VW should've offered in the T3 from the get-go
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Casey--

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

[snowsyncro]

Thanks for starting this; this will be interesting. Also interesting is that cylinder head. I was surprised to see a vacuum pump on a gasoline engine.

RonC

[nmerrill]

Ok, so as I mentioned, I intend to use VW 9A pistons with a 20V (7A) head - the 20V head is primarily so that the intake is on the "correct" side of the engine.

I measured the volume of my head using a serological pipette and canola oil. Three different pockets measured out to almost exactly 45.5 cc.

The 9A pistons are essentially flat top - two small valve clearances, and a 0.5 mm raised band surrounding them mostly cancel them out (I calculated about -0.14 cc total)
Multiple references on the internet indicate the 9A to have a compression height of 30.2 mm.
A VW piston manual I have indicates 29.8mm

So, if stroke is 95.5mm
rods are 144mm
block is 221.35
then the 9A pistons should pop out of the block by 0.2mm, which is the same amount they would on the 9A (difference in stroke is 1.35mm = (95.5 -92./2)

So, the comp ratio of this block, with 9A pistons and that head looks like this:

This is the Not2fast calculator and most of the specs are pre-filled from the VW 9A engine. I did change the piston dome spec which was wrong.

Anyone see anything else wrong in that data?
Since I will be running 034 EFI standalone, which has no knock sensing capability, and I've taken this van places that had 85.5 octane - only- before, I can't stay at 10.4:1 compression ratio.

So, using that calculator, if I had 1mm milled off the pistons, then the ratio would look like this:

Notice the change in deck height to 0.8- indicating the pistons at TDC should be 0.8mm below the top of the block, instead of 0.2mm above, as before.
Now the CR would be 9.6 or so. From what I've found, this should be OK for even pretty bad gas, with a careful tune.
What do you think?

Nat

[nmerrill]

[nmerrill]

Thanks for the response y'all..

So, everything looked great "on paper".
I tore the engine down...

Then I pulled # 1 and put a 9A piston on the rod to take a look at TDC...

HMMM

For those paying attention, what is wrong with this picture?

[D Clymer]

In the photo, it looks like the 9A piston goes above correct deck height at TDC. A 221.35mm block should have perfectly compensated for the stroke difference between the 9A and the 2.6 motor. It must mean you have a 220mm block. You can always shave the tops of the pistons by 2mm.

D

[nmerrill]

[D Clymer]

[MarkWard]

The valve reliefs are for a valve train that is not square to the piston. That is about a flat top piston. With your cc'd combustion chamber measurement, I'd think your compression is much higher than 9 something to 1. As long as your valves clear the pistons by .050" it should work. But my bet is high test with a knock sensor.
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☮️

[nmerrill]

[regis101]

[Howesight]

If you want to go with the 20V head, you are going to need a water manifold, compatible distributor, cylinder head, injector rail and injectors, etc etc. The 7A head also uses a different timing belt arrangement. Collecting these parts can add up to a lot of $.

Below is a link to a fellow selling an AAN turbo engine which will give you all the above, less the distributor, plus an intake manifold that is lower profile than the stock 7A manifold. Or . . . . you might just be tempted to install the AAN engine.

AAN engine for $1,000: http://www.audifans.com/marketplace/show.php?table=pm_audifans_Parts&id=21676

Here's a link to a fellow who modified an Audi 7A intake manifold to allow him to install a 3B Audi turbo engine, which is essentially the AAN with a distributor and peripherals for installation in the Type 44 Audi 100 chassis:

http://www.thesamba.com/vw/forum/viewtopic.php?t=210307
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'86 Syncro Westy SVX

[onwardtothestars]

I've been out of the Audi world for awhile but the last person I remember building a engine like you desire used a Eurovan tall block.

I think a 20V five banger would fit a little better in a vanagon anyway with the intake manifold on the opposite site of the head, unlike the 10v. Why not go ITBs ? ha
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lots of VW's

[Howesight]

[IdahoDoug]

Nice choice. You'll like the 034 stuff. I put their injector conversion kit and resistor bypass pigtail on my 20V. I may know where a 20V head is at a wrecking yard if you need me to pull and ship it. Though a lot of them are in your neck of the woods.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[danfromsyr]

always nice to see another I5 build.
not sure where in VT you are but we've taken our 2.5 Ev powered vanagon up over the camel's hump on Rt17
I still have some EV 2.5 and Audi I5 na & turbo motors in the shed. (no 20v or 7a though)

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[nmerrill]

[nmerrill]