Jamez

Will it be a good thing in the 1.8T with 150mm rods?
I guess the rod to stroke ratio would be better this way? And the forces to the cylinder sidewall would be less.

Also, with the different compression height the piston would be lighter, right?

Would it work?

xr4tic

They say 1.7:1 is the optimum ratio, and the 1.8T already has a very good 1.67:1 ratio stock.

You'd need custom rods, and custom pistons, and for the cost, it's probably not worth it.

It would probably be cheaper to do an ABA 2.0 swap, with 159mm rods, which gives a 1.71:1 ratio, and a 10% increase in displacement

Jamez

JE pistons for about the same price as you did...
different comp height doesnt add any cost as they all produces after order...

Pins and clips are the same.

I get Pauter 150mm rods with bearing and ARP bolts for less than 144mm corillo rods.

Like you answere to my post below. Thinner pistons will have less heat capability and then danger of detonation is bigger.
But on the other hand, with these longer rods, time/pistonspeed at TDC will be a little bit longer/slower, so getting things mapped correctly will be easier...

Also. I am thinking about doing an ABK-conversion, but then I probably would like to use the 16V head. It flows better and also handles more RPM than the 20V does in stock condition.

Actually I dont know. I love what you have done. Im kind of on a budget too, and I am having a hard time deciding what to do...

Here in norway an complete ABK-tallblock engine (its like the ABA) is about 2000$, so that adds quite some cost!

I've been considering TDi-stuff too, but I cant find any info on the tdi-block. it has 79.5bore and 95.5 stroke. I know it can be bored quite a bit, but I dont know if the block is taller than the AEB... Guess Ill have to find one and measure...

Morten.

xr4tic

is the piston pin getting moved up into the ring area.

A 92.8mm crank would require it moved up 3.2mm
A 95.5mm crank would require it moved up 4.55mm
150mm rods would require it moved up 6mm (86.4mm crank)

Here's a pic of the stock AEB piston (on the right)
<img src="http://home.comcast.net/~xr4tic/images/audi_vw_rod_match1_lo.jpg">

you can have the rings moved up, but the higher the rings go, the weaker the pistons become

I'm not saying you shouldn't do it, just that you need to be aware of the pros and cons of doing it. Doing it because of a better Rod/Stroke ratio is not the right reason (some argue that over 1.7:1 is too much)

A 16V would be nice, but then a new intake and exhaust would need to be made, and possibly even another block - I don't know if the 16V head has the extra oil holes like the 20V head.

Jamez

I've been in contact with JRC, and they have talked to JE. Making the pistons with the pin 6mm taller should not be a problem.
But like you say, it will be a close call, so it might get weaker.

What Im thinking is that Ill just change the rod bearings that are bad on my car, I believe/hope crank and rods still are good.
This way I'll be on the road for the summer.
Do you know if I can take off the subframe in front and get the oilpan out easily, or will removing the engine be required?
When bearings are changed Ill hope things hold up for a while. I had some detonations while mapping. That was probably what killed them the last time
(my 3" maf maxed out -&gt; strange things happend)

I guess I can rather start picking up parts for a talldeck block while my old engine still runs.
The ABF here in europe is from a golf/passat and has the talldeck, and a 16V head on it. It is 150ps from factory. Great item for building a strong engine. But rather expensive as it is popular for enginebuilders and people just wanting 150ps instead of 75 in their golfs.
I believe this is practically the same block as the ABA?

But there is also a 8V 115ps engine from Audi 80 2.0E called ABK. I believe this is a talldeck too.
This one is cheap and easy to get.
I'll check how the oilholes are on this one, try getting some gaskets and stuff, and check how it will match up with the transmission.
If everything seems right Ill check possibilities for builing one with a 95.5 Tdi-crank and 83mm bore. (2067cc)

I dont know if I might stay with the AEB head or go with a 16V though. With the extra cc I still get alot of extra power in the lower revs, and building for driveability instead of high RPM might be better. Like you say, the 20V head fits nicely in the A4 and flows pretty good, and you dont have to get custom manifolds and so on.

Jamez.

xr4tic

the engine is pretty easy to pull, as long as you have access to an engine hoist.

I've heard of the ABF, but not the ABK.

The main thing you'll have to watch out for on the tall-deck block conversion is the rods interfering with the gear on the auxiliary shaft, it's worse with aftermarket rods, and even more worse with the longer stroke of a 95.5mm crank

Jamez

my block has some bad ridges...
Actually, all cylinders have some on the top, on the exhaust side... I dont really understand why though
Head is fine.
Ive not opened up bottom yet, so dont know how crank and bearings are...

I'll have to bore the block or change it...
I get a used "ok" 1.8t block for half the price of an ABF-block...

Im really considering a talldeck ABF then!
I guess it wont be THAT much more work/cost...

XR4TIC: are you having any more trouble with head gasget using the 20V head on this block? Does the oilholes align "fair enough"?

What is this with the aux.shaft you're saying?
Do you have any pictures to show?
I guess almost all aftermarket rods are "wider" than the stock ones...

how much power are you running with the stock ABA rods now? Do you think they hold much power?

I think forged rods will be best...

xr4tic

after blocking off the three middle holes in the head, it fit fine (I used an ABA head gasket)

Heres some info on the aux shaft clearance problem:
<a href="http://forum.vwsport.com/viewtopic.php?t=1916">http://forum.vwsport.com/viewtopic.php?t=1916</a>

I really don't know how much power the stock rods can hold, mine were stress relieved, balanced, resized, ARP rod bolts, etc, etc

My best guess is I'm running around 350-375HP, and I run it up to 7500RPM+ on a regular basis