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Discussion Starter · #1 ·
I know there are a few people on here who have converted a 1.8t to a 2.0. and i am looking at doing the same. Cyl 4 on my 1.8 is very egg shaped, and a slight overbore will not be able to correct it. So i'm looking at going to a 1.9 or a 2.0. However after searching here and talking to Dan (D. Passt00 Thanks Man!!:thumbup: ) It's still unclear what is needed to make the change.

I've been told by some that i MUST get a new crank and pistons while other some say in only need new pistons. I am also worried that the 2.0 may streach the cyl walls to thin to be a reliable daily driver and i may have problems in a few years.

Thanks for the help:)
Ethan

Anything else I did not say that is required please let me know!
 

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82.5mm is the most bore I'd go with in a FI application on this bock. The 92.8mm crank can be sourced from the VW/Audi parts bin but may need alteration before use.

Increasing bore alone won't quite get you to 2L.
 

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Discussion Starter · #8 ·
that's the one i got!

Ethan-how much is it gonna cost for you to have the 4 cylinders bored, and for the new pistons and rings?
I think around 2 or 3 hundred for the bore and around 900 or so for the pistons and rods. We are taking the block to the machine shop today or tomorrow, so i should know more about the extent of the damage by then.

I'm almost to the point of just getting an already built 2.0 because it would me easy.:banghead: :beer:
 

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Just be sure all the math was done if a bore and stroke is performed, so your compression ratio ends up the same as before, otherwise, somone will be "knocking" on the door. ;)

Hvydrnkr (aka Chalon Duncan) had done what you're proposing; his was 1.9 I believe and you can probably contact Dick Chiang at Dynospot Racing for more details if he can remember ( http://www.dynospotracing.com ). There were a few problems (blown oil plug due to incorrect oil pump, and wrong crank type - automatic instead of 5 spd. flywheels hub). However, when it was done, it was a beautiful motor.
 

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Correct me if I'm wrong Herman, but changing the bore won't affect the compression ratio in the slightest -- only changing the stroke, or installing taller or shorter pistons, will do that.
 

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the deal finder!
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I think around 2 or 3 hundred for the bore and around 900 or so for the pistons and rods. We are taking the block to the machine shop today or tomorrow, so i should know more about the extent of the damage by then.

I'm almost to the point of just getting an already built 2.0 because it would me easy.:banghead: :beer:
200-300 for a quality bore of all 4 cylinders is cheap. make sure they do it correctly, and like Herman said, make sure you get the right sized pistons and rods.
 

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You're right. All else being equal ( VR same and same piston profile - flattop?) I didn't know if he was doing both. I guess I assumed that if a crank is involved, it's usually to increase or decrease the stroke. My bad. But I did say "do the math". I had to do the math when going from 302cid to 347cid. (rods and pistons were non-standard sizes); the one thing I didn't know was the volume of the heads. I eventually broke down and CC'd all 8 chambers and static CR turned out to be approx. 10.3:1 on average. [Keep in mind static CR but dynamic CR should not change either since that's reliant on the cam and he's not changing that.]
 

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Here's the deal. Depends.

In my pea-sized brain, I have to imagine that when you increase "just" bore and nothing else, you're still adding a minute amount of weight in both the steel rings and the pistons themsleves. Very anal German engineers will say you need to do SOMETHING with the crank for the cranks are all balanced to this size engine (1.8L) but increasing mass means the crank has to take this into account. I know we're talking grams but 100grams is "approx" close to 1/4 lbs. At 7,000RPM, well, you get the idea.

The crank can either be rebalanced, (less expensive and a good idea) or replaced with a crank that's designed for the specific displacement in mind. Regardless, having gone through 2 V8's now, I'm a strong advocate of spin balancing the motor's rotating mass. IF the machinist can do it with the stock crank, he's home free. Otherwise, a new crank is what $$$ ????? I only know that V8 forged steel cranks go for over $600!!!! well worth it to make it bullet proof but perhaps not in his budget.
 

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I'd like to add that if you decide on spin balancing, you do the following with the machinist to advise:

1) All heavy metal slugs are inserted perpendicular to the cranks counter weights. This way, they cannot be "thrown" out of the recess. My first crank had the slugs on the outer perimeter of the counterweight. If it were ever to go loose, I'd be looking for a hole somewhere in the engine block or oil pan.

2) To be absoutely certain, you bring everything that makes up the rotating mass; this includes:
crank
pistons
rods
wristpins
wristpin retainers
rings
all rod bearings
harmonic balancer
flywheel

The clutch should not be included since they tend to wear so they are balanced by the manufacturer to be zero imbalanced.
 

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Discussion Starter · #16 ·
Here's the deal. Depends.

In my pea-sized brain, I have to imagine that when you increase "just" bore and nothing else, you're still adding a minute amount of weight in both the steel rings and the pistons themsleves. Very anal German engineers will say you need to do SOMETHING with the crank for the cranks are all balanced to this size engine (1.8L) but increasing mass means the crank has to take this into account. I know we're talking grams but 100grams is "approx" close to 1/4 lbs. At 7,000RPM, well, you get the idea.

The crank can either be rebalanced, (less expensive and a good idea) or replaced with a crank that's designed for the specific displacement in mind. Regardless, having gone through 2 V8's now, I'm a strong advocate of spin balancing the motor's rotating mass. IF the machinist can do it with the stock crank, he's home free. Otherwise, a new crank is what $$$ ????? I only know that V8 forged steel cranks go for over $600!!!! well worth it to make it bullet proof but perhaps not in his budget.
I was planning on balancing the crank, so that part is really not an issue. Anyone know how much an aftermarket crank will run? I Never plan on more that 300hp for this car (who would want more than that on a FWD?) Do you think it would still be safe to run a balanced stock crank? For that matter is it even safe to bore the stock block out that much?

The machine shop is owned by a friend of mine so he is cutting me a really good deal:)

Thanks For all the help Guys! We could not get the block to the machine shop today, But i should know something by friday.
 

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Discussion Starter · #18 ·
contact eurospec...they sell all different crank sizes, oem and aftermarket. i'd say for your purpose( <300hp), an oem crank would be fine though.


http://www.eurospecsport.com/crankshafts.htm

fred 01 hybrid has a bored out 2.0. i know it was a "sponsored" motor, but i'm not sure the exact details.
I'll shoot them an email. I was going to today, but ran out of time. Only having one car down sucks:thumbdown

I Sent fred a PM yesterday and he hasn't responded. But i know he is a very busy guy so it's cool:)
 

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If your car is an AEB or ATW you can use a (Forged) 2.0L crank from a 93 to 95 Golf or Jetta ABA engine

If your engine is AUG code (chain drive oil pump) there are no factory forged 2.0L cranks with the long snout for the chain drive. In order to go 2.0L you would have to go to the Eurospec chromolly crank (I am a Eurospec dealer BTW :) )

However im looking into the FSI 2.0L crank as soon as I can get my hands on one because im almost positive it is direct fit into the 06A block and if so it is a forged 2.0L unit so when they start becoming available they would be a less expensive alternative to the chromolly cranks
 

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imo, you don't need an aftermarket forged crank at 300hp. first thing to upgrade is the rods, and even that isn't necessary at 300hp.

edited to add "aftermarket"
 
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