# Whats the difference in the AMU and ATC motors/head



## sabih786 (Apr 24, 2007)

180 = ATC
225 = AMU
i know the pistons/rods are different. but what about the head. the valves and cams are identical?


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## formulanerd (Feb 19, 2005)

they're both pre-VVT, so there shouldnt be any differences i dont think. aside from what you mentioned (pistons, compression ratio, etc) rods, wrist pins, crank should be the same


_Modified by formulanerd at 9:38 PM 5-8-2007_


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## sabih786 (Apr 24, 2007)

how about the head, thats my main concern, as i am replacing my amu head with an atc head, due to financial reasons, and because its more readily available.


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## formulanerd (Feb 19, 2005)

well the 1.8t typically has 2 different heads, big port and small port. you have a small port


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## sabih786 (Apr 24, 2007)

so the AMU and the ATC are both confirmed to be small ports.... 
so the head/valves/ cams are identical then?


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## formulanerd (Feb 19, 2005)

as far as i know, yes.
intake ports - 43x26mm
exhaust ports - 33mm
both have non-VVT intake cams


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## formulanerd (Feb 19, 2005)

where's cincy? maybe he can confirm/deny
the CR is different, but i'm almost positive thats due to different pistons, not the head.


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## sabih786 (Apr 24, 2007)

thanks for all the quick replies.. so if the only diff in the amu/atc motors is the pistons/rods/ whcih lower the compression so that the car can run more bost. the heads are the same. so me swapping an atc head on my amu pistons should work. and i will not have to swap the amu cams into the atc head.


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## formulanerd (Feb 19, 2005)

*Re: (sabih786)*


_Quote, originally posted by *sabih786* »_thanks for all the quick replies.. so if the only diff in the amu/atc motors is the pistons/rods/ whcih lower the compression so that the car can run more bost. the heads are the same. so me swapping an atc head on my amu pistons should work. and i will not have to swap the amu cams into the atc head.


correct, the heads are the same, and actually the rods should be the same, all the 20mm wrist pin cars should have the same rods (#027 198 401 B)
the top of the piston is what is going to determine your compression ratio. the later engines may or may not have stiffer exhaust valve springs (unconfirmed) but even if that was true, i dont think it would affect atc/amu engines.
and no, you wont have to swap cams, because the cams didnt change until VVT was incorporated (intake cam is different)


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## l88m22vette (Mar 2, 2006)

*Re: (formulanerd)*

and VVT was incorporated in...2002? 2003?


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## urugly (Jul 12, 2004)

*Re: (l88m22vette)*


_Quote, originally posted by *l88m22vette* »_and VVT was incorporated in...2002? 2003?

2003


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## sabih786 (Apr 24, 2007)

you know, from what ive read a lot of people didnt change their pistons when they had a TB break. 
http://www.sabihkhan.com/auditt/tb
and my nicks on the piston arent even as bad as this guy
http://forums.audiworld.com/tt/msgs/1611838.phtml


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## cincyTT (May 11, 2006)

*Re: (sabih786)*

transverse small ports are all the same ***vvt to vvt car and non vvt to non vvt car. Valve covers seem to be differnt but that is it. compression is made by the pistons not the head.
people only change the pistons if a valve hit and damage a piston.

* you can use a vvt on a non vvt car and vise versa but it requires a little more work.


_Modified by cincyTT at 1:05 PM 5-9-2007_


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## sabih786 (Apr 24, 2007)

i would be using a non vvt head ATC, on my non vvt AMU motor. 
is there work required for that or is it a simple swap?


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## sabih786 (Apr 24, 2007)

http://forums.audiworld.com/tt/msgs/1611838.phtml
I spoke with him and he actually did not change his pistons he just had the shop smooth it out.


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## cincyTT (May 11, 2006)

*Re: (sabih786)*


_Quote, originally posted by *sabih786* »_i would be using a non vvt head ATC, on my non vvt AMU motor. 
is there work required for that or is it a simple swap?

It should be a easy swap but you need a special head tool or you can use something as a replacement. I dont remember it off the top of my head but you can find it in a archive search (i think under gt-er)

_Quote, originally posted by *sabih786* »_http://forums.audiworld.com/tt/msgs/1611838.phtml
I spoke with him and he actually did not change his pistons he just had the shop smooth it out.

That would be fine. Should be about $20-25 each, dont hold me to that though. Aslong as they are smooth your fine.


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## stjacket (Apr 26, 2007)

*Re: (cincyTT)*

ok, i have a question in regards to vvt, i have a atc 2000, and the vag shows it as a vvt. WTF? is the vag lying, or is it a vvt. also all the info i have searched to include the specs from audi show that my 2000 atc fwd is a vvt. someone please clear this up!


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## cincyTT (May 11, 2006)

*Re: (stjacket)*

here is a break down of the 180's http://www.goapr.com/Audi/prod....html
and the 225's http://www.goapr.com/Audi/prod....html


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## sabih786 (Apr 24, 2007)

the ATC motor has 3 different timing belts (150/152/153) teeth. whereas my AMU only has 152.
http://www.importperformancepa....html
TBVW12
$39
(152 teeth)
TBVW12E
$39
(153 teeth)
TBVW12A
$35
(150 teeth)


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