# engine swap or not?



## Darth-Vento (Mar 16, 2006)

So i have a 97 a6 quattro, the mechanic tells me that the engine has about a year left on it and ive noticed a slight power loss last week. Im leaking oil from the rear main seal and am wondering if i should just replace the seal or the whole engine? which would be a cheaper solution? Ive been getting my hopes up and thinking bout ditching the 12v and getting a new 30v if its a direct drop and swap. 

what do you think the best solution?


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## Darth-Vento (Mar 16, 2006)

anyone know anything bout this subject?


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## tryin2vw (Dec 30, 2006)

I do not believe they are interchangeable. The VR6 is a transverse mount, the 2.8 30V is a longitudinal mount. Different transmissions, different exhaust set-up. 

Anything can be done with enough time and money, though. 

Why would your engine have about a year of life left on it? Bad maintenance? Need timing chain?


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## O_o (Nov 12, 2009)

He has the 12V V6, not a VR6. The 30V block is almost identical to the 12V. You might need to fab a couple of mounts, but I don't think so. 

It's by no means plug-and-play though. For starters, the 30V engine won't run properly with a 12V ECU. At the very least, there's no way to make the VVT work, and probably more, so you'll have to get the ECU from the 30V. Honestly, I don't know how much else is involved. You might need a bunch of the 30V sensors. Also, I'm not very familiar with the A6, so I have no idea how well the exhaust bits are going to match up. It's possible that you would have to fab new downpipes for it.


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## tryin2vw (Dec 30, 2006)

I still ask: Why does the tech say there is only about a years worth of life left in the engine?


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## Darth-Vento (Mar 16, 2006)

he says two of the cylinders have a low compression like 120 while the others have 140. dude said thats why he thinks it has less than a year on it. i put about a 1quart every few weeks. I though about a rebuilt but figure a new engine would be cheaper.


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## O_o (Nov 12, 2009)

Darth-Vento said:


> I though about a rebuilt but figure a new engine would be cheaper.


 It depends. If you're going to drop it off at a shop along with your Visa card and phone number, then yes, a swap is probably cheaper. If you're doing all but the machining yourself, a top-end rebuild will be cheaper. Piston kit + bore job = $1,500 or so. Another couple of hundred for gaskets & fluids, and for around $2k, you've got an engine that's good for another 100,000+ miles. 

Edit: it would be a bit stupid not to do the timing belt, water pump, etc. while you've got 'er stripped down that far, so make that about $2,500.


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## Darth-Vento (Mar 16, 2006)

i just did the timing belt at 130k not to long ago. 

you think a top end gasket change will help the low compression? not to sure how to raise it...


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## O_o (Nov 12, 2009)

Gaskets aren't going to help. 



> he says two of the cylinders have a low compression like 120 while the others have 140.


 Wait a minute... 120-140 psi? Are you sure the timing is set correctly?


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## plynch (Aug 30, 2006)

not sure where you are located but if you do swap it-which would be the cheaper option- you can pick up 12v v6 engines pretty much all day on the east coast, and depending where you are i can get them for 300 each.... and for 500 install it... but yeah the 12v is readily avail. i would'nt be throwing 1500-2500 down on a 97, the whole car is getting into that price range now, i sure would not pay anywhere near that for an engine unless it was certified 0-10k miles or something fantastic like that. and then still maybe not....pm me if you are on the east coast.


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## O_o (Nov 12, 2009)

> i would'nt be throwing 1500-2500 down on a 97, the whole car is getting into that price range now


Yeah, good point. I'm not convinced a $300 engine is going to run any better than what he already has though...


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## Darth-Vento (Mar 16, 2006)

yea thats what the guy wrote down. he wasnt able to get a one of the spark plugs out (6 i believe) and said that was the compression. Is that bad for our cars?

I live on the west coast and thats the price ive been seeing online and on CL( 900-1


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## O_o (Nov 12, 2009)

I honestly don't know what the minimum spec is, but it would have started at something a little over 200psi when it was new, so 120/140 is pretty weak.


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## Darth-Vento (Mar 16, 2006)

if it is 200 then what can i do to raise the compression ratio then? new gaskets or seals?


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## O_o (Nov 12, 2009)

Darth-Vento said:


> if it is 200 then what can i do to raise the compression ratio then? new gaskets or seals?


Well, you can't raise the compression _ratio_ without doing some internal work, but I digress...

For starters, a leaking head or base gasket would manifest itself rather obviously. Second, you have pretty uniformly low compression, and you would expect one cylinder, or one bank, to have low compression if it were a gasket or seal. So, I really think replacing them would be a complete waste of time and money.

From what you've described, it sounds like either:

1. The timing belt slipped a tooth. This would fit with your observation of a sudden power loss, and also the uniformly low compression (how low, I don't really know). The only cure is to adjust the timing.
2. The pistons/cylinders/rings are worn. This causes low compression, and usually high oil consumption, but almost never a sudden power loss. The only cure is a bore job and pistons. Again, I don't know what the minimum spec is for your engine. It's possible that 120 is still considered OK.
3. The valves aren't seating/opening properly, for one reason or other.


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