Plan if CFSA blows up?

I’ve kept a mental track of CFSA engine failures that have been posted online. Just the other day a girl I follow on Instagram had hers get rod knock at 60k miles. Checking online I don’t really see any engines for less than $9000 while some are as high as $15000. The mileage on these eBay engines varies and pricing is literally random but they’re all near 100k miles. That’s quite a bit of money for such high miles. Tack on a few thousand for labor and refresh and you’ve got a very expensive proposition on your hands. I don’t know if I’d continue with another CFSA. I’d most likely start the swap to 4.0tt. Have you all thought about what you will do if yours blows up?

This is probably a good place to discuss this in a new Post, I started talking about it in the Supercharger forum. As far as CFSA engines go you’re right. I got an Ebay engine that failed in 300mi. It had some water intrusion (probably during storage) which had probably damaged the bearing journals or bearings themselves. I went the route of Copart (IAAI is also great) and got a running car with 27k miles. Got it for not much more than many Ebay motors. I was able to drive this car right up and onto my trailer, really not hit that hard. Seemed to run great but I took an oil sample from the motor before I pulled it and sent it to Blackstone for an oil analysis. Sold the tranny recently, just sold an Airbag and one of the headlights last night. Got a few people interested in the Rear Diff as Audi wants $7k and even high mileage Ebay ones for for $2.5k.
But, if this engine fails I’m also going with a 4.0tt. Possibly a RS6/RS7 version although a S6/S7 still has plenty of power potential an stock have 100 ft/lbs more of Tq. RS6/RS7 version is a little different, more Forged internals, Turbos are a little larger and Forged rotors compared to the Cast rotors in the S6/S7, but the Blocks are almost identical. If you can get the S6/S7 car whole the advantage is you also get their DL501 with the extra clutch plates and an ECU which is already tuned for the DSG as the RS6/RS7 has the ZF HP8. I’m looking at a couple of cars already, may have a 4.0tt sitting in my shop soon.

If you start the process, please post it on here. For some reason people have tight lips on these swaps. I really like the DL501 and that Russian guy is using one on his without problems apparently.

I think getting it in the engine bay and hooking up cooling and stuff is pretty easy, the hard part is the software coding to get it to work on the Canbus so you don’t end up with any faults on the instrument cluster. RS5 would probably be the best B8.5 choice as the engine cradle should/is a very close fit to the 4.0tt. 034 Motorsports did it to a B8.5 S4 and even used the S5 DL501 which should be a little weaker than the S6/S7 DL501 (1 less friction disc in each clutch basket) and it was supposedly running well last i heard. I should/may contact them and ask if they are interested in coding another. I’m in no hurry as I just dropped in the 27k motor in my car, along with the headers, JHM Stg2, LWCP, LW DSG Flyweel, SAI Delete, etc…

I try to prevent blowing the engine up more than planning on a solution in case it blows up. The local RS5 guys are doing oil changes more often and being careful to test for coolant in the oil. The RS5s are old enough now to start experiencing the problems that the older B7 RS4s and V8 R8s have been seeing for years now of the o-rings and seals leaking coolant into the oil causing bearing wear/rod knocks. Also keep on top of the fuel injectors spraying correctly. I strongly recommend that you run fuel system cleaners through the fuel regularly like Redline, Hot Shot Gas Extreme, or the Audi fuel system additive. In case you need injectors then I have rebuilt OEM fuel injectors too.

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Can you identify which seals would be the ones to allow coolant into the oil system? I know with the N54 the OFHG could fail and allow them to mix but it rarely happened.

Sure thing. It is typically WHT006998 (x2) and WHT006998 (x2) that are o-rings for the coolant transfer pipes inside the upper rear timing chain covers. Here is a picture of parts diagram and of the actual part removed from a R8 engine.

If you are really unlucky then it is one of the seals for the upper oil pan or lower part of the block. Usually by where the oil cooler hoses are.

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Sounds to me like the seals should get done when the engine comes out for headers. All my cams have to come off anyways to replace the valve stem seals.

The coolant transfer pipes o-rings would have to be replaced when replacing the valve stem seals. The oil pan and lower block seals require a good bit more work to replace since the flex plate on the back of the crankshaft, big lower timing chain cover, spur gear drive unit, and oil pump have to come off.

Yeah I’d be swapping the flex plate and flywheel at that time as well, plus my spur gear is noisy at idle. My problem is, if I want headers, i need to take the engine out and partially apart anyways to remedy the issues I stated above. Since the cams have to come off and therefore timing, why not the bottom seals too, and at that point it’s going to be relatively cheap to take it all the way apart and install rods and pistons with rings gapped for boost and then supercharge it. What to do what to do…

I get the logic but you could just add ring gap to the factory piston rings as well since the stock pistons and rods are forged from Audi. In the past I have measured 0.004"-0.006" on RS4 engines which is way too tight imo. You can open that up to 0.018"-0.020" and it would be fine for boost.

You make a great point and I have considered manually opening the gap. I just have to eventually decide how far I want to go.

You’re right, once you get to that point things start snowballing into something bigger. At least if you take the lower pan off you can get at the Rod bearings and check them since they have been a failure point in several engines, and many of them on the lower mileage end of the scale. You can go with OEM Rod bearings but for the price I would go with King bearings (probably the best made). Also necessitates new Rod bolts (OEM are one time use or go with ARP which makes bolts to fit (same as V10 Lambo/Audi)).

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Very true. I think the right thing to do for a boosted engine, and this is probably a good list for anyone who plans on removing the CFSA for work, is: S6 flex plate, LWFW, top and bottom coolant seals, gap compression and oil scraping rings, king bearings, ARP rod bolts, headers, SAI delete, timing chains, lightweight JHM pulleys. Should help refresh the engine to keep it spinning for a long time, boosted or not. Add in a carbon clean, injectors, plugs, coils, etc… I wouldn’t boost this engine without doing all these things first. Add in some basic weight reduction and there shouldn’t be a problem blowing away all the current RS5 records.
The way things are going with the price of new cars, I can’t see myself buying anything else in the near future. I really want 2 RS5’s. One stripped bare for track prep, and one boosted street monster, CFSA or 4.0tt.
You know what blows me away? In the town I live in lies a massive company known for its wide array of snack cakes. You know what the president of that company drives? A Suzuka Grey RS5. Dude is a multi millionaire and still drives a 10 year old car because it’s that good.

CFSA Ring specs:
Measuring piston ring gap
– Insert ring at right angle to cylinder wall from above and push down into lower cylinder opening approx. 15 mm from bottom of cylinder.
– To do so, use a piston without rings.
Piston ring

1st compression ring new 0.20 … 0.35, wear limit 0.80, inch .007874 to 0.01378 limit 0.0315
2nd compression ring new 0.20 … 0.40, wear limit 0.80, inch .007874 to 0.01575 limit 0.0315
Oil scraper ring new 0.20 … 0.40 wear limit 0.80, inch .007874 to 0.01575 limit 0.0315

Did you rebuild yours yourself or have a shop do the work?

I didn’t rebuild mine. So now I have two CFSA engines with spun rod bearings, a 99k motor with rod bearing 4/8 spun and a 26.5k motor with bearing 3/7 spun. I bought a running but wrecked car with 27k and installed that in my car. The 26k motor was an Ebay purchase that had been stored improperly and had some water intrusion which damaged the bearings, it ran for 300mi before failing. I wasn’t willing to take a chance on another Ebay roll of the dice so I found a running but wrecked car. I had is shipped cross country to a nearby Depot and went there with my truck & trailer, started it up and drove it right up onto the trailer. Because I was a little gun shy I pulled an oil sample and sent it off for an analysis before pulling the engine.