kliped

Hey guys, does anyone know if all crec engines are created equally? Can i swap one from a 2016-2018 a6 or a7 into a 2017 q7? the price difference is staggering so i just want to make sure there isnt anything crazy different and its just a matter of swapping some simple things over (sensors, pipes, brackets)

kliped

For those wondering, I compared some part numbers and it appears that the block and heads are the same between the platforms, but the timing chain covers have different part numbers. Seems like it would be a well worth swap for the significant price difference.

buddywilson

i am also trying to figure this out. i am only noticing small things but will update if i find anything new

buddywilson

i got the VIN from a A6 engine i am thinking of getting to compare to my Q7. i then used Partlink24 and found very minimal differences. for me the timing cover was the same. but the valve covers for the A6 were an older revision (same part number) that was the same for some of the components. the only real difference in part numbers was the coolant houses exterior from engine like hoses going to coolant bottle and radiator and brackets. the plumbing that's on the engine i like the cross over pipe and the one that wraps around the block (cant remember the name). this is at least for my case. i pulled the trigger and bought the used engine. i will see if there are any other bigger differences and will update my progress.

this is all for a spark plug tip breaking off just days before planning on replacing the spark plugs as i had them ready to go in.

2kwik4u

Murphys law really borked you there eh? Sorry to hear that.

I'll be following along as you compare the two. Please report back what you find once you get the parts in hand.

kliped

i did the same, i have one coming that came out of a 2018 a7. should be here in the next couple days.

buddywilson

so i just finished the replacement. it took alot longer then expected due to finding broken stuff and improvising but here is the key differences that i have found

1. Rear lower timing cover is different. The only difference i could tell is for the CKP sensor. the sensor on the A6 to Q7 are different in length and design. for me i was in a pinch, measured the difference and put a 3.5 mm spacer and it worked. This also goes for the reluctor ring (what tells the CKP the position of the crank) they had different part numbers but where identical in size. so i took the reluctor ring off of my original engine. i also used the same drive plate (flywheel) from my Q7 just incase and it was cleaner looking
2. passenger side combi valve and heat shield are different on the Q7, need to swap for the cat to fit, the combi valve for driver side is the same im pretty sure but the shield was different. so i just swapped it all
3. the vacuum line coming off of the vacuum pump (after the one-way valve) is missing the split for the Q7 factory airbox bypass valve (N275) just remove the fitting and swap
4. this might only be for my case but the passenger side engine bracket on the new engine (wasn't there, but in part catalog i believe were different) the threads appear to never been used so i had to make my own tap and clean the threads, this also the same for the lower center transmission bellhousing bolt. the threads were corroded towards the end almost like the bolt that was used in the A6 was shorter due to maybe a bracket or just the bolt was shorter for its use case.
5. also just as a precaution i swapped the entire harness from my Q7 like the engine to ECM and the block harness that runs under the supercharger for the fuel system etc. i did this because it worked on my Q7 and i dont know the history of the new engine. easier to do it now not later if something happened

but its running and i just a few codes, P199E about cooling and bank 1 intake runner code, i did apply vacuum when installing and made sure flaps were on the correct side of divider but it felt hard to move so i have to inspect. i have a U code that i have to investigate. something about CAN but drove it home just fine

kliped

that is great news, thank you for that update. mine is still sitting on an engine stand as i have a few jobs ahead of it, hopefully here in the next couple weeks i can get after mine.

gbgastowers

That’s a huge amount of work. Hope it works out for you. Keep us updated. Just did an exhaust valve replacement. It was engine out and we had a hell of a time getting engine back in. Now I have the problem of not being able to fit the cats in due to no room. Going to have to lower subframe and hook engine up to hoist to get them in. Gunar

buddywilson

its not a bad swap, just tedious with all the minor things like parts electrical and cleanup of surfaces along with inspecting. i took the engine out through the front. i didnt do subframe drop