BUL engine!

[S4_Biturb]

Evening all. I WAS a proud owner of an A4 avant TFSI (2006) with the BUL engine, until two weeks ago when the balance shaft decided to chew up the chain. The internals of the engine are salvageable, however; im not convinced of a rebuild. My question is, where is the best place to source a BUL engine? (Ive been looking on the regular sites and contacted breakers etc). And most importantly, are there any other TFSI engine block and internals, compatible with my car?

Many thanks in advance

 

[Craig Cull]

Evening all. I WAS a proud owner of an A4 avant TFSI (2006) with the BUL engine, until two weeks ago when the balance shaft decided to chew up the chain. The internals of the engine are salvageable, however; im not convinced of a rebuild. My question is, where is the best place to source a BUL engine? (Ive been looking on the regular sites and contacted breakers etc). And most importantly, are there any other TFSI engine block and internals, compatible with my car?

Many thanks in advance

The block will need a rebore so it's either forged 83 mm Pistons and a bore out to 83mm with uprated rods, or another block with standard Pistons.

In a nut shell mate, that's your options.

Block is a no go unless you go for a bigger displacement along with a new head and cams etc

 

[Lizard-Racing]

I have a complete BUL bottom end for sale, has done 74k

 

[S4_Biturb]

Thanks for the replies. Ive had the block tested and theyve said its perfectly fine. They may need to re bore but bigger rings may suffice rather than pistons.
Reason i asked about other engines is that i can find BWE engines and other 2.0TFSI engine and internals so would like to know if they are at all compatible. If the BUL pistons are slightly bigger than the other blocks, would it be worthwhile to salvage what i can from my engine, purchase a BWE (for example) and modify it to suit? Or am i being mad!?

Many thanks

 

[Craig Cull]

Thanks for the replies. Ive had the block tested and theyve said its perfectly fine. They may need to re bore but bigger rings may suffice rather than pistons.
Reason i asked about other engines is that i can find BWE engines and other 2.0TFSI engine and internals so would like to know if they are at all compatible. If the BUL pistons are slightly bigger than the other blocks, would it be worthwhile to salvage what i can from my engine, purchase a BWE (for example) and modify it to suit? Or am i being mad!?

Many thanks

All the 2.0TFSI engines have an 82.5mm bore as standard, regardless of the output or set up.
I would be reluctant to use bigger rings as you run the risk of piston slap from cold and a smokey oil burning engine.

Your option is an 83mm rebore with an oversized piston of 83mm with a piston to bore clearance of 3.5thou to 4thou (engine builder will understand)
Depending on how close to a standard every day engine you treat it, depends on the bore clearance. Every day = 3.5
Rev it hard and for long periods of time = 4 maybe more.
But that's your decision. You only want to be rebuilding once really.