Question on 524td connecting rods

[Brewskie]

I'm in the process of gathering the rest of my parts for a turbo stroker. I've done loads of reading and know what all I need. My question is why don't people use the 524td connecting rods? I have an opportunity to purchase both the crank and connecting rods from a 524td with low(ish) miles for a good price. I currently have a b27 and b25 engine. I'm trying to build the engine outside the car so I can still drive it while I'm building it. It's not my daily so using the eta connecting rods isn't out of the question.

Are the 524td connecting rods a different length then eta? Or possibly weaker? Any info would be appreciated. Thanks in advance

[zaq123]

how long are those 524td rods? eta rods are 130mm. From my understanding, 524td crank and eta crank are both 81mm stroke cranks with 524td being forged crank. If your 524td rods aren't 130mm and you are looking for eta rods, I have clean set that I was going to use in my 2.8L stroker until I decided to go with 2.9L IE Mahle pistons that require 135mm rods

PS. aren't td rods 139mm? Just put a measuring tape on the rod, from middle of the big end to the middle of the small, no precision tools required. You should be able to see if its 130, 135 or 139 mm rods. If anything, any TD rods/crank are stronger than gas engine, I thing their length is the reason....there is only one way to find out...

[Brewskie]

I haven't purchased the td crank or rods yet. The crank I know works but from the searching I've done I can't seem to find much information about the td connecting rods. I wasn't sure if the td had longer rods or what

[zaq123]

I not an expert...but why 524td crank? found one with good mileage and condition? I would think its easier to source low mileage eta crank since td cars are known to rake up mileage. Also eta cranks are more common hence better selection choices. Does your build require strong forged crank?

[Brewskie]

Doesn't require a forged crank. More of a safety feature if/when I up the rpms. I haven't read anything about an eta crank failing under boost but I can pick the td crank for roughly what I can get an eta crank for so why not consider it.

[whitebulat22]

I'm not sure on the rods but I would probably lean towards the eta crank myself for reasons Metric mechanic has here in pg. 11- if anybody's seen an eta crank break they haven't reported it yet and the diesel ones live a much harder life. They're also 3.5 lbs heavier. They definitely seem to sell for more though.

[Brewskie]

Thanks for the link. I noticed it said they shouldn't break if left under 6750 rpm and 225 hp and my goals will be nearly double (300-350WHP). It did state the td cranks have failed but not the eta. The way it sounds the eta cranks were in a N/A engine not a turbo engine. Through reading on the forums I have seen great success using the eta crank in a turbo stroker build with impressive numbers and no reported failures but wouldn't a forged crank be a safe bet? If it's absolutely not needed for my goals and keeping the engine revving in the stock "i" range then I can look to source a more redily available eta crank(other then the one already in the car). I may be over thinking this as I know these engines are strong and can handle a good amount of power