EuroSpec Connecting Rods in AHU binding on Intermediate Shaft

[rotaecho]

So, I am building up an AHU engine to be a bit stronger. I purchased some EuroSpec connecting rods from Cascade German awhile back, since it was listed as 1z, AHU, ALH, RM, and BEW and were a good price.

Well, after getting the oversized pistons installed and putting in the intermediate shaft getting closer to finishing the build, I noticed I couldn't rotate the crank past 180deg.

Upon inspection it appears to be hitting the intermediate shaft. I believe at the fat end towards the front of the engine. Everything rotates fine when I remove the intermediate shaft.

What have people done in this situation? If I machine the shaft to the width of the center or end diameter will this cause structural damage to the intermediate shaft? Any advice here is appreciate.

And "Well you should have bought these XYZ rods instead!" would be fine, hindsight, but list them anyways, as I will likely be building another AHU again.

But for "now" what would be my best course of action without throwing the rods away?

Thanks

 

[burpod]

you want to slim down the i-shift and keep the taper. do NOT cut the whole thing down to a fixed width. i've done this, and i forget the specs of what i had to machine it down too.. but it's IIRC just rod 1 and/or 2 that are the issue. i had this written down but it's been a few years

for some reason 26mm comes to mind..

bascially, you want to keep the taper, and cut off 4-5mm iirc starting from #1 and evenly smooth it down on a lathe

 

[garciapiano]

Weight savings!

 

[Houpty GT]

I read about someone using a machined and lightened intermediate shaft. It was a sad ending.
I think it is fine to do the minimal material removal for the rods.

 

[burpod]

I read about someone using a machined and lightened intermediate shaft. It was a sad ending.
I think it is fine to do the minimal material removal for the rods.

i would guess that i-shaft was machined like the one i got done first... like i said, you have to keep the taper. you can still keep a good amount of beef on it, just don't cut it straight down and make it same width the whole way, which is what i've seen people selling... it will end up snapping at that first point where it was cut down

 

[garciapiano]

Sketchy

 

[rotaecho]

So, EuroSpec rods with the IM cleaned up (I actually went from thin area to the thick side.

****, I went ahead and had it thinned same length of smaller end to the large end before reading this. Guess I need a new IM shaft & different rods.

The problem is the "EuroSpec connecting rods" Cascade German is selling were hitting Rod #1 with the IM shaft and gear of the IM shaft with Rod 4. I already trimmed the rods to balance them. Testing clearance with the IM would require a lot more trimming on the rod side just by looking at it from the angle I can see.

Guess I'm looking for another intermediate shaft and proper connecting rods.

 

[burpod]

So, EuroSpec rods with the IM cleaned up (I actually went from thin area to the thick side.

****, I went ahead and had it thinned same length of smaller end to the large end before reading this. Guess I need a new IM shaft & different rods.

The problem is the "EuroSpec connecting rods" Cascade German is selling were hitting Rod #1 with the IM shaft and gear of the IM shaft with Rod 4. I already trimmed the rods to balance them. Testing clearance with the IM would require a lot more trimming on the rod side just by looking at it from the angle I can see.

Guess I'm looking for another intermediate shaft and proper connecting rods.

another rebuild disaster? sharp PANGing sound coming from head

i was going to post a more detailed thread involving this, but currently just trying to figure out this issue and get some ideas before i pull the pan off again or take the head off. my ahu, that previously skipped a timing belt, i rebuilt with forged rods, asv pistons, machined i-shaft, new...

forums.tdiclub.com

 

[garciapiano]

How much you wanna bet that these intermediate shafts are just not balanced or really strong in torsion at all from the get go? Enough rpms and they’re probably swinging around like a noodle in there…

 

[oilhammer]

I bet they barely deflect at all. They are only driving the oil pump and vacuum pump, and only have bearings at the ends. If they deflected much, the bearings would be wiped out in short order. The front bearing on the TDIs does eventually wear, but the rear one not so much. Older diesels, and the gassers, don't wear that front bearing as much... or at all.

 

[rotaecho]

Well, I thinned the gear as suggested by many on the VWDiesel FB group, but I didn't see how that'd help. As I had already thinned it down the wrong way (not keeping the tapper) I figured I had nothing to lose. Sure enough, still hits the gear towards the shaft side more than the gear flat end side.

I'm going to do some research on it, and either go another route with rods or put OE back in. OE rods maybe fine, I just rather have stuff built not to break. And since it was all open getting ASV pistons, figured what the hell. I guess I learned my lesson there.

Project is on the back burner for now. I am getting a gifted MK4 Golf that had a blown engine up and running, so I can have AC in the PHX heat here LOL.

Then back to van and MK2.