Big End Nuts and (stretch) bolts.

[mark-hans]

Guys, I am years trying to perfect the wbx rebuild.

Now I am faced with a set of wbx vw conrods that I 'think' have been in and out a few times (over 40 years?). I have 100 used conrods in my shop! I don't like the stretch bolts at all. I push them to 56Nm, 42ftp. They are 'tight'. But I can feel the stretch. OK, maybe I am becoming paranoid, but I don't like it. I want to fit new bolts into all my conrods and we are building more than 30 wbx's a year. This engine is making me crazy, but it's all in the details.

Where can I buy them, lots of them.

Thanks.
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Mark, Amsterdam.

[MarkWard]

I would reach out to ARP. They are the gold standard in fasteners. They have fasteners for many applications. I don’t know that they have a WBX 2.1 fastener, but they can also make custom runs. They did have Type 1 fasteners and fasteners for the VW inline 4 last time I checked. Maybe they could be adapted.

One recommendation, when you change rod end fasteners, it is best to check them for distortion and machine round if necessary.
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[mark-hans]

Being in Europe, could you give me a URL? Thanks for the lead. Any other ideas out there?
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Mark, Amsterdam.

[MarkWard]

[DanHoug]

[mark-hans]

Thanks Guys. That's great.
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Mark, Amsterdam.

[DanHoug]

GoWesty as well as VanCafe sell them. GP Group Classic Line is manufacturing/marketing some so check your vendors that have a pipeline from them as well.

it LOOKS like ARP part number 104-6002 is the correct diameter and length, 9mm x 53.5mm but you need to check whether those dimensions are correct.
https://arp-bolts.com/kits/arpkit-detail.php?RecordID=97

as per ARP's instructions, always resize the rod bore after installing new bolts. or just putting on used rods!!
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[mark-hans]

Can you expain this pls.

as per ARP's instructions, always resize the rod bore after installing new bolts. or just putting on used rods!![/quote]

I am at a loss...
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Mark, Amsterdam.

[MarkWard]

You can’t see, but a good machinist can measure it. If you are rebuilding engines and not checking the rod end dimensions you’ve been lucky. Different fasteners can have different clamping forces. This can distort the metal enough that it is no longer “round”. You need to assemble the rod to torque and measure for out of round. You then disassemble the rod and a machine shop will grind the face of the cap and maybe the rod face. Assemble again torqued and the machinist will hone the big end round to spec.

ARP fasteners are very strong with their own torque. They understand that distortion can happen and it’s good to make new customers aware that inspecting and machining likely will be needed.

Any time I build any engine I have the rods checked and I’m using Carillo rods. Unfortunately my machinist passed away from COVID. It’s easier to have a good machinist that you build a trust with.

That said, I know anyone can just slap an engine together and most of the time, it works out. Quality rebuilds require precision clearances which require precision measuring.
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[Wildthings]

The big end of rods tend to get a bit oval with time, maybe 0.0005 to 0.001". When you change the rod bolts, doing so can alter the alignment of the cap compared to its mating surface on the rod by a tiny bit as well.

[DanHoug]

Mark - here is a good article from noted engine builder Bob Donalds, now passed away. it explains, as others above have, the need to rebuild rods, at least the 2.1L rods.
https://www.vanagononline.com/articles/tag/2-1l/
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com