Rod bearings?

[lewis_jennings]

Hi everyone,

Before I supercharge the car I'm going to do the rod bearings,

Wanted to see what everyone here recommends/has tried.

Don't want to spend big money on a bmw set.
Was thinking of acl bearing. But seems to be loads of different prices about. One company selling them for 400+, another selling for 160 pounds.

Not sure what I'm looking for so any help or info would be great
Thanks

[PDJ]

I fitted King Race bearings

[AndyBeech]

Not many people have had a second set of bearings changed to give any meaningful data on what is good or bad or better so much of a muchness really. King or ACL are most popular options. Had King myself.

Bearing themselves should be around the £150 mark. I expect £300-400 included bolts as well and maybe even oil. Either way, I doubt there's much to be gained buying them yourself, I'd just phone round garages you trust and ask for an all in price. Anyone half decent will have done plenty of them before and probably have a set price.

[Ed Doe]

As above, ACL & King seem to be equally recommended by specialists (Hack Eng & Redish included).

£400 sounds like it includes ARP Bolts. As Andy has said, I'd not bother getting the bits yourself, just get a reputable specialist to supply and fit.

[lewis_jennings]

Alright nice one thanks lads!

Do you recommend replacing bolts also?
Im quite friendly with the specialist and after a bit of banter he agreed to charge a little less in labour if i threw him in the bearings so he didn't have to get them. He's also installing my supercharger kit so I said id give him everything at the same time to do.

[Ed Doe]

Alright nice one thanks lads!

Do you recommend replacing bolts also?
Im quite friendly with the specialist and after a bit of banter he agreed to charge a little less in labour if i threw him in the bearings so he didn't have to get them. He's also installing my supercharger kit so I said id give him everything at the same time to do.

As I understand it, the OE BMW big end bolts are single-use stretch bolts. However, the ARP bolts are reusable.

Either way, I would categorically not re-use the bolts already in there!

[lewis_jennings]

Alright nice one thanks lads!

Do you recommend replacing bolts also?
Im quite friendly with the specialist and after a bit of banter he agreed to charge a little less in labour if i threw him in the bearings so he didn't have to get them. He's also installing my supercharger kit so I said id give him everything at the same time to do.

As I understand it, the OE BMW big end bolts are single-use stretch bolts. However, the ARP bolts are reusable.

Either way, I would categorically not re-use the bolts already in there!

Good to know! Time to go on the hunt for the bolts too

[GuidoK]

Always change bolts.
Tbh I would go for OEM bolts, not arp ones.


Dont forget to have your oil pump pressure piston checked for wear. They are prone to wear.

[lewis_jennings]

Always change bolts.
Tbh I would go for OEM bolts, not arp ones.


Dont forget to have your oil pump pressure piston checked for wear. They are prone to wear.

What's the thought with oem over arp? Just out of curiosity.
Will mention about the piston also when I drop it in

[GuidoK]

What's the thought with oem over arp? Just out of curiosity.

ARP specs 2 ways to torque the bolts. The preferred way is to use a stretch gauge (basically a micrometer that measures how far the bolts are stretched).
The other way, the way they describe when you dont have a stretch gauge, is to just use a (1) torque spec.
Stretch gauges are often used in shops that build race engines.
And despite it's a ~£50 tool, I assure you that virtually no normal shop/garage will have one. So they'll be torqued with 1 single moment.

The bmw bolts are torqued to a series of torque moments, and an angle spec (and that done twice). That is a normal way to torque rodbolts, also with other brands (except for the s54 it's done twice).
BMW is very specific in this torque sequence method. This is a repeated stretch method.
So I don't think the arp bolts are an upgrade.

Be sure that the shop is familiar with the oil regulator piston. In Germany this is pretty normal with BMW specialized shops, not sure about the uk
The piston cannot be sourced at bmw. So if the shop can't source it from abroad, you'll probably have to pay for a complete pump (almost £600).

The wear on the piston looks like this:

[AndyBeech]

There will be plenty of people running both set ups, if your concerned I’d give someone like Hack Engineering a call and have a chat with them about what they recommend. They also have the various parts they can sell you if you want to skip looking about for them on the internet. They build lots of standard / race engined S54’s so they know their stuff. Redish will also be able to give good advice among no doubt other places.
Ring around and get some advice if your worried about it, they’ll be more than happy to help.

[Ed Doe]

I recently had acl rod bearings with arp bolts from redish, and pretty certain they used the stretch method, but yeah definitely redish and hack are both highly recommended and I'm certain hack sell a bottom end kit comprising acl bearings and arp bolts on their online shop

[Mr Tidy]

I had my shells replaced last year at an excellent BMW Indy.

He fitted ACL shells but OE bolts. I asked about ARP but he reckoned OE were just as good.

I had new engine mounts fitted at the same time - the old ones looked pretty tired after 78K miles!

[gr3mlin]

Tempted to do the same - car is on 47k miles, what are peoples opinions on getting the bearings done before supercharging?

[Ed Doe]

How many owners in the last 47k? Has it had bearings before now?

Personally for the peace of mind I'd do them, it's a comparatively cheap replacement compared to the complete s**t-fest if they go...!