S54 Timing chain guides

[ac427]

I think timing chain guide 'A' is the excellent Beisan part.

Does guide 'B' not wear as much as 'A' or is the BMW more up to the job the 'A' ?

[Obioban]

“A” is the only one that wears out (on any reasonable time frame) on the s54.

[terra]

Yep. It does look pretty similar in construction to the S62/M62 guides, so it does make me wonder... but probably not having that stupid U-shape helps it survive.

[heinzboehmer]

B doesn't wear on the S54, but the bolt that holds it at the top can back out.



Bolt 10 in both images. It's behind the thermostat housing, so worth checking whenever you have that off.

[Obioban]

Yep. It does look pretty similar in construction to the S62/M62 guides, so it does make me wonder... but probably not having that stupid U-shape helps it survive.

The s62 chain guides don't wear, either, IF you replace the tensioner itself every ~100,000 miles.

The M62 runs pretty hot (thermostat) compared to the S62/S54-- I suspect the heat is the difference.

[terra]

The s62 chain guides don't wear, either, IF you replace the tensioner itself every ~100,000 miles.

The M62 runs pretty hot (thermostat) compared to the S62/S54-- I suspect the heat is the difference.

Sounds like it should become SOP to tune the M62s to run at a lower temperature then (the joys of MAP controlled thermostats)

[mrgizmo04]

Several things going on on the (A) guide side vs the (B).

1 - there is a tensioner which sits against the guide, the tensioner weakens over time, allowing the guide and chain and also the bottom guide (against which the top guide in discussion sits and rubs) to flop around and wear against each other.

2 - the reason there is a tensioner on (A) side is to put pressure on the guide and keep the chain from flopping around during abrupt acceleration/deceleration changes (your right foot) in the engine. The (B) side is always in tension while the (A) side is not. So as the chain stretches, guide wears, tensioner weakens, the (A) side takes more beating.

I always bring things back to a bicycle, while very different some things carry over in concept. Think of the top of the bike chain (B side guide in this discussion) vs the bottom of the chain (A side guide). Either a fixie or one with a derailleur, no difference. Crank is synonymous to crank, cassette/rear gear is synonymous to valve train.