Anri,
So the ARP bolts have less stretch lengthwise under the same torque spec, and this caused the bearing clearance to be less than spec?
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Moving to the rod, bearings, bolts.
In S54 industry is a Fashion to use ARP rod bolts rather than looking at how it works.
ARP Manufactures great products.
Any of those who install ARP are aware of that if one is using different bolt
design the connecting rod Must be re-sized ? In the Instructional sheet row # 7
ARP politely says "Should always be re-sized", its worded very clever and R@R
options do love to load up the bill with parts and the Motor "it better than factory"
is the go.
Jonathan you paid money to have your freshly 20k miles bearing/s shown in the pic
look like they are 150k miles and you are not even tracking this car...if it was tracked...
then for sure the rod knock...
The evidence shows the bolt were placed without using ARP hi torque moly grease
it is also important how the bolts is torqued.
In the picture bellow pay attention on the rod side, the bearing has darker spots means
increased tension.
Moving forward.
Regards,
Anri




Last edited by Anri; 01-25-2024, 06:12 AM.
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I was pretty shocked to see how well they've held up since 2004 and with 155,505 miles on them - as far as I'm aware the motor has never been opened up and the pistons have never been out. Only thing done in that area was rod bearings about 25k ago and that was it.Originally posted by sapote View Post
Anri,
The piston looks absolutely like new with no sign of wear. How many miles on these pistons?
What contribute to the low wear -- tight clearance to minimize piston slapping or piston outer surface texture design to retain oil?
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Sapote,Originally posted by sapote View Post
Anri,
The piston looks absolutely like new with no sign of wear. How many miles on these pistons?
What contribute to the low wear -- tight clearance to minimize piston slapping or piston outer surface texture design to retain oil?
I think we went thru this in the previous S54.
But again few things are involved in this, its crazy
how much at "suppose" shitty rod ratio and F1 level
of piston speed etc all negative but facts speaks for it
self when its calculated right its not a problem.
Of course for example 1.74 rod ratio is better but
nothing wrong with existing 1.52 rod ratio. On top of
that the side skirt design is low profile in order to reduce
the piston weight and friction this is all negative...when
the rod ratio is in low number.
- BMW calculated the expansion rates very well.
- Slipper skirt from the factory to retain oil and reduce friction
(same dry film as the one I have done in the pic)
- Larger more aggressive groves (we spoke on this subject previously) to retain oil
- At last is the tune, the Factory tune is absolutely the best
in order to save the engine from detonation and other problems.
This engine has some minor pistons slap on a cold start
~30F which is normal but more important is it goes away after
around 2mins max.
My measurements shows that the piston to wall clearance
is on the lose side or max in spec. Tight is never good because
the target piston to wall is when the engine is at track at say 110C
on abuse or even let say in hot summer time. On S54s
with bad fan clutch during summer time with AC on in
traffic I have seen 108-110C were the needle will pass the
center this is were the piston will get scuffed mostly on the
exhaust side skirt due to growing excessively and will push the
oil away and will get tight to the wall.
This engine has I think 155k miles and I am sure it has seen
this hi temp conditions more than 1 time due to the bad head
gasket failure, indeed.
Regards,
Anri
Last edited by Anri; 01-18-2024, 05:47 AM.
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Anri,Originally posted by Anri View PostNote the factory lines on the skirt are like New...

The piston looks absolutely like new with no sign of wear. How many miles on these pistons?
What contribute to the low wear -- tight clearance to minimize piston slapping or piston outer surface texture design to retain oil?
Leave a comment:
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Originally posted by maupineda View PostHi ANRI, in your experience, is there an actual benefit to coat the bearings?
I get the same question over and over from customers and I always askOriginally posted by maupineda View PostI was thinking something like yours, or micro blue. Would you offer this service? I have a RB set for my car.
to understand the difference between Surface Treatment WPC vs
coating ! these are 2 different things.
Many benefits from every angle (too long to explain) If there was not
an actual benefts JE, CP, Weisco list goes on and on, none would offer this
dry film as an option everyone would offer surface treatment...
Yes I offer the RB service for $300 much better option than wpc.
Regards,
AnriLast edited by Anri; 01-17-2024, 09:03 PM.
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Hi ANRI, in your experience, is there an actual benefit to coat the bearings? I was thinking something like yours, or micro blue. Would you offer this service? I have a RB set for my car.Originally posted by Anri View PostPistons are all coated with Moly dry film
so do the ACL bearings.
Moving forward.
Regards,
Anri

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Wow they look new.Originally posted by Anri View PostPistons are all coated with Moly dry film
so do the ACL bearings.
Moving forward.
Regards,
Anri

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Pistons are all coated with Moly dry film
so do the ACL bearings.
Moving forward.
Regards,
Anri
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Cobra,Originally posted by cobra View Post
Billet CNC machined aluminum block
Don't get too excited about Billet Alu blocks..
Billet blocks are great but they carry their own issues
I can't see it with S54 given the fact we are after every
single CC on the S54.
Read the BMW PDF Bulletin carefully when they say the
block remained cast iron..
Regards,
AnriLast edited by Anri; 01-17-2024, 03:33 PM.
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Hey Arni, great work and thanks for sharing. How did you clean the pistons? Vapor Blasting?Originally posted by Anri View PostPrepped the pistons for Moly coating. Pistons
are checked and all in factory spec.
Note the factory lines on the skirt are like New...
Regards
Anri
-Rob
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I hope you don’t mind me asking, but what would that solution be? An aftermarket gasket? Please enlighten us allOriginally posted by Anri View Post
S54 multi layer gasket design relays heavily on that coating.
Cast iron block with the combination of aluminum head it
never works right in thermal expansion when the engine
warms up from stone cold! never ever. Aluminum on Aluminum
works much better (don't get depressed for the beloved S54
there is a solution!)
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