Sam's S54 Build 2/3 Teardown

[samthejam]

So I got a cheap S54 from marketplace awhile ago. Finally got it to my dads where I can work on it. It was a good deal with the 6 speed trans.

I already had a smoking gun, on why the engine put whatever car it was in to the yard. Both vanos tabs were broken.

Untitled by Sam DaJam, on Flickr

I wanted to check the bearings and crank before spending any money on it. They looked fine,

Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr

They all looked good, I've seen way worse. Will get new bearings obviously but crank and all of them were good.

However the oil pump chain, had 0 tension on it at all.
Untitled by Sam DaJam, on Flickr


Whoever owned this engine did not believe in oil changes. I also completely missed this prior but finally noticed the upper guide...
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr

All of that yummy plastic in the Carquest oil filter that was in there.


Untitled by Sam DaJam, on Flickr

So I have ended up with quite the project that is an hour and a half away from my house. The head is off now as well. The bores still have crosshatching but it isn't much. My dad has all the equipment to measure the bores and that will decide where I go next.

This will be basically, unfortunately be a full rebuild now. I really don't like getting stuff machined so hopefully bores come out as okay. This will be a nice slow burn though

[bigjae46]

So I got a cheap S54 from marketplace awhile ago. Finally got it to my dads where I can work on it. It was a good deal with the 6 speed trans.

I already had a smoking gun, on why the engine put whatever car it was in to the yard. Both vanos tabs were broken.

Untitled by Sam DaJam, on Flickr

I wanted to check the bearings and crank before spending any money on it. They looked fine,

Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr

They all looked good, I've seen way worse. Will get new bearings obviously but crank and all of them were good.

However the oil pump chain, had 0 tension on it at all.
Untitled by Sam DaJam, on Flickr


Whoever owned this engine did not believe in oil changes. I also completely missed this prior but finally noticed the upper guide...
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr

All of that yummy plastic in the Carquest oil filter that was in there.


Untitled by Sam DaJam, on Flickr

So I have ended up with quite the project that is an hour and a half away from my house. The head is off now as well. The bores still have crosshatching but it isn't much. My dad has all the equipment to measure the bores and that will decide where I go next.

This will be basically, unfortunately be a full rebuild now. I really don't like getting stuff machined so hopefully bores come out as okay. This will be a nice slow burn though

I think I still have a 400 grit honing stone if you need to touch up the cylinders.

If the crank is good then the rest is gravy. Just pull it apart, hot tank everything and then reassemble.

[George Hill]

Whats the plan for it... going in the ZHP?

[cobra]

I recommend wearing gloves to avoid getting used oil and chemicals on your skin for extended periods of time

[bigjae46]

I recommend wearing gloves to avoid getting used oil and chemicals on your skin for extended periods of time

Agreed. Your skin is an organ that absorbs things...like old engine oil. Old engine oil has fuel in it which contains benzene which is no bueno.

These are the best gloves I've ever used. Expensive but cost less since they are quite durable and last a lot longer than other gloves.

ANSELL, Gen Purpose/Medical-Grade, M ( 8 ), Disposable Gloves - 2TEL9|SG-375-M - Grainger

[cobra]

Agreed. Your skin is an organ that absorbs things...like old engine oil. Old engine oil has fuel in it which contains benzene which is no bueno.

These are the best gloves I've ever used. Expensive but cost less since they are quite durable and last a lot longer than other gloves.

ANSELL, Gen Purpose/Medical-Grade, M ( 8 ), Disposable Gloves - 2TEL9|SG-375-M - Grainger

I've been using the harbor freight 9 mil (black) nitrile gloves and they hold up quite well as well.

[samthejam]

Spec for bore out of round is .0002" and cylinder 1 is measuring off the bat is .001" for out of round.

Lookin like a https://www.bimmerworld.com/Engine/B...930286135.html moment

[digger]

try and get the Mahle MS piston in 4032 (not 2618) it is a closer material to the cast which is what you want for a NA engine.

[CrisSilberGrau]

try and get the Mahle MS piston in 4032 (not 2618) it is a closer material to the cast which is what you want for a NA engine.

Can you elaborate on that a little bit.

[samthejam]

Can you elaborate on that a little bit.

2618 is more for dedicated racing, it 's more of a traditional forge piston. Will clatter when cold and has a large expansion rate so need to have clearances right but very resistant to detonation.

4032 is a compromise between 2618 and cast it looks like. It looks like they are sold as PowerPak pistons by Mahle

[digger]

Can you elaborate on that a little bit.

the best pistons for NA are OE cast plenty of strength and properly engineered barrel and ovality and validated unlike forged pistons which are generic.

If going forged on a street NA because OE are NLA or geometry reasons (stroker, deeper valve reliefs etc) then 4032 is closer to a cast piston from chemical composition (which is good) but improved mechanical property standpoint (also good)
- less thermal expansion than 2618 so they can run slightly less clearances (around 8 tenths to 1 thou less) which reduces how much the pistons rocks around when its not at max temp (which it rarely is) so the rings and skirts don't get hammered as much
- they have better wear characteristics due to higher silicon (advantage can be partly nullified with coatings)
this all leads to longer life in a non all out application, while 4032 is not as strong and ductile as 2618 they are more than adequate for a NA modified street engine and step up in strength cf. cast of the equivalent chemical composition. forced induction 2618 is the goto

Mahle MS use both 2618 (M-SP25) and 4032 (M124P) for power pak but the catalogue for s54 lists only 2618 so need to enquire with them and might be small cost increase, whereas s65/85 is listed as 4032

[Ryan_R]

I have personally ran .0035 PtW with 2618 pistons and never heard a bit of piston slap. Even when starting the engine in 35 degree ambient temps. Modern piston barrel designs mostly mitigate that issue.

[digger]

I have personally ran .0035 PtW with 2618 pistons and never heard a bit of piston slap. Even when starting the engine in 35 degree ambient temps. Modern piston barrel designs mostly mitigate that issue.

the pistons are still moving around it is just that it is not audible as thicker oils add some cushion and as does pin offset, it is even worse with a stroker and steeper rod angles that normally ensue and the s54 isnt even in a good place to start with rod angles. The closer you can get with clearance without issue the longer things will last, less oil migration, less oil dilution, less blowby on the meter and happier engine.

if you can only get 2618 then Mahle MS would be the one to choose as they tech transfer with the OE parent company and hard anodize top ring groove and coatings by default with power paks, i would skip JE, CP and the usual suspects holding the pieces in your hand the quality is subjectively better with Mahle MS

[Ryan_R]

Skirt wear isn't an issue if you're running a quality piston with a coating. That's the whole point of the Mahle grafal coating. To provide skirt protection.
The Mahle 2618 pistons also don't require much clearance. They recommend .002-.0027" of PtW.
A lot of the myths people throw around comes from 30-40 years ago when oils were much less developed and piston design was done without FEA analysis.

I agree on piston quality with the exception of CP. I would put CP above Mahle. Having toured their facility in Irvine, there is no way a piston or rod would leave that place in less than perfect condition. Every single piston and rod goes through multiple QC stations before it leaves their facility.
Just my experience after having ran both companies pistons over the years.