Engine Rebuild Advice - To Remove The Head Or Not?

[Syfon]

Do the headgasket. I had the opposite situation of you, my headgasket failed between cylinders (low compression on 4-5-6) so I took the motor out, did rod bearings, fresh gaskets, and of course head gasket.

Already been ordered mate. The motor will have brand new gaskets/seals/etc. throughout!

[Syfon]

So I've collected the block, crank, head, pistons & rods, etc. from the engine shop. No problems with machining, ACL Race rod & main bearings supplied.

I've also received most other parts required for the rebuild. I'm still waiting on the Streamline Autosport airbox & CAT 280/272 cams.

Unfortunately, as of today, there has been another delay; the camshafts have been pushed back to early September. So it looks as though the motor won't go back together until late September / early October.

I'm replacing just about everything; new timing components, vanos completely overhauled by a local guy, new cooling system and all hoses (including heater box hoses etc.). Ecu flashed with oe csl software suit map sensor + a base tune suit 280/272 cams. Plenty of things I'm missing but you get the idea.

Bought her home from temporary storage at my yiayia's weekend before last (was sitting on axle stands for ~8 months).

There's a heap of odd-jobs to do inside and out so I've started ticking them off 1-by-1; painted the rear 6 point strut brace carbon black 416, cut the boot carpet/trim to fit around the brace and floor reinforcement. Have a pair of BMW Performance 6 piston calipers to rebuild and fit to the car (already have the caliper adapter brackets), and other bits and pieces.

As the engine/trans is out, I started cleaning the entire engine bay to make it look as new as possible. When I originally purchased the car, it ventured through the north-west of Australia on the back of a truck and was absolutely covered in the fine red desert dust we get here. This dust gets into literally every nook & cranny; it was freaking everywhere in the engine bay. I spent an entire day meticulously cleaning the engine bay! I've also gone through each individual part removed from the front end / engine and cleaned everything of any dirt/dust/grime/oil/etc. Once everything is re-assembled, it'll be sparkling clean

Hope to start a new thread soon detailing the rebuild as I move through each step!

[F1Dryvr]

Good luck and keep us posted. Im a couple days behind you. Im Going to pick up the block today. Feel free to post any fun details you pick up on the way.

Heres some links ive been using and reading and rereading and watching and rewatching. Every time i do i pick up another detail or two.

https://theshopmag.com/features/engine-pre-oiling/

http://www.rfdm.com/Daniel/MRoadster/BMWDocs/TIS/

https://www.newtis.info/tisv2/a/en/e46-m3-cou/repair-manuals/11-engine/11-21-crankshaft-bearings/C3tafF9

https://m3support.net/thread/186/e46-m3-cams-diy

https://dsportmag.com/the-tech/education/quick-tech-performance-engine-break-in-the-right-way/

https://www.youtube.com/watch?v=1Doa-0M2flg

https://www.youtube.com/watch?v=3jXSmimxHVE

https://www.youtube.com/watch?v=cZv4NioeTLs&list=PLtg0qB0ER7k5xQJIwzZDg_veJX-Cz_EJs

[Syfon]

Good luck and keep us posted. Im a couple days behind you. Im Going to pick up the block today. Feel free to post any fun details you pick up on the way.

Heres some links ive been using and reading and rereading and watching and rewatching. Every time i do i pick up another detail or two.

Of course! It's been a fun experience so far! I'll get a new thread up and running in a couple weeks chronicling my experiences throughout the entire process.

Thanks for providing those links. I'll check them out; no doubt there's plenty of important info in there.

Cheers

[Tones]

What's up with the liquid moly hate in here?

Sent from my Pixel 3 XL using Tapatalk

[digger]

Oversized bearings are NOT for situations where you spun a bearing, machine the crank and now have a smaller journal. Oversized bearings are used to account for manufacturing tolerances.

If you removing material...it needs to be heat treated. If you don't the rebuild won't last long. The reason a Lang Racing crank is $700 is the heat treating. Had 2 machine shops confirm this...they work on airplane motors.

The oversized rod bearings ARE so you can regrind the crank. The over sizes is "+0.25 mm" which is ~0.010" which is not to account for manufacturing tolerances as the clearances are an order of magnitude lower. On rods the color is top vs bottom shell

However on the mains it is different, the different colors account for the tolerances but the oversize mains +0.25 mm also have their own colors to. i.e the (0) have yellow green white and the (+0.25mm) have their own yellow green and white

[sapote]

So last night I removed the head. No issues at all with the head gasket or anything else for that matter. Bores look perfect, as do pistons.!

Looking at the rod bearings at 60K miles: it seems #3 rod spun was just purely bad luck as all other bearing show no copper layer. I think #3 happened to have more clearance and less oil pressure than the others.

[Kdubski]

I paid about $1800 in 2020 to rebuild my motor myself. Yanked it for a head gasket job, did rob bearings, various seals, vanos, and clutch. Did not rering the pistons. The $1800 includes about $500 of labor.

Did it myself at home on an engine stand. Took about 80 hours. Was my first time every disassembling a motor. Really endearing experience, brings you to a more intimate level with your car.

Dont regret the experience at all.

[180SXTCY]

Hey mate noticed you were from W.A.

Just curious who you used for all the machining ?

[Icecream]

I paid about $1800 in 2020 to rebuild my motor myself. Yanked it for a head gasket job, did rob bearings, various seals, vanos, and clutch. Did not rering the pistons. The $1800 includes about $500 of labor.

Did it myself at home on an engine stand. Took about 80 hours. Was my first time every disassembling a motor. Really endearing experience, brings you to a more intimate level with your car.

Dont regret the experience at all.

Good to know! I am debating rebuilding my old S54 with a spun bearing, then selling, or selling as is and can't make up my mind. Almost seems like rebuilding it would be more profitable, maybe. I will have to do main bearings, new exhaust hub so that is $800 right there plus at least another 800 in misc. I am sure (obviously no clutch/flywheel). Plus I think it would be fun to do and document along the way, I dunno.

[sapote]

Good to know! I am debating rebuilding my old S54 with a spun bearing, then selling, or selling as is and can't make up my mind. Almost seems like rebuilding it would be more profitable, maybe. I will have to do main bearings, new exhaust hub so that is $800 right there plus at least another 800 in misc. I am sure (obviously no clutch/flywheel). Plus I think it would be fun to do and document along the way, I dunno.

Only your brother or friends will buy your car with spun rod bearings. Strangers will think what else are wrong and cannot test the car due to spun bearings. So I think you should rebuild it first.

Why need new main bearings? Broken hub tabs? (Remember that father gave his 350K miles car to son with stock parts?)

[Icecream]

Only your brother or friends will buy your car with spun rod bearings. Strangers will think what else are wrong and cannot test the car due to spun bearings. So I think you should rebuild it first.

Why need new main bearings? Broken hub tabs? (Remember that father gave his 350K miles car to son with stock parts?)

It's just the engine. I already swapped another S54 into my car. New main bearings because the cost of parts is not crazy high and figured it would be a good idea while it is taken apart.
And yes, hub tab broken.

[Syfon]

Looking at the rod bearings at 60K miles: it seems #3 rod spun was just purely bad luck as all other bearing show no copper layer. I think #3 happened to have more clearance and less oil pressure than the others.

Yeah i think you're right! Oh well, the motor is back together now

[Syfon]

Hey mate noticed you were from W.A.

Just curious who you used for all the machining ?

Harris Engines in Osborne Park

[cidini]

I spun cylinder 3 rod bearing a while back.

Bit of background;

• 13 March 2004 build
• 93,000KM at time of spun bearing
• Owned since 50,000KM
• Oil changed every 5,000KM with Liqui Moly Race Tech GT1 10w-60
• Never revved above ~4,000rpm until oil is at least 80C

Engine is out of the car and crankshaft is out.

Cylinder # 3 rod bearing spun quite badly, and the corresponding crank journal was damaged (if I run my fingernail across the journal it does catch!). Main bearing # 4 has chunks taken out of it, the corresponding journal is damaged but still quite smooth.

I took the crankshaft to a local machine shop; the owner advised me to remove the head and replace rod # 3 as he is unable to machine the rod due to it being of a "cracked" design.

What is the best plan of attack here?

Am I better off replacing the crankshaft with a good used one (undamaged obviously) and keeping all the stock pistons/rods (i.e. just replace rod/main bearings and rod bolts and put back together, thus avoid removing the head)? What about cleaning and/or flushing the block/head to remove any trace of metal? I cleaned the sump yesterday and there was a lot of copper flake in there...

Or do I go down the path of removing the head, replacing rod # 3 (with an oem one), having the crankshaft machined/straightened, and putting slightly oversized bearings?

I've never built an engine before, so this is all new to me. I'm quite mechanically inclined but unsure what the best option is in these circumstances?

I'm thinking of doing the following;

• Remove valvetrain & head
• Remove rod/piston #3 (replace rod #3)
• Have everything ultrasonically cleaned
• Machine crankshaft rod & main journals (machinist also advised the crank will more than likely be bent by 2 or 3 thousandths of an inch)
• Rebuild with existing pistons/rods, corresponding oversized rod/main bearings
• New oil pump
• Bulletproof VANOS
• Replace all gaskets/seals/etc.

Cost is a pretty big factor here. I don't really want to go down the path of buying lightweight/forged JE/Carillo pistons/rods, however on the flip side I'm thinking of doing it along with cams as the motor is out. When in Rome lol

Keen to hear the advice from those who have rebuilt their S54 and what they did. The M3 has been off the road since July 2019, so I'm keen as a bean to get the ball rolling, and while looking for parts, I’ve also been checking out bmw breakers near me to see what’s available to help rebuild my motor!
EDIT: Head came off a while ago and everything has gone to machine shop!

Replace rod #3 with a new OEM rod and install a good used OEM crankshaft. Keep your existing pistons and rods, use new rod and main bearings, ultrasonically clean the block and oil passages, replace the oil pump, gaskets, seals, and refresh VANOS. This is safer and more cost-effective than trying to machine your damaged crank.