S54 Rebuild - Original Went Critical

[S54.sueño]

Well, it's sad to say that my engine is no more. What's even worse is that I bought the car last year in May, so I was able to enjoy it but didn't expect to be in this situation so soon. I believe rod bearing 5 gave out and piston 5 decide to make an exit through the side of the block. Before it left though, it was able to tap the head and bend some valves. You can see the damage in the pictures below. Maybe it's still salvageable lol.

A quick glance at the bearings didn't really show excessive wear but I'll have to double check when I get the chance. But, to add salt to the wound, I planned on replacing the rod bearing in August when I was out of summer school. Oh well.

I'm starting this thread because I have no clue what I am doing and could use some guidance along the way. I could have just bought a used engine and swapped it in my M3 but what's the fun in that. Plus, I was already able to get a used block and head at a decent price so if everything goes according to plan (it probably won't) I may end up with a fresh engine for maybe 2k more than had I gotten a used engine.

The used block and head have about 190k miles on them, I'm not concerned with the block too much, may or may not bore it to 87.25 but I'll probably buy Mahle pistons and Molnar rods to go with the block. Unless there are some other alternatives that I haven't heard of. I know that Darbshaw went with MaXspeeding rods which were cheap at the time, and I was honestly convinced of getting them myself, but they are the same price as Molnar now. Maybe I'm not looking in the right place. The crank I got with the block was also repaired by Lang which I've read good things about their process.

Right now, what I need help with is finding a good machine shop in SoCal (Near Pomona) to prep my block for assembly. Do I need to get the pistons first before sending it off? What should be done?(hone, hot tank, etc.) This is where experienced forum members who have connections chime in on recommendations. That would be very appreciated.

As for the head, at 190k miles should anything be addressed? If there is a shop that does both head and block that would be amazing.

[enjoy_m3]

Steve's machine shop is Azusa will be able to help you out. They are pretty busy though but pretty experienced with BMW engines. My advice is to get the Pistons first, oversize just to be safe because you never know with a block with 190k. Have it bored out to the piston size. This is not something you want to do twice. So the safer route is better.

[bigjae46]

When I was building a spare motor, I had the block done first. Measured the block, sent the crank, rods, pistons and bearings to get cleaned and balanced (need the bearings, rod bolts, damper and flywheel depending on the builder). The head is totally separate.

I'm inclined to say a used S54 is still the best route. It is rare for an S54 to have issues other than the common rod bearings and VANOS stuff.

[sapote]

I believe rod bearing 5 gave out and piston 5 decide to make an exit through the side of the block. Before it left though, it was able to tap the head and bend some valves.

I don't think the piston hit the valve at first. A relatively flat top piston cannot make the sharp dent into the hard steel exhaust valve, and there are smaller sharp cut on the same valve too. Aluminum alloy piston cannot cause these cut on the hard steel valve. So what did it? Cannot be the rod or broken rod as it was under the piston. I think the broken pieces of the cast iron cylinder wall got pushed up to the head, and with the help of a reciprocating piston, cut the head and the valves. The cracked or broken cylinder wall allowed coolant steam to get into the combustion and clean the valves and head really shine as shown in pic. The steam cleaning process must be going for longer than a few seconds for the combustion to be this shiny, especially the hard deposit on the exhaust valves. And what knocked a big hole on the #6 exhaust side of the block?
I like to see the bottom side of the block with crank and attached rods on it.

So I don't think a seized rod bearing could cause this -- the damages on the head and cuts on the valves.

[R717]

For the old engine, more details as to what was going on when it let go would be helpful. Interesting that chunk taken out of the intake port divider. That and the tons of impact points on the head lead me to guess it swallowed a bolt or nut, which broke /jammed the piston or bent the rod enough to fail.

Anyway I know with supply chain issues you want to get parts ordered asap but I would get the block checked first. 0.25mm is less than .010 in, with that many miles you're probably going to have to go out bigger than that to true the bores up. Get the block work started and then order parts after you have a clear plan.

[F1Dryvr]

https://nam3forum.com/forums/forum/main-forum/member-build-journals/66450-s54-engine-build-diary

This was my journey, so far its worked very well for me. Can definitely be done much more cost effectively, i kinda went all out, and certainly better as it was my first time!!! Agree w/ the overbore to 87.25. That will help improve the cylinder roundness and taper(common on stock s54 block) and still gives you another 0.25mm if needed if something goes wrong.

[S54.sueño]

Steve's machine shop is Azusa will be able to help you out.

Just sent them an email. They have pictures on their facebook page using a torque plate on an s54. This might be the shop i go with since Lang is good drive away and although I've read good things on their quality, their service doesn't seem to carry that reputation. I was also given the number to a so-called Ali's machine shop, but my calls don't go through except for one time, and he hung up abruptly while i was explaining my situation.

sapote Very astute observations. Unfortunately, since the block was useless and we're not allowed to work on engines where we live, my dad already sent it to the scrap yard. He got a whole $3 from it.

When I get a chance I'll take a closer look at the crank, rods, pistons, and what's left of rod #5. I do remember seeing the rod journal on the crank having a blue hue so there was a decent amount of friction regardless, but the main culprit may not be found.

F1Dryvr I have your write up and a few more bookmarked because they are a goldmine of information. Just wanna say thanks. I chose to go this route because i like the idea of going through the learning process and doesn't seem as intimidating anymore as long as i am meticulous along the way.

[S54.sueño]

So turns out Steve's machine shop is undergoing maintenance/upgrades. Won't be open for another 2 weeks and his appointments are for sept-oct.

I spoke with another machine shop and they said cast irons don't really need a torque plate. I'll be taking that info with a grain of salt. Guess I'll keep looking.

Also I'm confused in terms of headgaskets. If I do go with an 87.25mm bore, can I use an OE elring HG???

[JayVee]

How many miles on the car? and What oil were you running?

[Arith2]

I literally went through this. It had 71k miles but oil changes were neglected prior to me.



I bought an engine from Cali actually because I knew there would be service records. Sure enough there was. For an 85k mile motor I paid $5,300 with shipping to FL. It was a place called All German I think. Put 16k miles on it and it's been fine.

I thought it was a huge deal but now, looking back, it wasn't that bad. It's just heartbreaking mostly. You can't put a price on the joy these cars can bring. It should be alright if you follow repair instructions and get quality machine done and verify it yourself. Even reputable shops can make mistakes. In my case, I bought a running engine so no machine shop. That's the way I preferred it but what you're planning on doing is fine. A "new" engine will be much less money, labor, and headache. This is a great time really build it out though. Go all out if you have the funds for it.

[S54.sueño]

How many miles on the car? and What oil were you running?

Failed at 138k. Bought the car at 129k, did an oil change that same week with LiquiMoly and another change at 135k... Arith, cut me some slack, I saw it on FCP and the folks over at e46fanatics had no complaints so may not be the best oil and ill probably go with another oil for the next engine.

I don't think my crank was as damaged as Arith's but ill post pictures of the bearings and journals soon. I was able to leave some stuff at my parent's place.

One thing I should have addressed sooner and probably contributed to the failure were creeping oil temps... the temp gauge would sometimes rise on hot days in traffic or on spirited drives. It never got to the dot before the red and I didn't know how to check and correct it.

[eacmen]

Failed at 138k. Bought the car at 129k, did an oil change that same week with LiquiMoly and another change at 135k... Arith, cut me some slack, I saw it on FCP and the folks over at e46fanatics had no complaints so may not be the best oil and ill probably go with another oil for the next engine.

I don't think my crank was as damaged as Arith's but ill post pictures of the bearings and journals soon. I was able to leave some stuff at my parent's place.

One thing I should have addressed sooner and probably contributed to the failure were creeping oil temps... the temp gauge would sometimes rise on hot days in traffic or on spirited drives. It never got to the dot before the red and I didn't know how to check and correct it.

I don't think the use of Liqui Moly had anything to do with the failure. Its not my first choice but it is still a quality oil.

[tlow98]

Creeping oil temp like how far creeping?

the oil temp and water temp in these cars is a real gauge so you should expect to see some movement of both in different circumstances.

[JayVee]

Failed at 138k. Bought the car at 129k, did an oil change that same week with LiquiMoly and another change at 135k... Arith, cut me some slack, I saw it on FCP and the folks over at e46fanatics had no complaints so may not be the best oil and ill probably go with another oil for the next engine.

I don't think my crank was as damaged as Arith's but ill post pictures of the bearings and journals soon. I was able to leave some stuff at my parent's place.

One thing I should have addressed sooner and probably contributed to the failure were creeping oil temps... the temp gauge would sometimes rise on hot days in traffic or on spirited drives. It never got to the dot before the red and I didn't know how to check and correct it.

LiquiMoly is quality stuff, Both of my M cars get it, as does my diesel X5.

I believe you just answered all your curiosity. The red dot on the coolant gauge is simply the critical temperature. Anything to the right of 210*F middle mark for extended periods of time, (Including track days) is not okay. Your car was overheating and 100% caused the bearing failure.

[tlow98]

LiquiMoly is quality stuff, Both of my M cars get it, as does my diesel X5.

I believe you just answered all your curiosity. The red dot on the coolant gauge is simply the critical temperature. Anything to the right of 210*F middle mark for extended periods of time, (Including track days) is not okay. Your car was overheating and 100% caused the bearing failure.

Really? 210 is not that hot at all for full synthetic. Is there something about the s54 that doesn’t tolerate higher oil temps than 210?