S54 Engine Rebuild questions and journey

[Darbshaw]

So in my previous post, I found that my head gasket was blown due to the mid-range rpm rattling. I was able to get my head pulled today to find a completely demolished head gasket and a toasted piston on cylinder 2 and a couple of pistons that are pretty porous looking. This now leads me to a rebuild in mind. I am gonna cap off my previous post as this title fits the current issue better now and we'll start the journey now! //Please keep in mind this is all completely new to me, I grew up racing quads but my dad did the building and I didn't retain much from that time. So A LOT of stupid questions will be coming.

The current mileage is 164k

My current plan for my M3 is to eventually supercharge it and probably sit around 400-500 wheel. Tbh I like the idea of the non-intercooled supercharger kit with the ability to add the intercooler should I desire some more power. I am already planning to do an MLS head gasket while I'm here just to bulletproof its boosted future.

My questions come in regards to the bottom end of the engine. The cylinder walls look in fairly good shape and no obvious and apparent damage to anything besides the melted and porous bits of pistons. Since I am going to be getting new pistons, rings, etc, I plan to get the cylinder bore honed to get a truly fresh start back to it. New aftermarket pistons will run me roughly $1400 for just the head itself, let alone the connecting rods if I cannot reuse the current ones. I can fetch cleaned and used OEM pistons with conrods for roughly $300 shipped to my door. I read earlier that the weak point of these engines when power hunting is the rods and head gasket but they are good up to roughly 600 or so which I truly don't see myself ever chasing from this car/engine.

Would I run into any issues with a rehoned bore and running stock pistons and that stock diameter? Obviously the process to hone it takes away the material and would mean the ring gap would increase. Does anyone know how much is acceptable for these engines? Or if this is even a possible approach? Or does wanting/needing the engine honed pretty much ruin my chances to run the stock pistons and rods to save some money.

Last bit to start, is there even any real benefit to running new aftermarket pistons? Minus obviously being brand new but like power or efficiency gain? Or is it really only recommended for those true high boost high HP setups?

Thank you for everyone that is going to contribute or tag along for the ride! I may not respond to everyone's posts all the time but I do appreciate you all. As of right now, I am a little sad but really optimistic and excited about the journey ahead of me. If anyone is on this forum is around the Charleston/Huntington WV area and wants to tag along with a helping hand in person I wouldn't mind meeting a new friend along the way. I'm going to be doing all of this out of my decently small one-car garage on jack stands so it'll be a fun time.

Folder with pictures of the parts post teardown: https://drive.google.com/drive/folde...IN?usp=sharing (Hopefully it will give you guys access to the whole folder)

[SteelGreyM]

Well as you know im going through literally the exact same process. Just a few months ago I was in your shoes. I didn't know much about anything engine building. While I am nowhere near a pro, I have learned so much over the last few months in regards to engine building and especially these e46 M3 s54 motors. Here's some of the more important/prevalent things I have learned/figured out.

1) Not all machine shops are created equal. Pick out a shop that you have researched and know they do things properly. If you cant find anything you like, i'd even recommend going to a racetrack near you and asking around where people have gone. (racetracks typically have higher concentrations of people who have rebuilt their engines). MAKE SURE the shop you choose torque plate hones, decks, and align hones. DONT SKIP THIS STEP!!!

2) Dont half ass the build. What does this mean? Dont re-use your rods. Dont buy used rods. Dont mix and match old and new parts. Will it work? Sure. Will it work without issues for thousands of miles? Sure. But you're already there. Just get new rods and pistons. Have your head checked for straightness and pressure tested.

3) Plan for your build budget to double. This happens to everyone. Just plan for 2x the cost.

4) Future proof your build. This ties into tip #2. You said you wanted to boost the car. Are you going to be comfortable knowing your boosted M3 is running on 100k+ miles rods? What are you going to think if you blow a rod? Was saving that money really worth it? Think about all aspects of your future build and remember its better to over-do it than to under deliver and live with regrets.

And finally, take your time with the build. I know. You want to get this thing running in a few weeks and have your baby back. I felt the exact same way. I'm beyond glad I took the extra time to research every option and properly educate myself on what I was getting into.

As far as if you need to bore out or a simple hone will do... this depends 100% on your engines wear. When you bring your block into the machine shop the first thing they will do to it is bust out their dial bore gauges and check for out of round, taper, and diameter wear. Wether or not just a hone will clean up the walls is dependent on your engines wear. This is called engine blueprinting. If you just want to save time you can just have them bore it out .25mm over and buy oversize pistons.

It seems like you're on somewhat of a budget so do as much as you can at home like I am and leave the stuff you haven't done before to the pros. What does that mean for me? I pulled my engine, disassembled it completely, and delivered it all to the machine shop. I'm having them do bottom end re-assembly and when they finish that I'm having them torque on the head for me as well cause why the hell not. After that, ill be taking the engine home to finish assembly (timing) and reinstallation. I know this was a lot of info so feel free to ask questions.

[digger]

Oversized Mahle MS slugs and do it properly

[Darbshaw]

Okay well first step will be for me to obtain a hoist and engine stand to get this sad girl out of the engine.

1) Okay duly noted, I have a decent one in mind that’s nearby my house but I will call to confirm all these other criteria. I was originally just using them for a head refresh but now it’s obviously become a lot more. Hitting up some of my mechanic buddies to see if they have any good recommendations.

2) Getting the head checked was 110% the plan. As for reusing or recycling old parts, I’ll just stick with new ones then. Now I’m all for not cheaping out and going with the quality parts but my thing is doing something relative to the scale of what I require from the engine.

Are there any cheaper options for rods out there? This is not saying to find a cheap part, but to find one that isn’t extreme overkill for my current plans. I’m not going to need a rod that’s built to handle 1000hp. I will definitely used the reinforced pins for the extra security there but I’m talking about cost efficiency with this. The budget can expand, just obviously increases the time of the build.

I haven’t looked very hard at all but the cheapest (quality) rods I could find was a set running just under a grand. Which is and acceptable price imo. A google search does pull a couple of cheaper rod sets in the 500-700 range so I was curious if there were any reason to even entertain these.
Personally I just don’t feel the reason to have rods that are rated to go double of what my intended goals are. Spending 50% more on them at that. Unless there’s some piece of information to this I’m missing.

3) As said earlier in this post, I’m realizing and waking up to the price of the build. Goal is I’d like to have the car running by next summer so I have plenty of time to work my budget around extra requirements or unexpected costs. Just gonna have to be ready for an upset GF 😂

4) Thanks for the check with this one, really I wouldn’t feel horrible using recycled rods and pistons as long as everything worked properly. Like ya said though, do it once. Spend the extra time and money now to avoid it later

I figure most of my other steps are waiting until I can get this girl pulled and outside of the car. Figure I’m going to pull the tranny with it as well to just clean and refresh everything as it goes. This will be a process but hopefully a fun one at that.

I’m on my phone so I can’t see other messages besides what I have quoted here. What do you mean by “oversized slugs” iirc. I’m new to a lot of the lingo on that stuff so any clarification would help there.

If you don’t mind me asking steel, what was the quote you received for all your block and head machine work? As detailed as you could make it if possible. I know different locations will call for different pricing but may be worth to atleast have a ballpark

WV is kinda a desolate wasteland for a lot of custom work and to my understanding my nearest track is mid Ohio, a good buddy of mine is a diesel mechanic and he’s pointed me towards a couple good shops he’s had to use so I’m gonna start there

Again I appreciate all the response and help guys!!!


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[racinghart]

Post a WTB ad for all the parts that you need for the build. You never know but someone may be willing to sell a part that they’ve got sitting on a shelf at home. You may save a few dollars doing that. Good luck and keep us posted.

[Mspir3d]

Boost monkey has a torque plate I rented when I had my block honed. It was half the cost of renting one from VAC. They also had the best prices on parts. If you shoot them an email they are very responsive and can get you quotes quickly. I believe machine work was around 300 for my block. A friend did the work on the head though so that wasn’t included.

[SteelGreyM]

Boost monkey has a torque plate I rented when I had my block honed. It was half the cost of renting one from VAC. They also had the best prices on parts. If you shoot them an email they are very responsive and can get you quotes quickly. I believe machine work was around 300 for my block. A friend did the work on the head though so that wasn’t included.

Additionally, while many shops don’t have s54 torque plates, many shops do have m54 torque plates which will bolts right up.

[SteelGreyM]

Okay well first step will be for me to obtain a hoist and engine stand to get this sad girl out of the engine.

1) Okay duly noted, I have a decent one in mind that’s nearby my house but I will call to confirm all these other criteria. I was originally just using them for a head refresh but now it’s obviously become a lot more. Hitting up some of my mechanic buddies to see if they have any good recommendations.

2) Getting the head checked was 110% the plan. As for reusing or recycling old parts, I’ll just stick with new ones then. Now I’m all for not cheaping out and going with the quality parts but my thing is doing something relative to the scale of what I require from the engine.

Are there any cheaper options for rods out there? This is not saying to find a cheap part, but to find one that isn’t extreme overkill for my current plans. I’m not going to need a rod that’s built to handle 1000hp. I will definitely used the reinforced pins for the extra security there but I’m talking about cost efficiency with this. The budget can expand, just obviously increases the time of the build.

I haven’t looked very hard at all but the cheapest (quality) rods I could find was a set running just under a grand. Which is and acceptable price imo. A google search does pull a couple of cheaper rod sets in the 500-700 range so I was curious if there were any reason to even entertain these.
Personally I just don’t feel the reason to have rods that are rated to go double of what my intended goals are. Spending 50% more on them at that. Unless there’s some piece of information to this I’m missing.

3) As said earlier in this post, I’m realizing and waking up to the price of the build. Goal is I’d like to have the car running by next summer so I have plenty of time to work my budget around extra requirements or unexpected costs. Just gonna have to be ready for an upset GF 😂

4) Thanks for the check with this one, really I wouldn’t feel horrible using recycled rods and pistons as long as everything worked properly. Like ya said though, do it once. Spend the extra time and money now to avoid it later

I figure most of my other steps are waiting until I can get this girl pulled and outside of the car. Figure I’m going to pull the tranny with it as well to just clean and refresh everything as it goes. This will be a process but hopefully a fun one at that.

I’m on my phone so I can’t see other messages besides what I have quoted here. What do you mean by “oversized slugs” iirc. I’m new to a lot of the lingo on that stuff so any clarification would help there.

If you don’t mind me asking steel, what was the quote you received for all your block and head machine work? As detailed as you could make it if possible. I know different locations will call for different pricing but may be worth to atleast have a ballpark

WV is kinda a desolate wasteland for a lot of custom work and to my understanding my nearest track is mid Ohio, a good buddy of mine is a diesel mechanic and he’s pointed me towards a couple good shops he’s had to use so I’m gonna start there

Again I appreciate all the response and help guys!!!


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I went with molnar rods based on the recommendation of many people. I even contacted some of the top engine builders in the country and they recommended it. Many club racers use them. Molnar sells them for $655.

I can’t remember my exact quote for my head but I want to say $240? I also had a bent valve that needed replacing and needed a new valve seat. Not to mention how much would need to be taken off. That’s why I went with a new head. You can expect approx $100/hr from machine shops. That means around $75 to deck something. Same price to wash it. Valve guides typically run $240. Remember though, machine shops would rather bill you to run one of their machines than do actual work so be weary of what they recommend and do your own research. I can get you a detailed price sheet hopefully by the end of this month.

I’d recommend pulling the engine and trans together. Pull the front end off the car too it’s really not too tough. Be meticulous about bagging your bolts. I have *every* * single* bolt bagged and tagged. Even laid them out in the order I took them off.

Hopefully all this helped somewhat

[Darbshaw]

Stripping the car down has been on the back burner as of late. Sisters wedding was this most recent weekend and then between some family emergencies and working weekends I haven’t had a chance to even get the front pulled off.

Although I have been looking into parts more for the rebuild.
I’ve done a little more research on the Maxpeedingrods Conrods for our engine and the price point that they are at is hard to beat with true arp rod bolts. Along with that they seem to have a good reputation behind them with quality and what not.
I figure at the sub 1k point all of the rods you can buy are going to be Chinese rods that are USA finished. Along with the idea that these have been chemically tested on their material. I’ve been going back and forth on the idea of using these vs Molnar. I do think if I can put these to the test it may help a lot of people on future builds looking for the best cost per dollar.

As for bearings; has anyone strayed from oem for main bearings?

I’m looking into either ACL or just treated oem but haven’t really found much reason to even go to the treated oem.

Any preference out there for any of the mains?

Then for rod bearings I was looking into the ACL brand as well. Once again the price point these are offered at comparatively to the rest of the market is an extremely hard one to beat.

Any experience from anyone with the ACL bearings?

My biggest thing as I’ve stated before is justifying the extra cost. I don’t necessarily need to use cheaper parts, but if I don’t need to spend the extra 200-400 on those parts then I won’t.

My understanding with the rod bearings is that they are a mechanical flaw and one done in the design and engineering of the engine/crank itself. Rather than something that is remedied by a new bearing itself. So with that in mind unless you treat the cause rather than the symptom, rod bearings can and will always be a consumable in the engine.
I currently have WPC coated bearings in my engine (~40k mi) and I’m curious to see how the wear on these look well before the service point of them.


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[SteelGreyM]

Stripping the car down has been on the back burner as of late. Sisters wedding was this most recent weekend and then between some family emergencies and working weekends I haven’t had a chance to even get the front pulled off.

Although I have been looking into parts more for the rebuild.
I’ve done a little more research on the Maxpeedingrods Conrods for our engine and the price point that they are at is hard to beat with true arp rod bolts. Along with that they seem to have a good reputation behind them with quality and what not.
I figure at the sub 1k point all of the rods you can buy are going to be Chinese rods that are USA finished. Along with the idea that these have been chemically tested on their material. I’ve been going back and forth on the idea of using these vs Molnar. I do think if I can put these to the test it may help a lot of people on future builds looking for the best cost per dollar.

As for bearings; has anyone strayed from oem for main bearings?

I’m looking into either ACL or just treated oem but haven’t really found much reason to even go to the treated oem.

Any preference out there for any of the mains?

Then for rod bearings I was looking into the ACL brand as well. Once again the price point these are offered at comparatively to the rest of the market is an extremely hard one to beat.

Any experience from anyone with the ACL bearings?

My biggest thing as I’ve stated before is justifying the extra cost. I don’t necessarily need to use cheaper parts, but if I don’t need to spend the extra 200-400 on those parts then I won’t.

My understanding with the rod bearings is that they are a mechanical flaw and one done in the design and engineering of the engine/crank itself. Rather than something that is remedied by a new bearing itself. So with that in mind unless you treat the cause rather than the symptom, rod bearings can and will always be a consumable in the engine.
I currently have WPC coated bearings in my engine (~40k mi) and I’m curious to see how the wear on these look well before the service point of them.


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I'd go with the molars. Theyre a popular rod for s54 road racers and can handle tons of power. Id spend the extra $300 here for piece of mind. Im not sure what youre trying to go for with this build but think about if you'll be happy with your choice 2 years from now. Are you really going to be happy you cheaped out on your m3? The molnars are already huge bang for buck. I went with those.

Mains aren't an issue in our cars. Glyco is the OE. I got calico coated which is glyco with a coating.

I went with OEM rod bearings from FCP for their warranty.

[SliM3]

Would I run into any issues with a rehoned bore and running stock pistons and that stock diameter? Obviously the process to hone it takes away the material and would mean the ring gap would increase. Does anyone know how much is acceptable for these engines? Or if this is even a possible approach? Or does wanting/needing the engine honed pretty much ruin my chances to run the stock pistons and rods to save some money.

As long as you get new rings you'll be good. Used rings do not play nice with a fresh hone. Contrary to popular belief honing does not remove significant amounts of material; It only affects the surface of the bore (cross hatching) and should have no bearing on ring gaps.

Last bit to start, is there even any real benefit to running new aftermarket pistons? Minus obviously being brand new but like power or efficiency gain? Or is it really only recommended for those true high boost high HP setups?

Not really, unless you're looking to change CR or run higher lift cams that need additional valve relief.

[/QUOTE]

[Darbshaw]

As long as you get new rings you'll be good. Used rings do not play nice with a fresh hone. Contrary to popular belief honing does not remove significant amounts of material; It only affects the surface of the bore (cross hatching) and should have no bearing on ring gaps.





Not really, unless you're looking to change CR or run higher lift cams that need additional valve relief.

[/QUOTE]

Okay I’m glad to hear some additional response on this question. Do you know of any better options than oem for the piston rings?

Oem rings run for about $150/piston where that evens out to about the cost of just a whole forged piston set with everything included. (Weisco, JE)


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[Darbshaw]

Alright so I was able to find npr rings for the engine. A full set on eBay and then a set on back order for hackengeneering.co.uk these are both going to run roughly $250 which is justifiable for the cost.
I also read about Hastings piston rings but these seem to be something that I would have to size out as it seems that don’t make specifically sized ones for our engines.

Any reviews on npr for their rings or anyone who purchased these rings? I know Hastings is a tried and true trusted brand. Just a matter of finding the proper size for those


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[Syfon]

Alright so I was able to find npr rings for the engine. A full set on eBay and then a set on back order for hackengeneering.co.uk these are both going to run roughly $250 which is justifiable for the cost.
I also read about Hastings piston rings but these seem to be something that I would have to size out as it seems that don’t make specifically sized ones for our engines.

Any reviews on npr for their rings or anyone who purchased these rings? I know Hastings is a tried and true trusted brand. Just a matter of finding the proper size for those


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NPR (Nippon Piston Ring Co.) are the OE piston ring manufacturer for many many motor vehicle companies. They manufacture millions of sets of rings every year. I purchased these exact rings from Hack Engineering. Have already received and installed them on the oe pistons.

The rings look good straight out of the box. I mean, I don't exactly work with engines every day so it's not like I see piston rings all day lol but compared to the oe rings, they are the exact size/shape and have the same chamfer.

Make sure you orient the rings correctly! https://www.newtis.info/tisv2/a/en/e...s-pins/CQzlDQe

FYI, I'm doing a full rebuild on my s54. Spun bearing, machined crank, new oversize main & rod bearings, cams, airbox and refreshing literally everything else.

Have a read if you like! https://nam3forum.com/forums/forum/m...hweel-and-more

[Darbshaw]

NPR (Nippon Piston Ring Co.) are the OE piston ring manufacturer for many many motor vehicle companies. They manufacture millions of sets of rings every year. I purchased these exact rings from Hack Engineering. Have already received and installed them on the oe pistons.

The rings look good straight out of the box. I mean, I don't exactly work with engines every day so it's not like I see piston rings all day lol but compared to the oe rings, they are the exact size/shape and have the same chamfer.

Make sure you orient the rings correctly! https://www.newtis.info/tisv2/a/en/e...s-pins/CQzlDQe

FYI, I'm doing a full rebuild on my s54. Spun bearing, machined crank, new oversize main & rod bearings, cams, airbox and refreshing literally everything else.

Have a read if you like! https://nam3forum.com/forums/forum/m...hweel-and-more

I’ll definitely give it a follow once I’m off my phone, I think it’s breaking the link.

I may go the oem route for the pistons and rods then. Sadly I just missed a heck of a deal on eBay for 6 already cleaned and good to go. Just needing rings.

I think i May save the after market pistons and rods for if I really decide to go power hungry on the car. Although I don’t see me ever searching for more than 400-500 wheel.


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