[kevinb21]

Hey everyone! I recently made a thread describing the spun rod bearing my new to me 335i has along with its coolant consumption.(https://www.e90post.com/forums/showt...5#post26928705) I drained its oil and its GLITTERY!!, thus meaning its time for this engine to be rebuilt and flushed because I cant afford a new engine, and with 130,000 miles its not that far gone. I plan on replacing its rod bearings, Oil pump, timing chain timing chain guides, and valve and crank cover seals. To begin, I know bmw color codes their bearings but ive been thinking of just buying a king bearing set with a uniform .5 or .25 oversize. I assume the .25 is the better way to go as with a rod knock this bad im sure ill have to go over some parts of the crank with 1,000 grit sand paper to even things out. This engine is going to be modified later so I need this set of bearings to handle some stress. for the rest of the work I havent decided if I will be using an oem or aftermarket timing chain kit as the price difference is astronomical, and ill also be changing the oil filter housing gasket to try to solve its coolant oil intermix/consumption. ill also be doing the oil pump. I was looking for tips and tricks for the job along with general pointers for replacing the rod bearings when they are this far shot. any help is appreciated!

[Buug959]

If the bearings are that toasted and you plan on adding some power mods then I would definitely have the crank checked and polished professionally or replaced. It the tolerances aren't right when you put the engine back together it'll just tear up the new bearings and you'll be starting the job all over again. Or worst case you'll completely f*ck the engine.

[kevinb21]

Originally Posted by LemansE90335xi

If the bearings are that toasted and you plan on adding some power mods then I would definitely have the crank checked and polished professionally or replaced. It the tolerances aren't right when you put the engine back together it'll just tear up the new bearings and you'll be starting the job all over again. Or worst case you'll completely f*ck the engine.

is it possible that I can yield good results using plastigage, and 1000, then 1200 grit sand paper to smooth any imperfections? and I presume once I tear down the engine Ill see if the crank is truly ruined if so ill have it sent out. or ill sand it down and use an oversized bearing and repeat the plastigage? Honestly I dont know any affordable machine shops in orange county, and if i am going to spend that much id just buy a used engine.

[Buug959]

Originally Posted by kevinb21

is it possible that I can yield good results using plastigage, and 1000, then 1200 grit sand paper to smooth any imperfections? and I presume once I tear down the engine Ill see if the crank is truly ruined if so ill have it sent out. or ill sand it down and use an oversized bearing and repeat the plastigage? Honestly I dont know any affordable machine shops in orange county, and if i am going to spend that much id just buy a used engine.

Like you say, until you inspect the crank it's impossible to know how bad it is. You may get lucky. The problem I see with hand polishing a damaged crank is that it's hard to keep the journals round. Add to that the extra stresses of modifying for more power and you are pretty much building in an automatic self-destruct switch.
A quick Google search and I found a good looking shop in Hawthorne, CA. I can't imagine checking and polishing a crank would be too expensive considering the cost of a complete used engine. Maybe someone more local than I am can point you towards a decent engine shop near you.

[kevinb21]

Originally Posted by LemansE90335xi

Like you say, until you inspect the crank it's impossible to know how bad it is. You may get lucky. The problem I see with hand polishing a damaged crank is that it's hard to keep the journals round. Add to that the extra stresses of modifying for more power and you are pretty much building in an automatic self-destruct switch.
A quick Google search and I found a good looking shop in Hawthorne, CA. I can't imagine checking and polishing a crank would be too expensive considering the cost of a complete used engine. Maybe someone more local than I am can point you towards a decent engine shop near you.

Alright. I will send an update on which factory bearings my car has along with pictures of the crank once I get it torn apart, I assume I will need to go .25 larger but I'll make that call once everything is torn apart and I can plastigage the engine as well. I don't care what I have to do I am just not looking to have to take the entire crankshaft off the car as it's a whole extra process and I'll likely have to drop the entire engine for that which sucks a lot. I am hoping it isn't too bad since the car was driven 20 miles with the rod knock and the oil has LOTS of metal bits in it. All I can do is hope it isn't too destroyed but the engine sounds BAD. From the second the engine turns on it sounds horrifically loud and knocky.

[E92William]

I think it is definitely worth it to have at least the crankshaft checked. You don't wanna throw away all the work you'll do to this engine just because you decided to sand paper it to good enough visual specs. Could have a journal out of round

[kevinb21]

Originally Posted by E92William

I think it is definitely worth it to have at least the crankshaft checked. You don't wanna throw away all the work you'll do to this engine just because you decided to sand paper it to good enough visual specs. Could have a journal out of round

So I need to take the engine out of the car and remove the bottom end and crankshaft and bring it to a machine shop? Or at the very least separate the transmission so I can remove the crankshaft ... wow this project just got that much harder... yikes! Is there any way I can do this job without completely tearing apart the car?

[F31B48]

Basically no, there is no easy way unfortunately. Crankshafts aren't really something that can just be polished up with a bit of sandpaper. They do a lot of work (especially on turbo charged engines) and if they aren't 100% they will not last long at all. It's definitely an engine out job.

[feuer]

So you will get the tolerance with sandpaper lol seriously? From what I’m reading I strongly suggest you to just get an used engine.

[Buug959]

The "easiest" way to go is to remove the engine from the car so you have complete access to work on it. From there you can properly inspect the crankshaft journals ( with micrometer, not eyeball and fingernail ) and determine whether you are going to have the crank polished or replaced. If at that point you decide to get a used engine then the old engine is already out and you can install the "new" engine right after you replace all the usual gaskets.
The crankshaft is the muscles of the engine. If it's not right then nothing you do will make the engine work, period.

[tlow98]

Buy replacement engine.

[E92William]

I mean if you planned on doing this with the engine on the car you're gonna have a bad time. You can do it, go ahead drop the subframe take apart the rods put new bearings in and pray. But idk how much you value your time to do that without certainty it'll work well

[Smgs1992]

Unless you plan to build the engine for very high HP 700+ youre better off financially and based off what i’m reading just picking up a used engine

[Buug959]

If it were me I'd pull that engine and completely rebuild it with all performance internals with the aim of going single turbo in the future. I'd make a winter project out of it. But that's just me. I bought my car as a toy and a project, not as a DD.
I did another quick search ( literally 5min ) and found a used n55 motor in Texas with 17k miles and free shipping for $2500. That might be the best route for OP. It's a lot easier to replace an engine than it is to rebuild one.

[kevinb21]

Originally Posted by LemansE90335xi

If it were me I'd pull that engine and completely rebuild it with all performance internals with the aim of going single turbo in the future. I'd make a winter project out of it. But that's just me. I bought my car as a toy and a project, not as a DD.
I did another quick search ( literally 5min ) and found a used n55 motor in Texas with 17k miles and free shipping for $2500. That might be the best route for OP. It's a lot easier to replace an engine than it is to rebuild one.

I decided I am going to take this engine out of the car, and do a rebuild. ill get the crank refinished or replaced, new rod bearings, new timing chains, new seals, new valve seals, maybe a new headgasket??? there was noticable oil coolant intermix but I was assuming it was a oil filter housing gasket but Since I am tearing down the engine a new head gasket wont take long so throw that in the mix. since this car has a small ammount of wastegate rattle it also seems like a good time for 2 new td04 16t turbos. Going off online prices, even doing all this work will be significantly cheaper than a new engine, and I presume there is an added reliability considering Im shooting for 500hp. Aside from what I listed what else is a must do with the engine out of the car?

[Buug959]

Originally Posted by kevinb21

I decided I am going to take this engine out of the car, and do a rebuild. ill get the crank refinished or replaced, new rod bearings, new timing chains, new seals, new valve seals, maybe a new headgasket??? there was noticable oil coolant intermix but I was assuming it was a oil filter housing gasket but Since I am tearing down the engine a new head gasket wont take long so throw that in the mix. since this car has a small ammount of wastegate rattle it also seems like a good time for 2 new td04 16t turbos. Going off online prices, even doing all this work will be significantly cheaper than a new engine, and I presume there is an added reliability considering Im shooting for 500hp. Aside from what I listed what else is a must do with the engine out of the car?

I'd take a close look at the cylinder walls and be prepared to hone them if required. I'd also replace the piston rings. If you're sure you don't want any more than 500hp you'll be fine with the stock con-rods but remember that power is addictive. If there is any chance that you may want more power in the future then now is the time to upgrade them. An oil catch can, index 12 injectors, coils and plugs are also a must for more power. I'd also upgrade to a stage2 LPFP.
I'm sure I've probably missed something. I expect others to join in and add their recommendations. Good luck and keep us posted.

[kevinb21]

Originally Posted by LemansE90335xi

I'd take a close look at the cylinder walls and be prepared to hone them if required. I'd also replace the piston rings. If you're sure you don't want any more than 500hp you'll be fine with the stock con-rods but remember that power is addictive. If there is any chance that you may want more power in the future then now is the time to upgrade them. An oil catch can, index 12 injectors, coils and plugs are also a must for more power. I'd also upgrade to a stage2 LPFP.
I'm sure I've probably missed something. I expect others to join in and add their recommendations. Good luck and keep us posted.

Piston ring replacement is probably a good idea, my concern is If I hone the cylinders what size piston ring will I need, and will I be wearing down the cylinder liners, and It reminds me of my idea of sanding my crankshaft and how bad of an idea that is., upgraded connecting rods are expensive and I know once I leave the 500hp territory I'm getting into automatic trans, axles, differentials, and input shafts breaking. My ultimate goal is to outrun an f80 m3 or more who knows.

[Buug959]

Originally Posted by kevinb21

Piston ring replacement is probably a good idea, my concern is If I hone the cylinders what size piston ring will I need, and will I be wearing down the cylinder liners, and It reminds me of my idea of sanding my crankshaft and how bad of an idea that is., upgraded connecting rods are expensive and I know once I leave the 500hp territory I'm getting into automatic trans, axles, differentials, and input shafts breaking. My ultimate goal is to outrun an f80 m3 or more who knows.

Honing your cylinders won't change their shape just refresh the crosshatch ( use a hone, not sandpaper ). Unless there is a LOT of wear new stock rings will have to be sized to the cylinders and should have enough material to set the proper end gap.
I know that upgraded con rods are expensive but it will be much more expensive to go back and change them 6 months or a year down the road. That's why I mentioned them now. Like I said, you'll be fine with stock rods at 500hp.

[kevinb21]

Originally Posted by LemansE90335xi

Honing your cylinders won't change their shape just refresh the crosshatch ( use a hone, not sandpaper ). Unless there is a LOT of wear new stock rings will have to be sized to the cylinders and should have enough material to set the proper end gap.
I know that upgraded con rods are expensive but it will be much more expensive to go back and change them 6 months or a year down the road. That's why I mentioned them now. Like I said, you'll be fine with stock rods at 500hp.

would I need to send the head and bottom end of the engine off to a machine shop to be re finished? given the head gasket is not bad and even if it is bad its very very minorly bad, id assume there should be no warpage. Also are the head bolts that hold the head to the bottom end single use bolts? also the bottom crankshaft carrier has an injected silicone gasket I am hoping is replicable and requires no factory equipment. I presume It would be a good idea to also throw in new motor mounts. Any other n54 must replace items with the engine out

[Buug959]

Originally Posted by kevinb21

would I need to send the head and bottom end of the engine off to a machine shop to be re finished? given the head gasket is not bad and even if it is bad its very very minorly bad, id assume there should be no warpage. Also are the head bolts that hold the head to the bottom end single use bolts? also the bottom crankshaft carrier has an injected silicone gasket I am hoping is replicable and requires no factory equipment. I presume It would be a good idea to also throw in new motor mounts. Any other n54 must replace items with the engine out

The head is probably ok as long as you remove the head bolts properly... reverse of install torque sequence. OEM head bolts are torque to yield fasteners. They require a jointing torque and then a torque angle. According to the Bentley manual:

Lightly lube the bolts/washers and install them hand tight.
Step 1: Tighten head bolts to 30Nm in correct torque sequence
Step 2: Tighten 90 degrees using a torque angle pointer in correct torque sequence
Step 3: Tighten another 90 degrees using a torque angle pointer in correct torque sequence

You are going to have to get yourself a copy of the Bentley manual for your car. It has all the info you need to work on all aspects of it. It's probably about $150 but well worth it.
Motor mounts are a good idea along with a new water pump and thermostat. Check all your rad hoses and DEFINITELY change the rad hose fitting right below your OFH to an aluminum one. The plastic OEM one will fail and leave you stranded. You can find them on Amazon or Ebay for around $10-$20.

[kevinb21]

Originally Posted by LemansE90335xi

The head is probably ok as long as you remove the head bolts properly... reverse of install torque sequence. OEM head bolts are torque to yield fasteners. They require a jointing torque and then a torque angle. According to the Bentley manual:

Lightly lube the bolts/washers and install them hand tight.
Step 1: Tighten head bolts to 30Nm in correct torque sequence
Step 2: Tighten 90 degrees using a torque angle pointer in correct torque sequence
Step 3: Tighten another 90 degrees using a torque angle pointer in correct torque sequence

You are going to have to get yourself a copy of the Bentley manual for your car. It has all the info you need to work on all aspects of it. It's probably about $150 but well worth it.
Motor mounts are a good idea along with a new water pump and thermostat. Check all your rad hoses and DEFINITELY change the rad hose fitting right below your OFH to an aluminum one. The plastic OEM one will fail and leave you stranded. You can find them on Amazon or Ebay for around $10-$20.

I just got started ordering parts for the car, my end goal is the max horsepower I can get on crap California 91 octane gas. I plan on doing catless downpipes, fmic, mhd tune, colder spark plugs, and later in the future maybe lpfp and index 12 injectors. Given the engine is coming out of the car for new rod bearings, seals, headgasket etc, is it logical for me to upgrade the turbos? the only ones I can really afford are the eBay tdo4 800$ set of turbos. I've heard mixed reviews about them but im just wondering if upgrading the turbos will do me any favors since I don't want the burden of finding e85 or adding meth and all of that, I want the most easy street hp possible. My goals and wishes are 500 but thats probably optimistic. what do you think my best route is?

[335xi_full_throttle]

Originally Posted by LemansE90335xi

If it were me I'd pull that engine and completely rebuild it with all performance internals with the aim of going single turbo in the future. I'd make a winter project out of it. But that's just me. I bought my car as a toy and a project, not as a DD.
I did another quick search ( literally 5min ) and found a used n55 motor in Texas with 17k miles and free shipping for $2500. That might be the best route for OP. It's a lot easier to replace an engine than it is to rebuild one.

Could you send the link to that engine if possible?