[wheela]

Originally Posted by Dynamics99

https://www.bimmerworld.com/Engine/B...-435i-N55.html

The baffle system is integrated into the oil pan. There is a secondary oil suction pump.

I doubt yours will have it. The N55 in the F87 M2 received this upgrade as well as the F26 X4 M40i.

Thanks for the info! It looks like this is the s55 setup, I got the impression that they updated the n55 with upgraded n55 specific parts. Sadly this won't fit my car because it needs the s55 oil pan, but I'm x-drive so can't go that route.

[wheela]

Originally Posted by Dynamics99

https://www.bimmerworld.com/Engine/B...-435i-N55.html

The baffle system is integrated into the oil pan. There is a secondary oil suction pump.

I doubt yours will have it. The N55 in the F87 M2 received this upgrade as well as the F26 X4 M40i.

Oh snap, I just noticed you mentioned X4 M40i - that should be essentially an x-drive version of the s55 oil pan, but for x-drive n55, no? I may need to dig into this more, I had written off the s55 oiling setup due to being x-drive. X4 M40i may be the missing link... Thanks so much again for this info, this could turn out to be my next big upgrade after getting my Speedtech kit installed!!

[Dynamics99]

Originally Posted by wheela

Oh snap, I just noticed you mentioned X4 M40i - that should be essentially an x-drive version of the s55 oil pan, but for x-drive n55, no? I may need to dig into this more, I had written off the s55 oiling setup due to being x-drive. X4 M40i may be the missing link... Thanks so much again for this info, this could turn out to be my next big upgrade after getting my Speedtech kit installed!!

Let me know how it goes. Doing an engine rebuild with bottom forged end this year. Planning to single turbo next year.

[wheela]

I'll just close the loop on this and then stop thread-jacking. It looks like the X4 M40i didn't come with the additional scavenger oil pump like the S55. Also, that s55 oil pump retrofit kit says it does not fit X4 M40i. So it's looking like the X4 M40i oil pan is probably not the missing link to getting the s55 oiling system into an x-drive car.

[bosstones]

Originally Posted by wheela

I'll just close the loop on this and then stop thread-jacking. It looks like the X4 M40i didn't come with the additional scavenger oil pump like the S55. Also, that s55 oil pump retrofit kit says it does not fit X4 M40i. So it's looking like the X4 M40i oil pan is probably not the missing link to getting the s55 oiling system into an x-drive car.

There was this thread for S55 pan conversion but it doesn't seem like it was panning out (no pun intended).
https://www.e90post.com/forums/showthread.php?t=1900045

[yupetc]

Originally Posted by Dynamics99

Okay,

I have a question. Is it possible to bore out an N55 0.50 over for an 84.50mm bore? I dropped the block off at the machine shop originally for a hone and clean. Just talked to the owner and he said if I'm getting forged pistons I would need to bore it out to 84.50mm which is also what the AMP44 site mentions. The AMP44 has a piston coating on the thrust side.

https://www.amp44.com/index.php?rout...&product_id=96

Here is the link to the piston. The PTC is 0.035-0.040mm. What are your thoughts? Should I just get a hone and use the original pistons or go with the AMP44 pistons since it's within budget?

On an N55, be careful if you're going to ask the machine shop to bore out to 84.5mm because the block is aluminum and on cylinder wall it's arc-welded with 0.3mm of steel liner. If I were to do this, I would look for a whole cylinder sleeve job to be performed and have that sleeve set to match your piston's target clearance.

[yupetc]

Originally Posted by bbnks2

Forged pistons generally aren't very friendly to daily driving. The PTC clearance is greater to allow for more expansion. Stock cast hyper pistons call for <.001" PTC and forged pistons generally call for closer to .0025." This results is piston slap until the forged piston warms up.

If this engine is torn down I would ensure you CP pistons are coated. That may be the cause of your "shiny" cylinder walls. OR the cylinders walls are out of round. You used stock head bolts, right? No machine work just a hand hone or did you have the block bored out for bigger pistons? I find it hard to believe you used a hand sanding stone to bore out the block enough to fit an aftermarket forged piston. You may not have enough PTC clearance causing cylinder wear as the aftermarket forged pistons expand from heat. What was your final PTC?

I also wouldn't assume a change in .005" in ring end gap is due only to wear on the cylinder wall. Piston rings wear down as well and the ring end gap opens up a little as the rings conform to the cylinder walls.

Sorry I haven't replied to some of your comments earlier. I had to dig back into my notes taken when I built this motor to make a relative observation.

First, the CP's piston come with a installation sheet. For my particular piston, sheet states a 0.0027" piston-to-wall clearance. I ran 6-7 times dial gauging and bore gauging festivities to confirm that my PTC is at 0.0027"-0.0028" through 6 cylinders. I then applied a Cerakote's piston coating on the crown and then Microslick on the skirt. The Microslick coating did bring PTC down to about 0.0024"-0.0025" throughout all cylinders. So that's more peace-finding for me to use the pistons because I was weary of piston slap upon cold start. Oddly enough, never had I experience or hear any piston slap. Maybe that Microslick coating worked to seal better and also dampen the harmonics on a cold start up.

Upon this build, once again, I use that tripod stone grinder attached to a power drill and I went to town honing the cylinders to get that surface roughness prescribed by CP's installation sheet. I also did ensure a much proper rig gap this time and got everything put together. I almost want to say that the first time when I build this motor, I very likely have over-gapped the rings and allowed for too large of a gap to start off with. I'm sayign that because this time around when I make the measurements, the cylinder bore are all to spec, under 83.95mm diameter. And on the new CP rings, as I was gap-checking them, none of them needed filing down. So I simply slipped the rings on and build this motor again.

I'm about 3 weeks in with this new build. Drove it to the Colorado mountains and back (totalled nearly 3,000 miles). And the car's been running even stronger ever since. I also noticed the engine oil stayed same level throughout the trip. I really believe this time the ring gaps have closed up and I'm no longer losing oil through blow-by. Note that I did install a oil catch can to check for oil loss through the PCV system; after this big trip, I've observed about an ounce of milk-shake in that can, that's water vapor mixed with oil, so that's a good indication that things are going well with this build now.

[Dynamics99]

Just a little update. Still waiting on the pistons. Was supposed to be delivered Sept 5th... USPS has lost my package after being transferred out of customs. I have filed a complaint. Give it till next Friday. If I don't get it then I will be using the stock pistons with forged rods.

[Dynamics99]

Getting the block back today. It's been a while.

Just a quick question. USPS has lost my AMP44 forged pistons. So I will be using the OEM pistons. OEM Rings are so dam expensive. Is there a MAHLE part number for the rings or another reliable brand I can use? Also, where can I find the dimensions for it?

[yupetc]

Originally Posted by Dynamics99

Getting the block back today. It's been a while.

Just a quick question. SPS has lost my pistons. So I will be using the OEM pistons. OEM Rings are so dam expensive. Is there a MAHLE part number for the rings or another reliable brand I can use? Also, where can I find the dimensions for it?

Mahle piston rings for the N55:
4057635164955

Top Ring: 1.2mm
Second: 1.5mm
Oil: 2.0mm

Please double check before making any move. I pulled these from old notes, hopefully my digits are still correct.

[Dynamics99]

Originally Posted by yupetc

Mahle piston rings for the N55:
4057635164955

Top Ring: 1.2mm
Second: 1.5mm
Oil: 2.0mm

Please double check before making any move. I pulled these from old notes, hopefully my digits are still correct.

Okay,

I got Hastings Piston rings for a nice deal. I figured out the dimensions. Your dimensions are still correct. Idk if they come pre-gapped. Do I need a crankshaft locking tool to help me torque down the crank bolt?

[yupetc]

Originally Posted by Dynamics99

Okay,

I got Hastings Piston rings for a nice deal. I figured out the dimensions. Your dimensions are still correct. Idk if they come pre-gapped. Do I need a crankshaft locking tool to help me torque down the crank bolt?

When I torque my crank bolt down, I modified my Schwaban crankshaft locking tool which was meant for another motor variant; however, after figuring out where to drill the holes, I got mine to work after all. I'd say go ahead and get a cranshaft locking tool that comes in one piece with a fat and long handle so you can coast it against something to counter against your TTY sequence. I'm suggesting this because before I utilize this tool to do the deed, I was torque-ing it against the backside on the TDC locking key, cocked in the flex-plate hole plus I got some form of locking tool that I customized at the machine shop to lock the gears against a bracket which is bolted to the starter holes. This worked well, but I ended up with a bent flex-plate unknowingly. A bent flext plate or a flywheel, if it gives, will get you some low end vibration and chattering noise at idle, and it's hard to catch until you run out of things to look. So a crankshaft locking tool on the front end is best suited for this job.

For the actual torque down on TTY phase, I had to use a 3/4" drive 40-inch long breaker bar plus chuting the handle within a jack's long handle to get it done, all this while I had to also get my brother to help me secure the crankshaft tool in place. I didn't have enough power to muscle through the torque down in a single smooth motion, had to break it down in 45-degree increments. For this reason, I went with 290-300 degrees TTY rotation instead of the 270 originally prescribed by the OEM spec. That torque sequence got me a 10-day worth of exercises because that's about how long it took to recover from all that muscle ache after the deed. Good luck to you, bro, and be safe.

[Dynamics99]

Originally Posted by yupetc

When I torque my crank bolt down, I modified my Schwaban crankshaft locking tool which was meant for another motor variant; however, after figuring out where to drill the holes, I got mine to work after all. I'd say go ahead and get a cranshaft locking tool that comes in one piece with a fat and long handle so you can coast it against something to counter against your TTY sequence. I'm suggesting this because before I utilize this tool to do the deed, I was torque-ing it against the backside on the TDC locking key, cocked in the flex-plate hole plus I got some form of locking tool that I customized at the machine shop to lock the gears against a bracket which is bolted to the starter holes. This worked well, but I ended up with a bent flex-plate unknowingly. A bent flext plate or a flywheel, if it gives, will get you some low end vibration and chattering noise at idle, and it's hard to catch until you run out of things to look. So a crankshaft locking tool on the front end is best suited for this job.

For the actual torque down on TTY phase, I had to use a 3/4" drive 40-inch long breaker bar plus chuting the handle within a jack's long handle to get it done, all this while I had to also get my brother to help me secure the crankshaft tool in place. I didn't have enough power to muscle through the torque down in a single smooth motion, had to break it down in 45-degree increments. For this reason, I went with 290-300 degrees TTY rotation instead of the 270 originally prescribed by the OEM spec. That torque sequence got me a 10-day worth of exercises because that's about how long it took to recover from all that muscle ache after the deed. Good luck to you, bro, and be safe.

I shall try lol. I seen people online with a long pole to torque down the bolt. Will post an update when I get the bottom end completed.

[Dynamics99]

Okay, planning to get the crankshaft in and measure clearances for main bearings, rod bearings, and piston ring gaps.

Planning to go ahead with stock piston ring gap since I am using the stock pistons. Found out the clearances for piston ring gap, crankshaft main bearing gap, and rod bearing gap on ISTA.

Piston Ring Gap:


Crankshaft Main Bearing Clearance:


Rod Bearing Clearance:


Just double checking with this thread that shows Main and Rod bearing clearance.

https://www.m3post.com/forums/showthread.php?t=892838


Let me know if I should go ahead with stock piston gaps or go for
larger gaps. I'm only planning for MHD Stage 2+ with stock turbo.

Also the bedplate sealing on ISTA was done with a special tool? It says to lay the sealant first and then put the bedplate on to torque. I see online that there is a different loctite sealing tool which requires the bedplate to be torqued down first. Only asking because I wonder if I am using an older version to put this engine back together.

[fastboatster]

I have checked the procedure on some site we shouldn't name, it doesn't exist anymore). looks like bmw switched over to RTV sealant from anaerobic sealant. As such, this special tool seems to be just a silicone sealant application gun. it has a piston/plunger that presses against the bottom of the silicone sealant cartridge and helps to squeeze the RTV into the sealing groves in various oil pans and crankcases out quickly and evenly. something like this:
https://www.amazon.com/Permatex-8003.../dp/B000HBGHCW
do you need to use this kind of tools? no, but it makes it easier for sure. when I did an upper oil pan and timing cover reseals on some unrelated engine (3.0tfsi trash), I used a sealant that comes with an "applicator key", or it can be called squeezer roller key:

works almost as well as an rtv applicator gun. You do want to lay a nice, even layer of RTV right in the sealing groves, it should protrude above the surface for about as much as the width of the groove.

[yupetc]

On bedplate sealing, you will need this:
https://www.fcpeuro.com/products/bmw...BoC5jIQAvD_BwE


Without the proper tool, you will not be able to torque down the bed plate first then inject the sealant into it. The back pressure will be hard to fight against and if you don't have the correct equipment, you'll end up with sealant running away at the entrance. That's a fight you won't want to pick. Even with the special tool it's hard enough to do it.

I'm vaguely recalling this detail, but hear me out and see if it makes any sense to you:
The original BMW sealing compound was that Drei Bond 1209, and it's not very viscous to begin with, but once it settles, it forms a very hard epoxy-like polymerization. But BMW knows that upon re-servicing this seal, most of us wouldn't have this special tool they use at the factory. Instead, and I'm vaguely recall, but I believe Loctite SI 5970 has been the replacement. And all other alternatives stated in the FCPeuro site should be fine. And this Loctite compound should be beaded onto your crank case sealing gutter before you put the bed plate on. This Loctite has about 30 minutes to become tact-free. So you can take your time on this. What I usually do with this type of sealant is I'd apply it to the entire gutter first, then I would let it sit for about 20 minutes (you want to let it get close to being tact-free before you smash it down with the bedplate to get a more confident seal). But don't let it go past the fully formed tact-free point because it'll be vulcanized and too hard to work with. After you let it settle for that 20 minutes, then carefully put on the bedplate and gently and even guide down the bedplate bolts. You'll want to avoid as much shifting of the bedplate as you can. I do recall when I did this job that the gutter for the sealant is pretty shallow, so I probably had maintained no more than 1/8" thick bead width along the whole gutter.

After I've gotten the above taken care of, I torque the bed plate down in two stages before arriving at the the initial 15Nm mark. And between stages, I waited another 5 minutes each, then go for the 90-degrees TTY angle.

After final TTY torque down, I went ahead and added few beads of Drei Bond 1209 at the two flange joints where the front and rear main seals sit. That should be it.

[Dynamics99]

Originally Posted by yupetc

On bedplate sealing, you will need this:
https://www.fcpeuro.com/products/bmw...BoC5jIQAvD_BwE


Without the proper tool, you will not be able to torque down the bed plate first then inject the sealant into it. The back pressure will be hard to fight against and if you don't have the correct equipment, you'll end up with sealant running away at the entrance. That's a fight you won't want to pick. Even with the special tool it's hard enough to do it.


I'm vaguely recalling this detail, but hear me out and see if it makes any sense to you:
The original BMW sealing compound was that Drei Bond 1209, and it's not very viscous to begin with, but once it settles, it forms a very hard epoxy-like polymerization. But BMW knows that upon re-servicing this seal, most of us wouldn't have this special tool they use at the factory. Instead, and I'm vaguely recall, but I believe Loctite SI 5970 has been the replacement. And all other alternatives stated in the FCPeuro site should be fine. And this Loctite compound should be beaded onto your crank case sealing gutter before you put the bed plate on. This Loctite has about 30 minutes to become tact-free. So you can take your time on this. What I usually do with this type of sealant is I'd apply it to the entire gutter first, then I would let it sit for about 20 minutes (you want to let it get close to being tact-free before you smash it down with the bedplate to get a more confident seal). But don't let it go past the fully formed tact-free point because it'll be vulcanized and too hard to work with. After you let it settle for that 20 minutes, then carefully put on the bedplate and gently and even guide down the bedplate bolts. You'll want to avoid as much shifting of the bedplate as you can. I do recall when I did this job that the gutter for the sealant is pretty shallow, so I probably had maintained no more than 1/8" thick bead width along the whole gutter.

After I've gotten the above taken care of, I torque the bed plate down in two stages before arriving at the the initial 15Nm mark. And between stages, I waited another 5 minutes each, then go for the 90-degrees TTY angle.

After final TTY torque down, I went ahead and added few beads of Drei Bond 1209 at the two flange joints where the front and rear main seals sit. That should be it.

Hmm, should I go with the BMW Loctite 193140 Sealant Kit or use Loctite SI 5970. I've been looking at other forums also. Only wondering because I saw a video on YouTube where the technician assembling the bedplate said that using an RTV first might mess with main bearing clearance since liquid cannot be compressed so he advises using the 193140. Some forums suggest 5970 for resealing purposes since BMW uses RTV now for newer engines. Also, do I need some sort of bedplate alignment jig?

[yupetc]

Originally Posted by Dynamics99

Hmm, should I go with the BMW Loctite 193140 Sealant Kit or use Loctite SI 5970. I've been looking at other forums also. Only wondering because I saw a video on YouTube where the technician assembling the bedplate said that using an RTV first might mess with main bearing clearance since liquid cannot be compressed so he advises using the 193140. Some forums suggest 5970 for resealing purposes since BMW uses RTV now for newer engines. Also, do I need some sort of bedplate alignment jig?

Bedplate won't need a jig for alignment, there are dowel pins you're supposed to replace to align it. I don't remember the technicalities, but back when I did mine, I arrived at 5970 for what reason I don't remember. But that's what I have in my motor. It's been almost 2 years with no issues. Just mind the steps I mentioned so you can get a good seal. The incompressibility you're talking about refers to that Drei Bond because it is full liquid that BMW firstly used to inject into the gutters after they've torqued down the bedplate (aka the injection method). You're better off using the Loctite because you get to see yourself fully covering the gutters instead of injecting into the abysmal without knowing if you've got air pockets in there or not.

[Dynamics99]

Okay, I couldn’t find SI 5970 for sale but i found SI 5900:

Loctite SI 5900 Ready Gasket – 1-Minute Flange Sealant & Gasket Maker for Automotive: Sensor-Safe, High Temp, Low-Odor | Black, 190mL Aerosol Can (PN: 40480-743914) https://a.co/d/cZmGb8O

[yupetc]

Originally Posted by Dynamics99

Okay, I couldn’t find SI 5970 for sale but i found SI 5900:

Loctite SI 5900 Ready Gasket – 1-Minute Flange Sealant & Gasket Maker for Automotive: Sensor-Safe, High Temp, Low-Odor | Black, 190mL Aerosol Can (PN: 40480-743914) https://a.co/d/cZmGb8O

I haven't the patience to read up the whole feature list on this sealant, but whenever you get the chance, make sure this thing can settle under high moisture ambient conditions. The 5970 for sure can do that, this is important because in case it takes quite long for the "whole" sealant to cure completely, once the motor runs and get hot, your bedplate joint will need to withstand oil humidity generated by partial vaporization in operating temp.

[Dynamics99]

Originally Posted by yupetc

I haven't the patience to read up the whole feature list on this sealant, but whenever you get the chance, make sure this thing can settle under high moisture ambient conditions. The 5970 for sure can do that, this is important because in case it takes quite long for the "whole" sealant to cure completely, once the motor runs and get hot, your bedplate joint will need to withstand oil humidity generated by partial vaporization in operating temp.

https://www.fcpeuro.com/products/bmw...ml-83190404517

Found that FCP Euro carries the 5970 but in two variations?

Here is the Audi one:
https://www.fcpeuro.com/products/aud...50ml-d176501a1


If you look up 5970, Here are the results. :
https://www.fcpeuro.com/Parts/?keywords=5970



Which one should I get? Also, would Ultra Black RTV be an option? I'm hearing people struggle to use the Loctite 193140 Sealant Kit since it takes a lot of strength.

[yupetc]

I happened to use the Audi version. Didn't know there are that many variations involved. Mine was SI 5970. The sealant itself is very viscous, but I think that's for much better reasons. Ultra Black RTV by Permatex should be fine, too. When it comes to these quintessentially one-time jobs, I tend to stick with what's prescribed by the OEM as much as possible to eliminate inconsistencies. That's why I didn't use the RTV series flange gaskets. But at the end of the day, the minute difference in branding and type won't make or break your project.

Another reason I have against using the RTV flange sealant is I think BMW intend to use anaerobic type of sealing compound for this bedplate joint. The Drei Bond 1209, to me, applies and behaves a lot like the anaerobic type of sealing, runny and watery at first, but once bonded it's strong and hard, withstands impact, and counters the separation force in the trust vector direction. The RTV flange sealants don't usually have the last feature I mentioned. So that's something to consider.