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      04-20-2017, 01:24 PM   #1
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N20 Rod replacement only?

So been looking into all the power mods for our N20 and it's evident... we have rod issues, oil starvation on high G turns if tracking the car and the timing chain etc. But as for power and to fortify the bottom end for a daily rip around the city car, I want to see if there is a possibility to just upgrade the rods, bolts and bearings as they are the weak link in this motor. Yes, I know we can buy a full on out pistons and rods etc but that is expensive and time consuming process and requires engine to come out, so for most this is out of the equation! But what about just replacing the rods, can be around $1K and requires only the removal of the oil pan. Much cheaper alternative than a 6K + engine build.

Why haven't companies done rod replacements that are "Drop In Ready" so no balancing of the internals needs to be done? This would surely give a piece of mind and a far cheaper alternative than fully rebuilding the motor for someone who just wants mid to high 300's for a daily, right?

I know AWE and others made "Drop In Ready" rods for VW and Audi market etc. Why not see if this is possible for the N20? Most will not push more than 400 WHP on the Stage 2 Turbo's (rated to 380WHP) and would open the market up for bigger HP on these 4 cyl motors if price was cheaper to fortify the bottom end. Or is the block not accessible to replace the rods without taking it completely apart?

Just a thought and lets see what some of these big name companies/ vendors can chip in on this subject!

Last edited by D041987; 04-27-2017 at 12:54 PM..
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      04-21-2017, 07:56 PM   #2
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      04-21-2017, 09:27 PM   #3
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Just get an M3 and be done with it.
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      04-23-2017, 05:20 AM   #4
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Quote:
Originally Posted by D041987 View Post
So been looking into all the power mods for our N20 and it's evident that we have rod issues along with oil starvation on high G turns along with the timing chain etc. But as for power and to fortify the bottom end, I want to see if there is a possibility to just upgrade the rods/ bolts as they are the weak link in this motor. I know we can buy full on out pistons and rings but what about just replacing the rods or companies making just rod replacements that are "Drop In Ready" so no balancing of the internals needs to be done? This would surely give a piece of mind and a far cheaper alternative than fully rebuilding the motor for someone who just wants mid to high 300's for a daily?

I know AWE and others made "Drop In Ready" rods for VW and Audi market etc. Why not see if this is possible for the N20? Most will not push more than 400 WHP on the Stage 2 Turbo's and would open the market up for bigger HP on these 4 cyl motors if price was cheaper to fortify the bottom end. Or is the block not accessible to replace the rods without taking it completely apart?

Just a thought and lets see what some of these big name companies/ vendors can chip in on this subject?
Even on the VAGs, there were different sized bearings, etc. So maybe drop in, but you still want to mic everything.

Can you link to these "issues" you claiming? Or are these one or two hit wonders with no history of maintenance?
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      04-23-2017, 07:59 AM   #5
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Quote:
Originally Posted by D041987 View Post
So been looking into all the power mods for our N20 and it's evident that we have rod issues along with oil starvation on high G turns along with the timing chain etc. But as for power and to fortify the bottom end, I want to see if there is a possibility to just upgrade the rods/ bolts as they are the weak link in this motor. I know we can buy full on out pistons and rings but what about just replacing the rods or companies making just rod replacements that are "Drop In Ready" so no balancing of the internals needs to be done? This would surely give a piece of mind and a far cheaper alternative than fully rebuilding the motor for someone who just wants mid to high 300's for a daily?

I know AWE and others made "Drop In Ready" rods for VW and Audi market etc. Why not see if this is possible for the N20? Most will not push more than 400 WHP on the Stage 2 Turbo's and would open the market up for bigger HP on these 4 cyl motors if price was cheaper to fortify the bottom end. Or is the block not accessible to replace the rods without taking it completely apart?

Just a thought and lets see what some of these big name companies/ vendors can chip in on this subject?
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Just get an M3 and be done with it.
+1. Just get an M3.
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      04-24-2017, 01:00 PM   #6
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Not trying to be that guy but honestly this si for the true car enthusiasts that want to have something different and work with the platform they bough/ can afford/like. Please don't post on here with a suggestion to get a different car. If anyone of us could afford an M3 we probably would have gotten it in the first place! And M3's have rod bearing and other failures as well.

As for the issues with the 4 banger motor. They are VERY known issues! They have been posted a lot on this form from lot's of members and any BMW shop that deals with these motors you go to will agree and say the same about the bottom end being weak with timing chain issues being present. Mainly evident on 2012 to 2014 but seems less and less lately though.

As for the bearings that is a given. You will always want to mic and measure and install new bearings with the rods. But I am looking to see if/why this has not been an option or if the market is just not big enough for manufacturing yet or if the motor is just a PIA to work on and requires full disassembly, in which case not worth doing just the rods.

Last edited by D041987; 04-27-2017 at 01:01 PM..
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      04-25-2017, 07:37 PM   #7
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Quote:
Originally Posted by D041987 View Post
So this is not a suggestion post to get a different car. If anyone of us could afford an M3 we probably would have gotten it in the first place! Also there are some that like to mod and push the cars they have for fun and as a hobby.

As for the issues with the motor. They are very known issues, that have been posted a lot on this form and any tunner you go to will agree and say the same about the bottom end being weak with timing chain issues being present. Mainly evident on 2012 to 2014 but seems less and less lately though.

As for the bearings that is a given. You will always want to mic and measure and install new bearings with the rods. But I am looking to see if/why this has not been an option or if the market is just not big enough for manufacturing yet or if the motor is just a PIA to work on and requires full disassembly in which case not worth doing just the rods.
It's simply not worth it from a financial perspective.

The cost (labor + parts) of reinforcing the engine and then the potential cost of a replacement engine ($13,000 for a brand new short block) is extremely high.

I am willing to bet that if you experience a catastrophic engine failure due to increased power levels, the total cost of your car + modifications + replacement engine will greatly exceed the cost of an M3.
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      04-27-2017, 09:25 AM   #8
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There also were cases of blown M3's.
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      04-27-2017, 12:21 PM   #9
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Quote:
Originally Posted by Polo08816 View Post
It's simply not worth it from a financial perspective.

The cost (labor + parts) of reinforcing the engine and then the potential cost of a replacement engine ($13,000 for a brand new short block) is extremely high.

I am willing to bet that if you experience a catastrophic engine failure due to increased power levels, the total cost of your car + modifications + replacement engine will greatly exceed the cost of an M3.
Well this is why I made this thread as noone really wants to rebuild the engine cause it's just too expensive at this point in time. Having just the rods replaced could be as cheap as 1K give or take a few hundred depending on the process that is needed and shop you go to or do it yourself. Most cars you just drop the oil pan and can see/ replace a lot of the bottom end. If someone wanted to have a mid 300WHP daily with a Full Bolt On's and a turbo they would be set in getting the rods, bolts and bearings and a good flash tune. This would result in a much cheaper alternative than a full rebuild which is north of 6K and very time consuming. This also keeps a lot of the OEM setup with minimal intervention of the assembly for longevity and less issues than a full rebuild.

Last edited by D041987; 04-27-2017 at 01:07 PM..
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      04-27-2017, 02:16 PM   #10
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Good idea, but it is not always about rods, check this thread

http://www.2addicts.com/forums/showthread.php?t=1149005

I get what are you trying to say and if can be done under 1.5k than maybe it is worth it. But still I'm not sure if that guarantees prevention of engine failure and potential rebuild.
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      04-27-2017, 04:34 PM   #11
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Quote:
Originally Posted by ///CSL View Post
There also were cases of blown M3's.
... which were covered by a warranty if they didn't do anything foolish like substantial powertrain modifications.
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      04-27-2017, 04:37 PM   #12
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Quote:
Originally Posted by ///CSL View Post
Good idea, but it is not always about rods, check this thread

http://www.2addicts.com/forums/showthread.php?t=1149005

I get what are you trying to say and if can be done under 1.5k than maybe it is worth it. But still I'm not sure if that guarantees prevention of engine failure and potential rebuild.
Apparently the guy in that thread is a dealership employee and received a huge discount for his rebuild.
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      04-27-2017, 04:43 PM   #13
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BMW could void warranty if they found out that car has been on track day. There were cases, even on forum, were people had to go to court in order to get engine replaced by BMW dealer.

So in that case you if you plan to track your car I think it's better to have some money aside just for the worst case scenario. And if that happens it is alot more expensive to rebuild M3 than than it is for tuned 228i.

I get your point, but still think that they are different league in terms of finances.
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      04-27-2017, 05:54 PM   #14
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Quote:
Originally Posted by ///CSL View Post
BMW could void warranty if they found out that car has been on track day. There were cases, even on forum, were people had to go to court in order to get engine replaced by BMW dealer.

So in that case you if you plan to track your car I think it's better to have some money aside just for the worst case scenario. And if that happens it is alot more expensive to rebuild M3 than than it is for tuned 228i.

I get your point, but still think that they are different league in terms of finances.
Perhaps, legally, they could void your warranty if they found out the car has been used on the track. However, that should require some legal process to obtain that information which would be expensive. That's certainly not the preferred way especially if BMW does not suspect unauthorized powertrain modifications.

It's far easier to deny a warranty at the dealer level due to evidence that powertrain modifications may have contributed to the significant warranty claim. The physical evidence is essentially in the dealer/BMW's possession. It doesn't get easier than that.
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      04-27-2017, 06:08 PM   #15
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People who will want to do this do not care about warranty, the car will usually have Full bolt on Mods and bigger turbo's. So no need to discuss about warranty info on this subject and in this post! It's gonna turn into a speculation of what if's and that. But just as anything Dealer, they will deny coverage if engine goes and they check inside. Plain and simple just like any mod will void warranty. So take it at your own risk so end of warranty discussion.

Also as for that thread above. The guy was running a JB4 ONLY! With full bolt on mods and an upgraded Hexon turbo and was at the 350whp range! So with that JB4 piggy back alone and no back end flash, he lost the fuel trims (AFR) and other things and caused pre-detonation in the motor which blew the piston from running lean and hot. Would more than likely not happen if he was fully tuned via flashed ECU or a back end flash stacked on the JB4 for monitoring and keeping the fuel trims and other factors for the proper setup that he was running. Pistons mainly break from running lean and hot which is caused by detonation which is a result of a bad tune or another component that fails.

Last edited by D041987; 04-27-2017 at 06:40 PM..
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      05-03-2017, 03:16 PM   #16
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Originally Posted by Polo08816 View Post
Apparently the guy in that thread is a dealership employee and received a huge discount for his rebuild.
He had a ton of issues with his car as he liked to push the envelope. I don't believe he even has the car anymore; he went with something else
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      05-03-2017, 03:24 PM   #17
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He had a ton of issues with his car as he liked to push the envelope. I don't believe he even has the car anymore; he went with something else
I cannot say I'm surprised.
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      05-03-2017, 04:28 PM   #18
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He had a ton of issues with his car as he liked to push the envelope. I don't believe he even has the car anymore; he went with something else
Scuttlebutt is that the car was resold as CPO.


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      05-10-2017, 04:44 PM   #19
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Quote:
Originally Posted by Polo08816 View Post
It's simply not worth it from a financial perspective.

The cost (labor + parts) of reinforcing the engine and then the potential cost of a replacement engine ($13,000 for a brand new short block) is extremely high.

I am willing to bet that if you experience a catastrophic engine failure due to increased power levels, the total cost of your car + modifications + replacement engine will greatly exceed the cost of an M3.
I realize this is fairly old, but exactly this. Think about the cost of an entire project BEFORE you start to go down that road. Other problems crop up as you add power, too.
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      03-02-2019, 10:28 AM   #20
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i know it is an old post but just to make people aware the rods and pistons have a taper so fitting aftermarket rods won't work with standard pistons, i have just found that out while rebuilding my engine after bearing failure. i will now have to purchase forged pistons to be able to use the uprated forged rods i bought.
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      03-02-2019, 04:47 PM   #21
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Quote:
Originally Posted by sap1000 View Post
i know it is an old post but just to make people aware the rods and pistons have a taper so fitting aftermarket rods won't work with standard pistons, i have just found that out while rebuilding my engine after bearing failure. i will now have to purchase forged pistons to be able to use the uprated forged rods i bought.
What's all that running you?
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Sounds pizzagatey.
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      06-24-2019, 01:41 PM   #22
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Quote:
Originally Posted by sap1000 View Post
i know it is an old post but just to make people aware the rods and pistons have a taper so fitting aftermarket rods won't work with standard pistons, i have just found that out while rebuilding my engine after bearing failure. i will now have to purchase forged pistons to be able to use the uprated forged rods i bought.
Hey sap1000, can you share the parts you used in your build or start a new thread on that topic? pls?

Having seen so many rod bolt failures (across numerous car brands) from my amateur road racing days, I'm inclined to just swap the rod bolts, if that is possible. I still have not investigated if it is possible to drop the oil pan without removing the engine.

I've got 182K miles on my N20 and have a plan to replace the motor mounts and turbo in the next few weeks. And possibly the rod bolts, if it's not too much extra work...
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