[2000max]

Originally Posted by GeorgiaTech335coupe

Luckily, my block was fine. The sleeve was not damaged and only had some fused aluminum on it. That was taken off when the bored it out for the oversized pistons.

What was the cause of your engine failure?

[GeorgiaTech335coupe]

Originally Posted by 2000max

What was the cause of your engine failure?

No sure way of knowing. But by the looks of the pics, I'd say it happened over an extended period of time.

[flinchy]

Originally Posted by GeorgiaTech335coupe

Stratos, I think you are doing the right thing by buying a used engine. Save yourself the headache. My car has been down for just about 8 months now. And it is still going to be another month at least before we fire it up. Building the engine in this car is not fun, mostly because only a few have done it. It is also VERY EXPENSIVE. Much more expensive than you would think.

What are you putting in yours?

[Joshboody]

Good luck with the new engine Stratos!

If i recal correctly, you ran the car pretty hard at high speeds for long durations. Can you add some comments here... speeds and durations at WOT?

[stratos_335]

@GeorgiaTech335coupe: Rebuilding the engine with forged internals and machining the cylinders is as expensive as buying a very low mileage long block and installing it. But with rebuilding engine it will not be as reliable as a used one in my opinion. Machining or replacing the sleeve is an option that I'm afraid to take.

Sorry for your loss, the failure has exactly the same pattern as mine.

@Joshboody: No, you are a bit mistaken. I was using my car for daily driving and some 2-3-4 hard pulls once a month for some "action" with other tuned cars or exotics.

I speeded up to 314 km/h twice one year ago (v-box confirmed) and hard accelerated the car a few times a week and that's all. I think that there are many more cars with harder abuse and tunes it this website like racecars and demo tuner cars.


The engine failed during cruising (blue smoke) and blew on a short 3d gear pull

[GeorgiaTech335coupe]

Originally Posted by flinchy

What are you putting in yours?

CP pistons w/all options, 9.5:1
Carillo Rods

some other things too.

[GeorgiaTech335coupe]

Originally Posted by stratos_335

@GeorgiaTech335coupe: Rebuilding the engine with forged internals and machining the cylinders is as expensive as buying a very low mileage long block and installing it. But with rebuilding engine it will not be as reliable as a used one in my opinion. Machining or replacing the sleeve is an option that I'm afraid to take.

Sorry for your loss, the failure has exactly the same pattern as mine.

Building the engine with upgraded internals is A LOT more expensive than buying a low mileage engine and dropping it in. You can get used low mileage long blocks for about $4000. That is about what the upgraded rods and pistons cost. Not to mention you still have to pay for the machine work, assembly, new bearings (expensive), all the misc bolts, injectors. Plus you might as well do all the head stuff since it's open. That's a few grand right there.

Not to mention the downtime is far longer. Buy a used block and you can be up in a couple weeks.

If I could go back in time, I probably would've just found another used long block and dropped it in. Oh well, I'm married to the project now.

[914kid]

Georgiatech did you run METH?

[flinchy]

Originally Posted by GeorgiaTech335coupe

CP pistons w/all options, 9.5:1
Carillo Rods

some other things too.

awesome! i'm waiting for alex@ABR to finish all his RnD, for the beefier rod bearings, and everything being a little cheaper haha

Originally Posted by stratos_335

Rebuilding the engine with forged internals and machining the cylinders is as expensive as buying a very low mileage long block and installing it. But with rebuilding engine it will not be as reliable as a used one in my opinion. Machining or replacing the sleeve is an option that I'm afraid to take.

it will be a lot more reliable in reality... you can put it back together with studs = stronger fasteners... forged pistons = stronger... rod bolts = stronger.. wrist pin = stronger.. heck, lower comp = less chance of detonation.

[The Ghost]

Originally Posted by flinchy

awesome! i'm waiting for alex@ABR to finish all his RnD, for the beefier rod bearings, and everything being a little cheaper haha



it will be a lot more reliable in reality... you can put it back together with studs = stronger fasteners... forged pistons = stronger... rod bolts = stronger.. wrist pin = stronger.. heck, lower comp = less chance of detonation.

I disagree. Built motors are more durable, but typically last less than a stock motor (failures aside). Increased wear, etc
I'd also swap in a stock long block.

[flinchy]

Originally Posted by The Ghost

I disagree. Built motors are more durable, but typically last less than a stock motor (failures aside). Increased wear, etc
I'd also swap in a stock long block.

gotta look at the other factors though

a built motor will usually be run a LOT harder

a built motor at stock or lightly tuned levels will outlast the non built one... but at that point, it's a silly comparison... high power levels, the built motor will also obviously outlast.

increased wear can't just 'happen' because it's a built motor, it's because it's run really hard?

[AWTT335i]

Originally Posted by flinchy

gotta look at the other factors though

a built motor will usually be run a LOT harder

a built motor at stock or lightly tuned levels will outlast the non built one... but at that point, it's a silly comparison... high power levels, the built motor will also obviously outlast.

increased wear can't just 'happen' because it's a built motor, it's because it's run really hard?

I disagree. OEM motors are built with longevity in mind, hell just forged pistons will cause excess cylinder wear as they are clanging around in the cylinder bore before it heats up. Not to mention motors built for big power are generally built "loose."

[stratos_335]

I'm really afraid to machine the cylinder sleeves to 84.5 mm as they are very thin and will become thinner. And maybe there is some kind of a coating inside the cylinders that might disappear.

What about the open deck philosophy of the short block? My cylinders were worn on the top of them. Even with forged internals the cylinders walls may crack eventually.

Lower compression pistons? 20 psi will sound like 15 psi with lower compression pistons and will need custom reflashing and the fuel supported from the stock injectors might not be sufficient. That's why I'm searching for a used long block

[C.Pop]

Typically OEM engines are built very well -meaning, tolerances are very closely adhered to. It's hard for a decent shop to match these tolerances, and impossible for a shade tree mechanic. This coupled with the differing thermal expansion properties tends to give "built" motors a reputation for being able to take a beating, but not be good at longevity.

Properly built, upgraded internals should last a very long time provided tuning is reasonable.

[flinchy]

Originally Posted by AWTT335i

I disagree. OEM motors are built with longevity in mind, hell just forged pistons will cause excess cylinder wear as they are clanging around in the cylinder bore before it heats up. Not to mention motors built for big power are generally built "loose."

new forged pistons with the latest material composite don't have the massive expansion any more

a few years ago you would have been right

OEM motors are built around longevity at stock tune, not tuned like N54's here are.

Originally Posted by stratos_335

I'm really afraid to machine the cylinder sleeves to 84.5 mm as they are very thin and will become thinner. And maybe there is some kind of a coating inside the cylinders that might disappear.

What about the open deck philosophy of the short block? My cylinders were worn on the top of them. Even with forged internals the cylinders walls may crack eventually.

you could go to 84.25, FWIW. they're thicker than many other open deck blocks, and the cylinder to cylinder walls aren't thin at all haha (not thick, but not THIN)

and i don't believe there's been any pressure cracking of N54 cylinders, nothing to be concerned about to date, even with the cars at 700whp+

Originally Posted by stratos_335

Lower compression pistons? 20 psi will sound like 15 psi with lower compression pistons and will need custom reflashing and the fuel supported from the stock injectors might not be sufficient. That's why I'm searching for a used long block

not true, you can run far more boost and timing on any given fuel, ... and 'custom reflash' isn't exactly difficult or expensive for these cars.. in fact, it's very normal.

and fuel? the opposite is true, it means you can get more power on pump, you don't NEED the higher octane of high ethanol content.

Originally Posted by C.Pop

Typically OEM engines are built very well -meaning, tolerances are very closely adhered to. It's hard for a decent shop to match these tolerances, and impossible for a shade tree mechanic. This coupled with the differing thermal expansion properties tends to give "built" motors a reputation for being able to take a beating, but not be good at longevity.

Properly built, upgraded internals should last a very long time provided tuning is reasonable.

it's not hard for any **good** shop to blueprint a motor to MUCH tighter tolerances than OEM.... why would you bother getting your motor built at a shop that doesn't have said ability? in that case, yeah, don't bother modifying the motor, the stock longblock is 100% the best option.

[C.Pop]

Flinchy, I agree with your comments about my quote in theory. The problem is that in actuality, everyone thinks they're going to a good shop. There are far fewer good shops than purport to be good shops. I've seen lots of terrible machining done at "excellent" shops the result of which was the new, more durable parts of the engine self destructed within a couple of thousand miles. Usually the end user is bummed out because they spent probably too much money on their build and so it goes...

[buster84]

I agree that rebuilding can be a hit or miss. I rebuilt my mustang and never regretted it one bit. If you go the rebuild route you have to make sure you fill out a contract of everything you plan to get done, parts list ect... then you ask them how long it till take, then make them sign the contract with a list of penalties for not completing it on time, if nothing else is wrong with the car that isn't written into the contract. If they fail to deliver by the timeline those penalties will reduce your overall cost. I did this with my mustang and Saved 1.5k because he promised the car a month earlier. Their shop took on to many jobs and got behind. This was on a 4.6 engine. These are not easy and require very precise tools just like the bmw engine does. I spent a total of 6k, but got it stroked with forged internals, ported heads, cams, and a vortech install with a custom intercooler. It was a steel for what i paid. I also had lots of various little parts replaced that we agree'd on and a few extra he called me about. All these thing's were noticed with the tare down so its was just him saying, I noticed your timing chain was rubbing on your tentioners since im removing and reinstalling it all anyways, do you want me to buy new parts. I said yes. That does not affect the time of the build.

If you find a shop that say they can rebuild the bmw make them sign a contract. If they wont they have no intention to respect your timeline and know that once they take the bill and tare it down they can run you along for however long they want. This is what most shops do. Great shops will not do this.

Anyways, If it was me i would rebuild over buying a used engine. The only way i would buy a used engine is if i only planned to run the car stock, or with just a tune. Nothing more. You are obviously interested in a lot of HP and I highly suggest paying a little more for a rebuilt engine over a used engine. With full forged internals you will be capable of 800+ hp without worries if you ever decided to try and obtain that amount. Deciding between a used, vs rebuilt engine all comes down to your HP goals. If you can't afford to rebuild with ""Quality parts", then you obviously cant afford mucho HP. Then Stick to Stock.

At least with a rebuilt engine your engine will have a higher demand in the resale market with forged internals. With a stock engine, your at KBB and all that extra money you invested in it is tossed out the window. You will also have problems selling it if you cant provide proof of the exact mileage on the engine. If this was New then you would be fine, but when its used. You truly never know the exact mileage unless you were the one to pull the engine.

I for one would NEVER buy a car with a "Used" engine. To much of a risk with the amount of fraud that happens. Since the mileage can't truly ever be documented in a way to prove it. If the owner had pics of the car it came out of, with the dash mileage then "Maybe" but I'd still want well below blue book. I for one would buy a car with an upgraded rebuilt engine with documentation and would pay a little above blue book for it, Especially on a BMW.

I'm not saying you won't get bluebook for your car, but don't get mad when dealers low ball you and tell you that they can only sell it at auction ect... (without 100% proof of mileage, which uses makes it near impossible to prove) You will also get low balls from private parties. Just make sure that you look at all aspects, reasons for why you want a used ebay engine (or elsewhere) and what your long term HP goals are.

[enrita]

Originally Posted by GeorgiaTech335coupe

Building the engine with upgraded internals is A LOT more expensive than buying a low mileage engine and dropping it in. You can get used low mileage long blocks for about $4000. That is about what the upgraded rods and pistons cost. Not to mention you still have to pay for the machine work, assembly, new bearings (expensive), all the misc bolts, injectors. Plus you might as well do all the head stuff since it's open. That's a few grand right there.

Not to mention the downtime is far longer. Buy a used block and you can be up in a couple weeks.

If I could go back in time, I probably would've just found another used long block and dropped it in. Oh well, I'm married to the project now.

Totally right. Rebuilding will cost twice as much and it has to be done right.... I am on my 3rd engine

[GeorgiaTech335coupe]

Originally Posted by 914kid

Georgiatech did you run METH?

Yes.

Ran meth when on stock turbos and when single turbo. So I've ran it since prob 2008-2009.

[GeorgiaTech335coupe]

Originally Posted by enrita

Totally right. Rebuilding will cost twice as much and it has to be done right.... I am on my 3rd engine

Are you on your 3rd stock engine or 3rd built engine? IF it was built (I think you did that if I recall correctly), what have you done to it?

I have a lot of time and $ invested into my engine. I truly miss driving this car (been out of commission since Feb 2). And it better scare the shit out of me when I get it back with as much as I have invested in it.