engine and drivetrain Mahle vs JE Pistons

[kbmb02]

if you really have to have big power from an M10, slap a turbo on it.

You'll sacrifice less durability, drivability and cash,

and net more power.  And more torques.  Lots more torques.

 

But it's a big time investment to tune it...

 

Another thought: What if the goal isn't 'big power' and 'torque' ? Lightening the internals - whether it be simple like a lightened / aluminum flywheel, or beyond - like lightened crankshaft, rod/pistons, etc (all properly balanced, of course) - improves the throttle-response of the engine. That results in a 'peppier' 02 driving experience which I, personally, prefer.

 

(And hey - Slavs - if you had an engine which wouldn't idle below 4,000 rpm, I feel for you. That bites. However, I'm guessing that was an exaggeration.

note: I've improved others' poorly-conceived engine builds (and the resultant lousy idle / low-end) by shortening the distributor curve substantially - that provides more ignition timing at idle / more vacuum.

 

Done here. -KB

[TobyB]

Hee hee- (ok, I'll play Devil's advocate- remember, street car)

 

but the lighter parts wear faster, don't idle as smoothly, and are hard to get off the line.

The only place you really notice the reduced mass is in shifts, and that doesn't

make you any faster on the freeway.  Or on any road where your foot's not flat to the

floor whenever it's not on the brakes.

 

t

for the sake of argument

[Slavs]

I've been driving 02s as daily transportation / drivers since 1982.

And mostly in some of the worst traffic conditions in the country, perhaps clocking as much as 15,000 miles / year.

As a result most of my 02s have either been destroyed or undergone some major accident repair. I've learned over the years what lasts and what doesn't, and I'm very familiar with both the weak and strong points of the 02.

You can safely refer to me as the "Hardcore" when it comes to these things.

Fiddling around with high performance engine builds is counterproductive for anyone using their 02 as a daily driver.

Let's just take the flywheel and clutch as an example;

If you lighten your flywheel and engine internals, you will loose momentum since momentum is an expression of Mass x Velocity.

And it's good to have a certain amount of mass in your flywheel when you're barreling down the highway at 80mph. It's excellent for cruising and maintaining a speed. The larger 228mm flywheel not only grabs better, but is also better at maintaining a high cruising speed.

Furthermore, the more you lighten your flywheel / clutch assembly, the quicker you will have to shift. That may be OK for a race car, but how long do you think your transmission synchromesh gear will hold up ? This type of driving is tasking and becomes annoying, quickly. The weak spot on the 02 tranny is the 2nd gear synchro. The 02 transmissions will last a very long time, but if you abuse them, you will loose the effectiveness of the synchro on 2nd gear. Quick, hard shifting along with downshifting into second will destroy your synchro.

The factory has engineered the engine for all around performance and driving. Even the factory Ti's were very mildly tuned, using just a small bump in compression, mounting sidedraft carbs and leaving the standard 264 degree cam. They did this to maintain drivability for everyday traffic conditions.

Once you leave the street for the realm of the racetrack, everything changes. And, if any of you are fixated on this, then this is the way to go. Have fun, etc !

So, in the end, it all depends on how you are planning to use your 02.

[Simeon]

I think it is fair to say that all manufacturers have to make compromises when designing road vehicles that may not be considered when designing for the track. It is also fair to say that BMW probably made less compromises than most contemporary marques. Most aftermarket modifications will change this balance and should be made with your eyes wide open particularly if you then want to use your car as a daily driver. Most people are aware of the potential impact to longevity and driveability but we should always be aware that car companies are much better resourced to design cars than even well known tuners. Shade-tree guys are a step further away again.

[Slavs]

Yes, I agree. BMW seems to have designed the M10 with sporting aspirations in mind.

That is most likely the reason why so many tuners "tune" these motors.

 

Slavs

[kbmb02]

Yes, I agree. BMW seems to have designed the M10 with sporting aspirations in mind.

That is most likely the reason why so many tuners "tune" these motors.

 

Slavs

 

Curious: Would a 'tuner' include those who install and praise a Weber 32/36 progressive carb? (Which, to my knowledge, the designers at BMW never installed on an M10). Perhaps I'm a bit skeptical of folks who are selective and contradictory in their pontifications - whether they be about carbs, engine tuners or American history.

 

Keep in mind, Alpina was a tuner (there's a pretty long list, actually).

 

The commonality in commentary here is, "How do you drive your 2002?" If as a daily driver used in the worst conditions like Slavs, performance builds may not be the proper choice (but a Camry might be). If your 2002 is a 2nd (3rd/4th) car which you use primarily for spirited weekend drives through the twisty's, there are ways to tighten-up and personalize the driving experience (suspension, brakes, engine, etc). And for track days / auto-x / racing, the 2002 / M10 combo is a great platform. Best: buy a bunch of 'em. -KB

[Slavs]

The 32/36 carb is applied as an aftermarket carb to many different types of motors, from old Alfas and MGs to Landrovers, Datsuns,Mercedes etc. The list goes on and on. It may be better than a worn out stock carb, but in no way does it match the all around efficiency and drivability of the stock carb in good shape. Some drivability is sacrificed (A little low end is lost)along with MPGs.This is a common observation and complaint I found throughout the range of different types of cars outfitted with this carb. So, it is an aftermarket tuning application, where you pick up a little more power at the top by sacrificing mileage and a little drivability.

The 02 was first and foremost designed as a practical sports sedan for everyday driving. And if you wish, you can easily take it to the next level, but it was not sold as such. So it is perfectly suited for those of us who want to use it as a daily driver. No thank you, I don't need a Camry, nor do I need a hopped-up 02. Now, for you part time 02ers who want to get your occasional rush at the track. you may want to tweak your 02s.

Don't get me wrong, while I keep my engines stock or nearly stock, I always stiffen and lower my suspension to take advantage of the 02s handling abilities. But, I see n benefit in tweaking the motor on a daily driver.

[jfahuna]

A cast  piston will be a quiet motor because you are running a much tighter clearance piston to wall,and you will not have blow by early in its build.

A forged piston I do not care : low this ,platted skirt and on and on and on ,you will see that it needs to run a looser piston to wall clearance ,hence blow by and a whole lot of noise early in its life.

Now on a "race motor" forged  is what you want because they are lighter and will withstand the occasional detonating.

That is the reason for tear down after 20 to 30 hours of racing and inspection on race motors(unless they tear down themselves).

 

[kbmb02]

20 hours ago, jfahuna said:

A cast  piston will be a quiet motor because you are running a much tighter clearance piston to wall,and you will not have blow by early in its build.

A forged piston I do not care : low this ,platted skirt and on and on and on ,you will see that it needs to run a looser piston to wall clearance ,hence blow by and a whole lot of noise early in its life.

Now on a "race motor" forged  is what you want because they are lighter and will withstand the occasional detonating.

That is the reason for tear down after 20 to 30 hours of racing and inspection on race motors(unless they tear down themselves).

 

 

 

Suggest you do some reading about the different alloy types used in forgings. With certain alloys and designs, I can get the clearance tighter without scuffing. As quiet as a cast piston? No. But I like the ability to build lighter pistons - to build a long-rod motor - and to dial-in the C/R based on block and cylinder head provided ... all made possible by the custom forged piston building process. 

 

As for tearing down race engines after 20-30 hours, that’s dependent how far to the edge they’re built....  -KB

[markmac]

As for tearing down race engines after 20-30 hours, that’s dependent how far to the edge they’re built....  -KB

 

....as well as how far on the edge they are RUN.  An M12/7 (or similar) run up north of 9k rpms regularly probably less than the numbers mentioned above.  My engine builder suggested 3-4 race "weekends" and it would be a good idea to take a peek inside to see what the bearings are looking like.....

[AceAndrew]

23 hours ago, jfahuna said:

A cast  piston will be a quiet motor because you are running a much tighter clearance piston to wall,and you will not have blow by early in its build.

A forged piston I do not care : low this ,platted skirt and on and on and on ,you will see that it needs to run a looser piston to wall clearance ,hence blow by and a whole lot of noise early in its life.

 

 

2 hours ago, kbmb02 said:

 

Suggest you do some reading about the different alloy types used in forgings. With certain alloys and designs, I can get the clearance tighter without scuffing. As quiet as a cast piston? No. But I like the ability to build lighter pistons - to build a long-rod motor - and to dial-in the C/R based on block and cylinder head provided ... all made possible by the custom forged piston building process. 

 

As for tearing down race engines after 20-30 hours, that’s dependent how far to the edge they’re built....  -KB

 

 

Jack, I'm with Ken on this.  You really need to read up on differing types of forged piston alloys.  Coming from speccing plenty of engines and playing around with plenty of different cast/forged options, you can absolutely get same-as-factory clearances AND longevity AND greater performance.  

[Schnellvintage]

I also agree with Ken. The big thing I think is missing here is machining for the type of pistons and assembly for the type of build someone is doing, and for what purpose. Forged alloys can all vary based on manufacture and price. I have built many bmw 4 and 6 cyl engines for customers and for my personal vehicles. The materials used are key to a proper build for both HP and longevity. My last build was a street motor with Ross forged pistons, which I had to file every NEW piston ring to spec as they were slightly too big. More than 2k miles so far and no burning of oil or slapping in the holes and 128HP at the rear wheels. It could possibly be an error in the process of a build instead of the type of parts used. Also if the internals are not balanced properly (or at all) odd things can happen more often. Lastly, never assume the part you buy is in perfect condition. Measure and spec everything when building an engine.
For what it’s worth $0.02??
Matt


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[jrhone]

Slavs...you lost me when you said the stock Solex 1 barrel was a better performing carb than a 32/36....

 

Not to get into a pissing contest, but I put about 15-20k miles on my 02 a year...its heavily modded and is VERY easy to drive.  

 

292 Cam, Weber 38, Lightened Flywheel, 5 speed...all things that make my daily driver more fun (and better performing) than it was stock.  

 

[arminyack]

On 6/1/2015 at 11:25 PM, Slavs said:

I have an old 1965 1800ti motor in my garage. After disassembling it, I've noticed that the connecting rods are not the familiar H beam patter, but rather like a dull knife edge. The finish does not seem tampered with since it left the factory. So, they don't appear to be modified. I have a strong feeling that early M10 motors all shared this connecting rod construction. They look lighter, but I have yet to weigh them. Do any of you guys know anything about these early rods ?

 

Perhaps the metallurgy has improved for forged pistons. It's been a while since I had them and since I have attempted to build a motor other than stock.

 

I'm still looking forward for the day to build a stock spec 1600ti motor with the correct 1600ti pistons, carbs etc.

I've searched for 1600Ti pistons as well....I've only ever found this

https://www.oldtimer-motorenteile.com/product_info.php?language=en&info=p2428_pistons-bmw-1600-ti--67---68.html

 

I never got to the point of seriously inquiring about them though

 

My 1600 has a stock motor....about the only mod is a Tii exhaust manifold, as the Stahl header that was on the car when I bought it started coming apart at the seams. I put in a 5 speed, and it pretty much perfect. Its fun and easy to drive (loves to rev!)...will cruise 80-90 mph no prob. I have heard stories about the 118 heads burn up exhaust valves a little on the quick side when run consistently @ 4k rpm (like a 4 speed 1600 would on the freeway) Any truth to this?

[jfahuna]

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