E30 Zone

basically i have been offered a brand new 324td crank and the guy is saying that in the m20 with this crank and 130mm rods it will stroke it to a 2.8, is this right? and would this crank be good to use for a high power FI car??

that crank and 130mm rods and late pistons will give you a fairly low comp 2.7..

i wouldnt use diesel cranks they are strong and heavy yes, but are not designed to rev high.
No revs no power. get me?

Wiseman wrote:i wouldnt use diesel cranks they are strong and heavy yes, but are not designed to rev high.
No revs no power. get me?

The ability of a crank to hold revs would be a function of the strength of the crank and the weight of the reciprocating masses attached to it.

Attach lighter pistons/rods etc and your crank will hold more revs for a given strength.

wouldnt use diesel cranks they are strong and heavy yes, but are not designed to rev high.
No revs no power. get me?

absolute rubbish squire as i have a 324td crank in my car and mine and makes loads of ponies
yet to be tested properly as car is not fully mapped
its the strength of the TD crank which is good as its made from forged steel plus it has the capicty to take the 2.7 to low comp so it can be used in force induction as Alex ( turbo brown) has commented

The ability of a crank to hold revs would be a function of the strength of the crank and the weight of the reciprocating masses attached to it.

Attach lighter pistons/rods etc and your crank will hold more revs for a given strength.
_________________

Wiseman wrote:i wouldnt use diesel cranks they are strong and heavy yes, but are not designed to rev high.
No revs no power. get me?

so why are the swedes making around 1000hp on diesel cranks in m20 motors?
and revving to 9500rpm????
do your homework first please... get me...

Edited and close to warning : Posted by HartgeH27

Diesel cranks generally have longer strokes, the longer the stroke the harder it is to rev, hence your larger capacity to 2.8, like midnight wrote on the first quote.
The 324tds diesel cranks are designed with over square pistons, where by the piston is longer than the stroke, cranks like that can be used to rev high. you would ideally need super light pistons and rods and that are expensive, fair doos if yo run a diesel crank fowler but im just going onho id put a motor together, mmmm maybe thats how the swedes do it, you gona do 1000bhp too rossle eh?rev to 9500 rpm, it not a fucking mototrbike ya twat! just rememberthe sweids are wild, mental in fact, if you ve been to gatebil you would understand.


But its still heavy, ok its strong, so is the std crank in an m20, more than fit for 400 bhp, you honestly gona go for more power than that?. there is a reason people use a lightened and balanced crank, it revs smooth and quick, is more reliable with big power.
Oh and its not forged crank you donut, its a billet crank if you want to get technical, smart arse.

Midnight, i would just get the std pistons in your motor skimmed approx 4 mm, m20 pistons are manufactured by mahle(same as a YB Cosworth) and are more than up to the job, its cheap too, any decent engineering shop will be able to do it, or send them to me, have done it with cosworth and m20 pistons and it does not fatigue the crown in the slightest.

another way you can do it is by using the low compression 2.7 121bhp block and strap the high comp 2.5 head on with the domed chambers, this does work with a decent head gasket and arp head studs

ar, did the baby throw his toys out the pram???
so the cranks in a swedes car will hold together jus because they are wild and mental?
all im saying is that they are good for power. no need for insults towards me personally.
if you want to get personal il pm you my address and you can come see me....

Ok big chap your right good for power and 9500 RPM yeah, defo, aye, yeah, uh hu, for sure, yup,






www.andrewgallacher.com

take a look here, this is a little example, in the later pages he moved to a diesel crank, and 700hp daily.
http://www.e30zone.net/modules.php?name ... highlight=

But its still heavy, ok its strong, so is the std crank in an m20, more than fit for 400 bhp, you honestly gona go for more power than that?. there is a reason people use a lightened and balanced crank, it revs smooth and quick, is more reliable with big power.
Oh and its not forged crank you donut, its a billet crank if you want to get technical, smart arse.

so what point is still proven that the cranks are good for big power.
i know that mine can be taken to 7500 easily without making some adjustments to the engine.
agreed the sweedes are mental plus the supply of BILLET cranks is slightly higher across europe as the 324td was an option ine uroupe not many made the travel over here.
I can say i have offically destroyed a billet crank not a nice experience. ( Bloody expensive)
From a man playing with YB cossy stuff you must no you stuff but 600 is no mean feet but that is quite obtainable from a M20 motor.
but for the drivetrain its a diffrent matter lol

Fair do's fowler using a diesel crank in your setup is quality, i think utilising stock parts from other motors is winner winner chicken dinner, skimming pistons another great reliable tunning method utilises stock parts, saves money, as a general rule building any power lump using the diesel crank just seams wrong, its the whole weight balance,stroke capper but hey it works it works.
Ive only ever seen 1 324 tds in this country, they are rare as hens teeth.

The Getrag boxes are good for bout 350 aint they? they take a bunch of torque but eh, torques a box killer, the same boxes were used on certian amerian v8's im sure. quite fancy straight cut gears and an r&d Diff.



www.andrewgallacher.com

getrag box can take around 400 then they start to whine and eventually die LOL

fowler wrote:getrag box can take around 400 then they start to whine and eventually die LOL

Wouldn't worry about it, a Quaife diff lasted about 3 hours with Wiseman driving anyway

This is coming from a guy that drifted his recovery truck at crail. Wonder how long the diff in your truck will last.

quiafe diffs are bit pony IMHO i killed 3 in a MK2 escort all under warrenty thank god.
and i killed one in a cossie saff
so i would not wate my money on them

just saying that the td forged crank is no good for high rpms due to the throw, is plain BS. yes, a bigger throw will require more power to rev up, but then also a bigger throw provides that extra power it requires. its just plain geometry really.
there are several BMW engines with cranks that have even bigger throws, such as S50B32, and those have no trouble going for really high revs. actually the part that usually limits the M20 max rpm, are the rocker arms, not the crank.

but according to some people, the reason not to use the 324TD forged crank, is that when used on a diesel engine. the crank is exposed to a lot of rattle and vibration. hence the metal may be fatigued and when exposed to high rpms, may crack.
while eta cranks are hardly exposed to either rattle, vibration or high rpms. then even though those are cast iron cranks, those should be in pretty good condition.
also the eta crank is lighter than the diesel one. and cheaper too

Coyote_ar wrote:just saying that the td forged crank is no good for high rpms due to the throw, is plain BS. yes, a bigger throw will require more power to rev up, but then also a bigger throw provides that extra power it requires. its just plain geometry really.
there are several BMW engines with cranks that have even bigger throws, such as S50B32, and those have no trouble going for really high revs. actually the part that usually limits the M20 max rpm, are the rocker arms, not the crank.

but according to some people, the reason not to use the 324TD forged crank, is that when used on a diesel engine. the crank is exposed to a lot of rattle and vibration. hence the metal may be fatigued and when exposed to high rpms, may crack.
while eta cranks are hardly exposed to either rattle, vibration or high rpms. then even though those are cast iron cranks, those should be in pretty good condition.
also the eta crank is lighter than the diesel one. and cheaper too

The 324 td engine is designed using over square pistons, where the piston is bigger than the stoke length. So this crank actually has quite a short throw.
Stroke from a crank gives you torque not power,
The rest of your crank theory is flawed buy the fact that you think that the crank throw in the diesel 324 is big when in fact its quite short, thats probably why there are so many engines that have larger throws.
The s50 is also a petrol engine, so it will be designed to rev higher than a diesel anyway.
Its a billet crank not a forged one... I could go on here.


Www.exposetheBS.com

I will give you that your right about the rocker arms breaking. Dave from new tech not break some yeti on a 525I that shugg had in the garage not that long ago? Im sure G Broke sum 2, in Gb autos.
Sorry to hear that merco is leaving the garage to go work for deep penetration motorsport hector, my heart bleeds for you ayrshore

Seem to remember that Alpina used the 324td crank to build their 2.7....cheapskates like me use the more readily available eta crank and wise ones limit themselves to 6000rpm....with a mild cam the power is all over by 5000rpm,it's the torque that makes a 2.7/8 so worthwhile.

just a question wiseman before you get on your high horse, why do you think its a billet crank, and everyone i asked and serched even asked the dealers and they confirmed it was a forged crank??

.........

what are you on? something strong i presume....
and why am i a big man?

ladies put your handbags down this is a civilised discussion no antagontistic or aggressive comments please

lol

Mr. Wiseman; I've done my apprenticeship of lying on a hospital bed for ten solid weeks with a broken leg, and know exactly how depressing and frustrating it can be!
You seem to be a person that has some knowledge worth passing on the members of this forum, but it would be appreciated if you could prevent your frustrations from coming across in your posts!

Wiseman wrote:The 324 td engine is designed using over square pistons, where the piston is bigger than the stoke length. So this crank actually has quite a short throw.
Stroke from a crank gives you torque not power,
The rest of your crank theory is flawed buy the fact that you think that the crank throw in the diesel 324 is big when in fact its quite short, thats probably why there are so many engines that have larger throws.
The s50 is also a petrol engine, so it will be designed to rev higher than a diesel anyway.
Its a billet crank not a forged one... I could go on here.


Www.exposetheBS.com

hey mister wiseguy, the stroke gives you torque. and torque multiplied by the rpms gives you power. so a bigger crank gives you more power. its pretty simple really.

when i said throw, i meant stroke, my bad. thats the problem when english is not your first language.

anyway, the maximun rpms a well balanced crank is able to hold, is basically limited on the crank's strength. and diesel cranks usually are extremely strong due to the forces they are exposed to. the drawback of a diesel crank is the weight, that will increase the recriprocating mass and it will reduce the engines acceleration.

I had mentioned weight/balance earlier in the topic, no one cared. Torque is however calculated by the force applyed multiplied by the distance from the pivot point to the point where the force was first exerted. so technically if the force is applyed to a greater distance larger stroke it will take longer to complete one full revolution, reducing the rpm in your horsepower calculation, yet incressing your torque value, so horsepower would remain even(ish). txrpm/5252.

Your english is good, especially using a word like recripocating.

Do you run on bio-ethonal in argentina?

you are correct that if the force was constant, the same applied force would result in a lower RPM with larger stroke. but then a larger stroke, increases displacement, hence its not the same applied force.

no, down here we have regular fuel. 95RON and some premium 100RON. very few stations have biodiesel, but is merely a marketing gimmick, since its more expensive than the regular one.

brasil uses bio-ethanol and there are plans to start selling bio-ethanol here.

The 2.7 m20 engine has 2.7 displacment yet only produces 121 bhp compared to the 171 of the 2.5 , but it does put out 170 fpt, less power but more torque than the m20b25 engine, it has a larger stroke and incressed displacement.

Basically the same as uk forecourts, i have only seen bio-ethanol for sale at one place in scotland and it was supermarrket (morrisons) not a shell or a BP. strange

This is my eta M20,I used a 731(320i)head with a 325 cam....just a bit more than 121bhp....

Daimlerman - I believe Wiseman was reffering to the standard eta (or seta) engine as fitted to the 525e (and euro/us 325e). Not an M20 2.7L stroker parts bin special.

However the eta engine was built for efficiency so many of the restrictions placed on the eta engine restricted its power such as its piss poor head and cam and the power was not necceassarily restricted because of the crank.

The fact is the TD cranks are what the scandinavian boys use on the big power M20's it is the best available crank in the BMW parts bin since it needs no modding to fit, its also easier to get hold of a TD crank than it is an S50 or newer crank. Wether it is the best choice or not it does work it has worked and will continue to work, no one really knows if it can be done better with another crank since I've not seen anyone aim for big power with anything else.

I am happy to stand corrected though.

Erm,yes march...I was just showing that little more than a head/cam swap can release the potential of the eta crank.I agree that the TD crank is the best of the bunch especialy if you intend to rev beyond 5000rpm on a regular basis.My graph clearly shows that my engine does just what I built it to do,ie,provide oodles of grunt at mainroad overtaking speeds....just look at the pulling power between 2000rpm and 5000rpm.Last week this motor ran 406 miles on 52.29 litres of unleaded,I make that 35.24mpg.So I have not only the power,but good fuel economy as well.

Pretty sure that BMW don't go to the trouble of machining their S series (or any other series of engines) cranks from a solid billet!

I'd put money on all current model BMW cranks being forgings for the simple reason that if you wanna make more than just a handful of them, that's gonna be cheaper in the long run. And beyond that, forged cranks should be stronger for the same weight than billet ones.

wow quite a lot of info there, cheers guys basically im starting from scratch with my car, i want it to be a race car with a tax disc, so im basically making no compromises with the shell or engine, i wanna be making as much power as possible through the m20 block, but want the power to come in efficiently rather the bogging down throught the middle of the rev range, ive got a holset hx40 to put on it so obviously i am expecting a nice bit of lag, i just want to use every bit of potetial the m20 can produce, with as few down sides as possible, i also want the engine to rev quite high due to the turbo lag holding back till higher up the revs