General Forum : Interesting project... H27 based on 325 block...

nsbone

Posted Friday, Jun 30th 3:59pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 424

KL, Malaysia
e21 323/6 316, e34 520i, e32 730i

Hi,

Interesting project...building Hartge based on 325 block.. possible?

taken from M20 forum...

Quote:

To: mod_m20@yahoogroups.com
From: "mybmwe30"
Date: Wed, 28 Jun 2006 16:15:33 -0000
Subject: [mod_m20] Building a Hartge H27 copy Engine

I'm getting ready to under go a Budget minded 2.7 engine build. My
plans are to basically copy the Hartge H27 engine, a Friend of mine
sent me once of his genuine H27 pistons when he had the engine
rebuilt. After some research it turns out they are more then likely
M52 pistons. So my plans are to use an 88 325i block i have laying
around(I've got 3 m20 blocks but this one is in the best shape), toss
the 2.7 eta crank in(have laying around also). Then buy a set of M52
pistons and rods, then top it off with a 325i head with some mild
porting and slightly hotter then stock cam shaft. I've already have
the head also

so realy the only cost is the pistons, then the
rebuild parts like bearings, gaskets, rings etc...
The H27 specs are 84mm bore, 81mm stroke, 205 hp, 197 torque, 10.2:1
cr ration. I'm basicaly after making a very reliable daily driven
engine that makes a good bit of use able power.

Madhatter

Posted Friday, Jun 30th 5:13pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 49

Australia - QLD
E21, E24, E30

Nope.

You just have to remember the M50 and following blocks are taller than the M20. Fitting rods and pistons into the block while retaining the stock M52 items wont fit. You either have to play around with rod lengths and piston compression heights or shave down the crowns of pistons. If i wasnt totally shagged right now i would work out the height using the M52 stuff and an eta crank

imaradiostar

Posted Friday, Jun 30th 5:37pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 794

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

M50 pistons with 135mm rods and an 81 stroke crank with an "i" block (206.7) will work...but not perfectly. You'd have to remove about a mm from the top of the piston.

Ask me how I know.

jamie

MayanArch

Posted Saturday, Jul 1st 5:00am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1019

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Ray has mentioned using the M52 3.0 crank in the ETA block with custom pistons.

WIll the M52 pistons and rods work if you shave down the crown of the pistons?

Whats the throw on that 3.0 crank?

imaradiostar

Posted Saturday, Jul 1st 6:11am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 798

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

The 89.6mm stroke crank is pretty much the territory of custom pistons...unless you can find a piston that has a compression height around 27.5mm. Last I checked there aren't any OEM's producing pistons in that range.

Metric Mechanic sells pistons that'll work with this combo- I'm not a fan of the huge valve pockets and surface turbulence stuff but they'll work just fine and make a ton of power over a stock engine! Maybe you could convince Jim to sell you a Sport piston without the deep valve cuts!?

Another thing that needs to be taken into account is the shape of the combustion chamber- what head are you using? Flat topped pistons like the M50/M52 are really a poor match for the 325i 885 casting head. You might be able to trim the piston top in such a way that it could work but it wouldn't work as well as a custom piston.

jamie

bmw_m_320i

Posted Saturday, Jul 1st 8:11am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 682

Helena, Montana
none right now :(

THe closest pistons I could find to those specs in a bore that will work are from an Opel Speedster built from 10/2001 on. The main concern is that the wrist pin is 2mm smaller on the opel pistons. Here are the specs

Bore 86mm (standard size)
Compression Height 26.75mm
Wrist pin 20x62mm
overall length 48.9mm
dish .61x70mm (2.3476 cc)

These are OEM by Mahle

MayanArch

Posted Saturday, Jul 1st 2:34pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1020

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

imaradiostar wrote:

Another thing that needs to be taken into account is the shape of the combustion chamber- what head are you using? Flat topped pistons like the M50/M52 are really a poor match for the 325i 885 casting head. You might be able to trim the piston top in such a way that it could work but it wouldn't work as well as a custom piston.

So what is the ideal geometry for a piston top for a "i" head?

If you are going to put them on a lathe to trim down.......then it is pretty much just as easy making them slightly convex or concave on the surface, right?

This would be cheaper than forging custom pistons. You would just have to find an example piston for th emachinist to copy the top surface from.

WHat piston top would you copy?

bmw_m_320i wrote:

These are too short per your recommendations. Isnt it easier to cut a piston down, then to try to wedge a piston that is too small up?

Or...........maybe that small height difference is negligible?

bmw_m_320i

Posted Saturday, Jul 1st 10:45pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 684

Helena, Montana
none right now :(

The only pistons I could find that are slightly taller than 27.5mm have bores that are 80mm and below. You could deck the block to compensate, but after all of that it would be cheaper to get custom pistons to match the chamber

MayanArch

Posted Sunday, Jul 2nd 2:04am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1025

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

How do you guys calculate this?

What is the overall length of an M20 engine includding crank, rods, and pistons?

If you start with a 89.6 crank............how do you know what the length from the stroke/throw of the crank is to the top dead center of the block cylinder?

Also, and ETA block is 84mm bore, right?....not 80 or 86, right?

Why go with custom pistons and not custom rods? Wouldnt the rods be cheaper to make than the pistons?

What if you started with an 89.6mm crank and an M20 - 84mm bore - 325i piston? What would the rod length need to be?

bmw_m_320i

Posted Sunday, Jul 2nd 10:39am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 685

Helena, Montana
none right now :(

rods cost more, a set of pauter rods for an M10 cost about a grand, a set of custom pistons cost about $600-700

JJG323

Posted Sunday, Jul 2nd 2:59pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1241

Reading MA USA
1979 BMW 323i

Guys, I have looked into this or something similar.
Its the whole thing about building a better stroker.

But using the s52 crank, you need Both custom pistons $1500 or so and custom Panter rods. The rods are a least 1k so its expensive.

Or you can use the s50 crank, thats the new one that i have out of a 95 e36 m3. Than you can use the s50 rods, which BMW sells, or can be found used for $300 bucks. So with the s50 crank, MM or JE sells custom pistons that work with the 885 head and this stroker is doable - it just depends on what you want to bore the bottom end. Its a lot less that getting those paunter rods.

Some people only go to 85 mm, but 86 mm has been done on a NA engine.

MayanArch

Posted Sunday, Jul 2nd 3:34pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1026

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Metric Mechanic sells both custom pistons and rods for about $1000 per set.

So, how do you calculate the length of these components? I am curious.

MayanArch

Posted Sunday, Jul 2nd 8:59pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1029

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Yay!!! Some quick fun with CAD.

A quick cost of machining this piece is about $60 to 80 bucks.....out of the 4340 metal Metric Mechanic uses for their rods.

Weight is slightly less than MM.

imaradiostar

Posted Sunday, Jul 2nd 9:48pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 801

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

here's an answer that's more to the point. Factory pistons are a poor choice, factory rods are more than sufficient. The E30 M20B25 pistons are very heavy and high-friction. The M50 pistons, while lighter and much lower friction, don't have the correct combustion chamber shape. Regardless of the ability to draw up a rod or even have it produced affordably it won't matter if you aren't engineering the engine to work as a unit, all parts together. This is why engine builders get payed the big bucks to build engines.

I feel very strongly that anyone can build a decent BMW engine. I also feel strongly that not everyone can build an excellent high-power long lasting BMW engine.

What are your goals? Most power? Best economy? Stock appearance from the outside? Using existing parts you already have laying around? How long do you want the engine to last? Are you willing to accept a higher redline and/or shortened engine life to achieve your goals? What about oil consumption? I could build you a very high horsepower (over 300hp) naturally aspirated BMW engine but unless you plan to tear it down often and decarbon everything and inspect all the internal components it won't be a good engine for a car you plan to drive regularly.

Here's what I'm coming to. Everyone has different opinions on how to build an engine. I think Metric Mechanic has fine engines that will work reliably and the machining quality is much higher than what you or I will achieve with the (domestic-centric) local machine shops we have at our disposal. I very highly recommend sending the bottom end of your engine to MM and having them build it for you.

On the other hand; I don't like the surface turbulence tech on the piston tops and the lack of good squish/quench area and for acheiving best efficiency and detonation resistance I promise surface turbulence will hold you back. If it was as successful as they claim I promise OEM's would be using it!

So once again- are you trying to use off the shelf parts or do something different? What are your goals?

jamie

MayanArch

Posted Sunday, Jul 2nd 10:19pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1031

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

1.) FUN. Fun in building the machine of your dreams. If possible, safe, and economic....fun designing and building the machine of your dreams. Being able to say you dreamt up your engine, drew it, engineered it, and had it built.

2.) Bottom end horsepower, and a wide powerband.

3.) Relative fuel economy and reliability. If the engine only lasts 65k....and maximize on the fun and horsepower....I would be very happy.

4.) Budget. Dont want to accomplish that by being a check book mechanic. I have the most fun learning, designing, and seeing ideas come to life.

5.) Logic. I will never be able to create a crankshaft......but pistons and rods, maybe. The CAD program I use is tied to a machine shop. I wouldnt do the machining myself. I draw the 3D design - They source the material, machine it with their CNC machines, and ship it. They dont forge, and I have trouble getting them to do complex 3D shapes.

ALso, Miami has some of the best machineshops in the world because of how important it is as an airport hub.

I would use BMW components that get me the most horsepower.....IE the 89.6 crank...the Eta block...the I head.....and high performance head components from one of the tuner.

Then the question we have been discussing are the pistons, rods, and probably porting the head.

Custom intakes and custom exhausts are easy enough to do, if you have the knowledge on calculations and dimmensions. Supercharger anyone?!?

Used components are great and economical.

I dont want an engine I have to pull apart every 2k miles. I would want an engine that is high HP, with a wide power band, lots of low end torque.

I figure that my 1998 323is daily driver only has 60k on it. If I could build a monster that lasts me that long....and that reliable......then I would be happy.....and I would show it off to the world as a mountain climbed.

That would be my idea of fun.

imaradiostar

Posted Sunday, Jul 2nd 10:25pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 802

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

OK, more info. I realize I'm spouting info but not equipping you with the information to compare for yourself.

M20 blocks were available in two different heights- 206.2mm for the ETA engine and 206.7mm for the B25 engine. I'm unsure of the M20B20, B23 and Super-ETA deck heights. This measurement is from the centerline of the crankshaft main journals to the top of the block.

There are a number of cranks available to fit out blocks- 75, 76.8, and 81 mm M20 cranks are readily available. With the addition of a spacer and some clearancing of block internals (and the intermediate shaft) M50 family cranks can be made to fit. This means M52B28 84mm stroke cranks, M50B30 85.8mm stroke cranks, and M54B30 89.6mm stroke cranks. There are others, I just don't recall all the dimensions and designations at the moment.

We have a wide selection of connecting rods to choose from- 130mm eta/supereta rods, 135mm M20B25 rods, early M50 135mm rods, 95 M3 135mm rods, and so on. See the metric mechanic catalog for an example of the different ones available. Most BMW rods are relatively light and strong. All of the rods in this engine family (in the US, anyway) share the same size rod and wrist pin journals, making them interchangeable.

You determine piston compression height by subtracting 1/2 of crank stroke and rod length from the total block height. Let's use a practical example:

206.2mm ETA block - 130mm ETA rod - (1/2*81mm ETA crank)= 35.7mm from wrist pin centerline to top of block. This matches exactly with the value for compression height for that piston in the Mahle catalog.

Let's use my engine as another example- I have an 86 ETA bottom end that I rebuilt for my engine. I found that my block wasn't true and needed to be made level again- this is often the case and should be considered before ordering pistons and deciding on a final crank/piston/rod combo. I was using a 731 casting head which has a large flat squish area at the edge of the combustion chamber. I wanted to maximize this area for the best possible running engine so I decided to have 20 thousandths (about .51mm) removed from the top of my block.

This allowed the pistons to poke out of the block about the same amount- you would think this would be very bad. In this case it isn't. The M20 head gasket is about 1.75mm in the compressed. This means piston to head clearance ended up being a little over a mm- not as low as I wanted but I was paranoid about going too close. I verified this height by assembling the engine with pieces of solder on the piston tops and rotating the engine through a full revolution. I then removed the head and measured the crushed solder and it was roughly .045" (a little over a mm) thick for each cylinder. This allows my engine, correctly tuned, to run cheap 87 pump gas in the nasty Nashville heat and not ping even though my compression ratio is about 9.4 to 1.

I currently am building a new engine with the help of a friend that is a damn good engine builder. This time I'm using an ETA crank, 135mm rods, and M50 pistons. I will still be using a 731 casting head though there will definately be some modifications! I'm really not at liberty to divulge what we're doing (at my friend's request) but this engine should easily break 200hp with the correct setup and a reasonable redline- between 6500 and 7k. To the best of my knowledge we're trying some things that haven't been done to a BMW engine and I will update once it's built and tested. If it's not what we hope I'll be sure to let everyone know how to not build an engine!

Another thing you should research on the internet- look for info on rod/stroke ratio. Ideally you want this number around 1.8 though increasing numbers of engine builders are building engines with ratios around 1.5, citing quicker piston acceleration around TDC for better detonation resistance. OEM's and many older engine builders don't like this because it creates the tendancy to "push the piston through the cylinder wall." You end up with higher piston squirt loading from the piston rocking back and forth on the much shorter rod. With a longer rod the forces acting upon the piston would be much less. With a modern lightweight forged piston it shouldn't be a problem- they're engineered to take the abuse!

jamie

imaradiostar

Posted Sunday, Jul 2nd 10:51pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 803

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

Sounds like you're on a similar path to me. You're going to have to decide a few more things along the way.

The stock m20 intake manifolds become a limitation after a certain rpm and flow- you almost need to decide now if you're to keep them or go with some sort of ITB setup. JDBeyer's engine has an extrude-honed manifold to help with high rpm flow values.

A larger engine will run out of breath sooner- if you build a 3.1 liter engine with an 89.6 stroke crank and 86mm pistons but don't use ITB's or some similar setup for an extreme increase of flow at high rpm you're going to loose the benefits of your large stroke at higher rpm; the engine will feel more and more like a tractor, running out of breath at higher rpm. A smaller engine, say a correctly designed 2.7 or 2.8 with a moderate cam could retain a stock intake manifold and still have a decent feel at high rpm. There's still going to be benefit in a free flowing intake and exhaust system but you have to consider the cost and performance tradeoffs in your build.

Many people will try to run a high-compression engine but won't consider the effect of a camshaft on the compression ratio- this is called Dynamic Compression Ratio. An 11.5:1 CR engine with a 288 duration cam may actually be less likely to ping than a 10:1 engine with a 260 duration cam. There are programs on the internet that can help with calculating these values.

Stock M20 head gaskets have a compressed thickness of 1.75mm and a bore diameter of 85.2mm. This means you can safely run an 85mm piston out of the block without too much worry of the piston catching the head gasket. Cometic makes custom head gaskets for larger/smaller bore diameters and different gasket thicknesses. Metric Mechanic gets around all of this by running 0 deck height (piston doesn't poke out of the block at the edges) and milling a chamfer around the top of the piston to clear the factory head gasket- you can see the chamfer on the pictures in their literature if you look carefully. It's a neat way to get around the custom head gasket thing; he's a smart guy! Whatever the case, the volume of the head gasket needs to be considered in your calculations.

I'm not knocking the quality of the machine shops in your area but there is a big difference between machining parts per a spec/CAD drawing and machining a specific engine block for a BMW that twists and turns as things are bolted to it. I come from a line of machinists and tool & die makers and I've grown up around the complications the machinists have to deal with- a good machinist will know how to cut something to compensate for what will happen in the real world, from expansion/contraction to the slight bulging around cylinder head bolts. Call around your area and ask for a torque plate for a BMW M20 engine block- if a shop has one then it's a good indicator that they'll be able to correctly machine your block. If you're unable to find one then it may be worthwhile to send your block to Korman or someone else that does or simple limit yourself to a smaller bore diameter that'll result in less flex and use a ring pack that will be less sensitive to bore distortion- your piston manufacturer can help you with this.

It's not a bad idea to follow in the footsteps of others- JDBeyer or MarquisRex may be able to give you a number which you can give to a piston manufacturer and they'll be able to produce a set of pistons for you with minimal changes; all the tough work as already been done. It's easy to change a ring pack, move the wrist pin around, slightly change compression height or valve cuts.

Have I said too much?

jamie

MayanArch

Posted Monday, Jul 3rd 1:42am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1032

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

imaradiostar wrote:

Another thing you should research on the internet- look for info on rod/stroke ratio. Ideally you want this number around 1.8 though increasing numbers of engine builders are building engines with ratios around 1.5, citing quicker piston acceleration around TDC for better detonation resistance. OEM's and many older engine builders don't like this because it creates the tendancy to "push the piston through the cylinder wall." You end up with higher piston squirt loading from the piston rocking back and forth on the much shorter rod. With a longer rod the forces acting upon the piston would be much less. With a modern lightweight forged piston it shouldn't be a problem- they're engineered to take the abuse!

jamie

Jamie,

Thanks a bunch. Keep writing all you want. I definetly wont get bored, and I certainly appreciate the engine 101.

This is counterintuitive. An extra inch of rod beam is nowhere near as heavy as an extra inch of piston height.

I thought the idea here was to lower reciprocating mass. Replacing rod length with piston height counters that effort.......right?

MayanArch

Posted Monday, Jul 3rd 1:47am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1033

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

imaradiostar wrote:

Have I said too much?

Not at all. You dont know how much I appreciate this kind of in depth info.

MayanArch

Posted Monday, Jul 3rd 1:49am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1034

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

imaradiostar wrote:

I was planning to have a mandrel bending company bend some tubing to mimick the stock, but have a larger interior diameter. I was also going to redesign the intake box to better incorporate a supercharger........instead of being an afterthought.

MayanArch

Posted Monday, Jul 3rd 1:53am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1035

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

imaradiostar wrote:

Stock M20 head gaskets have a compressed thickness of 1.75mm and a bore diameter of 85.2mm. This means you can safely run an 85mm piston out of the block without too much worry of the piston catching the head gasket. Cometic makes custom head gaskets for larger/smaller bore diameters and different gasket thicknesses. Metric Mechanic gets around all of this by running 0 deck height (piston doesn't poke out of the block at the edges) and milling a chamfer around the top of the piston to clear the factory head gasket- you can see the chamfer on the pictures in their literature if you look carefully. It's a neat way to get around the custom head gasket thing; he's a smart guy! Whatever the case, the volume of the head gasket needs to be considered in your calculations.

Why does this even come into play. I was under the impression that the MOST you could bore an M20 block was to 84mm.......and that you were running it too thin anything beyond that.

imaradiostar

Posted Monday, Jul 3rd 7:14am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 805

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

There's a lot more gain to be had by replacing pistons than rods- rods from an M3 or 328i really aren't bad; they're pretty light and strong. The factory E30 325i/E34 525i piston is tall, has huge skirts with a pretty high amount of friction and high-tension rings. It's great for what they wanted it for- long life driven hard with a conservative redline. You'll find that rods and similar parts needn't be as strong if you go to a much lighter forged piston.

The other thing is it's difficult to stuff a large stroke and rod into a small block height- the aforemention value for the 89.6mm crank and 135mm rod makes a good example. You soon run out of room for a decent ring pack and you start making sacrifices like dropping the oil ring over the wrist pin. An OEM usually wouldn't do this as you'll take a hit on oil consumption. A guy building a weekend driver/racecar that is going to be driven hard will be willing to make this sacrifice.

When you have nice light reciprocating components it's possible to go to a much smaller wrist pin. One piston company suggested a 19mm wrist pin- if the piston is light it should be plenty strong! This will also make more room for rings and piston dome/dish and valve cuts, should you need them.

jamie

Bullmoose

Posted Wednesday, Jul 5th 11:58pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 8

Holland
E21 335i, E30 325i

I've used an M52 (328i) crank in my M20B28 engine.
The nose of the M20 and M52 cranks is different so a ring must be fabricated to have something for the front seal to run on.

I used 320i conrods and stock 325i (8.8 compression) pistons of which I modified the skirts. If you do the math you end up with a pretty nice compression ratio, no need to shave the block.
The rod/stroke ratio isn't perfect but there are stock engines out there that have worse ratios.

I am yet to fit the engine into a car so I cannot tell you the results just yet. Still need to choose a cam too, any ideas? I'm not looking for massive rpms.

MayanArch

Posted Thursday, Jul 6th 1:16am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1044

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Bullmoose wrote:

I used 320i conrods and stock 325i (8.8 compression) pistons of which I modified the skirts.

What year 320i and what year 325i?

The E30 and E36 320i didnt come to the USA.

JJG323

Posted Thursday, Jul 6th 5:04am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1248

Reading MA USA
1979 BMW 323i

Bullmoose wrote:

I've used an M52 (328i) crank in my M20B28 engine.
The nose of the M20 and M52 cranks is different so a ring must be fabricated to have something for the front seal to run on.

Yes, I have heard that this crank can be used. Like the s50 one it needs a front seal to be fabricated on it. Question on the 328i m52 crank, what is its diameter?

Bullmoose

Posted Thursday, Jul 6th 1:54pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 9

Holland
E21 335i, E30 325i

If you mean the stroke, it's 84mm. It fits inside the M20 block without modifications (except for the ring of course).

Marquis_Rex

Posted Friday, Jul 7th 10:07am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 451

UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT

The 328i crank I put in, into a modified M20 had a total counterweight radius , of about 73mm.

Compare this with 67.5 mm for the stock cast 81mm eta crank and even 68mm for the forged 86mm throw US M3 crank.

For me it was marginal but the forged 328i 84mm throw crank had fouling issues with the auxiliary shaft/distributor drive/oil pump drive.

MayanArch

Posted Friday, Jul 7th 2:40pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1047

Florida, USA
Baur E21 2.7 1982, Baur E30 318i 1985, 323i 1978

Marquis_Rex wrote:

For me it was marginal but the forged 328i 84mm throw crank had fouling issues with the auxiliary shaft/distributor drive/oil pump drive.

What does this mean?

Marquis_Rex

Posted Friday, Jul 7th 10:47pm [Edit] [Quote] [IMS] [View car]

Member
Post nr. 452

UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT

MayanArch wrote:

Marquis_Rex wrote:

For me it was marginal but the forged 328i 84mm throw crank had fouling issues with the auxiliary shaft/distributor drive/oil pump drive.

What does this mean?

The extra
counterweight radius of the crankshaft of the 328i crank fouled with the dristributor shaft/auxiliary shaft.

It was marginal, ALMOST cleared.
With an 86 mm stroke crank it would definately foul- so this would have to be tackled!

JJG323

Posted Saturday, Jul 8th 2:12am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 1251

Reading MA USA
1979 BMW 323i

Marquis_Rex wrote:

MayanArch wrote:

Marquis_Rex wrote:

For me it was marginal but the forged 328i 84mm throw crank had fouling issues with the auxiliary shaft/distributor drive/oil pump drive.

What does this mean?

Hi I heard that it has been done.
but personally I have the s50 crank, and thats what I am using the next time around.

imaradiostar

Posted Saturday, Jul 8th 3:36am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 814

Nashville, TN
81 323i, 82 525i, 85 524td, 90 535i

The metric mechanic catalog online indicates the the 328i crank has more clearance issues than the US M50B30 crank- your mileage may vary!

Marquis Rex- you're saying you used the 84mm stroke m52 crank?

jamie

Marquis_Rex

Posted Saturday, Jul 8th 10:50am [Edit] [Quote] [IMS] [View car]

Member
Post nr. 454

UK
BMW 323i 2.7-as featured in Total BMW Nov 2002,Porsche 911/993TT

imaradiostar wrote:

Yes it does-good point!
I didn't use the 328i crank on my engine, unfortunately,but I built an engine for a friend once.
Anyway the clearance issues aren't insurmountable.

I would like to know if the Euro-S50 crankshaft could be used, Jim reckons it would be difficult.....