Notepad thread for NV M50B30 build

[The Dark Side of Will]

Friend wants to build M50B30 using NV M50 block/head and M54B30 rotating assembly, for an E28 swap.

I'm just looking for all the numbers to put it together.

M50 block deck: 210mm (?)
M54B30 stroke: 89.6mm
M54B30 rod length: ??? (135?)
M540B30 piston compression height: ???

Are there any longer rods around?






Info:

http://84.45.115.78/e30zonewiki/index.php/M50#Components

http://www.usautoparts.net/bmw/engines/m54.htm

Alrighty here goes a really long post...

I've just been doing some extra numbers and research on this and have come across some slightly conflicting information.

Heres my maths - please feel free to correct me if I am wrong as I want to make sure that these numbers are 100% correct.

M52 B28
Displacement:2793cc
Displacement/6 cylinders = 465.5cc per cylinder
Stock compression: 10.2

This being the case, when the piston hits TDC there must be 50.59782161cc above the piston for the combustion to take place within the space in the combustion chamber itself, the space within the confines of the head gasket as well as the space below the deck of the block and the top of the piston.

I came to this number as...

465.5cc + 50.59788261cc = 516.0978261 total air volume

and to check that this is the correct figure...

516.0978261 / 50.5978261 = 10.2 compression ratio

So therefore without question we must have 50.5978261cc of space floating around here.

They can be in 3 places:

1. Combustion chamber itself
2. Area within the head gasket space
3. Below deck height but above TDC of piston top height

So after some searching it seems to be a reasonably well accepted fact that the stock M50/M52 combustion height is 33cc

Then we have the 1.75mm compressed head gasket height and make an assumption (someone please provide an exact figure if available) that the stock head gasket is 85mm in diameter to accommodate for slight overbore.

If we chuck these numbers into http://www.online-calculators.co.uk/...ndervolume.php we will see that the cubic capacity of the compressed head gasket area is 9.934375cc.

So after this together (50.5978261 minus 33 minus 9.934375
) we have a remaining 7.6634511cc left between the top of the piston at TDC and the top of the deck.

With this number we can now work out the total height of the space between the top of the piston at TDC and the top of the deck by revisiting our trusty cylinder calculator at http://www.online-calculators.co.uk/...ndervolume.php.

The calculation comes in at 1.38mm below deck height.

Taking into consideration we have a stroke of 84mm, connecting rod of 135mm and piston compression height of 31.82mm.

Using this method of calculation, the deck height should be 210.2mm




However, using another simpler method of finding the deck height we can simply calculate it with the following facts.

Fact: M54 deck height is 211mm
Fact: M52TU and M52 share same rotating assembly (pistons, rods, crank)
Fact: M52TU and M52 2.8l variants have the same 10.2 compression ratio
Fact: M52 compressed head gasket thickness = 1.75mm
Fact: M52TU compressed head gasket thickness = 0.70mm

So the difference between M52 and M52TU head gasket thickness is 1.05mm

Therefore 211mm minus 1.05mm = 209.95mm

Using this method of calculation the deck height is 209.95mm

However, the cylinder heads of the M52TU/M54 motors is likely to be different to the M50/M52 cylinder heads so that would throw off the accuracy of this method. Does anyone have any specs on this?

Now if you've read all that, thank you for taking the time and please feel free to correct me if I have made mistakes along the way! Open to constructive criticism.

[StereoInstaller1]

if the plan is a 3.0l M5x, why not an M54? Do you have other reasons for sticking with the older motor?

I dig the idea of a 3.0l in my E34, that is my goal too...I just want the double VANOS too.

[Bimmerman325i]

Why go to all the trouble of doing a frankenstein 3L engine and then neuter it with no vanos?

Just get an S50, or do the M54 internals on an M50/52 with vanos. Or, since you'll be pulling the motor apart and ideally doing a cylinder hone at minimum, just get it bored to S52 spec and run S52 parts on a 3.2. Or, for even cheaper, just swap in an S52 with vanos....they're not going for much money.

There are plenty of people who have done this frankenmotor and have been woefully unimpressed even WITH vanos.

[The Dark Side of Will]

An NV M50 can be a relatively maintenance free engine for 300K... not so with VANOS.
My friend's old school and likes that (and the E28 swap).

Got links to build threads?

[Bimmerman325i]

Uh.....change vanos's seals every ~150k for $40 and you're good to go.

It's a nonissue.

[The Dark Side of Will]

Replace cracked spring plates, reflow solder on solenoids...

[The Dark Side of Will]

http://www.r3vlimited.com/board/showthread.php?t=285432

Hmm... aluminum block.

Also:

M54B30:
84 x 89.6
Block Deck: 211 mm
Conrod: 135 mm
Piston CH: 28.32
17.4 cc dish
34cc chamber volume

http://bimmersport.co.nz/topic/34811-m5052-30-stroker/

http://www.r3vlimited.com/board/showthread.php?t=231252

http://www.importperformanceparts.net/imports/wisecopistons_bmw.html

http://forums.bimmerforums.com/forum/showthread.php?1761383-Calcing-m5x-compression-ratio

http://www.e30tech.com/forum/showthread.php?t=118551

http://www.usautoparts.net/bmw/engines/m54.htm

M50B20 from 1992 used 145mm conrods?
M50B25:
84 x 75

Block Deck: 210

http://www.bmwland.co.uk/forums/viewtopic.php?f=1&t=142879

Conrod: 135 mm (1989) OR 140 mm (1992)

http://www.usautoparts.net/bmw/engines/m50.htm

Piston CH: 38.2


2.0 -> 145mm rods
2.5 -> 140mm rods
2.8, 3.0 -> 135mm rods

44.8 throw, 210mm block deck, 145mm rods = 20.2mm piston deck
44.8 throw, 210mm block deck, 140mm rods = 25.2mm piston deck
44.8 throw, 210mm block deck, 135mm rods = 30.2mm piston deck

http://www.bimmerfest.com/forums/showthread.php?t=726686

A basically 1" compression height is theoretically doable with custom pistons and 140mm conrods on the 89.6mm stroke.