M50 block deck height

[Mr.SWISS]

The point I was making was that the Bi-Vanos motors (M54/M52tu) use a thinner head gasket to compensate for the higher deck height when compared to the M50/M52 single vanos motors.

You're corrvect. Dual vanos Al motors use a head gasket about half the thickness of the single vanos Fe engines.

[blink977]

I've started assembly today, still need oil pump and oil pickup tube for e36. I'll be keep updating....

[Mr.SWISS]

I've started assembly today, still need oil pump and oil pickup tube for e36. I'll be keep updating....

If it's goin in an E30 you want an E34 pan and pick up tube brah.

[blink977]

If it's goin in an E30 you want an E34 pan and pick up tube brah.

I know,I already did similar on E30, but now I'm doing it on E36.

[Leo_328i]

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.

[thedean]

I thought the deck height was 210mm? I think I have it somewhere in my notes. I'll take a look at get back to you tomorrow.

[Leo_328i]

I thought the deck height was 210mm? I think I have it somewhere in my notes. I'll take a look at get back to you tomorrow.

Let me know!

[esoes06]

Nv m50 block height 210.7mm. I checked it out today. M50 vanos block 210mm