Engine, Conrods & Head ID

[Eiger]

Hi,
I recently bought a stripped down 2.5 engine as a project and I'm busy noting the parts before rebuilding it with some new bits - interestingly I can't find any reference to the part numbers I have on the block, conrods and head in the 944 parts catalogs yet - so your knowledgeable input would be appreciated:

Engine is stamped M44.06 & PN is 944 101 110 1R- anyone know what it originally came out of or anything interesting about this block designation?

Head is 944 104 303 8R which from what I've found on various US posts, a later higher compression head with a different shape combustion chamber 'cup' to earlier cylinder heads...which is nice:

Note the chamber shape:

Thread here: clicky

And then the connecting rods - which are attached to the euro spec 10.6 CR pistons (which I'll be replacing with some custom pistons even though they seem relatively new) - from what I can tell these may be the later conrods - but I'm not 100% certain if they're forged or cast but they do look OEM:

thanks for your insight

 

[Jonny944CS]

Hi Eiger,

An M44.06 engine is the updated version of the M44.03 found in pre 85.5 cars. 06 engines were fitted to cars with automatic transmissions between '85.5 and '87. Your engine code denotes a 1986 manufacture date.

IIRC, theses 'updated' engines featured several modifications including improved oil pump, balancer shaft bearings, knock sensors and slightly modified cam and ignition timing to enable running with 95 RON fuel.

For the cylinder head, I believe numbers ending in 'R' were used for the raw castings.

The pistons look original. The #1 stamped on the crown denotes the tolerance code (either 0,1 or 2). Mahle and KS were joint suppliers of pistons. From memory the KS pistons have a very interesting design of gudgeon pin support.... [&o] If you plan on replacing the pistons do be aware that they were supplied with a special Iron coating to enable them to run on the AluSil bores.

 

[Jonny944CS]

And then the connecting rods - which are attached to the euro spec 10.6 CR pistons (which I'll be replacing with some custom pistons even though they seem relatively new) - from what I can tell these may be the later conrods - but I'm not 100% certain if they're forged or cast but they do look OEM:

According to Porsche; all 944 conrods post Feb 1984 were cast, using ribbed-face nuts. # 944 103 001 01

'82 - 84.2 were sinter-forged steel, using smooth-faced nuts. # 944 103 001 00


edited to add sinter-forged and part #'s

 

[Jonny944CS]

Head is 944 104 303 8R which from what I've found on various US posts, a later higher compression head with a different shape combustion chamber 'cup' to earlier cylinder heads...which is nice:

Very interesting about the different head castings, it never ceases to amaze me as to how many small things are changed and tinkered with.

I have just checked the 2 heads I have (both '84 M44.01) and they read '6R'. So perhaps the change to 8R was done for the 85.5-on engines (M44.05 and M44.06).

I would guess the smoothing of the chamber port shape was done to improve flow, both around the valves and also the mixture formation around the spark plug when the piston approaches TDC. Thus enabling improved resistance to ignition of fuel/air mix outside of the flame front => enabling reliable operation with 95 RON fuel"¦ possibly??

It also seems the conclusion from the Pelican thread is that the chamber volumes are identical 6R/8R, so no compression ratio change (A rise in CR surely would be counter-productive in helping the engine deal with lower octane fuel).

Photos from the pelican parts forum

 

[George Elliott]

Eiger, great Forum this....you never get 'I don't know" replies, and for me never cease to be amazed at the detail observations of most contributors, such as this thread.
George
944t

 

[Eiger]

Brilliant! Thanks Jonny944CS. What do you know of the cam?
[]

 

[Jonny944CS]

It appears the exhaust cam duration was increased symmetrically by 8°. To suit the needs of an exhaust catalyst, perhaps?

I'm not sure about lift. I assume it changed for the 2.7l, as the timing is the same but the part number different.


Now it is your turn, what do you have planned for the engine? - do tell []

 

[Eiger]

Ah. Excellent!

The engine is little bit of a project with a steep learning curve [] but it does involve some free 'ceramic' pistons from a friend (and I get to choose which ones too [] )... I figure I might as well make the most of it...

So if I have that cam (which is likely) that's a good thing right? What some would call fruitier than the earlier 944 but not fruity enough and may require that I get an aftermarket cam from what I've been advised (with mapping of course to harness all this goings on).

Incidently, do you know if the fitment/manifold spacing on the intake side of the head is the same for 8v and 16v heads?
- in other words would a 16v intake manifold bolt onto an 8v head?
(I know there are other issues - I'm just wondering if it does - it's the bolt on compatibility I'm trying to establish)

 

[sulzeruk]

Tried to send you a PM but your inbox is full.
Alasdair

 

[Eiger]

cleaned up my inbox - please resend Alasdair. thanks