nize

i've already tried searching the forums to try to find info on this, and came up empty. i apologize if this has already been discussed.

i'm wondering if anyone knows if there are any differences between the 951 turbo-s block and the 951 non-s block.

i'm mainly interested in any differences in the bottom end, crank, pistons, rods, bearings, etc.

thanks.

Chris White

nutin'
I have seen S engines with and without forged rods, the block casting is the same, the crank is the same and the pistons are the same.

fastmover

I don't know what the differences are, except the engine number of m44/52 vise m44/51. In my knowledge of working on Porsches for the past 11 years at the dealer level, if Porsche assigns a different part or engine number there is something different. But most likely the engine number encompasses the entire engine assembly, and therefore the turbo and the intake and maybe the cylinder heads ( I don't remember if the non s had sodium filled valves and porcelin exhaust ports) are different and that's why the different engine type number. I am going to look up engine block numbers to see if they are different, if so then there is a difference somewhere.

Semper fi

nize

afaik, both the non-s and the s have the ceramic exhaust ports. not sure on the sodium valves though.

but those are differences in the head, what about the block? i also thought it was odd that porsche would stamp identical blocks with two different numbers, but maybe they really did mean the entire engine even though the stamp itself was on the block.

caster951

Sodium filled valves are found on all 951s.

951Saga

The Engine number on the M44/51 block is back near the speed and reference sensors and the M44/52 (turbo S) number is near exhaust header 4.
OPRV and TB tensioner are different.

Dal Heger

That's not a difference between the 44/52 and 44/51 engines, that's a model year difference. All 87+ 951 engines had the updated spring loaded tensioner and the "new" style OPRV.

There is no substantial difference between the 44/51 and 44/52 engines other than the turbo and the ecu programming.

Chris Prack

2.5 blocks are all the same. Turbo, turbo S or N/A. Same block.

Loquat15

FYI

944 blocks are nice since you can take out all the metal and get some good $$$ for the aluminum, the sleves are non-magnetic :-)

Olli Snellman

On 1986 & 1987 M44/51 blocks stamping is there but 1988 M44/51 block has it in the same place as M44/52.

If you buy a new block from Porsche, they do not have these codes at all. They same spare part block to all models which has it's own number.

nize

do the m44/52 blocks have the coolant drain plug like the m44/51 blocks?

Chris Prack

My 89 does.

hosrom_951

Someone correct me on this, though the blocks are the same, the turbo S have the cylinder head studs installed 1 or 2mm deeper than the standard turbo.

It is not a difference, but a nice info (if it is correct).