M104 3.2 engine block replaced with 2.8 OK? - PeachParts Mercedes-Benz Forum

VEGASTECH777 · #1 03-11-2008, 03:58 AM

Hi All!,
My '94 E320 dropped a valve seat and eat a piston. Today I came across a "93 300E 2.8 at the wrecking yard. The head was already missing but all I am interested in is the short block assy. Its cheap to buy and this one happened to be a remanufactured engine with new pistons etc, thus making it a very appealing buy for only $100US!
I have a good 104 cyl head assy and my question is this. Is there any reason that 2.8 would not work as a direct replacement for a 3.2 bottom end? I know the displacment will be different. And I did notice the 2.8 has flat top pistons where as the 3.2 has a small dish type piston.
What are the chances of valve interferance? Im pretty sure the injection system will adapt itself to the smaller displacment but let me know if Im wrong here. Thanks from Las Vegas, Nevada...

mbdoc · #2 03-11-2008, 08:01 AM

Not much difference, BUT a 3.2 head on a 2.8 engine might not work!

VEGASTECH777 · #3 03-11-2008, 12:47 PM

I did some reserch last night. The 2.8 and the 3.2 both use the same head, injectors, head gasket, camshafts etc. Im putting on my shoes right now and Im going for it. After running this through my head all night I feel that it should work fine. The only thing I see that will have to change is the fuel management adaptaion at the mass air sensor reading due to less air flow. Which I think shouldnt ne a problem. Its the same everything physically the only differance is bore and stroke. Well this will play itself out and we will soon know for sure as Im going for it. I will post my results once the engine is running or not.

Sometimes you have to go with your gut instict!

VEGASTECH777 · #4 03-17-2008, 07:07 AM

Ok went to the wrecking yard and bought the shortblock. Ive got it all cleaned up and most of the parts transfered. The cylinder head I picked up cheap long ago has issues. Its worn circular rings where the head gasket metal seals are. Im bummed out and pissed. But I want to take a gamble and get the car running because its not worth much the way it is.
Im gonna JB Weld the head and torque the **** out of it and say my prayers. Oh and by the way the 2.8 can replace the 3.2 but what you have to look for if you are buying a complete used engine is the camshaft sensor tab on the intake cam as they differ. Just swap the gears or the whole intake cam assy since both engines use the same cams. And it should work. Well Ill keep posting and let you all know if this was good or a disaster. In either case Im going for it! Pray for me!