M104 Cylinder Head differences... - Page 12 - PeachParts Mercedes-Benz Forum

MAG58 · #**166** 03-09-2010, 11:01 AM

I'm having the cam ground. Might as well get some more lift and duration while I'm at it.

efraser · #**167** 03-12-2010, 12:12 AM

interesting subject.
for the m103 12 engine, for the flow #'s.specs,etc. does it matter if it is from 2.6l or 3.0l or are there different m103 engines.

i can get my hands on a m103 head from a 2.6l engine for free, to do anything before i put it on my 3.0l engine. so i have no down time

Turbo E320 · #**168** 03-12-2010, 01:00 AM

Quote:

Originally Posted by kynsi

Same here, intake has so little duraton. I threw it away too. Exhaust cam looks more like normal sporty cam. How did you make base cirkle compensate. By removing those little sockets from hydraulic adjusters?

You mean the exhaust cam and gear doesn't just bolt in? What has to be modified?

400Eric · #**169** 03-12-2010, 01:24 AM

Quote:

Originally Posted by efraser

interesting subject.
for the m103 12 engine, for the flow #'s.specs,etc. does it matter if it is from 2.6l or 3.0l or are there different m103 engines.

i can get my hands on a m103 head from a 2.6l engine for free, to do anything before i put it on my 3.0l engine. so i have no down time

The 2.6 head has smaller intake valves so it's not good for the flow tests or your 3.0 engine either.

efraser · #**170** 03-12-2010, 01:33 AM

Quote:

Originally Posted by 400Eric

The 2.6 head has smaller intake valves so it's not good for the flow tests or your 3.0 engine either.

so could i get the intake valves enlarged to what the 3.0l has.
i was going to put new valves in it anyways, along with new valve stem seals and what ever else needed to the head.(without to much money into it)
this post got me interested

my 3.0l head has 3 rocker arms that do not tighten down, constant ticking and valve stem seals leak

400Eric · #**171** 03-12-2010, 05:29 AM

The bowls need to be opened up too to match the bigger valves. Unless you are experienced with such things you'll have to pay to have that done which may make this head more expensive than starting with a 3.0 head would be. Another risk is the guy you hire may not know what he is doing and actually hurts the head's flow. Hopefully, these issues don't apply to you in which case you are fine.

Also be sure the 2.6 head doesn't raise your compression ratio too much. I don't know if that head has a smaller combustion chamber or not. Maybe somebody else here knows. The lower swept volume of the 2.6 requires a reduction of combustion chamber volume of some sort via either the head, head gasket, piston dish volume , or a combination of those. If it was via the head, that's another potential issue.
Regards, Eric

MAG58 · #**172** 03-12-2010, 01:08 PM

I'm about 90% sure it does. The 2.6 head is quite a bit different from the 3.0 head, and not in a good way. If you've absolutely got to have a smaller CC combustion chamber, it would be cheaper and make more sense to have the 3.0's Combustion chambers welded and re-shaped. Working the little head wont get you much anywhere, and truth be told, custom pistons would be a cheaper and more effective route than either.

teezer · #**173** 03-12-2010, 01:42 PM

been following this since the beginning and there are hints to my question but not really answered

can you put a 1990 104 head (cis) on a 1989 103 block ??

MAG58 · #**174** 03-12-2010, 02:59 PM

Quote:

Originally Posted by teezer

been following this since the beginning and there are hints to my question but not really answered

can you put a 1990 104 head (cis) on a 1989 103 block ??

Technically: Yes. Practically? not really. The pistons are different, and you'd have to get ALL of the timing gear off of the M104 including the front timing gear off the crank.

JayRash · #**175** 03-12-2010, 03:08 PM

teezer,
i once considered same, so here goes a list of the main issues.
The M104 cis head has an oil hole at the right front that wont match on the M103 block. On the block this oil path is a few mm either to the left or right dont really recall now, any way this can be dealt with little shop work.
The bigger issue is that the M103 uses a single chain to drive the cam where as the 24v head needs double chains. So u need to change all guide rails, tensioner, chain cover on the engine and the oil sump.
Those are from the top of my head, and im sure more will pop up once u dig deeper into into.

teezer · #**176** 03-12-2010, 06:48 PM

thanks ~~~ are the 103 & 104 interference motors, when the timing chain breaks, bad things happen ??

i've seen kolbenschmidt's piston listing somewhere saying that the same number fits 103 & 104

jhodg5ck · #**177** 03-12-2010, 07:29 PM

Quote:

Originally Posted by teezer

thanks ~~~ are the 103 & 104 interference motors, when the timing chain breaks, bad things happen ??

i've seen kolbenschmidt's piston listing somewhere saying that the same number fits 103 & 104

Yes...big and ugly.. braking an I6 timing chain would be impressive..!

Jonathan

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400Eric · #**178** 03-13-2010, 08:13 AM

The M104 has too many other improvements like the windage tray and piston cooling oil jets to name a few. What ever is donating the head, just get the rest of the engine too!

Another problem is the fact that all MB CIS-E systems saw changes in 1990 that prevents the use of the 90 and later M104 engine management stuff in an 89 and earlier car unless you modify your older car to accommodate the later systems changes. So you would either have to do that or come up with a way to tailor your 89 and earlier system to run the M104 or rig up an aftermarket set-up like Mega Squirt. Too much headache! Just get an M104 powered car! They are getting cheap enough even for a cheapskate like me!
Regards, Eric

kynsi · #**179** 03-13-2010, 10:48 AM

Quote:

Originally Posted by Turbo E320

You mean the exhaust cam and gear doesn't just bolt in? What has to be modified?

Different base circle...

It leaves prox. 0.7mm cap betbeen cam and follover which adjusters can`t compensate. When I removwed a socket inside the follower, little adjuster piston came out more and the cap was gone. In this case parts must be installed by grease.

Im little worried about that, does the little adjuster piston inside the follower stay in its place whith out it`s socket.
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MAG58 · #**180** 03-20-2010, 04:00 PM

Back to the topic at hand...

I just recently pulled a 104.990 out of a 1993 300SE (build date 11/92). This motor interests me because it mostly voids the majority of our head arguments...

1.) It has EFI, but no plastic mani or two part manifold. The block doesn't even have the bosses for the lower manifold. It has an aluminum manifold much like the CIS mani, but setup for EFI and throttle by wire. The MAF sensor is bolted directly to the top of the TB, not on the other side across the top like the later models. It has the early model valve cover and the air filter looks the same as the CIS motors. The Injectors themselves are not the thin saturated EV1 style injectors on the later motors, but rather are shorter and fat, appear to be the same in color and markings as the S500 injectors from the same year.

2.) It has the new style head, and looks pretty much like the later style heads on the intake, but has more meat around the ports. It is also sealed by one metal gasket much like the .98 motors, instead of the o-rings found on the other 3.2's.

3.) It has a distributor on the front exhaust cam much like the .98's.

4.) It appears to have both the webbing from the .98 and the newer .94/.99, not one of the other.

I haven't had time to rip into the block itself yet, but I'm really interested. I'm pretty sure the head has the dual slider setup on the timing chain as opposed to the idler gear that the .98 has since it has the water outlet out the front like the later models and not out the side as the .98 was.

Has anyone seen this particular motor before? I have no information on it in my 104 FSM's as there doesn't seem to be an intermediate period between the two. Mercedes makes it seem like an abrupt switch over. ?