300SL M103 (Head Job)

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BlackBeauty

New Member
Joined
Jan 7, 2003
Messages
4
Location
Tiny Island
Car
300CE
Hello,

My buddy has a 300SL with the M103 engine. Front seal is leaking and it burns oil. We're gonna take the head off for a valve job. Need some expert advise:

1. He thinks he wants to skim/shave off the cylinder head while it's off to get some extra compression. He's thinking 1-1.5 mm. What do you guys think?

2. His lifters are a little noisy at higher rpms. Do we need to replace the lifters?

3. Also, he wants to do some port and polish job at the same time. Any advise?

4. After he's done with his, it'll be my 300CE. Seems like these M103s definitely need a head job after 150,000km.

Appreciatively,
BlackBeauty 300CE :)
 
Last edited:
Yeah, always a good idea to get a head skimmed (to a certain degree) when putting it back on.
It will set you back about £30 to do it...

The hydrolic lifters to get a little noisy on 103's but make sure you are runnign good oil...They may need replacing.

never done a polish/port job on one...

Most 103 300's last very long indeed, normally way past 150,000km and if they go, its normally the bottom end that tends to give in rather than the head.
Check the service history, its quite unusual at that mileage to have major problems. ;)
 
M103 12 Valves

Koolvin, it's a 12 Valve M103.

He wants to replace them with bigger pistons if he can find them (ANY IDEAS??:confused: ) - that means a full engine rebuild!! Damn, with bigger pistons like that of the AMG 3.4L, it'll be fun with nice torque.

V12, you have any idea if the M103s use hydraulic lifters? My 300CE also has the chitty-chitty lifter sound. Been using Mobil 1 since 50,000km. Mine now has 151,000km. My buddy's SL has 167,000km.

Also, u guys know where we may find performance cams for this engine? Renntech as them but priced at US$1450. Damn.... :mad:

Appreciatively,
BlackBeauty300CE
 
It's the valve stem guides that wear with these engines, once higher miles are reached, hence burning oil.

Replace those and with new valve stem seals it will be perfect.

Ensure only an experienced shop with Mercedes head experience deals with it.
 

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