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I understand that the M180 gas engine in the 404 was available with a higher compression head which upped the horsepower considerably. Apparantly the chances of finding one of these heads are low.

This being an OHC engine, is it possible to have my standard head planed down and/or install a thinner head gasket to increase the compression ratio?

Has anybody heard of this being done? Am I missing some obvious reason why this would not work?

It would seem to be a fairly easy way to gain 10 or 20 hp, which would make a big difference in driveability with out starting to break things.

Thoughts anyone?
 

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I believe the combustion chamber geometry is different between the two heads. The HC head has less "squish" area than the regular head. A smaller bathtub if you will. I do not think you can deck the heads enough to pick up the compression. You may be able to gain a little, but not as much as finding a nice HC head.

If you were to attempt this, keep a close eye on the interference of the valve train and piston, and let us know what you find!!

Also, you may want to try to find a head out of an early 70s 250S sedan. These were mechanical FI engines that made gobs of power. Same block. The heads may have ports for the FI nozzles, but that would be easy enough to change. The 2.2L engine has a larger bore than the 1.8. Not sure how the head seals up... but that could cause issue too. I have not had these apart... but studied as much as I could.
 

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Lots of info on the heads here Pagoda SL Forums Do some searches, this is mainly for the M127, M129, and M130 engines that are injected. You probably, just guessing , would want a head from a carbed sedan. Check that site though, you can learn alot about the markings on the heads to decipher what you can look for and what will fit what.
 

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HC heads

Actually there are heads out there that will bolt on and bring the compression up to about 8.5:1.

Try looking for a head from any of these sedans:
1960 - 1965 220b
1960 - 1965 220sb
1968 - 1969 230

There are probably more but I know that these sedans came with the M180 in them.

Be prepared to spend some $$$$ at the machine shop. If you get a head from an old sedan it will have a bunch of miles on it. You just couldn't kill the old ones and the bodies rotted off the chassis before the drive train quit.

If you search the MB for high compression head there should be at least a couple of old threads that come up.

Regards,
Jeff
 

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BTW... there is lot of good information about this topic in the FAQ/DIY's. One of the bits of info is a link to Pirate where I compiled material on the heads. Lot of effort went into compiling, linking, and creating the DIY FAQ. If you come across anything that would be good info for it.. please pass it on to me.

To get to the DIY/FAQ use the ULTIMATE STICKY on top of this forum.

PS- There is a DIY/FAQ sticky in the MB forum at Pirate too. You'll see some familure names that helped create that one too.
 
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