We are in the process of refurbishing another 1986 190E 2.3-16 with a warped head due to overheating. The unit is about 0.012" from being true or flat, and before I authorize the shop to take that much material off, I was hoping someone would be able to identify what the material removal limits are. The manual I have from MB only lists the differences between the 16 valve engine and the 8 valve version in the 2.3 liter four of the time. The Haynes manual I have is also similarly indirect about the 16 valve engine - it implies all is the same unless otherwise noted. In most cases this is not a concern, however, before I get the head cut I would like to confirm the allowable dimension for cylinder head height, after remachining. The Haynes manual lists the following:

"New" Cylinderhead height: 98.4mm to 98.5mm [3.877" to 3.881"]
Minimum Cylinderhead height after machining: 97.8mm [3.853"]

This would leave 0.022" of stock to remove, presuming the minimum condition of the cylinderhead height now, and presuming the head has never been off before (bought the car on eBay two years ago, solid vehicle, cosmetically a little stressed, but no rust and a solid engine at the time. Daughter drove it with the thermostat stuck closed, thus the problem). The Haynes manual also notes there are some allowable deviations from perfectly flat, and suggests a longitudinal distortion of 0.006" is allowable as is a transverse distortion of 0.002". If anyone can confirm these values apply to a 190E 2.3-16 with the Cosworth head, I would be very grateful. Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim, min for the M102.983 engine is 129.97mm

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks M.B.Doc! Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

The head has approximately 0.025" of "meat" on it to allow the 0.012" of warping to be removed. I am a little concerned about what this might mean to the camshaft bearings. I presume the whole head warped, including the material that supports the camshaft bearings, meaning they will now be misaligned. Is there a way to correct for this, or is it likely the head is junk? Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

On race car we always cut head at or even below min. Never had cam alignment problems!

Did have 1 head line bored after replacing several cam bearing caps! Very $$ as a lot of the area around the lifters had to be removed to use camshaft line boring equipt.

Would bet the head is still good!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks again. I will assemble the camshafts into the head with the valves out, using copious quantities of oil, and see if it binds. If it is really hard to turn is there an allowable oversize for the bearing bore? Thanks again, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

AT one time MB offered an oversize camshaft, but no more. The head that I had to have line bored was a "freebe" from Benzmac that a dealer had screwed-up a timing chain job & the camshaft had seized. I bought 2 new cam bearings from MB & then the machine shop Cut .002-.003" from each of the other caps & then surfaced the top .002-.003" & then line bored the head. Raced that head several seasons!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The head is at a local shop for disassembly beyond removing the camshafts, tappets and shims. I took the cams, bearing brackets and fasteners over to them this afternoon, but they were busy and told me they would assemble the unit themselves tomorrow and get back to me. I have no idea what "too tight" might be, and could use any guidance you might be able to offer. I am inclined to just reassemble and roll the dice though. A new head is mucho bucks, and this head, other than being warped and having some Brinnelling at the combustion chamber sealing surface is fine. The total material removal required will be about 0.012" and there is about 0.024" to 0.025" available. I was thinking of just cutting it to the minimum to get the most of the compression increase. That may be meaningless, but other than the head warping and the gasket leaking (visually apparent at the rear of the No. 4 Cylinder), the engine on this unit is in great shape. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

cutting the head to min spec won't help compression at all The compression is made thru piston protrusion! Save as much material as possible!

As long as the camshafts turn freely you shouldn't have any problems.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Wow, M.B.Doc, I was always under the impression that when you cut the head at the interface to the block, the volume of the combustion chamber got smaller, and the effect was that at top dead center the change was a greater proportion of the available volume than at BDC, making the net effect a higher compression ratio. The change is small though, and I heeded your advice. The test came out a little odd, the camshafts turned freely once they broke away, but they were a little harder to break away than I expected. Going ahead with the repair, minimum material removal, and fully expect it to come out fine. Thanks for the help. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

The head is being reassembled now, new guides, new exhaust valves, new seals and we'll see about what else. Got the parts from Phil at FastLane and sent them off to the machine shop yesterday.

Now, getting busy preparing to reinstall the head. Any hints on cleaning the piston tops and the black crap around the top of the cylinder? The piston tops are slightly discolored (grey) and have some greyish carbon deposits on them. When we took the head off there was quite a bit of flaky grey stuff inside, which we vacuumed out. But I would like to clean as much of this stuff off as possible, and would like to know if there is a reliable method for keeping the debris away from the piston to cylinder wall, or is just vacuuming all you need to do? I will cover the oil and coolant ports to prevent junk from going in there. I am just curious about what to use to clean the cylinders right at the top, the piston tops, and preventing this stuff from getting into the crevice at the cylinder wall to piston interface. Thanks, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)