Bosch spark plug confirmation for M110.982 280sl 1975?

[body_infinity]

Hi guys, wanted to know if anyone can confirm the bosch spark plug type and gap to suit the m110.982 engine? Helping a mate service his 1975 280sl when I noticed the plugs it was using were the Bosch W7CC I was sure these use the W7DC, we were actually going to go with the hotter plugs W8DC with 0.8mm gap but not sure now as the plugs on the car have a shorter electrode than the w8dc? can anyone confirm please??

thanks again BI

[vox_incognita]

http://www.beru.com/english/produkte/produktfinder.php?hersteller=MERCE&modell=SL+%28R107%29&typ=280+SL+%28107.042%29&ktypnr=748&action=step04
...beru states 0,8mm...let`s see bosch:
WR 7 DC+
lectrode Gap 0,8 mm, D1 2,7 mm, Outer Thread 14 mm, Spanner size 20,8, 1 terminal, Thread Length 19 mm, Thread Pitch 1,25 mm, Spark Position 3 mm, Tightening Torque 28 Nm

The bosch online catalogue also shows those 3 types :

0 242 232 504 Super 4 (4 electrodes)-WR 78
0 242 235 541 Platinum plus WR 7 DP, 4216 (0,8mm gap)
0 242 235 663 Super plus Blister N02 - WR 7 DC, WR 7 D+, WR 7 DC+, +1, 7900 (0,8mm gap again)

from:
http://www.bosch-automotive.com/ecat-online/

[MunichTaxi]

They have a search feature, to look up you vehicle (and purchase).

http://www.ngk.com/default.asp

I have them in a 1977 280S Euro (Weber Carb) I am preparing for the road. Engine starts in a 1/2 second.

I just intalled them in a 1987 Toyota Van (104,500 miles).
That 2.2L engine now is crisper, and better low end torque.

[body_infinity]

Originally Posted by vox_incognita

http://www.beru.com/english/produkte/produktfinder.php?hersteller=MERCE&modell=SL+%28R107%29&typ=280+SL+%28107.042%29&ktypnr=748&action=step04
...beru states 0,8mm...let`s see bosch:
WR 7 DC+
lectrode Gap 0,8 mm, D1 2,7 mm, Outer Thread 14 mm, Spanner size 20,8, 1 terminal, Thread Length 19 mm, Thread Pitch 1,25 mm, Spark Position 3 mm, Tightening Torque 28 Nm

The bosch online catalogue also shows those 3 types :

0 242 232 504 Super 4 (4 electrodes)-WR 78
0 242 235 541 Platinum plus WR 7 DP, 4216 (0,8mm gap)
0 242 235 663 Super plus Blister N02 - WR 7 DC, WR 7 D+, WR 7 DC+, +1, 7900 (0,8mm gap again)

from:
http://www.bosch-automotive.com/ecat-online/

Hi and thanks for the info, he was told Bosch dont sell the non resistor plug w7dc (I have a few stored away for my benz) and all he can get is the WR7DC - the reason I ask is that the wires on the car are bosch with 1K ohm on them (resistor)? is there any problem using WR's with this setup?

BI

PS I have always used Bosch on Merc not sure about NGK but have heard only positive feedback so you never know

[Tony 12]

My '79 W123 with M110 engine had WRDC's in it when I bought it and it ran really badly once warm. Changed to non-resistor NGK's and all is well again.

[body_infinity]

Originally Posted by Tony 12

My '79 W123 with M110 engine had WRDC's in it when I bought it and it ran really badly once warm. Changed to non-resistor NGK's and all is well again.

Hi tony thanks for this I can confirm also that he had probs with the WRs mostly when hot and trying to start her, so I gave him some of my NOS W8DCs and she runs & starts great now hot and cold so I am sure its best to use non resistor plugs with the 1K ohm wires, I will most likely also go to NGK if unable to locate the non resistor Bosch plugs.