Geeking out on M130 camshaft choices

[bracurrie]

I am replacing the camshaft on my M130.980 1970 280 SE engine. By what is available today I have two choices:
1- 180-051-08-35 in Mercedes camspeak the 08

2- 114-051-05-01 the 05
The 05 cost $200 more. Worth it?

ID #	int op	int cl	ex op	ex cl	duration
5	16	46	53	15	130
8	11	47	48	16	122

[rumb]

from w113 site:

Re: Camshaft wear
« Reply #5 on: August 26, 2009, 05:51:44 »
Just for reference, there are four different camshafts (plus additional variations) present on the M130E. The camshaft journal diameter changed at engine 130.983-10-004596 and 130.983-12-007229. There were also different versions for the US market and non-US market. The non-US market camshaft is often referred to as the high-output cam as it has more valve overlap and results in more horsepower. The four camshafts are:
US, 1st version: 180 051 08 35
US, 2nd version: 114 051 05 01
non-US, 1st version: 180 051 09 35
non-US, 2nd version: 114 051 02 01
However, the non-US 1st version camshaft is not available and has been replaced by the second version. This means that installing the high-output cam in an early engine requires replacement of the camshaft bearing towers (114 586 04 05) as well. To the best of my knowledge, the three camshafts are available as is the camshaft bearing kit. If you would like a quote of price and availability on any of these parts, please send me a PM or email to dgallon@cox.net. (If you want to see all the details of the different camshafts, refer to page 00-0/14 in the BBB or Service Manual.)

[Frank Reiner]

Originally Posted by bracurrie

I am replacing the camshaft on my M130.980 1970 280 SE engine. By what is available today I have two choices:
1- 180-051-08-35 in Mercedes camspeak the 08

2- 114-051-05-01 the 05
The 05 cost $200 more. Worth it?

bc:

If the car is equipped with an autobox, use the 08 grind. The duration is only slightly shorter than the 05 and will give better torque.

On the subject of duration, the numbers in the table do not make sense.
If the opening and closing points as given are seat-to-seat (they seem to be), then for the 08 the intake duration = 11+180+47 = 238degrees.
In other words, the intake valve begins to open 11deg. before top dead center (BTDC), is open for 180deg. between TDC and BDC,
and then closes 47deg. after bottom dead center (ABDC).

[bracurrie]

Thank you Frank.
I do not understand the numbers either, but I am not an engineer. The table I used in the original post is from the cam chart Joe Alexander compiled some time ago. There may be errors.
Joe recollected that the difference in performance between the 05 and 08 camshaft wasn't worth the trouble. The 09 is the ultimate but the engine has to be thrashed to realize the difference.
I believe that because the emissions measurements that necessitated the changes in the 08 the were largely below 3,000 RPM that there might be some difference at low RPM.
Since I like the 3,000 to 5,000 range for cruising I don't think I will be disappointed. Fueling and ignition timing improvements would, I suspect, be more impactful on performance.
All I can reasonably expect to be able to acquire is the 05 from NOS in Germany and the 08 from Mercedes. Since I can get the 08 next week at a lower cost I am going to go with that.