More Camshaft Questions

[Likes2Laff]

I've read lots of camshaft posts and seen lots of good info, but I still have a question.

I see:

"Hottest cams of the era were #02,#09 #76, and #84 (142 degrees total duration valves open) most of these were early or late W113 camshafts."

My 250SL has an #86. Which of the above camshafts would work without having to change anything like bearings?

[Likes2Laff]

Also, at what lobe lift are those duration numbers measured at. I believe most modern measurements are done at .05" while they use to be done at lower lobe lift. Also, I think the modern way of doing it is based on crank angle but it's easy enough to double the number when cam angle is used. Thanks!

[MikeSimon]

If you do not want to change the bearings, you need to determine which size you have. most of the later cams have the larger size and will not fit the small bearing cam towers.

[Likes2Laff]

That's why I noted that I have camshaft #86, the one that most commonly came in US 250SLs. The he question on the table is which of the "hot" cams doesn't need the bearing changed for a 250SL that came with an #86.

[Benz Dr.]

I used a 230SL cam on my engine and an offset woodruff key to obtain 12 degrees BTC on the intake valve. This is optimal valve timing for our cars.

[Likes2Laff]

Which number camshaft did you use? Is it 142 degrees duration? I thought the 250SL and later camshafts work of different design than the 230SL...can they be used just by relocating the woodruff key?

[Likes2Laff]

I see that 180-051-8401, 230SL #84 camshaft is available from Mercedes Benz. Any thoughts regarding using that on a 250Sl that currently uses a #86?

[Benz Dr.]

It's been about 25 years since I did this job so I can't remember. The spec for a 230SL cam is available.
 Offset woodruff keys are available in different sizes but each cam gear tooth is 18 degrees so you can advance a tooth and then retard with an offset key to dial in the exact amount you need. Or, you can advance or retard valve timing by using just the key.
I used a degree wheel on the camshaft and a dial indicator on the intake valve. Make sure you have at least .9mm clearance between the intake valve and piston measured at 5 degrees ATDC or you could have clearance problems. 18 degrees advance will cause intake valves to hit pistons. It's a sound you won't forget. 

[Likes2Laff]

Thanks, @Benz Dr.

I've had custom pistons made with valve pockets. I would not be using the camshaft off the shelf. Either it will be further modified or used as the basis for a custom unit to be created.

[Likes2Laff]

Found it! Measured at .4 mm lobe lift. Also, found the profile specs in the BBB and the Technical Data Passenger Cars 1969 Issue (late 1966- late 1968 models). Has 230SL as well as 250SL.