Pagoda SL Group

Off Topic => Other cars => Topic started by: Pawel66 on March 02, 2025, 20:28:25

Title: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: Pawel66 on March 02, 2025, 20:28:25

I am failing to find it....

Can anyone help?

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: ja17 on March 03, 2025, 05:19:47

Hello Pawell,

The procedure is covered in almost all technical literature factory, or aftermarket. You can also go to the 190SL Groupe website and get technical information. The "IPOG" (International Ponton Owner's Group" website is also a good resource, since the procedure is the same on those early sedan engines. You do not need to be a member to access their technical information. What exactly are you looking for? I can help you in every detail if you cannot find what you need.

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: Pawel66 on March 03, 2025, 07:03:45

Thank you for your kind attention!

I am part of the International 190sl group as well as Ponton group. I asked the same question on 190sl forum, true I have not asked it in the Ponton group.

I understand the procedure in essence and I have the parameters values.

But I understand for 921 it is a bit different as you measure clearance vs. Stem, not lobe. I wanted to make sure I have it step by step and do not miss anything. Will I get away without special tools and how?

If it is as simple as it seems - I will remove valve cover and will see what to losem and what to adjust - I will probably manage ok. If there are small topics I have to be aware of - I wanted to know about them.

I have an engine after the first 500km. Topics such as head bolts re-torquing are covered in Owners Manual in these cars. So is lubrication. Valve adjustment is not there.

Pawel

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: Pawel66 on March 03, 2025, 15:55:44

I might have found what I was looking for, attaching for the benefit of others.

I will complement it with some practical advise from 190SL forum. I bought both craw foot and open socket 14mm, hope this is what I need to turn the adjuster.

Joe, thank you again for chiming in!

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: ja17 on March 04, 2025, 05:23:09

Good, yes the measurement is between top end of the valve stem and the tappet in the rocker arm in this case. I like to tighten down the adjustment screw until the feeler gauge is locked and doesn't slide easily, then I back it off till movement is just permitted with some slight pressure. It was a frequent routine with the VW beetle back in the day since they were equipped with same type of adjusters and needed adjusting on a regular basis. With this style adjuster the valve adjustment usually grew tighter over time, unlike the Pagoda style adjusters which usually gets looser over time.

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: Pawel66 on March 04, 2025, 06:48:41

Thank you for the tip!

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: WRe on March 04, 2025, 08:40:57

Hi,
attached the procedure for a M121 B.I engine which could be similar.
...WRe

Title: Re: 190SL Engine 121.921 Valve Clearances Adjustment Procedure
Post by: Pawel66 on March 04, 2025, 11:55:12

WRe, thank you!

I found this one too, it is just that it is a bit scarce of pictures, so I kept looking...

Thank you all for help!