Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: alchemist on September 14, 2024, 20:40:46

Title: No vacuum at distributor, M110 engine
Post by: alchemist on September 14, 2024, 20:40:46
Hello: I am posting a puzzling issue on 1974 280SL, R107, European version with M110 engine. I know this post is not within the scope of Pagoda's group, however, I could not find any literature covers this engine. I though that someone at the pagoda's group might be familiar with this engine.
The issue is that no vacuum at the distributor at idle. If you see pic, I marked 3 points at the intake manifold. I have full vacuum at points 1 & 2 but not at point 3 which is the venturi area. There is a rubber hose connect point 3 to the distributor. I cleaned the venturi and made sure that port 3 is fully open. The puzzle is why there is vacuum at points 1 & 2 but not 3, knowing the fact that port 3 is a part of the intake manifold and it should have vacuum when the butterfly if fully closed. The car runs and idle well  even with no vacuum at idle.
Title: Re: No vacuum at distributor, M110 engine
Post by: stickandrudderman on September 16, 2024, 09:41:42
It should have vacuum at either closed or open throttle, not both. If it doesn't have vacuum at any throttle position then the port is blocked.
Title: Re: No vacuum at distributor, M110 engine
Post by: ctaylor738 on September 16, 2024, 12:24:48
Do you have vacuum to the distributor when you open the throttle?  Maybe the distributor is a vacuum advance rather than vacuum retrard type.

Cheers,

CT
Title: Re: No vacuum at distributor, M110 engine
Post by: alchemist on September 17, 2024, 17:29:44
The distributor is connected to port #3 with a hose, eliminating distributor's advance/retard option. I  measured at port 3 after clean it and found no vacuum. If I open the throttle, the RPM goes higher indicating that there is no blockage and there is a flow of air. It is a puzzle.
Title: Re: No vacuum at distributor, M110 engine
Post by: alchemist on September 17, 2024, 17:39:00
When I measure at port 3, eliminating the distributor by disconnecting the vacuum hose, there is no vacuum at idle. When I open the butterfly, the RPM increases and still no vacuum. It is a mystery. The intake manifold I have on M110 engine is very similar to the Pagoda's 280SL by design. The vacuum system should work as the same as the Pagoda. I re-routed the distributor hose to connect to port 2. So, currently, the distributor has vacuum, but from a different port.
Title: Re: No vacuum at distributor, M110 engine
Post by: ctaylor738 on September 18, 2024, 15:32:31
What model M110 engine is it?  I have the big M110 manual with vacuum diagrams.  Maybe one of them will shed some light.

CT
Title: Re: No vacuum at distributor, M110 engine
Post by: alchemist on September 20, 2024, 16:48:07
Hi Chuck:
My M110 engine is in R107 1974, it is rare and it's model is 280 SL. It does not have a vacuum diaphragm like diesel engines.  The vacuum is generated by the intake valves very similar to the pagoda's 280 SL. Thank you for your contribution.
Title: Re: No vacuum at distributor, M110 engine
Post by: alchemist on September 20, 2024, 16:51:44
I do have a service manual for M110, vol. 1, but it does not cover the European injection and intake manifold. It covers the USA versions only.
Title: Re: No vacuum at distributor, M110 engine
Post by: rwmastel on September 20, 2024, 20:13:51
When Chuck asks what type of M110 it is, I believe he's asking about more of the engine number.  See my screenshot from M110 wiki page.
https://en.m.wikipedia.org/wiki/Mercedes-Benz_M110_engine
Title: Re: No vacuum at distributor, M110 engine
Post by: rwmastel on September 20, 2024, 20:19:46
Going by application, it looks like one of these two.
Title: Re: No vacuum at distributor, M110 engine
Post by: rwmastel on September 20, 2024, 20:26:16
Ooooo, aaaaa!  This is the one to find if you're looking to upgrade your Pagoda. 156 kW (212 PS; 209 hp) and 255 N⋅m (188 lb⋅ft).
Title: Re: No vacuum at distributor, M110 engine
Post by: ctaylor738 on September 21, 2024, 13:00:23
So if it's a 1974 car, it would have D-jet (electronic) injection, correct?

CT