Day One: Intake - PeachParts Mercedes-Benz Forum

PanzerSD · #1 11-08-2009, 01:59 AM

When I first bought this 1978 SEL, I was always intimidated by the 'Octopus' perched atop the manifold. This intake job, that I'm in the middle of, is my first jump into the deeper mechanical aspects of the M117 Engine, and I have to say that It's really simpler than it looks, nor is it as temperamental as you think.

I had a couple problems with bolts, one being broken flush with the head, and the other just stripped head.

I also have no new injector cups, seals, o-rings, to replace with

So I did a DIY job on the Injectors, and I think it'll work. I cleaned up the cups as best I could, greased and inserted the old injectors and seals. They were still fairly supple, so I think it'll work. the O-rings for the cups were SO brittle I had them all in my hand, and I turned them to dust. I happen to have a bulk supply of O-rings.

I then took a small amount of silicone sealant and I 'caulked' the bevel on the cup, like you would a bathroom seam with sealant.

Most people's first thought is to put the un-cured sealant on the cup and install right away. but if you let the bead cure, it forms an O-ring of sorts, where you can't really have one. I felt the cured sealant contact the head when I inserted it so I think it's ok.

I have also added a rubber washer, about a 16th" thick over the top of the cup around the injector. When the hold down is tightened, the rubber presses down on the cup and seals the top of the cup surprisingly well!

I stopped for the day about an hour ago

back at it tomorrow. *Phew*

Graham · #2 11-08-2009, 11:17 AM

After going to all the trouble of taking that manifold off and installing new donut seals, you should really put in new injector seals. They are cheap even from the MB dealer. Even stores like NAPA can get aftermarket ones. You don't want bits of silicone getting sucked into the engine.

PanzerSD · #3 11-08-2009, 12:47 PM

Quote:

Originally Posted by Graham

After going to all the trouble of taking that manifold off and installing new donut seals, you should really put in new injector seals. They are cheap even from the MB dealer. Even stores like NAPA can get aftermarket ones. You don't want bits of silicone getting sucked into the engine.

What I did with the injectors is temporary until I can get all the injector parts I need. NAPA Canada can't get them. The nearest MB dealer with a parts department is 6 hours away, I'd have to go get them.

PanzerSD · #4 11-08-2009, 01:28 PM

I forgot to mention the state in which I found the intake seals (8) ALL of them were just barely making seal with each half of the manifold BEFORE I loosened the bolts. I think that is where my problems were. No vacuum for ANYTHING it was all getting lost at those connections.

Graham · #5 11-08-2009, 01:31 PM

Quote:

Originally Posted by PanzerSD

I forgot to mention the state in which I found the intake seals (8) ALL of them were just barely making seal with each half of the manifold BEFORE I loosened the bolts. I think that is where my problems were. No vacuum for ANYTHING it was all getting lost at those connections.

Just as well you did them!

I have been thinking about taking mine apart, but I don't like the idea of breaking bolts! I may just pay my indy for a couple of hours work and let them worry about breaking bolts! That is IF I get to that - My vacuum is still quite good.

PanzerSD · #6 11-08-2009, 01:32 PM

I DO have injector seals!!!
http://www.********.com/catalog/moreinfo.php?pk=482380

This is what one parts store gave me, I almost returned them, but they were $1.49 for the set of 8 so I payed for them anyway. Is this an updated seal for the K-Jet fuel injectors??

PanzerSD · #7 11-08-2009, 01:35 PM

Quote:

Originally Posted by Graham

Just as well you did them!

I have been thinking about taking mine apart, but I don't like the idea of breaking bolts! I may just pay my indy for a couple of hours work and let them worry about breaking bolts! That is IF I get to that - My vacuum is still quite good.

yeah, breaking bolts isn't fun. Stripping the heads out is even less fun! Luckily I had a 4.5 from a 74 car that I robbed a bolt from

PanzerSD · #8 11-08-2009, 08:32 PM

Ok, all together and done, no Vacuum leaks throughout the intake, but my injectors are leaking. See THIS thread. I order the new seals tomorrow.

Over all, nothing has changed really, still gutless and still no vacuum. I sprayed carb cleaner everywhere and only my injectors (5 of 8) are showing leaks. With only those parts leaking, where is my vacuum going??

I still have the worn cams in that engine, could the limited travel of the intake valve reduce the amount of vacuum available to the engine??

Tomguy · #9 11-08-2009, 10:06 PM

I believe what you mean to ask is "Will the engine pull less vacuum if it's taking less air into the cylinders?" - to which the answer is yes. If your cam is as worn as mine were, I can see it being a serious cause. Other than that, replace the injector seals and check to see if your brake booster or your AT modulator are leaking. My booster will hold vacuum overnight.

PanzerSD · #10 11-08-2009, 10:51 PM

Yeah, I was wondering how the bad cams effect the Vacuum Ok, I know what I gotta do now

PanzerSD · #11 11-10-2009, 06:21 PM

Got Injector Seals and holder O-rings on the way, again FROM NAPA, it just goes to show it matters who you talk to.
Oiler fittings for my cams, I'll have to get from the dealership.