Changing Fuel Injector Seals on '74 2.7 CIS - anu advice

[Tidybuoy]

I'm going to change the fuel injector seals on my '74 2.7. I already purchased new seals for the injector and the injector sleeve and seals for the sleeve.

I'm open to any advice. I'm wondering if you just pull really hard to get the old injectors out (as was the case on my old BMW 320i).

Also, when changing the intake manifold gaskets, is any gasket sealer used or just the gasket?

I'm slowing working on vacuum leaks and I'm starting here.

Thanks......................Vern

[manbridge 74]

Well. I would say this....

If old injectors pulled right out, then just replace o-rings. Why? Because there is usually so much carbon/unburnt gas deposits around injector mounting sleeve that replacement is not needed due to gunk buildup.

Start with o-ring replacement and check for suction of flammable gases? Seems reasonable here.

And I would use Hondabond or Yamabond for intake runner sealant. Why? Because they have to seal their own air cooled contraptions and it is available at corner dealer. And it has the track record of working against the political status qou.

Stock up while you still can.

[psalt]

Vern,

You need to remove the stakes in the manifold to install the new sleeves without damage and you are better off doing this first before you attempt to remove them. The sleeves usually get destroyed if you just try to pull them out. The stakes are rectangular punch marks and can be cut off is a very sharp tool or ground off with a carbide bit. The injector sleeve O rings are made of the same material as the injector seal , but they are subjected to much higher temperature and usually bake and fall apart. The threaded sleeves uses by other OEMs with CIS seem like a better idea. My experience is the sleeves leak before the injector seals go.

[manbridge 74]

My experience has differed a bit.

But I am in Colorado where rubber degradation might be less than what OP experiences.

So, take your time and don't s***w anything up.

Report back.

[Tidybuoy]

I haven't actually tested for any leaks yet (i.e., spraying around with starter fluid, etc..) however, you can wiggle the injectors quite a bit and that seems like a leak is very possible. in addition, the car surges and bucks a lot when cold. It even runs poor when warm but if driving on a long trip (2+hours) it runs perfect. To me, this means vacuum leak as 2 hours is enough time for the engine to warm as well as all rubber connections finally heating up.

Since the car is new to me and I don't know when any of the rubber hoses, etc have been replaced, I intended to replace everything. I'm starting with the injectors and manifold and will move on from there.

thanks for the tips.......Vern

[psalt]

Vern,

If you are also replacing the runner to head gaskets, remove the sleeve stakes while the runners are off the engine. There will be less chance of getting debris in the ports. You do not need to use sealer on the gaskets, clean off the old gaskets and torque the nuts to 18 ft/lbs. Disconnecting the throttle linkage and loosening the airbox mounts help when you are trying to remove the runners.

[manbridge 74]

But I would add this. If runner to head gaskets are hard, as say a penny, put some sealant in there.

If new, proceed as psalt suggests.

All is not gold that glitters.

And you might consider starting from tank to FD. Then move on to injectors.

[Tidybuoy]

Originally Posted by manbridge 74

And you might consider starting from tank to FD. Then move on to injectors.

Just curious, what hoses are from the tank to FD that are vacuum related?

I will start with the manifold gaskets and injector seals since I already purchased and received these parts. Vacuum lines will be next.

[manbridge 74]

Unless there is a vacuum line to fill tube, no.

My 74s have two lines. Both at the bottom of tank. One is return, one suction.

At this point, might you remove tank sending unit and shine light into nether regions? Maybe rust/dirt in tank bottom?

If compressed air will not clear blockage you must remove tank and clean it.

Checked for kinked return line at tank first.