CIS to Carbs '74 - installation best practices

[jwetering]

Yes - the cam is more radical than an S-cam. Only sometimes in traffic will the engine falter when I brake.

[RoninLB]

meaning the booster will affect your engine ?

[Porsche_911s]

Thanks for posting the pics. I'll check out the other thread about the brakes.

One question, did you use the metal fuel lines going through the car? If so, how did you connect to it? Do you remember the size fitting you had to use?

[jwetering]

ronin - I find that sucking the air out of the intake manifold by applying the brakes can affect my idle yes.

911s - no I used rubber fuel grade hoses in the engine compartment, with the hose clamps designed not to cut into the rubber. I also used the stock rubber line going into the tunnel. I think the line in the tunnel itself is metal...but don't quote me.

[aircooledsonly]

If you can get this set up to work please let me know, I inherieted an another MOTOR MEISTER project form hell. The car is undrivable. I will post the details regarding this nightmare shortly. Jay Moore, thanks The engine is a 2.7 cis with Zenith carbs. As delivered to my shop it has 135 mains, 195 airs, and 36mm venturis. AFR is 8 to 1 at part throttle.

[randywebb]

I wonder what would happen if all the shops in the western US posted a sign that said they would work on MorMeister cars only with a $500 surcharge for diagnosis and problem-shooting...

[RoninLB]

Originally posted by jwetering
ronin - I find that sucking the air out of the intake manifold by applying the brakes can affect my idle yes.

for entertainment I'd confirm that the booster check valve is still operational. The plastic valve is in-line.

[jwetering]

Originally posted by RoninLB
for entertainment I'd confirm that the booster check valve is still operational. The plastic valve is in-line.

hhmmm - I'll definitely look at that. Where's the valve located?

[RoninLB]

mine is in the engine compartment.

also confirm a good rubber grommet seal from the vac line into the booster.

[Porsche_911s]

Here is a pic, I got them installed and it runs. However, this is no way near the final install. I ran out of time today and had to do a quick and dirty install to move the car before it starts raining.

Here is another question I have, how do you vent the oil tank? (the large hose that went to the CIS air box)

[aircooledsonly]

If you can get the Zeniths to work on your 2.7 cis engine would you please let me know as that is what I'm dealing with and as is the engine is untunable.Thankyou Jay Moore. P.S. the problem may not be the carbs, it may be that it is a Motor Meister engine.

[Porsche_911s]

Am I over thinking this? Is it as simple as getting an after-market "mushroom" chrome breather that will attach to the hose?

[RoninLB]

Originally posted by Porsche_911s
Am I over thinking this? Is it as simple as getting an after-market "mushroom" chrome breather that will attach to the hose?

you're not over thinking. There have been a couple of good threads on this in the past year. There is a track consideration of a necessary catch can. Either yes or no. If no then is there ring blow-by. If no track requirement then a K&N mounted directly to the tank is doable. My install uses a 1ft hose leading foreward under the compartment shelf. Then of course there is the routine breather connection to the air cleaner cover.

Do a search as some pelicanheads have done some nice installs.

[jwetering]

I ran a simple K&N mushroom for a few years, but it made a he!! of a mess. There's a fair bit of blow-by mist when you spend a lot of time "0N" it.

I now run a hose forward, down under the parcel shelf, and then under the oil tank exiting where my rear valence would be if I had one. You can see the hose in the last of the three pics I posted. One day I'll fabricate some kind of catch can. I notice Bob Tilton has just started a thread on catch can designs. Catch it if you can (haha).

[Porsche_911s]

I'll get a breather tank and go from there.

Does anyone know what does conversion is for the -AN hose size to standard measurements? I.E. is -8AN ~ to 1/2?? I am trying to find some hose for the 1/2 nipple on the fuel tank to the fuel pump.

Thanks for all the replies!!

[Porsche_911s]

Well this is probably as good as it gets... I updated the first page to hopefully help others (or discourage them LOL) who are looking to do something similar.

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[RoninLB]

Originally posted by aircooledsonly
If you can get this set up to work please let me know, I inherieted an another MOTOR MEISTER project form hell. The car is undrivable. I will post the details regarding this nightmare shortly. Jay Moore, thanks The engine is a 2.7 cis with Zenith carbs. As delivered to my shop it has 135 mains, 195 airs, and 36mm venturis. AFR is 8 to 1 at part throttle.

I love carb stories.

What happened on this one?

[RoninLB]

Originally posted by Porsche_911s


Well this is probably as good as it gets...

looks great.

Do you have specs on the dizzy curve ?

[Early_S_Man]

Stephen,

Your plugs are too HOT, and your venturis are probably too large for a SC/DC-10 CIS-cammed 2.7 ...

You should be very, very careful of too much ignition advance with those hot plugs! BP6-ES would be a better starting point, maybe BP7-ES in hot weather.

What is the power peak rpm with the DC-10 cams? My best guess would be around 5900 rpm.

[Porsche_911s]

RoninLB- No specs on the dizzy, it's basically the RS dizzy so those specs should do. Thanks for all your past posts, I tried to copy most of what you did!!

Warren- I was fouling plugs like crazy so I went with the hotter plug. I updated my info on the first page to reflect your comment. I am inline for a gastester or may just break down and get the LC-1. Once I can fine tune my system I will lower the heat range on the plug. I know the 5ES was a hot one and I don't want to blow a hole in the piston!

CAMs & Venturies- I am not even going to touch this subject, I defer all questions to the experts. If you want a hotter CAM talk to the Camgrinder... Current venturies are suggested size for my current setup. Hopefully I will upgrade CAMs (perhaps Ps&Cs) next winter and will address venturies if needed.

I just wanted to pool info to one page to share my experience. And it's an on going one as I fine tune the system.