CIS to Carbs '74 - installation best practices

[RoninLB]

Originally posted by Porsche_911s

Fuel lines: CIS fuel lines are fine if lines are in good condition. Older lines will have to have a line pushed over them and clamped with EFI clamps. '78 lines and newer have metric ends and either lines will have to be made or fittings converting to barb can be used. I went with Marine grade fuel line rated to 100 PSI. 5/16 line

My stock fuel lines had a metric coupling fitting after they exited the tunnel in the Tranny area. I disconnected both couplings and brought the engine feed side to a hose shop where they removed the metric coupling and attached the coupling to aeroquip ss 6AN measured length lines. Not all hose shops have the contraption for doing this particular coupling. The metric fitting and 6AN fit together perfectly.



Thx for the dizzy info.

[Porsche_911s]

Originally posted by Early_S_Man
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.

Warren,

Can you go into more detail as to why the 5ES would be too hot? Is it because the CIS piston's are high dome? Because the engine is low compression?

Thanks,

[moneymanager]

I can't add information on why the NGK 5ES might be too hot, but I can tell you that Richard Parr, who runs PMO and was of immense help in setting up my carb setup, recommended I switch to them in lieu of the Bosch plugs I had installed. He told me they would be fine in my motor (Elgin modified S cams, pmo's, 9.5 CR, bigger ports etc in a 3.7) and suggested that if I was nervous I should pull them every couple hundred miles and inspect carefully. NGK has a good web site showing you the difference between a plug which is too hot and one which is fine. I checked mine a couple of times and found them spot on. I stopped worrying.

[moneymanager]

Just reread my post above. 3.7 should be 2.7. Sorry for any confusion.

[RoninLB]

Originally posted by moneymanager

Just reread my post above. 3.7 should be 2.7. Sorry for any confusion.

don't let it happen again.



otherwise, you're among the lucky few who have been able to discuss carbs with Richard.

with all due respect to others who comment where carbs are discussed I must humbly express that Richard is like no other in that realm. His position as a starting point must lead to satisfaction imo.

imo it's a Carb eat MFI world.

[moneymanager]

Will do my best. And after only one glass of wine!
Agree though, Richard is THE guru.