NO COWL BUMPS with C-85

[Jim Herpst]

Ok since I can mount a dipole antenna in the Tail (vert stab) as I am still uncovered what is the unshielded tribe using for a new harness as well as plugs. All new cowling is being installed. I am good with the Luscombe 8e Twin pipes but otherwise want to keep it as clean as possible. Still even going with the original air filters and dzus fasteners replacing the trunk latches as they were not original on an early 46. Idea is as clean as possible assuming no Cowl bumps>>>What new harness and plugs to go with.? I have an option to purchase a pair of SF4LN-21 Bendix cores for a reasonable price if that helps someone with an answer. I would like to purchase the harness ready to go. I can remove my old unshielded ends that are simple clip on the plug from the old 65.....

[astjp2]

Rem37by plugs are short

[Woody]

Good luck finding GOOD coils for those mags.

[Jim Herpst]

Good luck finding GOOD coils for those mags.

Oh really? I could see that with eisman mags but Bendix?.

Also to those responding this is a good valid and appreciated response I hope to continue to also recieve feed back to my orginal question on the harness and plugs.

Thank you all

[Scott]

I could not get the dipole to work on some frequencies, but I had it mounted in the fuselage not the fin. I think you'll have a higher probability of success with it mounted in the fin.

My ingnition is stock, unshielded (except the P leads are shielded). With the dipole the noise was tolerable, worse with the belly antenna.

My suggestion would be to go with a standard shielded system (on whichever mags you choose) including the P lead capacitors, except for the top plugs and clips ( not even the short shielded plugs will fit under my stock cowl). Terminate the shield on the top wires at the clips ensuring they can't short the ignition.

With this setup I expect the noise to be minimal and you can always turn off the top mag on the ground in marginal reception areas.

You can also add the ercoupe cups later if you want.

[Jim Herpst]

Scott,

Thank you for your straightforward input. As we get older hearing is even more important for safety. In fact I will be hiding a micro air radio or the like behind the left glove box door that will be only secured for show time for better receptionon on the recieve end .

I really can't afford to play around with this much as usability is key and I thought yours was better. I hear you on the thought with the vertical mount ...frankly I was on an assumption you had it there already and had great success.
Now I am leaning toward bumps. I have a metal man that can form them as part of the top cowling doors which is kind of nice.

[Woody]

Jim.
I have had the old lunch box mags and they re great. They will throw a 1" spark on test bench. HOWEVER when the coils get hot they will not crank. I swaped mine out 30 years ago. My neighbor has a good friend in magneto business. He asked him to rebuild some sf4's and he said throw them away. I will send you some s4rn's. That was from a well respected mag overhaul facility. Someone told me fresno air parts had some new coils for sale. My bet is they are 50 years old and have the same insulation. If they work for you that's great. I got tired of trying to hot start.

Tom

[Scott]

It's possible the short plugs will fit in the top rear cylinders. Fresno still sell the erocoupe cups that should fit for the fronts. $45 ea last time I looked. May even be less costly than paying to have someone fabricate the bumps.

By the way, I was/am concerned about the ringing in my ears too. I broke down and parted with my annual flying budget and bought a Bose A20. Makes a huge difference, primarily because you can hear at much lower volume, so the ignition noise goes down too!

[Jim Herpst]

Jim.
I have had the old lunch box mags and they re great. They will throw a 1" spark on test bench. HOWEVER when the coils get hot they will not crank. I swaped mine out 30 years ago. My neighbor has a good friend in magneto business. He asked him to rebuild some sf4's and he said throw them away. I will send you some s4rn's. That was from a well respected mag overhaul facility. Someone told me fresno air parts had some new coils for sale. My bet is they are 50 years old and have the same insulation. If they work for you that's great. I got tired of trying to hot start.

Tom

Tom,

I may have provided the wrong numbers of the mags I can purchase. They are definitely NOT the old bendix Scintillating lunch box mags. .I can understand the coil issue on those . In fact Eisman has the exact same problems.

I am referring to new style Bendix mags. Hence my question re coils.

I will follow up here with the numbers.

Ok

The numbers of the mags I can get are two s4ln-21...both impulse and both the newer bendix mags.
Thanks
Jim

[Jim Herpst]

It's possible the short plugs will fit in the top rear cylinders. Fresno still sell the erocoupe cups that should fit for the fronts. $45 ea last time I looked. May even be less costly than paying to have someone fabricate the bumps.

By the way, I was/am concerned about the ringing in my ears too. I broke down and parted with my annual flying budget and bought a Bose A20. Makes a huge difference, primarily because you can hear at much lower volume, so the ignition noise goes down too!

Scott,

I m going to have to figure all this out and not end up with Rube Goldberg set of wires. short plugs non insulated front but use ercoupe cups. Rear insulated but still short plugs correct?

[Scott]

The wires just need to have tight bends at the plug ends. I think they're 70 degrees but don't quote me.

Yes the rear plugs would be the REM37by and are shielded type.

The front plugs remain the stock unshielded type, but they fit in the cups. The lead attaches to the side of the cup, and I believe you'll need to re-cut the threads.

There's an extensive thread on here somewhere that provides more specific information.
S

[Scott]

Here it is:

https://vb.taylorcraft.org/forum/taylorcraft-technical-topics/engines/8236-ercoupe-cups?8001-Ercoupe-Cups=&highlight=ercoupe+cups

[Jim Herpst]

Thank you Scott. Ok those here running shielded wires what angle degree are you using for minimal bumps if you have bumps. Some of the bumps I have seen are huge!

[3Dreaming]

I don't have the picture anymore, but I've posted a picture before of some we put on a clipwing with a C-90. They were a short teardrop shaped bump. Only for the front plugs, with BY plugs and a Slick harness with shortened center nut. The slick leads will bend and take up less room than any 90° plug lead that you buy.

[Woody]

Jim,
That makes a big difference. The Bendix s4ln or rn for a 65 are great mags. I have them on the clip wing and slicks on the bc12D.