Twin Cam Special radio

[rjbaren]

Today I installed a radio.  It worked fine till I started the engine, then pure static and noise.  Doesn't matter if it is the radio or CD.  I connected the continuous power from the fuse box next to the connection where the brown wire is.     The ignition wire came from an adapter from the previous owner's under dash cassette deck. Does anyone have any ideas on how to correct this? 

[BDA]

Are you running resistance cables or plugs?

[rjbaren]

I just pulled a plug.  It is an NGK BCP5ES.  Not sure about the wires.  I will have to look for the invoice.

[jbcollier]

Those are non-resistor plugs.

Welcome to a fibreglass car.

There is a whole procedure in the manual for when you fit a radio.  Basically you install capacitors on all the motors, some of the switches, coil (+ side), and build a faraday cage around the distributor, wires and spark plugs. Pretty involved and not a complete success when you are done.

[BDA]

JB has the real scoop but I have to say that I use resistor plugs (and wires which are required for Pertronix ignition) and don't do any of the other things he mentioned and it seems to work for me (that could be that my ears are not that sensitive!). I would try BPR5ES (I think that's the resistance version of what you have) first and see what happens.

[rjbaren]

I will try the resistor plugs.  I have a feeling I have copper core wires too.  That will be step two if needed.  I hope I don't need any more steps.
Thank you.

[jbcollier]

http://www.lotus-europa.com/manuals/s2work/m/index.htm#23

[EuropaTC]

I will try the resistor plugs.  I have a feeling I have copper core wires too.  That will be step two if needed.  I hope I don't need any more steps.
Thank you.

If you have copper wires then I'd fit suppressed caps, I use NGK resistor plug caps, they are about 5k resistance IIRC and work well. I don't think anything else is suppressed on the car, if it is it's been there since 1972 !

No crackling on the radio on FM at least although I mostly play music from either an SD card or USB input.

Brian

[rjbaren]

Yesterday I changed to resistor spark plugs and my CD player sounds good.  The Radio has static but is much improved.  I am going to fit the plug caps next.

[rjbaren]

I called NGK technical assistance and they said the resister plug offer 5K resistance which is the same as the resistor cap.  He advised using one or the other, but not both.  I know I have copper core ignition wires and I may try using suppression wires next.  Next step I will go for a drive later today or tomorrow to test the radio on the road rather than just backing the car out of the garage.

[rjbaren]

I drove to, of all things, my first car show with the Lotus.  It got lots of looks and was the only Lotus in attendance. 

I have installed the resister plugs and I can listen to CDs while driving but there is some static.  The radio is terrible, all static.  It's a shame to change the wires as these copper core wires are brand new, but I think I will get some suppressor wire and make up a set or buy a set from R.D. Enterprises.

[BDA]

I'm assuming that your static happens when the engine is running and the frequency changes with the engine rpm and not at other times which strongly implies ignition interference. Otherwise, the problem is likely to be somewhere else.  Windshield wipers can cause radio noise too which I think is addressed by the snippet from the manual that JB posted earlier.

I think I would only go to the trouble and expense of changing your wires if your ignition required it (eg. you have a Pertronix ignition) or as a last resort. I'm not sure they will make any difference in your radio. I say this because I had no problems with my radio even though I had stainless steel stranded high tension wires - when I found out that Pertronix says that resistance wires are mandated because solid wires could damage the Pertronix unit, I changed them. It made no significant change in my radio sound.

There is a slight possibility that your antenna lead is picking up interference. If your antenna is in the rear, your ignition could be messing up its signal that way.

Unfortunately, if it is ignition related, beyond the advice from the workshop manual that JB posted and using resistor plugs, I have nothing to add. A conversation with someone like Ray or George at r.d. or Ken at Dave Bean might be illuminating.

[Lotuswins]

A little trick is to find a portable transistor radio, and move it around the engine while running, to see if you can find the source...finding one of those may be tricky though LOL....

They do make input filters for radios, you may try hooking the radio up to a pure source, like a different battery, and see if the interference continues.  I have resistance wires personally, and have no interference with my old Becker radio, but it may have better filtering than most.   On my Healey I had some interference, rpm related, and put some caps on the alternator output, which quieted it down. 

Keep at it, I'm sure its solvable.

Jerry Rude
4005R

[EuropaTC]

I know NGK said to use either suppressed plugs or HT caps and not to use both, but why not give it a whirl ? The cost should be less than new silicon based leads and it's very easy to do.

I'm not an electrics guy (black magic) & I can only relate what I've read without any great understanding, so take what I say with some caution.

From what I can see you can have anything up to 12k resistance on a standard ignition and modern systems with higher outputs can go well above this (but they are designed to do so for spark duration, ours aren't).

Your copper leads will have zero resistance over the length so if you have 5k from a cap plus 5k from the plug then you'll be around 10k. That's basically what I'm doing and there's no problem with either starting or running. Although I'm using a "sports" higher output coil and a Pertronix set-up, maybe that gives some headroom. 

Modern silicone leads have (I think) a quoted resistance per unit length, so an 24" lead will have more resistance than a 12" one. Again from looking around, it seems to me that manufacturers can have anything from 9k to 20k/metre resistance on a lead (typical data sheet attached) so modern leads in conjunction with resistor plugs (5k) won't be too far away from the 10k figure anyway.

Other things I've read that should improve things are around making sure you have good earths on the radio & aerial and getting the aerial away from the engine bay - which it usually is on the Europa anyway.

Brian

[E Paul]

when you installed the radio, did you happen to take out the wood blocking plate? I want to go radio-less and need that part.
Thanks,
Paul