Perma-tune CD or Bosch CD?

[PorscheRB]

The '74 needs a new C/D box apparently... which is better, buying a rebuilt Bosch unit or buying the Perma-Tune new with the built-in coil?

Thanks

Ian

[widebody911]

Hands down, get a used or reconditioned OEM unit. This will save you a "my car died and it won't start" post in the future.

[jmohn]

I have absolutely no experience with any of the after-market CD stuff (Permatune included), but from the numerous posts I've read about ignition problems involving those products, I wouldn't use anything but an OEM replacement (reconditioned, if at all possible).

Jerry M
'78 SC

[jchatfield]

Search on the MSD 6AL and I'm sure you'll find a lot of support for this upgrade. It is one of Wayne's projects in the 101 Projects book. I installed one and am thrilled with it, so I have a 3 pin CD that works. You can buy it for $100, but the MSD is really much better, especially if you use carbs, as I do.

[Early_S_Man]

Ian,

Which box do you have, now? It doesn't really matter, as either one can be repaired. So, you don't actually have to buy another one, though having a spare on hand doesn't hurt!

Why do you think your current ignition unit is bad?

I suggest reading a few threads on the subject ... and doing some thorough testing before spending a bunch of money needlessly:

72 911 T all the sudden no spark

no start questions??

Ignition Troubleshooting??????

[fred cook]

You probably should go with either the rebuilt Bosch unit or an MSD box. I put an MSD 6A on my '80 911 and it works perfectly. The only downside is that you will have to run one power lead (off the primary power connection on the starter). The rest of the wires will either plug directly into the stock master plug or connect directly to the coil, etc. The advantage to using the MSD is that you will save about $150 even if you also replace the coil (recommended).

Good Luck!

Fred Cook
'80 911SC coupe

[fintstone]

My permatune with Bosch blue coil works great.

[PorscheRB]

The car broke down on the drive home from hershey, the local wrench AAA towed to says there are two burned out resistors (I think he said resistors) in the CD box and that I needed a new one. I ordered the reconditioned part from our sponsor, and I'm going to ask for the old one back and fix it if I can to add to the spare-parts pile.

Sadly, I was given no choice but to allow someone to work on my baby since it was too expensive to tow back home.

Thanks dudes

Ian

[Early_S_Man]

Ian,

Here are some previously-posted pics of the internal parts, so you will know what you are facing ... and a schematic. I can post the parts layout and parts list later, this weekend, maybe.

Almost all of the replacement parts can be found at Electronics Goldmine, All-Electronics, Hosfelt, MPJA, etc.

[Ryce Stallings]

Permatunes are heat sensitive. I have had major ignition problems until I paid the price for the Bosch Unit.

One time it quit at night in the middle of the Everglades. I can tell you one thing don't open the door if that happens to you!

I have a friend with a 356 that stopped running intermitantly. Same story, the Permatune Unit.

[Randy Webb]

What years does the 3 pin OEM CDI unit fit?

[Par911]

Ian, get the Bosch CDI box or a MSD unit!

[MY83SC]

Dang...From Warrens posts, looks like not much to the unit. Should be able to test the components and replace as needed. Heck, wouldn't cost much to replace most everything....But then,,,easier said than done

[Steve@Rennsport]

Originally posted by Randy Webb
What years does the 3 pin OEM CDI unit fit?

Randy:

3-pin CDI's were used from '69 to '77.

[no substitute]

Originally posted by widebody911
Hands down, get a used or reconditioned OEM unit. This will save you a "my car died and it won't start" post in the future.

Oh yeah. Ask the man who's owned both. Bosch all the way.

[David]

Has anyone had an MSD box fail? I've heard they do, but I used one on my 280Z for years without problems.

[azasadny]

I replaced my PermaTune in 7/02 and have not had a problem since. I also replaced the Bosch blue coil, rotor, points, plugs, etc... at the same time. The Bosch CD unit was extremely expensive new (~$1600) and I didn't have the time to find a used one.

[cegerer]

My Permatune unit has been in without problems since 1979?

[Early_S_Man]

Curt,

I bet your Perma-Tune is a blue one, like this ...



Anybody try the M&W CDI replacement unit, yet?

[cegerer]

Yup, it's blue. Is that a "different animal"?