Spark Plug Wires
 

My 1988 SC has a miss that just recently developed - it's getting progressively worse. After looking at the plug wires for defects, splits, arcing, etc., I decided to troubleshoot the easiest thing first - replace all the plugs. It didn't help. I still have the miss regardless of engine speed or gear selection (it even misses at idle). Next on the list are the plug wires. However, after pricing these things (upwards of $300 a set), I decide to see what this BBS has to say about replacing the wires. I've seen several posts about making your own. Hmmmm. This is do-able and reliable?? I'm all for saving a few bucks. Can anyone direct me to where I can get a hold of the directions to make "homemade" wires? I assume I will keep the boots at the distributor and at the plugs and just replace the wires themselves. Right? Any help would be appreciated. :)

Yaami, I have one suggestion, MAGNECORE. I'm not sure if our host sells them but you can buy them directly from Magnecore if not. 150.00 a set..

Cheers, James

Pelican does sell them- about the same price as above.

here is the link:
http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_911REC_main.htm

While I am sure that Magnacore and other aftermarket wires are good performers, I can warn you that outside those truly trusted designs, aftermarket wires are generally a BAD idea. There was a recent thread outlining a poor experience with what we suspect were 'imposter' Beru wires. I have chosen to stay with the factory Beru spark plug and Bosch distributor ends. And yes, you very definitely can replace just the wires. The hard part is crimping the screw tips onto the wires so that they can be screwed into the Beru spark plug connectors. Your wires just unscrew from them. JW has the special crimp tools and they probably have them in Mercedes shops. Either have JW send you some wires with ends crimped on, or take some HIGH QUALITY 7mm metal-core wire to a Mercedes dealer and buy the screw tips and beg them to just crimp them on for you.

I am experimenting with soldering the tips on, and am having good luck with that, except that the outer crimp still needs to happen. JW provided the part number in a recent post, as did Warren a few weeks ago. There has also been some discussion about shaking the Beru connectors to make sure continuity is present during vibrations. And check them at temperature for resistance value, which is probably not as critical.

Yes, you can replace just the wires. A 100-ft roll of good wire will cost roughly $30, or you may get it by the foot, probably as much as $1 per foot. Don't pay more than that. The ends are about $1 each. So, total cost is somewhere around $20 or less. You don't need more than about 12 feet.

Superman, While I agree that many aftermarket wires are poor quality and are usually accompanied by unrealistic claims, Magnecore are truly the exeption. Go to any Club Race or SCCA event and you will see many folks using these wires. They are extremly high quality, have excellent ends and there service is superior. Making wires is definitely a good option if you have the ability and if you can locate good crimping tools and connectors.

Cheers, James

All true. Well said. I am sure Magnecore wires are great. My warning is just general. I have tried cheap aftermarket wires on German cars before with very disappointing results. Many people have.

I installed a set of Magnacore's on a friends car last month. They do not fit into the old harness's without enlarging or they pinch the outer cover. I noticed also a lack of positive engagement when the Beru spark plug boots would definitively snap onto the wires. I wasn't impressed and would stick with the originals in this case.

Michael,

Were the Magnecor's on a 911 engine, and if so, how well did they seem to fit and seal against the valve cover?

I put em on my SC and I love em.

A couple of points:

1) They are 8.5 mm instead of the stock 7 mm? so of course they will not fit through the stock wire looms without modification. (I think Magnecor also makes smaller diameter wires, not sure. check the website for 7mm versions).

2) I was not real happy with the fit in the distributor cap. I had to push like a madman to get them all the way seated. I re-checked later and they were tight, but I was worried at first.

3) It took some fishing to get them seated properly on the plugs.

Total installation time (including wire loom mods) was about an hour.

Results include a huge improvement in how well the engine ran. I've had no problems whatsoever with them ove the past 6 months, only time will tell if I have any in the future. I was impressed b the build quality of the wires, so I don't really expect any problems. I just wish they fit a little better in the cap.
So far the Magnecor wires are the best $129 I've spent on the car.

I'm very happy with my Magnecors (install post here).

Building your own sounds like a great option but...

I would never feel TRULY comfortable with the fact that I built them. Every time your car acts up you will be asking yourself "is it my wires?"

IMO, spend the money for the peace of mind.

I too installed 8.5MM wires on my motor (78SC). The installation was about 15 minutes. The quality is great and the red wires look great on the motor. You can get 7MM or 8MM wires. I got them from Steve Timmins of InstantG and they fit perfectly for less than the Magnecor site's list price. He may have has some instock since he ordered four sets when I got mine. They did show improvement. For all we spend on our cars, a good set of wires is cheap for $140 or so. Imagine your synapses not firing right, kind of like a bad hangover after New Years Eve. Sorry Wayne....I was in a rush to get them and Steve could overnight them for Saturday morning delivery. Consolation: I'll be placing a Pelican order this week for some parts :p

Thanks for the responses. I tend to agree with Botman though. Being the novice "wire builder" I could not be sure that future ignition problems were not related to the wires I built - I'm a little insecure that way ;) If Porsche wasn't so proud of their wires, I could get them cheaper from Pelican. Magnecore is looking promising. Sorry Pelican - you will have my future business.

Pelican also sells the magnecor wires. Their price is reasonable and is very close to what other places charge, plus you get to use this board! That's worth a few bucks here and there :-)

Still Learning......
 

I'm late on this but I'm curious as to why my OEM wires have the additional braided leads attached to them. They separate from the main spark leads and are secured back to the coil mount plate.
:confused:
I assume they're purpose is for earthing/grounding? I've not seen this set-up before on other vehicles. Changing over to Magnecore - they appear to missing these "extra" wires??
Why?
Aren't they needed?

Thanks.

No, they're not needed. They were designed to fix a condition that did not actually exist (blown air boxes due to crossfire). Mine are in a box in the garage.

The braid is not entirely w/o purpose; it will knock down the RF. Which can cause interference with radio gear.

After some investigation, I've settle on the Magnecore (from Pelican, of course). I'll get the wires on Thursday this week. After the installation, I post again to let you know the results. I appreciate all of your input. SmileWavy

put my manacors on last on last night

If you look closely at the engine pic on the first page of 101 projects, the red wires are Magnecor's....very nice. I will swithc to them when I tune up my targa.



ChadC
71 911S Targa