View Full Version : Ohming plug wires
XfireZ51
02-28-2016, 01:29 AM
So as part of my winter projects, I decided to rebuild the starter. Every once in a while I get the "zing" but no engagement w the FW. I wait a moment and then it starts. So pulled the plenum. Knowing that I was doing this, I also decided that after 8 years, the MSD wires probably needed a refresh. Unfortunately, MSD no longer makes a set for the LT-5 and I wasn't going to build my own. I did find a set of Magnecor wires at Lingenfelter. A bit pricey but u don't change wires everyday either. Got them yesterday and pulled out my DVM.
The longest wire measured 5.3k Ohms. Then I pulled the plenum and measured the MSD wires. 130-140ohms. Wow the Magnecor measured what is supposed to be normal. But the MSDs are almost a short? Pretty consistent through all 8 wires. The Maganecore appear to be within spec, while the MSD are very much out of range. Is that what happens to plug wires over time?
WVZR-1
02-28-2016, 09:30 AM
So as part of my winter projects, I decided to rebuild the starter. Every once in a while I get the "zing" but no engagement w the FW. I wait a moment and then it starts. So pulled the plenum. Knowing that I was doing this, I also decided that after 8 years, the MSD wires probably needed a refresh. Unfortunately, MSD no longer makes a set for the LT-5 and I wasn't going to build my own. I did find a set of Magnecor wires at Lingenfelter. A bit pricey but u don't change wires everyday either. Got them yesterday and pulled out my DVM.
The longest wire measured 5.3k Ohms. Then I pulled the plenum and measured the MSD wires. 130-140ohms. Wow the Magnecor measured what is supposed to be normal. But the MSDs are almost a short? Pretty consistent through all 8 wires. The Maganecore appear to be within spec, while the MSD are very much out of range. Is that what happens to plug wires over time?
You need to find the specs of the wires you have. There's a very wide value based on the "wire construction", then you generally need to determine the
Ω per foot and evaluate them in that fashion so for starters you would divide by length then multiply by 12 for an "Ω per foot". Every manufacturer is going to have multiple values for their various product. Are the MSD's poor? I don't think you can use what you've measured to arrive at a decision without knowing the "design characteristics".
I believe I've seen MSD spec'd at maybe 40 - 50Ω per foot.
***Which Magnecor did you buy from Lingenfelter? What was expensive?
There might still be 3 available 80161 (8mm), 87161 (7mm) and 85161 (KV85 - 8.5mm)
Hib Halverson
03-03-2016, 01:03 AM
So as part of my winter projects, I decided to rebuild the starter. Every once in a while I get the "zing" but no engagement w the FW. I wait a moment and then it starts. So pulled the plenum. Knowing that I was doing this, I also decided that after 8 years, the MSD wires probably needed a refresh. Unfortunately, MSD no longer makes a set for the LT-5 and I wasn't going to build my own. I did find a set of Magnecor wires at Lingenfelter. A bit pricey but u don't change wires everyday either. Got them yesterday and pulled out my DVM.
The longest wire measured 5.3k Ohms. Then I pulled the plenum and measured the MSD wires. 130-140ohms. Wow the Magnecor measured what is supposed to be normal. But the MSDs are almost a short? Pretty consistent through all 8 wires. The Maganecore appear to be within spec, while the MSD are very much out of range. Is that what happens to plug wires over time?
If your MSDs are "SuperConductors" then 130-140-ohms is normal. The general rule with SuperConductors is 50-100-ohms per foot. There is a huge difference in the design of MSD SuperConductors and "Magnecor" wires and that's why there is a big difference in resistance.
As for durability of MSD SCs...eight years is nothing. The set I have on "Barney", my '95, has been there since 1997. I've pulled the plenum twice since then and measured a couple of the wires and they've always been in spec. I have another set of SuperConductors on the LS6 in my 2004 C5 which have been there since late 2004. MSD makes a heck of a long-lasting spark plug wire set, that's for sure.
It's a shame that MSD has discontinued PN 32809, which was the red SuperConductor wire set for ZR-1s. It was the best plug wire set you could get for an LT5. The MSD SC wire design offers very low resistance, very high suppression and, apparently, great durability.
I have a brand new set of MSD SuperConductors for an LT5 and once my car is sold, maybe I'll put them up for sale.
Oh...and what's with this word "ohming". Only ricers use that word and, actually, there really is no such word.
XfireZ51
03-03-2016, 09:25 AM
Hib/WV,
I read more on the topic and it is consistent w your comments. My current MSDs
appear to be within spec. I am also using the MSD coils and they seem to be firing just fine. I have used MSD products for many years and found them to always be very reliable and up to the task.
Any thoughts on the Magnecors? These are the KV8.5s. $130 for the set.
I got them from Lingnfelter assuming that if Lingenfelter used them... I may buy those MSDs from you HIB. Maybe Graham would chime in as to why Lingenfelter selected the Magnecors.
I'm rebuilding my starter, so that's precipitated my interest in new plug wires after 8 years. I initially wanted to get a new set of MSDs but as we found out, they are no longer in production. We'll see how the Magnecors work. Meantime,
I'll keep the set I just pulled off.
MSD PN 32809 are still available at O'Rileys Auto Parts 72.00
Hib Halverson
03-03-2016, 12:09 PM
Hib/WV,
I read more on the topic and it is consistent w your comments. My current MSDs
appear to be within spec. I am also using the MSD coils and they seem to be firing just fine. I have used MSD products for many years and found them to always be very reliable and up to the task.
Any thoughts on the Magnecors? These are the KV8.5s. $130 for the set.
I got them from Lingnfelter assuming that if Lingenfelter used them... I may buy those MSDs from you HIB. Maybe Graham would chime in as to why Lingenfelter selected the Magnecors.
I'm rebuilding my starter, so that's precipitated my interest in new plug wires after 8 years. I initially wanted to get a new set of MSDs but as we found out, they are no longer in production. We'll see how the Magnecors work. Meantime,
I'll keep the set I just pulled off.
I can't speak to the durability of Magnecor wires, however, I will say the reason I like MSD SuperConductor wire, for not only the LT5 but all my engines (except, obviously, those which are coil-on-plug) is that its design provides low resistance but high supression. The low resistance means more of the coil's energy gets to the plug and less is lost due to resistance of the plug wire, itself. The durabilty of the product is something I sort of discovered by accident by virtue of 1) the set I have on my ZR-1, which has been in service since 1997 and 2) the set I have on my 71 Big-Block which have been installed since the mid-90s.
Fun fact: the original development work on the product which became Super Conductor was done by GM in an attempt to solve a problem NASCAR and professional road racing teams had with racing ignition systems causing serious ignition interferance problems with the two-way radios used in race cars along with telemetry systems used in race cars. The resulting wire design was then either given to or purchased by (I don't know which) MSD which commercialized the product and marketed it under the "SuperConductor" brand.
MSD PN 32809 are still available at O'Rileys Auto Parts 72.00
I just searched the O'Reilly Auto Parts web site and there is no listing whatsoever for any MSD spark plug wire set for LT5 engines.
Perhaps there are a few brick-and-mortar locations in the O'Reilly system which still have stock. If that's the case, buy those wire sets.
Gunny
03-03-2016, 06:19 PM
MSD Part #32819 (http://www.oreillyauto.com/site/c/detail/MSD0/32819.oap?pt=2815P&ppt=C0334)
Summit lists MSD 32809 as NLA; one search revealed the above link but the part number may be incorrect ... bottom line, looks like it might work but it's also possible that it's the wrong part
Jitse
03-04-2016, 03:46 AM
I like to make my own spark plug wires from MSD, but I can't find the part number for the spark plug boots, on the MSD webpage you can see them in a picture with all there other boot types. ( ZR1/marked with M)
Did somebody now that part-number?
-=Jeff=-
03-04-2016, 08:35 AM
I like to make my own spark plug wires from MSD, but I can't find the part number for the spark plug boots, on the MSD webpage you can see them in a picture with all there other boot types. ( ZR1/marked with M)
Did somebody now that part-number?
MSD no longer has the boots. When I called to inquire about the wires, I also inquired about the boots only.. none are available
MSD Part #32819 (http://www.oreillyauto.com/site/c/detail/MSD0/32819.oap?pt=2815P&ppt=C0334)
Summit lists MSD 32809 as NLA; one search revealed the above link but the part number may be incorrect ... bottom line, looks like it might work but it's also possible that it's the wrong part
Summit lists the 32819 as a set for the Gen III LS series motors of the late 90's early 2k
Jitse
03-05-2016, 12:00 PM
Did someone know about a equivalent Boot which fits the LT5 heads.
I know Jerry sells them in a complete aftermarket spark plug wire set.
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