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OT? preserving plastic wire insulation

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
Might be a little off topic but similar issues with machine wiring. Around 1995-1997 Ford and Volvo experimented with wire insulation and now many of those vechiles have cracking crumbling insulation on the underhood wiring harness. I have had issues with my wifes underhood wiring.
I picked up a used harness that looks to be in good shape, May have been replaced under recall. Is there anything I can do to help preserve the plastic insulation? It will crack and turn hard near heat and oil as well as engine coolant. I was thinking silicone spray and then wrap in foil tape to reflect heat. Ford later added plastic boots and more wrap to try to help.

I may go ahead and replace the main wiring to the starter and alternators, any suggestions for what kind of insulation to look for. For larger wires like that the insulation choices get more limited. and they run right near the exhaust headers. This has caused some underhood fires. After I watched the engine cooling fan burn up while driving in town Ford did replace a little of the fan wiring under recall for free.
Bill D.
 
I had the same problem on an 84 Crown Vic. The insulation was like old dried bubble gum. I was getting by on "liquid tape", as it would have taken a complete unbundling of the harness to tape the bare wires. The only good way to fix it is to duplicate the harness with better wire. I got rid of the car for that reason alone. I work in electronics and I've never seen insulation do that before.
 
Volvos are notorious for this. Sadly using higher quality wire is the only
guarantee. You can try sleeving with teflon in high heat areas, but it's
a holding action.

When I wire vehicles these days, it's teflon insulated wire only.

Jim
 
Volvos are notorious for this.

Not the old ones, which is why I still have the '89 wagon..... despite my wife leaving me the craiglslist ads etc....

it was my understanding that this was due to using a supposedly "greener" type of wire....... With about the same result as the early lead-free solder, more failures, more scrap and landfill.

As far as I know there is NO FIX other than total replacement, which if you can't do it yourself, is more $$ than a new car.
 
Most plastics that are soft and flexible have pthalate plasticiser chemicals added which are considered toxic and are being phased out. The trouble is that they have yet to find a suitable replacement chemical, which is why you have these crumbly wire insulations showing up.

Pthalate plasticised insulation is no good for high frequency insulation though as the loss factor is too high, I nearly melted a high current capacitor I made using gummy PVC instead of hard PVC.
 
"Not the old ones,"

Actually yes. In fact most of the volvos around here of that vintage, when
the driver steps on the brakes, all the tail lights go out because the ground
wires are all rotted out. They run the tail lights back through the
brake circuits typically. Sometimes only on one side, but mostly on both.
 
For engine harness wiring i would normally use HUBER+SUHNER RADOX 155S FLR Single Core Cable.

Starter/battery cabling, again same manufacturer.

Expensive, but reliable.
 
Huber, Suhner stuff is great for putting microwave connectors on, but given their
prices I think I'll stick with teflon insulated wire from Newark, thanks!
 
Not the old ones, which is why I still have the '89 wagon..... despite my wife leaving me the craiglslist ads etc....

it was my understanding that this was due to using a supposedly "greener" type of wire....... With about the same result as the early lead-free solder, more failures, more scrap and landfill.

The first batch of bad Volvo "environmentally friendly" self destructing wiring harnesses were used from around '79 to '87. Volvo must not have learned their lesson and history is repeating itself. I've got an old '75 164 and the wiring is fine with hardly any signs of deterioration. My two '90 model 240s' wiring harnesses are holding up remarkably well also. Too bad Ford sold Volvo to the Chinese, good quality parts are going to be even harder to find.
 
Huh......

I have had a '72, a '79, an '86 , and now the '89...... All DL wagons or equivalent. I have NEVER had a wiring insulation issue on any one of them, and more than one of them has been at least drinking age when I got rid of it.

it gets hot in St Louis, every summer, so if it was gonna happen, it probably should have in 20+ years.
 
If I might interrupt this with a minor (and hopefully temporary) diversion into machine tools, my French Cincinatti Toolmaster has a nifty built-in tapping facility which is rather let down by a couple of uncharacteristically stupid electrical engineering details.

One is with the microswitch whose release reverses the spindle rotation for periodic withdrawals of the tap.
This is actuated from a conveniently placed pushbutton on the other side of the head, in the end of the drilling/tapping sensitive downfeed lever, via a pair of pushrods and an angled ball.
All very sweet so far.

(Another microswitch on the depth stop retrieves the situation if you should fall into a trance and overshoot the bottom of a tapped hole. )

The first (Crouzet - since discontinued) microswitch is exposed to oil from the power quill feed box, and relies for protection on being totally encased in an elastomeric jacket, including the integral wiring.

This would possibly be OK except that the actuation is transmitted to the internals by a small diameter pushrod which (predictably) pokes a hole through the shrouding in no time flat. This could have been completely avoided by interposing a disk of metal, about the size of a small coin....

Once the jacket is breached, the only place for the oil to go is down the inside of the wires from the switch, conveying it into the electrical passages in the head which would otherwise be oil free.

The second problem is that the insulation of the control wires is rubbish, evidently soluble in oil, which turns it to something like modelling clay.
(Modelling clay mixed with oil, hence mushy)

Not a happy recipe, needless to say.

(If anyone finds themselves dealing with this, I did post a fix in the Heavy Iron forum last year)

Getting back off-topic ;-)

What is it with Volvo - as with many other Euro brands, possibly - that makes them so (electrically) unreliable and ridiculously expensive to keep on the road?

Not much point having a small environmental footprint while you're driving them, if they have to be scrapped after only a small portion of their potential lifespan. What a colossal waste of resources...

A mate of mine (a highly resourceful, self reliant rural guy) bought one for his wife (all wheel drive 'Cross Country' wagon), and it's effectively removed him from the tax base.

Seems to me as if he spends every hour of his life since then either earning the money for parts for the wretched thing, or installing them.
 
Huh......

I have had a '72, a '79, an '86 , and now the '89...... All DL wagons or equivalent. I have NEVER had a wiring insulation issue on any one of them, and more than one of them has been at least drinking age when I got rid of it.

it gets hot in St Louis, every summer, so if it was gonna happen, it probably should have in 20+ years.

Sorry, I was off by one year, the bad harnesses were used from '80 to '87.
See this page for more info: Dave's Volvo Engine Wire Harness Page
The 86 probably wasn't old enough to start to exhibit the problem. I've seen it mostly on 80-84s recently, so depending on climate and mileage, it could take 25-30 years before it becomes apparent. Also, it usually doesn't cause problems unless the wiring is disturbed. The insulation hardens, but stays mostly intact until you try and move it.

What is it with Volvo - as with many other Euro brands, possibly - that makes them so (electrically) unreliable and ridiculously expensive to keep on the road?

In the old days, Volvo and other European manufacturers were on the cutting edge of fuel injection, emission control, and other electrical engine management. So there was just plain more stuff to cause problems compared to American cars of the day. Volvo had fuel injection on some models as early as 1973. It was a trade off, better emissions and fuel economy at the expense of a more complicated system.

However, the electrical design on the 240s was not well thought out. Relays and modules are not centrally located, but spread out in various hard to access places, hanging from pigtails off the wiring harnesses. The fuel pump relay and overdrive relays fail the most, however the fix is a simple matter of removing the cover and re-soldering a connection. Maintaining an old Volvo is cheap and easy if you are mechanically and electrically inclined, and can do the work yourself. However, it could be an expensive nightmare if you have to take it to the shop.

The old Volvos were mechanically more reliable than the American makes at the time. In the late seventies or early eighties, you were lucky to get 50,000 miles out of a GM car before the engine or transmission wore out. Meanwhile the Volvo with it's cast iron tractor engine would go well past 250K without a rebuild.

All that changed after Volvo moved over to front wheel drive models in the mid nineties. They are not as reliable mechanically as the older, rear wheel drive cars. They are difficult to work on, plus are plagued by electrical issues as well. I wouldn't have one. When my old 240s finally bite the dust, I'm calling it quits on Volvo.

The Euro brands don't produce anywhere near the volume of cars that the Japanese and Americans do, so their R&D budget may be the limiting factor in developing a reliable electrical system with all the bells and whistles they include. Parts are probably expensive due to lower volume as well, or possibly the swank factor too. A retied guy that worked a GM parts counter for years commented on how they had different numbers for the same part depending on the brand. The Cadillac number was priced higher than the equivalent Chevrolet.
 
Lucas factory motto: "A good days work & home before dark".

In hot weather my 1953 MG-TD would suffer from fuel starvation.

Lift right side of hood, apply wet rag to Lucas fuel pump located conveniently on top right of firewall, turn on ignition and hit fuel pump a couple of taps with hardwood stick kept for the purpose, pump would start the kerchunk, kerchunk, kerchunk, close & latch hood, start engine, and drive on.

Paul
 
In the old days, Volvo and other European manufacturers were on the cutting edge of fuel injection, emission control, and other electrical engine management. So there was just plain more stuff to cause problems compared to American cars of the day. Volvo had fuel injection on some models as early as 1973.

The 72 has dual SU carbs, that needed to be synched..... twice a day.

They sucked... literally, they sucked the damper fluid out of the bore of the piston rod that guided the air pistons in the carb..... which pistons then got way out of kilter, messing up the mixture bigtime.

The otehr problem was that the car wanted Sunoco 260 gas, very high octane, since it had something over 10:1 compression.

Before I got rid of it, I bought a second head, and had it laid back to 8.5 or so. That stopped the crazy knocking one the Sunoco 260 went away.

The newer ones have always been a lot less trouble.

Only one Volvo has ever had to be towed, and it was a 21 year old 1979. At the time of towing, it had a lathe in pieces in the back, which was a bit of a problem. We made a stop at home first......
 








 
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