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1998 V70 Melted distributor rotor

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

bronco
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bronco

1998 V70 Melted distributor rotor

Post by bronco » Thu Oct 24, 2019 10:21 am

So as I was merging onto the freeway yesterday my V70 died in a really ugly area at the top of an on ramp.

I'm right in the way of people trying to merge on and there was a sharp radius to the ramp so as they exit the turn I'm basically dead in the way :roll: .

I managed to roll backwards onto the ramp a bit and get the passenger side practically touching the guardrail and thankfully during the 40 minute wait for a tow no one slammed into the car. It was dangerous enough that I couldn't really try to figure out what was wrong.

I get home and there are no codes on the scanner , I can't get my pressure tester on the fuel rail so I pull the core and crank it and plenty of fuel sprays out.

Then my spark plug tester that I keep in my bronco won't work so I put a timing light on the coil wire and it flashes so I think its got spark but for whatever reason I decide to put the pickup for the light on #1 wire and no flash , no spark on any plug wire but spark on the coil wire ! :shock:

So I decide to pull the cap off and when I do a cloud of white dust puffs out and I find the rotor is completely melted??
rotor1.jpg

in pic 2 its hard to see but there is a round burnhole in the underside
rotor2.jpg
in pic 3 you see the inside of the cap covered with the white dust from the burned rotor
rotor3.jpg
has anyone ever seen this ? Is it indicative of a bad part or something else ? Not sure what brand the cap and rotor are they were new but not in a box I found them in a baggie left by the previous owner in the pouch on the back of the drivers seat. They were put on about 2000 miles ago if that
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misha
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Re: 1998 V70 Melted distributor rotor

Post by misha » Thu Oct 24, 2019 2:57 pm

If there is not stamped Bosch on both...cap & rotor....that's why they burnt.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

bronco
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Re: 1998 V70 Melted distributor rotor

Post by bronco » Fri Oct 25, 2019 7:00 am

Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car



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erikv11
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Re: 1998 V70 Melted distributor rotor

Post by erikv11 » Fri Oct 25, 2019 9:33 am

Glad you didn't get slammed on the side of the road!

A Bosch rotor has allen heads.

What is the date code on the wires? I'd also check if they are all fully seated.


'95 854 T5-R, Motronic 4.4, 185k
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abscate
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Re: 1998 V70 Melted distributor rotor

Post by abscate » Fri Oct 25, 2019 10:22 am

bronco wrote:
Fri Oct 25, 2019 7:00 am
Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car

There isnt enough current in a spark plug wire to generate "melt plastic" type temperatures. Thats probably just bad parts.


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bronco
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Re: 1998 V70 Melted distributor rotor

Post by bronco » Fri Oct 25, 2019 8:00 pm

abscate wrote:
Fri Oct 25, 2019 10:22 am
bronco wrote:
Fri Oct 25, 2019 7:00 am
Googling outside of this forum is bringing up various discussions of too high plug wire resistance causing melted rotors .

Also that some rotors have resistors built in and those can disapate too much heat and melt the plastic

I don't see a name on the melted rotor , its black and is marked 3/47 on the upper side of the base and F 168 on the lower side. The bolts have an allen head unlike the torx head on the rotor I pulled from my parts car

There isnt enough current in a spark plug wire to generate "melt plastic" type temperatures. Thats probably just bad parts.
I only say that because I'd seen it in my fords that had CD type ignition boxes . There was a box made by crane that could burn holes in the cap :lol:

I do have a used Bosch rotor in there at the moment , I'' get a new one and keep the one I have in there as a spare .

I do want to check the wires and plugs though to see what the plug gaps are at



bronco
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Re: 1998 V70 Melted distributor rotor

Post by bronco » Sun Oct 27, 2019 7:31 am

the car stunk like rotten eggs for about an hour after I got it running , I think cranking it with no spark probably dumped a lot of raw fuel into the cat



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