Shirley Knott Posted July 17, 2018 Share Posted July 17, 2018 Yes, I'm a neanderthal. Despite routinely running sub £1k cars for more than a decade including near 30 year old MX5's etc, I've never owned anything ancient enough to run a distributer type set up. That is until I bought the 940.... Tonight I've whipped the cap and rotor off partly because maintenance= good craic and also because Mrs Eunos has gone out with Eunos Jnr and I'm slightly bored. This is what I've found.... 1. Weird 'track' marks on the points... 2. Similar silver coloured areas of wear on the end of the rotor arm... 3. And some minor signs of oil leakage... Worth mentioning both the cap/rotor are aftermarket 'Beru' items by the look and not 'proper' Volvo items and as mentioned, I'm clueless/unable to appraise them Could a grown up step in please and let me know whether this all looks good? GrumpiusMaximus 1 Link to comment Share on other sites More sharing options...
Shep Shepherd Posted July 17, 2018 Share Posted July 17, 2018 I think that's normal. At least that's what the cap and rotor on The Volvo look like after a while AlabamaShrimp and Shirley Knott 2 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 Thanks Shep Meanwhile I've given the 'points' (Are they even called that?) and the rotor end a quick rub back with some sandpaper, now all look golden/good again... Just about to give them a quick spray with brake cleaner to freshen up and then re-fit. GrumpiusMaximus and Shep Shepherd 2 Link to comment Share on other sites More sharing options...
Mally Posted July 17, 2018 Share Posted July 17, 2018 It is normal wear, but advice is usually to very lightly rub the cap.They used to say rub the rotor arm on the tyre. Never rubbed much off when I did it.Not supposed to heavily sandpaper them but it will still work.Buy a new cap and rotor arm and stick them in the boot just in case. Shirley Knott and AlabamaShrimp 2 Link to comment Share on other sites More sharing options...
bigstraight6 Posted July 17, 2018 Share Posted July 17, 2018 Make sure you get rid of all those minute bits of fillings in the cap, that can cause problems with ‘tracking’ resulting in very poor running..... Shirley Knott 1 Link to comment Share on other sites More sharing options...
Neil clark Posted July 17, 2018 Share Posted July 17, 2018 Don't use rough paper. I was told any marks can cause arcing. Just smooth paper. A V12 cap is a thing of beauty danthecapriman and Shirley Knott 2 Link to comment Share on other sites More sharing options...
danthecapriman Posted July 17, 2018 Share Posted July 17, 2018 It’s normal to get a bit of blackening on both contacts on the cap and rotor. It just happens with time on cars with this style system.As mentioned, your not meant to go mad with sandpaper, just give it a light rub back. I use a fibreglass pencil or scouring pad type stuff for cleaning contacts up.Yours doesn’t look to bad really but make sure it’s clean and dust free before reuse. This is what a bad one looks like... This is the one I removed from my 740 when I first got it.The contact posts are burnt to buggery and actually worn well into the brass material. The cracked side was like that while on the car too! It was running still believe it or not, badly but running! The rotor arm was similarly past it.The date stamp on that cap was 1987! Almost certainly the cars original part. It should have been changed years ago of course. Shep Shepherd and Shirley Knott 2 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 Thanks chaps. I've just given the whole lot a spray out to clean, dried and re-fitted. Feel slightly dubious about having gone at it with 80G sandpaper Either way all is back together now and the car runs/idles as before so no harm done *Crosses fingers* Daft thing is there were no running issues as such and the old girl doesn't misfire etc, I simply got bored and thought I'd have a look Link to comment Share on other sites More sharing options...
danthecapriman Posted July 17, 2018 Share Posted July 17, 2018 Don't use rough paper. I was told any marks can cause arcing. Just smooth paper. A V12 cap is a thing of beautyThis. What happens if you use rough paper is it can cause a rough surface to the brass contacts. This can cause racing which makes things worse. It also creates a high resistance joint so you get heat and voltage drop.If you go too mad it can also enlarge the gap between the cap contacts and rotor contacts which also isn’t good. Shirley Knott 1 Link to comment Share on other sites More sharing options...
sierraman Posted July 17, 2018 Share Posted July 17, 2018 Last time I bought a rotor arm and distributor cap would be about 13-14 years ago so I'm no help. Cabr imagine a new one being at all dear so if in doubt put a new one on if they're a couple of quid. Shirley Knott 1 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 ^ I think this might well be an idea, reflecting on the comments others have made and given I've take 80G sandpaper to the original (I'm a Neanderthal as stated) I've perhaps completely unnecessarily taken a good part and borked it If only I'd been more patient and waited half an hour eh? @Dan, did you fit genuine Volvo or aftermarket? Link to comment Share on other sites More sharing options...
danthecapriman Posted July 17, 2018 Share Posted July 17, 2018 ^ I think this might well be an idea, reflecting on the comments others have made and given I've take 80G sandpaper to the original (I'm a Neanderthal as stated) I've perhaps completely unnecessarily taken a good part and borked it If only I'd been more patient and waited half an hour eh? @Dan, did you fit genuine Volvo or aftermarket?I fitted a non genuine part to mine, but I went for a decent brand not the cheapest one I could find.The caps for some of these Volvo’s aren’t particularly cheap tbh. They’re quite a bit more than the ones for old Fords and stuff anyway. Shirley Knott 1 Link to comment Share on other sites More sharing options...
Des Posted July 17, 2018 Share Posted July 17, 2018 That cap and rotor are perfection, any engine not completely happy being graced with that deserves to pop a rod. Shirley Knott 1 Link to comment Share on other sites More sharing options...
Parky Posted July 17, 2018 Share Posted July 17, 2018 I might polish it up with some peek in case the concours d’elegance club du la cap distributeur collar me in Tesco’s for a snap inspection. Otherwise that’s all grand as is. As long as there isn’t a tiny hairline crack running through it Shirley Knott 1 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 I shall run the car for a while and see if any permanent damage has been caused via my 80 grit assault on the cap. What a plank. Lessons RE 'Not broken don't fix it' have been learned Link to comment Share on other sites More sharing options...
MikeR Posted July 17, 2018 Share Posted July 17, 2018 as the rotor should be the "-" side of the spark supply , the spark should be jumping from the rotor to the outer cap insert on its way to the spark plug , to help this , make sure the edge of the rotor is nice and square and sharp to help the "-" ions leave the metal ....... same idea applies to most things dealing with high voltages ... lightning spikes for example , pilot light gas lighters , spark plugs .... Shirley Knott 1 Link to comment Share on other sites More sharing options...
stonedagain Posted July 17, 2018 Share Posted July 17, 2018 Thanks Shep Meanwhile I've given the 'points' (Are they even called that?) and the rotor end a quick rub back with some sandpaper, now all look golden/good again... Just about to give them a quick spray with brake cleaner to freshen up and then re-fit. Don't rub too much off the rotor arm & dizzy cap contacts, there is meant to be a specific gap between the rotor arm & contacts. Sanding makes the gap bigger, weakening the spark as it has to jump further. BTW Beru is of the top German brands! Shirley Knott 1 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 Don't rub too much off the rotor arm & dizzy cap contacts, there is meant to be a specific gap between the rotor arm & contacts. Sanding makes the gap bigger, weakening the spark as it has to jump further. BTW Beru is of the top German brands! Balls. You're about he 5th person to say that. *Logs onto to EucroCarParts and and starts shopping for a new cap/rotor* Link to comment Share on other sites More sharing options...
SiC Posted July 17, 2018 Share Posted July 17, 2018 If you rub too much off the rotor arm and cap it's been proven that it will cause Nuns to die and Kittens to get sick. danthecapriman, clayts450 and Shirley Knott 3 Link to comment Share on other sites More sharing options...
Shirley Knott Posted July 17, 2018 Author Share Posted July 17, 2018 If you rub too much off the rotor arm and cap it's been proven that it will cause Nuns to die and Kittens to get sick. 1000's of kittens have already been effected. New cap browsing in progress... EDIT: Joking aside, I shall see with time/use if I have buggered the cap, if so not the end of the world I suppose. Link to comment Share on other sites More sharing options...
Timewaster Posted July 17, 2018 Share Posted July 17, 2018 I think Beru is OE on some stuff. Not rubbish by any means. And make sure the brake cleaner is dry before you restart.I've seen an apprentice go nuts with the cleaner, clip the cap back on, flick the key - BANG! Bits of dizzy cap all over the workshop. danthecapriman 1 Link to comment Share on other sites More sharing options...
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