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Re: Sprint misfire at lower rpm, especially under load.

Posted: Tue Jan 03, 2017 8:27 am
by GrahamFountain
mahony wrote:personally i would switch to electronic ignition also as it's a more reliable system.
I've no problem with the points, and it wouldn't stop the dizzy caps from cracking.

Actually, I have a dizzy already kitted out with same, but I've never had a problem it would be a worthwhile fix for. I may get round to fitting it on the works TR7 Sprint as I build that up though.

So that alternate cap takes the standard Sprint rotor arm then?

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Tue Jan 03, 2017 2:17 pm
by dursley92
You can sometimes find one of the proper distributor wrenches on Ebay, SnapOn part S9467. This is mine I found a few years back and you don't use it very often but worth its weight in gold and been loaned out a couple of times as well. Search for a 7/16 distributor wrench, they are usually in the USA. Quite a few folks make their own by bending/welding a 7/16 ringspanner.

Image

Re: Sprint misfire at lower rpm, especially under load.

Posted: Tue Jan 03, 2017 7:59 pm
by Carledo
Another of the advantages of an electronic ignition is that the timing never goes out, so once it's set, you never have to muck about with all these fancy tools.

There really is no excuse for keeping points, the quality of modern replacement points and condensers is abysmal, a tiny bit of play in the dizzy bearings sends everything haywire, the points gap (and therefore the dwell and timing) is CONSTANTLY altering due to point heel wear and at high revs the points "bounce" limiting performance.
Cheap reliable electronic setups are now readily available, are easy to fit and once set up, need no further attention.

WHY WOULD YOU NOT FIT ONE????????

By the way, I think Jonners' solution of the Maplin job that keeps the points is a waste of time, points still wear out, even if they don't burn out and timing is still affected. Certainly a megajolt type programmable ECU controlled system is best. But £30 worth of Autospark is cheap, easy to fit, reliable and the time, money and agro you save from not having to constantly tinker with the distributor (or worry about the points closing up or another chinese condenser burning out every time you hit a motorway slip road) makes it a no brainer!

Steve

Re: Sprint misfire at lower rpm, especially under load.

Posted: Wed Jan 04, 2017 5:17 pm
by GrahamFountain
Carledo wrote:WHY WOULD YOU NOT FIT ONE????????
Because it ain't broke, so I won't fix it!!!!!!!!

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sat Jan 14, 2017 12:53 pm
by Jon Tilson
The maplin kits are anything but a waste of time...
They are cheap, preserve originality and are totally reliable. Plus if they do ever fail they can be reverted to standard with a few seconds of reconnecting.

You can keep the wear on the points "heel" to a minimum with a bit of lubrication. Timing should stay on for about 12000 miles before any adjustment is needed.

95 quid for a magnetronic can be far better spent elsewhere IMHO.

Jonners

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sat Jan 14, 2017 6:40 pm
by Carledo
Jon Tilson wrote:The maplin kits are anything but a waste of time...
They are cheap, preserve originality and are totally reliable. Plus if they do ever fail they can be reverted to standard with a few seconds of reconnecting.

You can keep the wear on the points "heel" to a minimum with a bit of lubrication. Timing should stay on for about 12000 miles before any adjustment is needed.

95 quid for a magnetronic can be far better spent elsewhere IMHO.

Jonners
The only bit that matters here is "preserves originality" and that is only important to the sort of cars that only leave their climate controlled garages to go to concours events on covered trailers. My own opinion of such cars is well known so I won't dwell on it!
Yes this system will keep point heel wear to a minimum, but it won't eradicate it totally and it won't cope with distributor wear that can give erratic dwell and timing either.
And finally, yes a Magnetronic - or its big (and even more expensive) brother the Optronic - is a lot of money for what it is, but at no point did I suggest using such, I prefer to opt for the £30 Autospark system that I have been using on a number of customer (and my own) cars for a good number of years without any problems. And £30 will not buy you many sets of poor quality points or go more than 1/3 of the way towards a cheap copy distributor.

Steve

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sat Jan 14, 2017 7:17 pm
by mahony
Fitted a electronic ignition about 15yrs ago , cost was £75 , current price of points and condenser is about £10 , would have had to change points and condensers at leat 8 to 9 times in 15yrs so do the math and also get better running and timing spot on , its a no brainer :D

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 12:20 pm
by trackerjack
My Stag had one set of points to operate 8 cylinders, it would rev to 6.5k and the sparks would stay OK for just 1500 miles on a new set of points. After 1500 miles it would not rev cleanly and hence was no good to me as I hillclimbed and tracked that car. I fitted a Luminition kit and forgot problems completely.

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 12:26 pm
by GrahamFountain
mahony wrote:would have had to change points and condensers at leat 8 to 9 times in 15yrs
If I was wearing points out at that rate, I'd be worried there was a problem somewhere. Was it that the contacts were burning or that the heal was wearing out? It's not a job I've ever found needed doing that often, even when I was doing three or four hundred miles a week in a Sprint. Plus, just looking on ebay, points and condenser are only £2.75 inc Drat and P&P.

I admit that swapping them with the dizzy in situ is a pain and pulling the dizzy's a problem with the short 7/16th socket gone walkies. But all I've had to do is regap them three times in the last 4 years. Then again, I only do about a hundred to one-twenty miles a week these days.

But I do like being able to check the timing with a multimeter across the points, when the car won't run well enough to check with a strobe. I can see a plug spark from where I can reach the ignition switch, but unless I can get it to at least tickover, I can't see when that's happening relative to the crank without a meter across the points. And at the price of meters, even from Maplins, I just keep a cheepo in the boot. A very useful diagnostic tool in many ways.

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 12:38 pm
by mahony
Cost of points was based on Rimmers current price, the estimated points and condensers replacement was a rough guess based on a distant memory of having to change them quite regularly back in the day , at the end of the day it's your choice .

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 12:40 pm
by GrahamFountain
trackerjack wrote:1500 miles on a new set of points
Presuming the contacts were the problem, not the heal, there must've been something seriously wrong somewhere. I assume you were replacing the condenser, so it shouldn't have been the back-EMF causing the points to arc on opening. Maybe the coil? A coil with too much primary inductance or too large a primary to secondary gain (M), might swamp the standard condensor and cause arcing. Poor electical connection to the condensor, to either side of the points, would do that too.

But it's only my claimed experience that points last me nearly forever on a standard electrical set-up in good condition and with the wooly pad greased now and again. And I don't expect anyone to take that at face value.

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 1:04 pm
by trackerjack
The clue was in the fact that I used the car to its absolute maximum on track and hill. How many times do classic owners do that? Most classics are garage potatoes these days.
Remember the Stag is an 8 cylinder revving at 6K and above so it works twice as hard as a 4 pot. Rover had the same problem and came up with a twin point dizzy and their engine peaked at a mere 5K or so.
This was before they went electronic of course.
The fault lies with the under specification as usual.
Why do you think the Japs blew us out the market place if it was not reliability?

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 1:18 pm
by GrahamFountain
mahony wrote:Cost of points was based on Rimmers current price, the estimated points and condensers replacement was a rough guess based on a distant memory of having to change them quite regularly back in the day , at the end of the day it's your choice .
Ah, grimmer prices. I admit I don't know the quality of the ones off eBay for £2.75 - though I fear I may have an idea about the Rimmer Bros ones.

I guess I can see how, considering the difficulties in changing points on the Sprint engine – I have done it a couple of times over the last 30 years or so of running Sprint engines for daily transport –, it sticks in the mind. But I still think electronic ignition has its drawbacks as well as its advantages. I admit that a points system being essentially imune to the E1 component of an nEMP isn't and probabaly never was a real one - what would be the point of being one of the few able to drive to a place of work that isn't there.

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 2:29 pm
by GrahamFountain
trackerjack wrote:The clue was in the fact that I used the car to its absolute maximum on track and hill. How many times do classic owners do that? Most classics are garage potatoes these days.
Remember the Stag is an 8 cylinder revving at 6K and above so it works twice as hard as a 4 pot. Rover had the same problem and came up with a twin point dizzy and their engine peaked at a mere 5K or so.
This was before they went electronic of course.
The fault lies with the under specification as usual.
Why do you think the Japs blew us out the market place if it was not reliability?
I take the point about the Stag making them work twice as hard. And the only V8 I've owned was a Rover nee Buick 3.5, which was too flaccid to count, even on P6 pistons and SD1 heads.

But I still think I drive like a "field in a forest" too much of the time, and always have. And at least one of them daily drives, the one on twin 45's, was often revved to over 6k on the run over the Wolds. And having the points burn out in 3k, or even 6k, would've had me looking for the cause of the problem - though I admit electronic ignition is a way to fix problems without ever knowing what they are. If it doesn't cause you insomnia, like it would me, I guess that's okay. I do think there are nearly always problems that come from "upgrades" that aren't always obvious.

As to the "Japs" beating us purely on reliability, I think it's a lot more complex than that; I think the British susceptibility to "a bargain" plays a part – and I don't think that susceptibility is all that well restricted to the northern half of the island either, despite the stereotyping. They never did so well in industries where lower overall labour costs and newer production methods weren't as significant. Like aviation, for instance - where reliability is a fairly important issue, to say the least (MTBF's drive so much), and nobodies record is perfect.

Graham

Re: Sprint misfire at lower rpm, especially under load.

Posted: Sun Jan 15, 2017 4:07 pm
by Carledo
Back in the days when the Sprint was new and I was coming to the end of my apprenticeship, there were service intervals for the cars, and for points (though oddly, no specified interval for condensers) The interval was check and adjust every 3000 miles and replace every 6000 miles.
For ordinary daily drive cars, i reckon this was probably sufficient, Joe Public accepted that his car would lose it's "edge" after a couple of thousand miles and the smart ones used this performance drop (probably accompanied by poorer cold starting) as a sign that a service should be arranged.To people like me (and Jon) this was pretty intolerable. Being able to do it ourselves just meant that we spent most weekends under the bonnet tinkering to try and maintain the edge. I was working for a Lucas Agent in 76 when the Lumenition Optronic system was launched to the public (Lucas were appointed dealers for Lumenition) so I not only got to know of it early on, I got a healthy staff discount on it too. And I have been sold on EI ever since. No more changing points, no more breakdowns due to suddenly failed condensers, no more constantly fiddling with the dwell and timing to get the edge back. Just set it up and then leave it alone! In those days it was a revelation, truly a fit and forget thing. Even if it did cost the best part of a weeks wages! Now we have EFi too and that never goes out of tune either, it works or it doesn't!
I guess in one sense, I miss the old days, when a car would come in running like a bag of spanners and i'd give it a touch here and a tickle there and send it out purring. There was a sense of achievement, the "I did that" feeling which is totally missing from the job today. I suppose you could call it Job Satisfaction.
This is, however, a completely subjective mechanics view of it, from a customers point of view, the need for constant, expert, tinkering, must have been maddening (and expensive)
And no matter how much we may wish for it, we can nether turn back time, nor halt progress. I have a somewhat stone age mind, like most classic car buffs, I mistrust mobile phones, hate idiosyncratic and stroppy computers and can't program the digital TV recorder. But one of the REALLY GOOD things to come from the digital age is cheap, reliable EI and I think it benefits us to take advantage of it!

Rant over, Stone Age Steve :lol: