Engine: 2.1 Carb B21A: Backfiring Redblock - Help Please

[MissDMeanor]

Originally Posted by malb

Thanks fo the pic Julie. Your dizzy seems to be in much better condition than mine internally, but I guess I have a lot more miles on the clock. My main interest was the earth braid from the points mounting plate to the baseplate. I suspect that this has been replaced as the two plates and the braid seem to be near new. My braid failed at about 300,000km, and madam was very nasty until it was found and replaced.

Your setup looks good, but I suggest that you train the braid so that it passes between the vacuum advance arm mechanism and the black spring steel ball housing so that it doesn't wear on the vac advance in the future.

One other thing to check is that the vac advance is working properly. Timing at idle with a strobe should be about 12deg before top dead centre with the vac advance hose disconnected at the mainifold and the nipple capped. When the vac advance hose is reconnected, timing advances to about 30 deg BTDC under influence of idle vacuum. If yours does not do something similar, then there could be a problem with the vac advance.

My Betsy is in disgrace again as she shed a welsh (freeze, core) plug again going to work a week ago, piddling all her coolant out on the road and doing a major bake yet again. Came home in disgrace on the back of a truck, two months before the scheduled rebuild starts. Engine is coming out at the moment to replace the plug.

Thanks again for the suggestions Mal. All works have been put on hold now as I don't have the tools - I've ordered some and am still waiting but they should be here soon.

I now have the luxury of a garage, a 740 and an 850 so I think I'll not be renewing the insurance or tax when they run out next month and just tinker with her as and when.

Oh dear, Betsy has lost her dignity? I remember old Ford blocks prone to spewing core plugs - I hope she suffers no long term damage. What's causing it do you think?

Good luck with Betsy & maybe you could do a thread on VOC of the rebuild?

[MissDMeanor]

Originally Posted by Roger Jennings

Hi Julie,
In one of the earlier posts the comment was made that the plug leads were replaced. Would it be worth checking them one by one to see if one may be faulty. I had a problem with a previous 740 which I fitted new leads to and one of those was not properly crimped so whilst it 'seemed' to idle ok as soon as it was under load the misfire was apparent.
Best of luck sorting the problem though hopefully in the near future.
Roger

Hi Roger

Thanks for your post. It is something that crossed my mind too as the leads had just been replaced. We did check them all with a meter and they are all working fine although I did neglect to mention this in my posts.

[MissDMeanor]

Originally Posted by minesa240x3

Sorry to hear that your still having problems,but you will sort it soon.Fantastic pictures and explanations as you try solving your fault.Others will undoubtedly benefit from your experience,well done and best of luck,
By the way does Rosie corner well,And true to the 200 series the back and front wheels are spaced differently,

Hi Brian

Thank you - I do hope the thread helps others too. And that anybody making a suggestion that I don't follow up straight away doesn't get offended. I'm working through a list of possibles at an extremely slow rate!

Rosie doesn't corner too well lol. Something as simple as pushing a trolley down the road I manage to make a meal of. The handle kept coming off the other day (much too heavy load), I walk the Great Dane too who likes to pull me and Rosie over and I generally make a pig's ear of it!

[Mike_Brace]

Originally Posted by MissDMeanor

Hi Roger

Thanks for your post. It is something that crossed my mind too as the leads had just been replaced. We did check them all with a meter and they are all working fine although I did neglect to mention this in my posts.

Checking the leads with a meter won't show whether they are breaking down under load. I had a new set fitted to my Italian GLE when I first got it. A few months later I was on holiday in France and only just managed to limp back home. Since then I prefer to spend a little extra on genuine leads and always carry a spare set (well full set of engine electrics) just in case.

Mike

[MissDMeanor]

Originally Posted by Mike_Brace

Checking the leads with a meter won't show whether they are breaking down under load. I had a new set fitted to my Italian GLE when I first got it. A few months later I was on holiday in France and only just managed to limp back home. Since then I prefer to spend a little extra on genuine leads and always carry a spare set (well full set of engine electrics) just in case.

Mike

Thanks Mike lol, I'm trying to cross things off the list

PS finally took a photo of the glovebox - will email over to you shortly

[Checkpoint Charlie]

Hi Julie,
Thinking about this problem one question comes to mind how did the ignition timing get so far out. how about this for a theory if someone replaced a cam belt it is likely they got the cam belt alignments wrong and that was how the ignition timing got so far off. If the valve time is also off that could explain why the car runs at idle and backfires when running. A check would be to whip the spark plugs out and turn the engine over wit a socket to check the No 1 piston comes up to top dead centre at the right point as shown be the timing marks and the valves are both closed. I suspect you may find the valve timing is off. Fixing that is a matter of following the process for replacing the timing belt and ensuring that all items are aligned with the appropriate marks. IPD made a video showing how to do the job and if you could buy or borrow it then seeing it is so much easier.
Regards,
Checkpoint Charlie

[supertramp]

Hi, Julie, you said the coil was too hot to touch, it may well have suffered damage (maybe the distributor got wet during that flood?) which only shows up at higher revs or under load. Swap it with a known good one from another contact breaker car and see if it makes any difference. Quick, easy and you don't need many tools!

[MissDMeanor]

Thanks Checkpoint - Mike Brace also suggested that too. I don't think she's ever had a timing belt change so that is next on the list along with a couple of other things.

And thanks too Supertramp - this is something we considered a while ago and is on the elimination list.

The toolchest and tools I ordered still haven't arrived so I'm not going to be doing anything for the time being. Mildred's insurance has run out so I'm going to Sorn her and tinker with her when I get a chance (will be next year now).

So thank you every one for all your suggestions, Mildred is currently hibernating. Next instalment/episode in the saga will be early in 2008 hopefully

[Checkpoint Charlie]

One possibillity is if the belt tensioner was loose the belt could have slipped a toot or two.
Regards,
Checkpoint Charlie

[MissDMeanor]

Hello all

I thought I ought to let you know what was wrong with Mildred after all.

Thanks to my lovely bro we've found out the cause of the backfire was the condenser breaking down even though it was fairly new

Thank you all for your help and input

Mildred has now emigrated to Southern Ireland with her new Volvo enthusiast owner