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Sat Feb 25, 2017 5:47 pm

Having a misfire issue with my '64 and I'm running out of ideas...

Symptoms;
Seems to idle fine and I can work the throttle with my hand without having an issues. However, once the engine actually has some load on it, I get all kinds of misfires, flat spots, and seriously bogged down. If I come to a stop, in most cases she'll just shut down, but will start up again with no problems.

Equipment;
Stock 1600DP
Freshly rebuilt by Volkzbitz 34/3 Solex
New 205k dizzy, chinese single vacuum/mechanical advance - came complete with points, rotor, cap and condenser
Bosch Blue coil (No idea which rating it is, left my meter at work :/)
New plugs wires
Plugs were replaced 3 months ago, checked today - super black. Cleaned and regapped
Timing is a 7.5 BTDC
Valves at .006"
Points at .016"

Checked;
No vacuum leaks
Idle cut off operable
Dizzy clamped firmly
Points gapped properly and opening consistently
Valves adjusted
Free flowing fuel (No kinks in lines)
Compression is good 110psi +/- 5 on all cylinders
Vacuum advance operable

Not checked;
Coil rating - Been running it for more than a year, if it's starting to fail - possible that it could cause these symptoms?
Ignition ground at Fuse box - My wiring is a bloody bird nest, engine seems to run fine until it's at full operating temperature but as standard operating procedure suggests, shakes rattles and rolls like a mother; could crappy good causes these symptoms?

Running out of ideas...thoughts?

Anything helps.

Thanks in advance,
/Tusk.

Sat Feb 25, 2017 5:58 pm

Tusk wrote:
Plugs were replaced 3 months ago, checked today - super black.

Would figure out why that is happening and fix it.

Sat Feb 25, 2017 6:01 pm

Eric&Barb wrote: Tusk wrote:
Plugs were replaced 3 months ago, checked today - super black.

Would figure out why that is happening and fix it.

I've a hunch it's because the carb isn't tuned properly. I've having issues tuning is because the engine ability to run is so erratic with all the issues that it's having at the moment. I'll get it tuned pretty good, drive it, it's all good, park it. Go to drive it again, and it's a mess again. Hoping that solving the misfire/crappy spark issue will allow me to tune this turd properly.

Fair to think or foolish?

/T.

Sat Feb 25, 2017 6:11 pm

Problem is there are a dozen possible causes and could be more than one going on at this time. If the fuel pump is putting out too much fuel pressure, bad carb shut off valve, too heavy or cracked shut off float, cracked carb, choke not adjusted right or working, incorrect carb jetting, incorrect carb adjusting, etc...

Sat Feb 25, 2017 6:22 pm

Eric&Barb wrote: Problem is there are a dozen possible causes and could be more than one going on at this time. If the fuel pump is putting out too much fuel pressure, bad carb shut off valve, too heavy or cracked shut off float, cracked carb, choke not adjusted right or working, incorrect carb jetting, incorrect carb adjusting, etc...

I agree with this. However, I think I can rule out the carb being an issue. It was rebuilt by a fellow with an extremely good reputation for rebuilding these carbs specifically. The only thing he didn't do was put on the idle cut off, I had to use my own and I'm pretty sure it's just a crappy chinese one. I can hear it click when I turn the key on. However, I wonder if it's losing voltage for short moments and kicking back out when I'm on the throttle. I've got a stock mechanical fuel pump, if anything I don't think it would have enough fuel pressure; either from a worn rod or because the pinion gear is worn, at that point though, I would think it'd wouldn't run at all?

/Tusk.

Sat Feb 25, 2017 6:24 pm

It could be yer coil going.

Sat Feb 25, 2017 6:31 pm

jzjames wrote: It could be yer coil going.

This was suggested as well and luckily I've got a new one on hand. I'll be putting that on in the morning. Finger crossed for that to be the fix. Hoping to get as many suggestions as possible until then in case it doesn't fix it.

It's funny, felt like the coil was working fine earlier when I zapped myself with it.

20,000 volts is a really interesting sensation.

/T.

Sat Feb 25, 2017 6:46 pm

I would suggest that you take it out on the road, put some load and a few miles on it at > 2000 rpm, then check your spark plugs again.

If they are still black my thought is that you are getting too much fuel pressure. If plugs are black get yourself a cheap fuel pressure gauge and measure it. You wouldn't want more than 3psi or so, if that much.

I just went through this with my '59 bug with '65 engine. Got my fuel pressure dialed in and my car runs better than it has in years.

Good luck.

Sat Feb 25, 2017 6:52 pm

fl59bug wrote: I would suggest that you take it out on the road, put some load and a few miles on it at > 2000 rpm, then check your spark plugs again.

If they are still black my thought is that you are getting too much fuel pressure. If plugs are black get yourself a cheap fuel pressure gauge and measure it. You wouldn't want more than 3psi or so, if that much.

I just went through this with my '59 bug with '65 engine. Got my fuel pressure dialed in and my car runs better than it has in years.

Good luck.

Did this as soon as I got home as I thought something similar; plugs are getting super gacked from crappy mixture and combustion. However, they were still pretty clean once I got home from work. It was about a 15 mile trip. It's running bad enough that I can't do much more than that unfortunately.

Sat Feb 25, 2017 9:00 pm

I'm confused on the "new" Chinese 205K distributor? Which distributor is this? Did you mean 034 SVDA distributor? A 113905205K is a SVA distributor from 1966-67 and requires a totally different vacuum signal from the carb than you get from a 34-3.

German Solex 34-3's were designed for either the DVDA or SVDA distributors. Which Solex do you have? Did Tim at Volkzbitz alter this carb to fit one or the other distributors?

Sat Feb 25, 2017 9:24 pm

Yeah, there are some rotors that just do that with some spark wires.... I had iron filings in my point's cause I drilled a hole in my distributor internals and didn't get them all out. That's what it would do.

Sat Feb 25, 2017 9:33 pm

wcfvw69 wrote: I'm confused on the "new" Chinese 205K distributor? Which distributor is this? Did you mean 034 SVDA distributor? A 113905205K is a SVA distributor from 1966-67 and requires a totally different vacuum signal from the carb than you get from a 34-3.

German Solex 34-3's were designed for either the DVDA or SVDA distributors. Which Solex do you have? Did Tim at Volkzbitz alter this carb to fit one or the other distributors?

It's a cheapo dizzy I bought from M&T, I'd bought one a couple years ago that actually worked quite well for longer than I expected and in the end, it was only the diaphragm that failed. In terms of numbers an such, I've no idea. The part number that M&T uses is 205k, I figured it was some kind of late 205 replica. I'd put one on this engine to replace the 009 that was on it when I bought the car, coupled with a chinese 34/3, it worked pretty good. Or better than the 009 with the 30/31 that was on it.

Sat Feb 25, 2017 9:35 pm

Update;
Replaced the coil with a new Blue Bosch. Seems to be working very well now. Idles and drives tits. Fingers crossed in doesn't give me trouble in the morning. But that seems to be what the problem was.

Thank you everyone who contributed. Any other suggestions are welcome if you think of them. I'll post up by the end of tomorrow to double confirm the issue is solved.

/T.

Sat Feb 25, 2017 9:39 pm

Yes it could have been the coil!

Sun Feb 26, 2017 6:54 am

You may still have a carburetor/distributor mismatch. Can you provide a picture of the installed distributor?