need help with dist cap conversion!!!

[gokuboy26]

Hi folks!
I have a 66 midget. It has the 25D distributor. The cap has the wires that come out the side... I wanted to upgrade it so the wires can come out the top.

I was told the cap with lucas part number DDB106 would work with it. I got the cap, it fits perfect... I swapped out the cap and wires, but now I get no spark at all.

The rotor is new, but I had replaced it a few months back.

I'm not sure if it makes a difference, but it does have the pertronix ignition...

Any ideas? Am I wrong to assume the stock side-wires cap can be converted to a top wire?

 

[taskadog]

I don't know the correct part #, but if the cap fits well the only two probems could be cap or rotor.
Try a new roter and if that doen't work, return the cap as defective.
This assumes your connections (wires) to the cap are making good contact.
Phil

 

[bthompson]

Odd...I have a 25D with Pertronix and a top-wire cap. (Just specify a cap for an MGB instead of a Midget at your local auto parts store, that's what works for me.) The caps should be interchangable, so what works for one should work for another. Are your wires firmly plugged in? Sounds silly, but my replacement wires had their boots way too close to the end of the leads...They looked like they were plugged tight, but weren't making contact. I had to slide the boots back about an inch to make sure they were pushed fully home.

 

[gokuboy26]

I'll double check all the connections tomorrow. hopefully thats all it is... The rotor still looks new... so my gut says thats probably not it...
My wires caps were actually not pushed on far enough... tomorrow I'll pull everything and redo the wiring. I'll let you know how it goes.

I'll also post a pic of the car so you can see my toy!

 

[gokuboy26]

Here it is.
Technically its my Dad's car... I'm fixing it up for him.
I owed him some money, and got this for him instead (with his approval! lol)
My LBCs are a 58 TR3, and a 69 Spitfire.
Cost for the midget was $900 last spring... it wasnt running.
I put in a new ignition switch and battery, and it got running!

 

[gokuboy26]

engine (with old cap and wires)

 

[dklawson]

Another silly question (and thing to check)... did you remember to put the rotor in the dizzy before fitting the cap? It's happened to most of us at one time or another.

Those plug wires seem dangerously long.

 

[scoutll]

Also, make sure the little spring loaded center contact is in the cap. Over the years, I have found a couple of new caps where it has fallen out.

 

[Pythias]

the big question is did the cap and rotor come from Jeff at ADVANCE DISTRIBUTORS? ... if so the problem is in the coil or the plug wires. If not, WHY not? Get A Red Rotor from him.

NFI

 

[gokuboy26]

I'm feeling dumb... it was just the plug wires... I was thinking it had to be something else because i didnt have any backfires at all. thanks for all your help!

 

[JPSmit]

I'm feeling dumb... it was just the plug wires... I was thinking it had to be something else because i didnt have any backfires at all. thanks for all your help!

And may I say on behalf of the entire board that this is the first time that has ever happened.

Seriously, I don't think there is one of us who hasn't done that or something similar, I can't tell you the number of times I have overlooked the simple stuff. welcome to the club, you're in good company!

 

[bill_powell]

A couple of months ago I spent about 1/2 an hour sitting in a Lowe's parking lot trying to figure out why my car would not start, or even turn over. Totally dead. I checked over everything I could think of. Couldn't find anything wrong. I mean nothing. Nada.


See this switch? The big honking red one to the left of the gauge?

That's the battery cut-off switch I installed last year. The one I had obviously bumped by accident to the 'off' position in the parking lot. I turned it back on. The car started right up.

Sometimes I'm so stupid I amaze myself.

 

[gokuboy26]

So, I'm still getting some backfiring upon revving the engine...
I'm thinking the timing is off... and I'm also eyeballing the vacuum advance line... which, if you look in the picture is old, gnarled, and metal...

First I'm going to time it... the timing marks look to be on the underside of the crank pulley. so... if I'm using the strobe from underneath the car I won't be able to reach the distributor.... is timing then a 2 person job?

 

[dklawson]

Jeff at Advanced Distributors sells a timing tape and pointer kit for the 1275 that will allow you to put timing marks "up" where you can see them. Just Google "Advanced Distributors" and follow the products link to find the pointer kit. I don't know if the kit is suitable for other engine sizes. Jeff would be able to answer that.

You said the engine backfires when revved. Is the backfire under the bonnet or out the tailpipe?

The vacuum advance really only does its thing at cruising speed. If you feel it is creating an air leak, remove the line at the carb and plug the carb port during your tuning.

 

[gokuboy26]

You said the engine backfires when revved. Is the backfire under the bonnet or out the tailpipe?

It backfires out the carb, so, under the bonnet

 

[JPSmit]

backfire under carb is pre-ignition - you are running too lean.

 

[dklawson]

As John-Peter said, the backfire may be fuel/mixture related and not related to your recent ignition component changes. It may not be simply a mixture issue though. You may be running on one carb due to blockage or a hung float valve, or there may be heavy deposits limiting fuel through the main jet/needle. Gummed up carbs are fairly common on cars that were parked and left for a long time with fuel in the float bowls.

 

[gokuboy26]

well... This car DID sit for about 2 years prior to coming into my possession, so thats going to be the first thing I will do then... I'll clean out the carbs, and if that doesn't help... adjust the mixture... and if that doesn't work,,.. then it would stand to reason a rebuild would be in order.

Thanks guys

 

[JPSmit]

You are over complicating things.

1. if it runs, the fuel is OK - you might want to run some sea foam or something at some point BUT, the carbs work now - DON'T mess with them re cleaning.

2. If it runs, and backfires, timing might be an issues but, mixture is more likely the issue.(and maybe vacuum? - I don't know much about vacuum so I am going to let someone else wade in - tough if it is metal, there's a pretty good chance it is tight even if knarly.)

3. Get it running (under load if possible) turn it off and check your plugs. you can post pics here or, there are many pics on the net. The colour of the plugs will tell you what you need to know.

4. Lean or rich is turning the one nut under the carb (and balancing) Sort this out first before you start worrying about timing or cleaning or you will drive yourself crazy! (don't ask me how I know)

One factor at a time.

 

[Bayless]

Starting on a car with unknown history, I would always recommend at least checking the electrical tune, points, dwell and timing first. This only takes a few minutes at most. If those are off, you'll likely never get it running right. Then if you do a bunch of fiddling with the carbs and eventually have to correct the electrical, you'll just have to start all over on the carbs later.