Changed Distributor Cap - Runs .. Barely
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,694
Likes: 329
From: Scottsdale Arizona
Changed Distributor Cap - Runs .. Barely
I changed the rotor and distributor cap today. I was amazed to find that there were not any index marks on the cap. By this I mean that I could freely turn the cap until I secured it with the tabs. Needless to say that now that I tried to start it, it's running pretty rough. I didn't have time to adjust the timing, but presumably this will solve the problem.
My questin is regarding the cap. I did go with an Accel cap and rotor because it was all that wqas in stock in my size (1981). Once the tabs were unhooked, by old cap turned the same way. Is this normal? I've never seen a distributor cap that didn't index up in some way.
My questin is regarding the cap. I did go with an Accel cap and rotor because it was all that wqas in stock in my size (1981). Once the tabs were unhooked, by old cap turned the same way. Is this normal? I've never seen a distributor cap that didn't index up in some way.
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
If it ran better with the old cap on I suspect the new cap is in the wrong position, check (look for) picture of wiring (firing) order and that'll give you an indication of the position of the cap by checking the order of the wires. Hope fully one of our guru's will chime in with a more precise way of doing it.
Drifting
Joined: Mar 2003
Posts: 1,608
Likes: 3
From: Canberra AUSTRALIA
St. Jude Donor '05-'06
I ain't no guru but had a similar problem.
I have an el cheapo Carquest brand cap on my car. I ordered in a brand new ACDELCO rotor and cap. Car ran like junk. I looked under the cap and saw lots of metal flinings. Cap was not made/machined right. Went back to old cap. We checked the cap on an engine analyser and it was giving bad spark for about 20% of the time. I had it locked (indexed) in the right place.
Bottom line the quality just is not there with a lot of the old parts. If you can find an indexed cap then order one in but check the quality while you are at the store. I am going to order another $5 cap as a spare as I returned the ACDELCO.
I have an el cheapo Carquest brand cap on my car. I ordered in a brand new ACDELCO rotor and cap. Car ran like junk. I looked under the cap and saw lots of metal flinings. Cap was not made/machined right. Went back to old cap. We checked the cap on an engine analyser and it was giving bad spark for about 20% of the time. I had it locked (indexed) in the right place.
Bottom line the quality just is not there with a lot of the old parts. If you can find an indexed cap then order one in but check the quality while you are at the store. I am going to order another $5 cap as a spare as I returned the ACDELCO.
Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
Update
Finally had a little time this morning to see what's up. I removed the distributor cap to make sure that it wasn't full of metal shards. It wasn't. When I put the cap back on, I advanced it aproximately the equivalent of 30 degrees. A little hard to start but revs like a champion. Backfires when you back off now. Presumably I over did it a little 
.
It's about 90 out now so I doubt that I'll try again until later, but I plan on moving the timing araound to see if this takes care of it.
I also need to put a mark on the balancer at TDC to try to see where I really am at. I know how to find TDC but can't see the right conectors on the starter solenoid to hook up my remote starter switch. Anyone know which are the right two? Centre and ...
.It's about 90 out now so I doubt that I'll try again until later, but I plan on moving the timing araound to see if this takes care of it.
I also need to put a mark on the balancer at TDC to try to see where I really am at. I know how to find TDC but can't see the right conectors on the starter solenoid to hook up my remote starter switch. Anyone know which are the right two? Centre and ...
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,694
Likes: 329
From: Scottsdale Arizona
Originally Posted by lucky76
Something is wrong with the cap, you shouldn't have to make a new TDC mark. Get another distributer cap and try it.
Bit of an update though. I played with the timing a little. I have no way of knowing where I am, but my goodness what a difference. I spent much of the afternoon trying to burn the tread of my back tires (they need to go anyhow). Absolutely shocking what a difference this made. Only a hint of detonation at high revs and it was over 100 degrees out today.
