NotLaw
Active Member
- Joined
- Mar 18, 2008
- Messages
- 498
- Location
- Cedar City, UT
- Car(s)
- '90 Saab SPG, '84 K5 Blazer, '67 Fairlane 500
So bringing this out of my Fairlane thread to a place it might actually get seen, I've got an ignition issue with the Fairlane.
To quote from the Fairlane thread:
And a video of the issue, that I filmed on the first drive after replacing the Distributor Cap and Rotor with Napa Echlin parts.
The video is in 2nd gear, cruising at about 40 mph, and starts just after I put my foot to the floor.
[/QUOTE]
Going back out to the car later, I noticed this:
about .125" of up/down movement in the shaft. Is this normal? could it even cause this kind of issue?
I pulled the dizzy out of the engine and looked over it, I did not see any unusual wear on the shaft, gear, or housing. Everything looked OK.
I also recorded this video, which shows that under no load, the ignition system works just fine.
I topped out at ~4700 RPM or so, per my Innova digital timing light. The engine was not hot anymore (having been about 4 hours since the last drive) but it was not cold either.
As for specs:
Engine is a rebuilt 302 with a Comp Camps Nostalgia+ flat tappet cam with 15000 miles since the rebuild.
Spark plugs and wires were replaced at the rebuild, and gapped at .040"
Distributor is a Skip White HEI conversion distributor, first installed into my old 298 engine in August 2013. Power is supplied to it by using the original ballast wire to trigger a relay, sending +12v direct from the battery along a 14 gauge wire. This is the same setup that has been on the dizzy since almost day one.
The ignition module is a replacement Autozone one, replaced about 1.5 years ago.
Coil is the original Skip White coil, and the cap and rotor are of course, new.
I can consistently reproduce the issue by putting the engine under heavy load in any gear, though I cannot say I have ever noticed it under 1900 RPM. The temperature of the engine does not appear to make a difference unless it has had a whole night to cool off. My first drive this morning took about 15 minutes before I started having the issue. Every test I have made during the day today I have been able to reproduce it immediately.
Thoughts? If the end play is not a typical cause of this kind of issue, my next step is probably going to be an ignition module.
It's what I replaced the last time I had strangeness with the ignition, though I can't remember what that strangeness was now...
To quote from the Fairlane thread:
...
A week or so before I F-ed up the diff, I had an issue where I was accelerating, hard onto the interstate (talking WOT, 6000 rpm shifts, etc) and at approximately 5200 RPM in second gear, I got a hard judder from the engine, like the ignition was cut. It sounded like I had slammed into a rev limiter at full chat. Repeated hard ignition cuts. I backed off for a moment, and got right back into it and it was smooth up to my 6000 rpm shift.
I never had the issue again, and a little poking around in the ignition and fueling system revealed nothing. I could not reproduce it, so I shrugged it off. After all, a problem that cannot be reproduced is not a problem.
On my test drive of the diff yesterday. the problem came back and in full force. The difference is this time, It did it while I was cruising at 75 mph on the interstate. Almost felt like the engine tried to stall at 2800 rpm, flutter, rough hesitations, something that felt like a massive back-fire, the lot.
I checked my spark plugs and they told me that I was running ultra lean, (and a check of the Adjustable Part Throttle screw in the Q-Jet confirmed this, it was practically bottomed out) so I fattened up the mixture a bunch, and went on another test drive.
I also checked and confirmed the ignition timing at 14? initial advance, and 30? mechanical advance all in at 2500 rpm or so.
No change.
This morning I pulled the distributor cap off, and found this:
It doesn't really look too nice in there at all. This is the original Skip White cap and rotor that came with my dizzy when I bought it somewhere around 20,000 miles and and engine ago.
I'll replace it, and see where things go from there. It's definitely feeling like an ignition problem though.
Maybe a Ignition Module? (if the cap and rotor don't fix it)
...
And a video of the issue, that I filmed on the first drive after replacing the Distributor Cap and Rotor with Napa Echlin parts.
The video is in 2nd gear, cruising at about 40 mph, and starts just after I put my foot to the floor.
Going back out to the car later, I noticed this:
about .125" of up/down movement in the shaft. Is this normal? could it even cause this kind of issue?
I pulled the dizzy out of the engine and looked over it, I did not see any unusual wear on the shaft, gear, or housing. Everything looked OK.
I also recorded this video, which shows that under no load, the ignition system works just fine.
I topped out at ~4700 RPM or so, per my Innova digital timing light. The engine was not hot anymore (having been about 4 hours since the last drive) but it was not cold either.
As for specs:
Engine is a rebuilt 302 with a Comp Camps Nostalgia+ flat tappet cam with 15000 miles since the rebuild.
Spark plugs and wires were replaced at the rebuild, and gapped at .040"
Distributor is a Skip White HEI conversion distributor, first installed into my old 298 engine in August 2013. Power is supplied to it by using the original ballast wire to trigger a relay, sending +12v direct from the battery along a 14 gauge wire. This is the same setup that has been on the dizzy since almost day one.
The ignition module is a replacement Autozone one, replaced about 1.5 years ago.
Coil is the original Skip White coil, and the cap and rotor are of course, new.
I can consistently reproduce the issue by putting the engine under heavy load in any gear, though I cannot say I have ever noticed it under 1900 RPM. The temperature of the engine does not appear to make a difference unless it has had a whole night to cool off. My first drive this morning took about 15 minutes before I started having the issue. Every test I have made during the day today I have been able to reproduce it immediately.
Thoughts? If the end play is not a typical cause of this kind of issue, my next step is probably going to be an ignition module.
It's what I replaced the last time I had strangeness with the ignition, though I can't remember what that strangeness was now...