saudivette
Clueless In Sandland
*Disclaimer*
I bashed my head at work a few months ago and the resultant gash required a couple of stitches. I'm assuming now that I must also have suffered some brain damage. Read on...
I've been trying to tune the BOSS and after reading Lars' papers, had a go at it.
No go.
The car seemed to idle happily enough around 16* BTDC with the vacuum advance removed and plugged but there was almost no mechanical advance at all. I had a look around the distributor and finally saw where the flyweights had been contacting the inside of the rotor. I removed some plastic and kept trying it until the flyweights didn't leave a tell-tale mark on the rotor any more. Started the car again and no difference.
I looked at the distributor again and even though the flyweights look like they're mired in grease, they actually move very easily. However, they were able to move a long way before coming under spring tension, as you can see in this pic:
When I pushed the reluctor (correct name??) around so the flyweights were at full extension and under full spring tension, they weights half cover the rotor screw holes. Given the thickness of the plastic of the rotor, there would have been very little flyweight movement from the sloppy pic above to them contacting the inside of the rotor:
WTF?
I had a look around the net and every single pic of an HEI distributor looked different to mine. I pulled mine apart a while ago but took pics during disassembly and reassembled it the way it was. So how the hell did my distributor get like that?
Anyway, I thought that I'd stumbled onto why the car was behaving like a POS and I couldn't tune it. I went into town this morning and bought a new cap and a second hand distributor. Side by side you can see my original (on the left) is around 90* out:
I stripped the one I bought and put the shaft and flyweight assembly into my pretty red distributor. I lined it up and dropped it into the engine and when I tried to start it, it fired up straight away and ran lovely. The engine revved nice and quickly and the carb stumble I talked about in another thread, is almost gone!
I let it warm up and this is where the brain damage part comes in :huh:
The car was idling nicely and sounded better than it has since I've been trying to time it. I plugged my vacuum gauge into manifold vacuum and I'm getting around 11-12" Hg. I disconnected and plugged the vacuum advance and connected the timing light. According to my timing tape, the car's idling at 34* BTDC. If I dial in 36* on the timing light, idle now hovers around 0*. I revved the engine up and saw that the timing mark was moving but stabilized and pegged out around 2500 RPM but the timing shows around 12* BTDC. The timing tape's on the right way:
Like I said before, WTF??
I thought I must have had the distributor a tooth out or something so I incinerated my hands and messed around realigning No. 1 TDC, dropped the distributor back in and it's exactly the same. I didn't double check that the TDC mark lines up with No. 1 cylinder at TDC though as it was too damn hot to pull the plug...
I disconnected everything and took it for a little drive around our compound. there's speed humps everywhere so I couldn't go fast but even with those odd readings, the car is running better than it ever has. The slightest goose on the throttle and there's some squealing from behind me. But, I want to set total timing and work out the advance curve.
Feel free to take the piss out of me if I've done something foolish or overlooked something, but please tell me what it is!
I bashed my head at work a few months ago and the resultant gash required a couple of stitches. I'm assuming now that I must also have suffered some brain damage. Read on...
I've been trying to tune the BOSS and after reading Lars' papers, had a go at it.
No go.
The car seemed to idle happily enough around 16* BTDC with the vacuum advance removed and plugged but there was almost no mechanical advance at all. I had a look around the distributor and finally saw where the flyweights had been contacting the inside of the rotor. I removed some plastic and kept trying it until the flyweights didn't leave a tell-tale mark on the rotor any more. Started the car again and no difference.
I looked at the distributor again and even though the flyweights look like they're mired in grease, they actually move very easily. However, they were able to move a long way before coming under spring tension, as you can see in this pic:
When I pushed the reluctor (correct name??) around so the flyweights were at full extension and under full spring tension, they weights half cover the rotor screw holes. Given the thickness of the plastic of the rotor, there would have been very little flyweight movement from the sloppy pic above to them contacting the inside of the rotor:
WTF?
I had a look around the net and every single pic of an HEI distributor looked different to mine. I pulled mine apart a while ago but took pics during disassembly and reassembled it the way it was. So how the hell did my distributor get like that?
Anyway, I thought that I'd stumbled onto why the car was behaving like a POS and I couldn't tune it. I went into town this morning and bought a new cap and a second hand distributor. Side by side you can see my original (on the left) is around 90* out:
I stripped the one I bought and put the shaft and flyweight assembly into my pretty red distributor. I lined it up and dropped it into the engine and when I tried to start it, it fired up straight away and ran lovely. The engine revved nice and quickly and the carb stumble I talked about in another thread, is almost gone!
I let it warm up and this is where the brain damage part comes in :huh:
The car was idling nicely and sounded better than it has since I've been trying to time it. I plugged my vacuum gauge into manifold vacuum and I'm getting around 11-12" Hg. I disconnected and plugged the vacuum advance and connected the timing light. According to my timing tape, the car's idling at 34* BTDC. If I dial in 36* on the timing light, idle now hovers around 0*. I revved the engine up and saw that the timing mark was moving but stabilized and pegged out around 2500 RPM but the timing shows around 12* BTDC. The timing tape's on the right way:
Like I said before, WTF??
I thought I must have had the distributor a tooth out or something so I incinerated my hands and messed around realigning No. 1 TDC, dropped the distributor back in and it's exactly the same. I didn't double check that the TDC mark lines up with No. 1 cylinder at TDC though as it was too damn hot to pull the plug...
I disconnected everything and took it for a little drive around our compound. there's speed humps everywhere so I couldn't go fast but even with those odd readings, the car is running better than it ever has. The slightest goose on the throttle and there's some squealing from behind me. But, I want to set total timing and work out the advance curve.
Feel free to take the piss out of me if I've done something foolish or overlooked something, but please tell me what it is!
:withstupid:
