250 HEI conversion...with locked out timing!

[66Submarine]

Finally decided to put the HEI I had to use today and stick it in the '71 250 that's currently powering my DD truck.

Install was obviously very easy, with only a couple wires needing to be made up. I hit the key and it lit right up, so I went to adjust the timing; set it to something like 12º as a starting point. All good so far.

But then I hit the throttle with the timing light on it--NOTHING! No mechanical advance at all. I popped the cap off again and it turns out the mechanical advance is apparently stuck beyond belief for some reason.

First thought at this point? Something like: "Damn it...guess I'll just have to stick the old distributor back in for today."? NOPE!

More like: "What's this no-comp turd run like with the timing locked out?"

I marked the balancer with a paint marker where something like 36º would be and cranked the timing in. My father actually picked up the timing light as I was doing it, but I think he told me to stop at something like 32º (I'll need to verify my mark and put a light on it again, but I think that was it).

The result? It actually seems to run great like this! It'll start to spark knock slightly at about 1,500RPM when lugging hard at WOT, but above that it's fine--and even below that you have to pretty much be at WOT before it does it (this is obviously using 87 octane).

Thought some of you guys might find this entertaining/interesting.

[TJ's Chevy]

The HEI on mine has vacuum advance....I had been running mine for the longest time with out any advance at all....ran fine....should with that 4 barrel. lol But when I hooked the advance up the top end power increased a tad.

[66Submarine]

No, I mean the mechanical advance! The vacuum advance just pulls a little more in at a cruise when you have the vacuum.

I.E., with the old distributor I had 12º initial timing at idle (IIRC) and the distributor was supposed to have 24º of mechanical advance @ 4,100RPM, for a total of 36º at 4,100RPM and above. Right now I have 32º all the time.

The vacuum advance is hooked up (I think that might still work? ).

[Jurassic-1]

I had the same thing with a V8 Distributor. It was gummed up so bad it would not advance. I removed the roll pin and pulled the shaft out and cleaned it up then lubed it and presto it works again.

[TJ's Chevy]

Originally Posted by 66Submarine

No, I mean the mechanical advance! The vacuum advance just pulls a little more in at a cruise when you have the vacuum.

I.E., with the old distributor I had 12º initial timing at idle (IIRC) and the distributor was supposed to have 24º of mechanical advance @ 4,100RPM, for a total of 36º at 4,100RPM and above. Right now I have 32º all the time.

The vacuum advance is hooked up (I think that might still work? ).

Whoops..lol...I read yer post to early in the morning.

[66Submarine]

Originally Posted by Jurassic-1

I had the same thing with a V8 Distributor. It was gummed up so bad it would not advance. I removed the roll pin and pulled the shaft out and cleaned it up then lubed it and presto it works again.

I'm not in any hurry to "fix" it--I really didn't want the super lazy OE advance curve to begin with.

It is really stuck, though; it's not that it just wouldn't advance, I couldn't even move it when I took the cap/rotor off and messed with it. I'm sure I could take it apart and fix it, but I don't really see any need/reason to mess with it right now.

The 454 I just picked up should be going in there pretty soon, anyway.

Originally Posted by TJ's Chevy

Whoops..lol...I read yer post to early in the morning.

Been there before...