[JamesRS]

I have a problem with my BBC HEI distributor drifting after the car warms up. I can set the timing and tighten down the distributor and everything appears okay. As soon as the car warms up and I get on it a little, the distributor rotates and timing needs to be set again. It almost seems like the distributor does not sit all way down on the manifold when I tighten up the distributor hold down clamp. The clamp that I am using is one of the spectre angled hold down clamps and I'm wondering if that might be the culprit. I haven't done any custom milling or surfacing of the heads or the manifold and the Distributor is brand new. I was also thinking about using 2 or 3 distributor gaskets to see if it would sit better, but I'm not sure that would be a good idea. Any suggestions?

[WakBordr7387]

You said it was a spectre hold down clamp? Thats your culprit right there, I had the exact same problem on a 350 with that same clamp. I had to pull over and turn the distributer back just to get it home a couple times. Get a stock replacement one if you can. I couldn't find one, so I bought anothe chrome one from a different company, and haven't had that problem again and its been a year since.


Brad

[JamesRS]

Thanks Brad, I was suspicious of it, but now you've confirmed it. I'll get a new one today.

[club327]

Have you ruled at the fact that your distributor may be seizing internally causing drag? Or when the distributor sits in the hole without a clamp is there a gap between the manifold and distributor flange? If so then you'll need to add some spacers as you mentioned otherise there'd be too much tension between the distributor and oil pump assemblies when the clamp's tightened up.

[astroracer]

Another thing to check is the length of the clamp bolt. If it's a tad too long it may be bottoming out before it fully tightens on the clamp... Also check the threads in the bolt hole to make sure they are complete.
Mark