Fi distributor

[Jerry G.]

Can an FI distributor be installed a tooth off? Given that the top rotates independent from base, I didn't think so, but I'm getting odd timing results. Jerry

[Bruce B.]

Re: Fi distributor

I believe it can be installed 1 tooth (or more) off and since the rotor is attached to the dist. shaft It will affect timing.

[William C.]

Re: Fi distributor

Well, yes and no. some more details, what year car/distributor number? If '63-65 or a 250 hp engine, the movement is somewhat restricted by the vacuum advance running into things, so if your timing is just "off" by 20 degrees or so, you might have it a tooth off.

[Clem Z.]

Re: Fi distributor

if the rules allow i would look into this, http://www.davessmallbodyheis.com/

[William C.]

Re: Fi distributor

Certainly interesting, but I'd hate to add it into a malfunctioning system. I doubt that what it fixes is the issue at hand here. We haven't been given enough information to troubleshoot. Properly setup and installed, the FI distributor system works well.

[Jerry G.]

Re: Fi distributor

It's a 62 version with no vacuum advance, all mechanical. breaker-less ignition retrofitted.When it advances over 4000 RPM it sounds like it's popping through exhaust. It's advancing into a situation that causes a pop. I couldn't get it to 38( got to about 32 and then popping) degrees advance at 6000 RPM. Full distributor advance at 6200 RPM of 11 degrees( distributor degrees)

[Michael W.]

Re: Fi distributor

The 'tooth off' concept only applies if the distributor outer body cannot be rotated far enough to achieve the desired timing setting without running afoul of some obstacle. Usually this is the vacuum canister or an intake runner.

[William C.]

Re: Fi distributor

I'm not at all sure that the problem you are describing is a distributor location issue. I'd pull it and have it checked on a machine and then with confidence in the distributor I'd look for other issues. As Michael noted, tooth off affects only the ability to obtain proper timing within a limited range of distributor rotation. The fact that you are measuring proper advance as rpm increases would indicate the problem lies elsewhere. I'd worry more about the "Breakerless" setup and any other NON-oem components you might have neglected to mention. As one old racer had painted on the front fender "tricks are for kids" The stock systems were designed to be above all, reliable. I can't say the same for many aftermarket adaptations.

[John D.]

Re: Fi distributor

Jerry, It is quite common for an FI owner to install his distributor a tooth off.
Lot of difference between a 62 and 65 FI distributor. As detail oriented that you are I assume you updated the 62 distributor as it has a different main shaft with football, different distr cam and of course the weights and springs are not the same as a 65.

Ever see a midyear FI distributor with a dent on the side of the vacuum advance? In the early 90's there was an NCRS National in Warren, MI. One of the sight seeing trips was the Flint engine plant. An assembly line worker said they used to smack the side of the vacuum advance with a hard rubber hammer to help get the distributor installed so it was not one tooth off. JD

[Jerry G.]

Re: Fi distributor

Hi John. You know me, nothing but the best...Don Baker did the complete rebuild and conversion. I think what I take from this thread so far is that as long as you can time the motor it doesn't make any difference which tooth your on, at least with no vacuum advance can to deal with.

[Jerry G.]

Re: Fi distributor

Some additional information. The distributor is equipped with Petronix breaker less points and MSD box. I just finished checking for obvious things like a valve lash problem or loose wires. The motor starts and runs fine as long as I don't try and put more that about 16 degrees initial advance in it. When I turn the rotor cap to give it a few more degrees of advance it just dies, Sound electrical right? Well i started it back up and jiggled and twisted every wire around the ignition I could find...nothing. i'm a little stumped at this point. Any ideas?

[Clem Z.]

Re: Fi distributor

cut a hole in a old dist cap at #1 cylinder location and using your timing light to shine into the hole check the location of the rotor tip in relation the the cap terminal at speed

[William C.]

Re: Fi distributor

Check the wire coming out of the distributor for fraying. rubbing, or other short-circuit issues.

[Jerry G.]

Re: Fi distributor

Not sure I know what to look for. Doesn't it have to be at the #1 terminal if I can get the timing light indication at idle and at speed? It has to be there right??

[Michael H.]

Re: Fi distributor

cut a hole in a old dist cap at #1 cylinder location and using your timing light to shine into the hole check the location of the rotor tip in relation the the cap terminal at speed

That's what I was thinking too. Rotor index to the distributor cap terminals. If the electronic pickup isn't creating ignition at the same position that the original points did, the rotor tip may not be aligned with the cap terminal.