1963 FI Timing

[John P.]

I have a 63 FI timing issue. When my number 1 cylinder is at TDC my rotor points to the number 1 cylinder, however, I am unable to advance the timing far enough because the vacuum advance canister hits the coil bracket. If I rotate all the plug wires clockwise one step on the distributor I am unable to retard the timing enough because the vacuum advance canister then hits the FI unit. Wrong vacuum advance canister? Wrong distributor cap? Any thoughts or suggestions would be appreciated.

[Joel T.]

Re: 1963 FI Timing

Hi;

Had the same problem with my '63 340 engine.... in my case the solution was to pull the distributor and rotate the drive gear 180 degrees on the distributor shaft and then re-insert... There is a "dimple" on that drive gear which is supposed to align with the tip of the rotor; i.e. both facing the same way... there are some situations, for which I do not have an explanation, where they need to face opposite directions in order to get correct timing.

I did this and now my all is well.

Good luck,

Joel

[Timothy B.]

Re: 1963 FI Timing

John,

Joel has the correct answer but keep in mind advancing timing is when the distributor is turned counter clockwise,(pulled toward intake manifold).

Put all the wires back to the correct location and fix the problem, #1 wire on the first cap position clockwise from the point window, my memory tells me it's just outside the window area.

[John P.]

Re: 1963 FI Timing

Joel, I like it. I'll give it a try and post the results.

Tim, you are absolutely correct on the advancing issue. My fingers were unable to type what my mind wanted to say.

Thanks.

[Duke W.]

Re: 1963 FI Timing

Cars have spent decades with the distributor gear indexed 180 degrees out. AFAIK there's nothing about this in any service manuals. It's a system knowledge thing you have to learn. I figured it out in 1966 when I experienced the issue, and there are many discussions in the archives on the subject.

Make sure the wires are indexed IAW the 1963 Corvette Shop Manual. There is a very clear diagram. The #1 wire is on the tower nearest the right edge (from the perspective of sitting in the driver's seat) of the cap window.

With the gear properly indexed and correct dist. installation indexing and the initial timing in the 8-16 degree range, the window should be about half-way between the rotational interference points.

Duke

[Michael G.]

Re: 1963 FI Timing

I went through this last year and Joel's recommendation is good one. Take the distributor out, remove the gear, rotate it 180 degrees, pin it, and reinstall the distributor in the recommended position.

I have two 63 FI cars. One has the original cam, the other an aftermarket "clone" of that cam. I have found that neither of the distributors from these engines work properly in the clone-cam engine unless I orient the gear so that the "dimple" is 180 degrees from the rotor.

I'd guess the clone cam is made differently. Since it works fine this way, I have no desire to taken the engines apart to investigate, I just live with it

[Timothy B.]

Re: 1963 FI Timing

Michael,

Just about all the aftermarket cams will require the gear be turned to properly allow the vacuum can to fit when the engine is timed correctly.

[John P.]

Re: 1963 FI Timing

Success!

[John H.]

Re: 1963 FI Timing

In order for all of this to work though, the rotor had to be aligned straight down the center of the engine, not toward the number one cylinder. This is not consistent with many mechanics that recommend the rotor be pointed toward the number one cylinder at TDC.

With the #1 cylinder at TDC on the compression stroke, the rotor should be positioned aligned with the #1 wire tower in the cap, not pointing to the #1 cylinder at the left front corner of the engine. If the rotor is pointing to the #1 cylinder, the distributor orientation will be WAY out of whack. I don't know where some of this stuff comes from.

[Michael G.]

Re: 1963 FI Timing

John, I also have the same Elgin cam. With the #1 cylinder at TDC, your rotor should not be facing directly to the front, it should be slightly to the passenger side of the centerline of of the engine, (toward the front). I think you're one tooth off.

[John D.]

Re: 1963 FI Timing

With the #1 cylinder at TDC on the compression stroke, the rotor should be positioned aligned with the #1 wire tower in the cap, not pointing to the #1 cylinder at the left front corner of the engine. If the rotor is pointing to the #1 cylinder, the distributor orientation will be WAY out of whack. I don't know where some of this stuff comes from.

Well spoken John.
Meanwhile one of the replies above said Most All of the replacement cams require that the bottom gear be rotated 180 degree.
I don't know about that. Now I am not familiar with the Elgin Industries 30-30 cam but Elgins E 900-P Service replacement Duntov 097 cam does not require the bottom gear be rotated.
Either does the FM CS113R 097 cam require the gear be flopped 180.
It is rather easy to install an FI distributor and be one tooth off you know.
Ever wonder why you see midyear vacuum advance with a dent in them?
If Dr. Mike is looking in he will remember (hopefully) the seminar he had Down on the Farm in early 90's right after the NCRS national in Warren. Dr. Mike invited a fellow from the assembly line to give a presentation for the MAC chapter and guests.
The worker said he used a mallet to smack the VA so he got the distributor in correctly-so it wasn't one tooth off. JD

[Timothy B.]

Re: 1963 FI Timing

I remember a post from John Hinckley that stated the indexing for the aftermarket camshaft gear at the rear is not called out in the blueprint like the GM camshaft.

I guess it's not on all aftermarket camshafts so I should have said it's not uncommon to find aftermarket cams needing the distributor gear turned.

It's very easy to install the distributor and walk the gear around to the exact gear location without screwdrivers etc. to move the oil pump drive.

The original poster may find after he sets the rotor just clockwise of pointing to front he may need to turn the gear back to the original indexing. That vacuum can looks very close to the intake manifold.

[Duke W.]

Re: 1963 FI Timing

John, I also have the same Elgin cam. With the #1 cylinder at TDC, your rotor should not be facing directly to the front, it should be slightly to the passenger side of the centerline of of the engine, (toward the front). I think you're one tooth off.

That's correct. With the gear properly indexed on an OE and most aftermarket cams and initial timing set in the proper range, the dist. window should be approx. normal to engine centerline and the #1 cap tower/rotor tip should be about 20-25 degrees to the right of engine centerline.

If the oil pump drive pin doesn't mesh with the slot, use a paint mixing stick to tweak the position of the slot.

Duke