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Discussion Starter · #1 · (Edited)
I'm sorting out this 69 gtv and finding things I do not understand. As I recall from earlier engines and instruction manuals, timing is set at BTDC on #4 cylinder.
Correct? I find my engine timing marks 180% out of this location, ie. The distributor is pointing at #1 when crank is at "I" on the pulley and #4 cylinder is on induction stroke. Question: could this be the result of the cams being reversed?
 

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timing

I'm sorting out this 69 gtv and finding things I do not understand. As I recall from earlier engines and instruction manuals, timing is set at BTDC on #4 cylinder.
Correct? I find my engine timing marks 180% out of this location, ie. The distributor is pointing at #1 when crank is at "I" on the pulley and #4 cylinder is on induction stroke. Question: could this be the result of the cams being reversed?
Yes, very much so. The "I" mark should be timed at 70 degrees BTDC with #1 approaching induction stroke = #4 about to fire. According to Wes Ingram though, Spica engines will run with the injction timing severely screwed up, with some loss of performance. Turning each cam 180 degrees is the proper way to fix this, although you could also slide the pump end of the injection belt off, turn the pump pulley 180 degrees and slip the belt back on. Quite easy to do when the rad is out.
 

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Richard Jemison
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Cams reversed??

:eek:
Then the engine would run backwards!:p

The cams "could" have been installed 180 degrees out. Reversing would not matter as both cams are the same.
The oil pump drive as well could have been installed without lining up the distributor drive notch correctly. (The dist. fits in one position only)

The correct setting is 70 degrees BTDC. on # 1 cyl. (1 9/16 forward of the "M" (TDC) mark. The `69s were changed from the orig. timing during the model year.
Is it running poorly?
 

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(The dist. fits in one position only)
In a perfect world, it should only fit one way.

However, we have seen a few distributors installed 180° out. I think that either some of the drive dogs at the bottom of the distributors aren't made with enough offset, or that they can wear to the point where they can be installed wrong.

Joe
 

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Discussion Starter · #5 ·
Richard,
Thanks for the reply. 180 deg off on cam rotation is what I should have realized. Any way, after re-following Ingram's directions, The "I" mark is lined up on pointer. You mention a mid-year change for 69s. Does that mean the "I" pulley mark is not to be used? I don't have a degree wheel, and I don't understand your direction: 1 9/16 before "M". Is there a technical bulletin on this? The car was running rich and fouling plugs. I am trying to get all settings back to spec. At this point it will not even fire. I appreciate your knowledgeable help.
Barry
 

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Barry -
The 69s were originally delivered with the injection pump timing 80 deg ATDC. Alfa subsequently changed the injection pump timing to 70 deg BTDC of the #1 cyl intake stroke (= 70 deg BTDC of the #4 cyl power stroke). They issued a tech change to re-mark the 69 pulleys to the new standard (70 deg BTDC). Since owners had to take it upon themselves to take the car into the dealer for the modification, many never did. It's possible that you may have a car with a pulley that was not modified. If you look closely at the pulley you will see the "P" mark, then the "M" mark, then the "I" mark as you move clockwise around the pulley. The "I" mark should be 70 degrees clockwise from the "P" (TDC) mark. You can eyeball it and tell easily if the pulley is mod'd.

I recommend that you go back and start from scratch and re-time the engine. Start with rotating the engine to the "P" (TDC) with the #1 piston at the top of the stroke and the valves closed. Remove and reset the distributor shaft so that the rotor is pointing forwards. Time the distributor statically with a test light. Reset the plug wires so that the #1 wire goes to the cap terminal corresponding to the rotor position. Reset the plug wires, 1-3-4-2 going clockwise around the distributor cap.

Next rotate the engine so that the #4 piston is at TDC ("P" mark on pulley) of the power stroke (valves closed). Then rotate the engine CCW about 70 deg so that the "I" mark is located under the reference pointer. Reset the injection pump timing belt so that marks on the injection pump toothed pulley and the pump body line up within 1/2 a tooth.

The ignition timing and injection pump timing are now set. The engine should start. Once started, recheck the ignition timing with a strobe.

There are several previous threads on this specific subject. Here's one: http://www.alfabb.com/bb/forums/carburetors-fuel-injection/51088-timing-69-1750-spica.html
 
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