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Hey everyone, recently swapped in an L28ET into my 78 280Z that is currently installed as an NA until my megasquirt is ready. Im running into a strange timing issue. My oil pump is installed properly with the shaft pointing to the top distributor bolt hole, my cam sprocket is set properly per service manual, wires are plugged into the distributor cap in the correct firing order, engine set to top dead center on the first cylinder and the timing marks lined up on the crank pulley. 

 

When i run the timing light i have to turn the distributor cap so far counter clockwise that the cap is no longer in the adjustment bracket when i have it set to 10 degrees. If timing by ear and what the car runs well at, im at about 30 degrees. 

 

I know its a bit premature, i dont have any photos ready for this yet but i was hoping someone may have some insight as to what could be a potential area as to why my timing shows SO far off. 

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NewZed    56

 

When i run the timing light i have to turn the distributor cap so far counter clockwise that the cap is no longer in the adjustment bracket when i have it set to 10 degrees. If timing by ear and what the car runs well at, im at about 30 degrees. 

 

 

Does it drive well, or just idle well?  Seems like you have a running issue, and/or a measuring issue.  Even if you get the distributor set to where you can adjust to 10 within its range, it will "run" better at 30.

 

Sounds like you checked all of the right things, plus a few that don't really matter.  Do you have the timing light lead on the correct plug wire?  

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Does it drive well, or just idle well?  Seems like you have a running issue, and/or a measuring issue.  Even if you get the distributor set to where you can adjust to 10 within its range, it will "run" better at 30.

 

Sounds like you checked all of the right things, plus a few that don't really matter.  Do you have the timing light lead on the correct plug wire?  

 

Timing light set on the 1st plug wire, closest to the front of the engine.

 

When i turn the distributor cap to 10 degrees it idles poorly and revs very sluggishly. Setting it "by ear" where it sounds the most healthy by idle revs and throttle response puts me to about the middle of my adjusting bracket and that puts me at about 30 degrees. The timing light is in good working order, tested it on a few other vehicles to try and remove that from the equation as well.

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NewZed    56

Is it a dial-back timing light?  Maybe it's not set to zero.

 

You still have the basic problem of it runs better at 30 degrees than 10.  You have two problems.

 

When you say you're running it NA do you mean you have the NA injectors and NA EFI system?  Did you have an NA engine in the car before and did it run well?

 

You have two basic problems that might or might not be connected.  Best to think about them separately.

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Posted (edited)

I see, i had an NA engine in there before hand with stock set up, timed out just fine. This engine is the dished piston F54 with a P90 but im running stock size NA injectors, stock wiring, stock NA distributor, stock EFI everything and ECU for NA application.

 

Timing light was zero'd out

Edited by Spooky_Intentions

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Leon    35

Set the engine to TDC @ compression stroke (make sure both #1 valves are closed, check through oil filler hole). With engine at TDC, look where both the rotor in your distributor is pointing and where your crank pulley timing indicator is pointing. Take your time (no pun intended) and ensure everything lines up perfect before taking measurements.

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NewZed    56

My oil pump is installed properly with the shaft pointing to the top distributor bolt hole, my cam sprocket is set properly per service manual, wires are plugged into the distributor cap in the correct firing order, engine set to top dead center on the first cylinder and the timing marks lined up on the crank pulley. 

 

Leon mentioned the one thing that you didn't check, but assumed was right.  Where the rotor points is the #1 cylinder, if all of those other things are set.  Put the #1 plug wire there.  

 

You might find that one of your other plug wires actually shows expected timing for when it runs right.

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Chickenman    4
Posted (edited)

It sounds like you could be a Tooth off on your timing spindle. BTW, Stock timing for the L28 Turbo engine is 20 BTDC ( because of the low compression ).

 

 

 

My oil pump is installed properly with the shaft pointing to the top distributor bolt hole

 

That is not quite the correct procedure. The shaft Tab does not quite line up with the top dizzy mounting hole. It is offset a bit to the right. 

 

correcttiming.jpg

 

Triple check that the outer inertia ring on the damper hasn't slipped. Bring #1 piston up to TDC and verify that it is a TDC with a Piston Stop tool or a long thin screwdriver in #1 hole.

 

Using the screwdriver method, slowly rotate crank by hand until #1 is almost at TDC. Insert long thin screwdriver and touch to dome of piston. Continue to slowly rotate crank by hand. ( Best to remove all plugs ) . You should feel screwdriver rise, pause and then proceed to drop downwards. At the halfway point of the " Pause " that is true TDC. Then see if your  mark on the damper lines up with the TDC  mark on the indicator tab. They should be very, very close.  

Edited by Chickenman

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Ssaga    10
Posted (edited)

I have almost same problem.Have double, trippelchecked everything.

Cam and crank at TDC, distributor spindle at 11:25, can't reach within scale for

timing. Also tried to change a notch on the spindle by lowering the oilpump. Still not possible to reach within scale.

However the difference when changing notch on the spindle is that the timing goes from excesive retard to excessive advance.

My next thought is that the mechanic advanced springs are old and worn, letting the weights spin out to easy.

Pictures show the spindle positions I tried.post-4361-0-94339900-1496443251_thumb.jpgpost-4361-0-74872700-1496443324_thumb.jpgpost-4361-0-94339900-1496443251_thumb.jpg

Edited by Ssaga

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It sounds like you could be a Tooth off on your timing spindle. BTW, Stock timing for the L28 Turbo engine is 20 BTDC ( because of the low compression ).

 

 

That is not quite the correct procedure. The shaft Tab does not quite line up with the top dizzy mounting hole. It is offset a bit to the right. 

 

correcttiming.jpg

 

Triple check that the outer inertia ring on the damper hasn't slipped. Bring #1 piston up to TDC and verify that it is a TDC with a Piston Stop tool or a long thin screwdriver in #1 hole.

 

Using the screwdriver method, slowly rotate crank by hand until #1 is almost at TDC. Insert long thin screwdriver and touch to dome of piston. Continue to slowly rotate crank by hand. ( Best to remove all plugs ) . You should feel screwdriver rise, pause and then proceed to drop downwards. At the halfway point of the " Pause " that is true TDC. Then see if your  mark on the damper lines up with the TDC  mark on the indicator tab. They should be very, very close.  

 

VERY interesting, mine points closer to the left side of the hole rather than the right! This may be something to adjust and try out tonight!

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I have almost same problem.Have double, trippelchecked everything.

Cam and crank at TDC, distributor spindle at 11:25, can't reach within scale for

timing. Also tried to change a notch on the spindle by lowering the oilpump. Still not possible to reach within scale.

However the difference when changing notch on the spindle is that the timing goes from excesive regard to excessive advance.

My next thought is that the mechanic advanced springs are old and worn, letting the weights spin out to easy.

 Sorry to hear that, this is a most frustrating experience. I went off of "pointing at the hole" by a friends recommendation so i think my oil pump may not be situated properly. I will be checking that as well. I wish you luck!

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Chickenman    4
Posted (edited)

In addition to the timing bolt that tightens down the dizzy adjustment plate ( 10mm head ) there is also a small bolt with an 8 mm head on the underside of the timing plate that allows additional adjustment. 

 

Make a Mark on the dizzy body that correspond with #1 spark tower terminal. Rotate engine to the actual timing mark. Be it 10, 15, or 20 BTDC ... and then pop the Cap off and see where the rotor is pointing in relation to #1 terminal. It should be fairly close.  Loosen timing bolt (s ) and adjust so that rotor is centered on the mark you just made. Put everything back together and double check timing. It should be just about bang on. 

 

Note: if rotor is off by a bunch, you are off a Tooth or more on the distributor and oil pump drive spindle. 

 

Picture of bolt on bottom side of dizzy that allows additional adjustment. Normally this bolt is in the middle of the slot. This one is at end of slot because owner had spindle shaft a tooth off.  

 

 

64.jpg

Edited by Chickenman

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Pharaohabq    13

Good to hear.  I was going to say that, on the Cam timing there's 3 tabs that allow for chain stretch, if that was set wrong too, it could be affecting where your timing lines up for the distributor, butt I don't know that it would be as much as you saw (30 degrees).  Being a tooth off on the Dist is pretty easy since you have to kind of "twist" it in to get it to seat at the right timing point... 

 

Sounds like you have a good engine, was it originally from a turbo car?  Are you doing the Mega-squirt yourself, or using a kit?

 

phar

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