Timing

[solgroms]

So i broke down the other day, and it turned out to be the timing was off. I got it timed good enough to limp it home, but now im having some trouble setting the timing and getting it running at all. halp

[Draker]

So i broke down the other day, and it turned out to be the timing was off. I got it timed good enough to limp it home, but now im having some trouble setting the timing and getting it running at all. halp

 

Do you know anyone with a timing light?

[solgroms]

Yeah ive got one. we got it timed 12* BTDC and my truck wont fire up, it sounds like it wants to but it wont fire up. 

[datzenmike]

Try backing the advance off slightly. Turn dizzy counter clockwise.

[solgroms]

how should the rotor be set?

[Doctor510]

Yeah ive got one. we got it timed 12* BTDC and my truck wont fire up, it sounds like it wants to but it wont fire up. 

Do you have a points type distributor, if so, check the gap,  0.020"

[datzenmike]

how should the rotor be set?

 

Where should it point? On an L 16 I'm not sure but it really doesn't matter, what's important is that it point to under the plug wire on the cap above it that goes to #1 plug. I wouldn't worry about direction. If it's running (was running) it's close enough.

 

I have a '73 Nissan FSM (factory service manual) I know it isn't a 521 but similar engine and is says ignition timing is 5 degrees on the L16 so try retarding the distributor slightly. Turn counter clockwise.

[distributorguy]

Check for spark (and spark quality) at the plug.  If you haven't replaced points, condenser, cap, rotor, and most importantly plug wires in a while, now is the time to do so.  Clean and gap your plugs as they will be fouled if spark is off.  If the plugs are dry, you have a fuel issue, not timing.  

 

With all this considered, another possibility is a timing chain tensioner failure.  These motors use the same one that goes in MGs and they have had a rash of failures with new replacement tensioners over the last several years.  The rubber block falls off the backing plate.  This results in wild jumping timing marks.  OEM used is better than new, unless you special order the Jaguar unit, also very similar and the block is as good as OEM.  

[banzai510(hainz)]

this will be ez to find when you ck  the cam timming if distributor guys is right. I havent seen where the tension fails like that before.

 

line the crank up to Zero turning it right then check the cam timming  dash and the V notich marks. f good then ck the distributor for issues. locks up bushing worn(esp if still points and condensor)

 

ck the valve lash . usually the exhaust valve will get tighter and no compression as they wear

[datzenmike]

Timing chain tensioner or the timing chain itself only affects cam timing, has no connection to ignition timing whatever. Ignition timing is driven directly from the crank not the timing chain..

[distributorguy]

Oh yeah.  Forgot about that - I work on too many British cars where the distributor is always driven off the cam.  

Eliminate that.  Look at spark quality and fuel delivery.  

 

The only distributor problem these are prone to is internal seizing (lack of lubrication.)  The advance mechanism will stick, and you get no advance so low power and overheating at higher speeds but a fine idle.