A piston stop to find true tdc is you best friend right now. Like Greg mentioned, if the balancer has spun and the TDC mark is off, everything your seeing could be a lie!
As for too much initial and starter kick back? My street racer is locked out at 39 and starts effortlessly hot, cold, whatever. And I run a little bitty [email protected] / [email protected], .686 / .686 on a 106LC! Now thats a hell raiser!
True, when I "tune" the Spark Instant, I first REMOVE (lower) spark advance, watch for a major power reduction and STOP the retarding, then I add back 1 or 2 degrees.
Now, a "tip" for understanding the Spark Instant difference in an engine with "crank-fire" DIS vs "cam-fired" Distributed Ignition.
Lets state a know good value of 36 degrees Advance with the Distributor. (Distributor Triggered)
The same Spark Instant event would take place with a 32 degree Advance amount WHEN a Crankshaft Ignition is fitted. (Crankshaft Triggered)
This result is from Timing Chain/Timing Belt stretch.
True, when I "tune" the Spark Instant, I first REMOVE (lower) spark advance, watch for a major power reduction and STOP the retarding, then I add back 1 or 2 degrees.
Now, a "tip" for understanding the Spark Instant difference in an engine with "crank-fire" DIS vs "cam-fired" Distributed Ignition.
Lets state a know good value of 36 degrees Advance with the Distributor. (Distributor Triggered)
The same Spark Instant event would take place with a 32 degree Advance amount WHEN a Crankshaft Ignition is fitted. (Crankshaft Triggered)
This result is from Timing Chain/Timing Belt stretch.
Lance
Lance ---
Are you sure you're answering the right thread? This guy doesn't have EFI - doesn't even have an electronic distributor... so not sure what you're responding to here.
You're right on the cam. I used his description on the "roudy" part... 'cause a XE268 ain't roudy...
But Vic has had "issues" with this motor all the way thru -- or I should say - starter issues and getting this thing running...
Half the time I've helped someone - they've gotten a motor from somewhere - and they really don't know where the balancer came from (what it's off of) - or the timing cover... whether it's been checked against TDC... and they've no idea what the distributor is out of. Could be out of a truck for all they know... so this is the routine I go thru when things are "unknown".
Just had this with a buddy here - couple drunks put a "motor" in - he had more issues than you could write about. Bet he spent 1500 bucks on "tune ups" - and it just was a dog. I finally asked him if ANYONE had actually checked to see if the timing marks everyone was using were indeed what they said they were. They were off about 8*.
I had to do the old --- pull all the plugs -- put in a piston stop. Roll her forward make a mark - roll her back - make a mark - in the middle is 0*...
WAY OFF... Woke the old pig right up getting the timing where it was supposed to be.
LOL.. quite the story, ill be timing tomorrow morning, ill post up results after i do my work.. thanks for the support
awful awful weather, NW hit us hard with winds and constant rain! i have no exhaust, so i cant pull the car out to time! dont expect a peek of sun til THURSDAY!.. ill keep my fingers crossed for some early nice weather..
Open headers will change everything also. Not so much timing, but carb tuning. Open exhaust will cause a lean condition in a otherwise tuned car, which can cause back fires through the carb that will blow your eyebrows off. Make you think you have a timing issue.
I would not spend too much time tuning without exhaust.
There are some users that state "add timing to find best torque", this is WRONG !
Now for the "tip", all tuners should have a "starting point" in their mind.
That is the reason I make the CAS/CS report.
Another method to find the correct "Spark Instant" is to record torque over a period of time.
When the torque value drops as time increases, the ignition timing may be too great.
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
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