PLEASE USE AN OPEN MIND WHEN READING THIS THOUGHT.....
That broken rotor issue I had with the replacement motor has been gnawing at my brain since I discovered it.
Going back to when I pulled the race motor after it blew up....
I had pulled the distributor before I removed the engine from the truck
so as not to take a chance of the engine tilting back and breaking the cap
against the firewall while lifting the engine out of it's bay.
I had removed the wires from the spark plugs and left them connected to the cap.
I set the cap on the bench, and then removed the distributor
and set it on the bench as well.
After removing the engine, and mounting it on the stand....
I wanted to put the distributor back in so it did not get miss placed.
I did this because I was not going to mess with the
engine for awhile.
Upon reinstalling the distributor, I had noticed the the rotor
locating tab was broken.
Being that I was not pressed to get this engine repaired for awhile....
I gave it no thought to why it was broke.... I just ordered a new one.
(which I forgot in time that I did).
Being that at that moment, I knew I had just ordered a new one
I thought I would try out this JB Plastic weld I had laying
on the shelf, to see how strong it was.
After a few days.... I was amazed at how it cured.
I gave it no more thought and installed it in the distributor
so as not to lose it....knowing a new one was ordered.
Well a month went by and Coty demanded that I install
his back up engine so we could make the family reunion
Mud Bog that was coming up.
The engine ran great all day long at the bog and
let go at the end of the day while shifting from
1st to 2nd at about 6500 rpm's.
Now after a few weeks... I had discovered the rotor I had ordered
and decided to install it before I forgot again about it.
That's when I discovered that the repaired rotor
had broke.
After installing the new rotor... The engine fired up
instantly!!!
NOW..... THIS IS WHERE YOU NEED AN OPEN MIND.
I was convinced that the race engine blew up because of lack of fuel.
The calculations show that the pump was too small...
and the fact that I did not allow more fuel to be added under boost,
just reinforced the theory.. The engine leaned out.
ALL ON ME !!!!
For the last week... I have been thinking alot about how and
why that rotor had broke...
I have come up with a theory that almost might make sense
to me, and wanted to run it by you guys..
I THINK THE ROTOR HAD BROKE IN THE RACE MOTOR
AND CAUSED IT TO STOP RUNNING.
Now from the pictures above, it was on it's way out
anyway. But I think the rotor broke first before the lean condition
destroyed the engine.
My theory is: that the plastic locating tab is pushed down
into the plate in the distributor. This is a very thin
plate..basically sheet metal.;
and the locating hole was produced
from a punch and die .... This hole has a sharp edge
from the piercing .
The rotor tab is plastic.
I am thinking that the force of that thin plate
was pushing enough on that plastic locating tab to
actually start cutting it's way into the tab...and eventually through.
Think about this.... If it did cut a slot in that rotor..
The rotor would actually advance itself from the plate
edge moving into it... ADDING timing .
Let that soak in for a moment..
Below is a quick sketch I made showing ho far the plate would
have to cut into the locating tab.. in order to move only 1 degree
That would surly be a major problem under boost!
It would explain a lean condition too.
Ultimately the plate cut all the way through the tab
and caused the rotor to spin freely on the post.
Which is why the engine quit running.
I haven't measured the tab yet but I would guess
it to be .187 thick.
If so.... you could divide .187 by 0.026 and
find that it could advance the timing by about 7 degrees!!!!!!
THIS IS ALL THEORY ... BUT A CUT ROTOR.... ?????
I feel this is not too wildly out of a possibility.
Would love to hear your thoughts on this theory...