[T3] On a 73 T-3 SB fuel injected aut trans pinging .

William J catnine09 at dslextreme.com
Wed Dec 6 00:40:13 PST 2017

----- Original Message ----- 
From: "Jim Adney" <jadney at vwtype3.org>
To: <type3 at vwtype3.org>
Sent: Tuesday, December 05, 2017 9:58 PM
Subject: Re: [T3] On a 73 T-3 SB fuel injected aut trans pinging .

> On 5 Dec 2017 at 18:44, William J wrote:
>> The Bently state to set the timing to have the lines off and plugged and
>> only states the engine RPM at 850 idle . Is this correct? And if so when 
>> you
>> raise it back to 950 plus or - 50 RPM this may advance the timing a bit. 
>> for an
>> auto matic car.  What is the best way?
> It's always a problem if the distributor is already started up the
> advance curve at idle. This leads to the vicious cycle I mentioned
> earlier. You might want to try lowering the idle speed slowly while
> watching the timing to see where the advance starts. For the AT AH,
> it should start somewhere above 1000 rpm. So timing at 950 should be
> fine. Note that since there's no advance between 850 and 950 for the
> AT AH distributor, either speed should give you the same correct
> result.
> But, if you find that your advance is starting below 1000 rpm, you
> might try swapping the springs, just in case they got swapped before.
> If that doesn't fix it, you're looking for someone with a distributor
> machine.

 I had the AH in the car before and used points and it worked fine . Before 
I took the springs off I took photo's of which spring went on each 
adjustment post . I also checked and compared it to the AF and they were the 
same . If you look at the upper shaft / advance shaft where the springs hook 
to the adjustment posts one side has a larger hole with a number stamped 
near it think it was 980 . This is where the lighter spring goes . I checked 
even though I saw no evidence either one was ever taken apart . At some 
point someone sprayed red grease all inside the AH , you couldn't see it 
until I removed the points plate most of it was slung all over and that 
plate the late type has larger openings plenty of room for a spray nozzle to 
move around. I know the AF Dist was never touched and it did work fine yet 
it had rust on the springs and weights and on the inside walls of the body 
which is aluminum so it looks like rust that was flung there and comes off 
faily easy . Point is the springs are on proper from my photo's and 
comparing the two .
> As for the springs, one will be snug when stationary and that one
> will hold the advance to zero until its preload is met, then it
> controls the early, low rpm, advance.
> The other spring has an elongated loop so it doesn't come into play
> until some higher rpm, then it stops the advance until the
> centrifugal force also overcomes that spring's preload; that gives
> the flat section of the advance curve.
> Once the second spring's preload is met, the advance continues, but
> now the advance curve is less steep, because the centrifugal force is
> working against the combined strength of both springs.
> One other thing to check is to look at the 2 arms that got adjusted
> at the factory to set the advance curve. Look for any signs of
> damage, because sometimes someone loses the screw that holds the
> little plate that holds the points connector to the outside of the
> distributor. If they replace that screw with something longer, it can
> reach in and bend those arms when the distributor turns. That
> completely destroys the advance curve calibration.

 I looked at them and they are not bent also all the screws were the stock 
ones on both Distributors . I should have checked the AF from the 72 long 
ago. That car sat for years at a U-haul across the street from the Ford 
dealer I worked I bought the 73 I have from that Ford dealer , it was 
sitting in their small used car lot. The 72 I bought for parts the fuel tank 
was all rust inside and I'm sure moisture got in the Dist too. Course all 
the oil caked on the engine saved a lot of it . It has to much up and down 
play so I know the fiber shaft spacers are shot yet I don't feel any side to 
side play in the main shaft or the upper section . I think I can save it.

 I still may go back to points if I can find well made ones . The Pertronix 
is 19 years years old . I'd rather change points on the side of the road 
than deal with removing the pertronix then install points. They worked fine 
. I only changed over because I was told they hold timing and seemed like 
every set of points I had no matter how careful I aligned the contacts they 
always ended up touching on one edge then it would miss . One day one of the 
Ford tune up techs told me I should try the electronic so I did. I had to 
fiddle to get mine to line up better than out of the box . Now that I don't 
drive all that much points would be fine .
> Hint: Any time you've done distributor work, always spin the
> distributor shaft by hand before reinstalling it. If there's an
> interference problem, it's MUCH better to discover it by hand, before
> you let the engine force it around.

 I did that as well just to make certain nothing was hitting anything.
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
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