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Mon Aug 09, 2004 12:49 pm

Right before I shift up, I'm losing power...and backfiring.
Here's what I got:
1600 DP, 009 w/ Pertronix, 34 PICT. Timing is good...7* BTDC, right?
I do have a flat spot that I can't get rid of, but I don't think that's the problem.
Now here's what's stange...today it started after I filled up with gas. I've been using 91 or 92 octane, because I had this problem before right after I filled up with gas. I added an additive, and it seemed to fix the problem. Bad gas, right? Well...did I get bad gas again??? :shock:
This time was a different gas station.
Any help would be greatly appreciated!

Mon Aug 09, 2004 12:58 pm

Sounds like a timing issue. Also one other note. I fought the infamous duel port-009-34 pict flat spot problem for years. It seemed as when I tuned it just perfect it would come back right away. I got some Kadrons and the problems is gone. A lot of people will tell you that they don't like the .009 because of this flat spot.

Mon Aug 09, 2004 1:20 pm

Just because the timing is right at idle doesn't mean it's advancing correctly. Check the timing at full advance and make sure it's advancing enough.
Also check the valve adjustment, could be part of backfiring...

Mon Aug 09, 2004 1:25 pm

teamspatula wrote: Just because the timing is right at idle doesn't mean it's advancing correctly. Check the timing at full advance and make sure it's advancing enough.
Also check the valve adjustment, could be part of backfiring...

This might be a dumb question:
How can I be so sure that my timing is right on without a degree'd pully?
Yes, I will check the valves. Although, I did them about 2 weeks ago.

Mon Aug 09, 2004 7:44 pm

I just marked my pulley.

on a regular sized pulley
46.5 mm is 30 degrees.
15.5 mm is 10 degrees.
7.75 mm is 5 degrees.
etc

get a piece of tape and mark TDC and whatever your total advance is in milimeters.

align the tape mark with TDC and tape it round the top of the pulley. mark the total advance on the pulley with some white out or paint.
there u go!!! :) YOU DO HAVE A TIMING LIGHT RIGHT?

also make sure you know what kind of pully you have...I assumed my 1 mark pully was TDC but found out it was 5deg ATDC... made a huge difference!

Mon Aug 09, 2004 11:26 pm

or buy a cheap degree pully, or borrow one. put the degree pully flat against your stock pully, and make your marks.

it needs to be timed at full advance with the 009. no exceptions. 28-32 degrees at full advance (3000 rpm's will do it), whatever runs best for you between those marks.

Tue Aug 10, 2004 8:57 am

You don't need a degree pulley, you can get a "better" timing light with
a built in advance curve. That way when you preset it say for 32 BTDC
you rev the engine to the appropriate rpm, Hit it with the light
and the strobe will be on TDC, adjust till you line up and your at 32 BTDC

Tue Aug 10, 2004 10:10 am

As long as you have the 0 TDC mark on the pulley, you can check it with an advanceable (if that's a word) timing light. Just hold the carb wide open, adjust the dial on the timing light to where it's flashing at the 0 mark, and there you will see what the total advance is reflected on the dial.

Tue Aug 10, 2004 11:27 am

teamspatula wrote: As long as you have the 0 TDC mark on the pulley, you can check it with an advanceable (if that's a word) timing light. Just hold the carb wide open, adjust the dial on the timing light to where it's flashing at the 0 mark, and there you will see what the total advance is reflected on the dial.

and for the record remember to turn the nob back before timing another engine. I was going ape sh*t when I was trying to time my Bus motor because I didn't realize that the advance on the timing light was at 10. I also read on the cal-look forum that someone pulled out their motor and replaced the cam all because they didn't return the timing light back to 0.

Wed Aug 11, 2004 3:33 pm

If by backfiring you mean firing into the intake manifold you may have an intake valve hanging up. If you mean firing in the exhaust, you may have unburnt fuel getting into the muffler where it ignites. That could be any kind of miss. If you mean pinging, then the timing is too far advanced.