Question about ignition timing

[race-it]

I have a 347 with weber 44's. I am a novice at this but found out yesterday that after taking my cobra to two different weber shops they never checked the floats or the timing. They just started changing jets! So after some $600.00 and weeks of frustration I tore into the weber for myself. Following the manual I quickly found that my floats were all off, way off. 1/4" off on the closed and 1/2" + on the open. Once I set floats to 10mm and 32mm and reinstalled jets to factory settings, the engine lost about 90% of the popping and was drivable. It still needs tuned but at least I can drive it. I learned the expensive way, Read the book and don't trust anyone just because they say they know webers. Their is a specified order of checks that must be looked at before one starts changing jets. I may not know how to actually do the test yet, but at least I know what to expect to see someone do in a chronological order. So following the manual, My floats are now set. Next is setting timing. QUOTE "Static timing is of secondary importance to the performance level of a small block with four IDF's, but setting maximum advance is critical. It must be set correctly before the carburetors are tuned. The total advance should be 36-38 degree at maximum rpm." What does that mean and how do I set that. I marked 36 and 38 degree on the dampener. I have a timing light. What rpm do I check timing at?

I want to thank all of you who have been helping me with this project. Like me I'm sure you thought the floats and timing had been properly set.

Is their anyone in the NW Cobra Club who knows how to check timing and would be willing to do so? I can bring the car to your place or you can come to mine. Drinks and chips are on the house. As a special incentive, Steve Bisson said you could sit behind the wheel of his cobra and twirl his hey chain!!!!!!! WOW what a deal!!!!!!!!!

Jim

[jwd]

Jim,

Keep bringing up your RPM until the timing mark stops moving. Have someone watch your tach so you'll at what RPM your advance curve stops. Do you have a vacuum advance? If so, be sure to disconnect it and plug the hose.

Jim (TOO)

[jhv48]

All of your advance should be in by about 3200 RPM. Hook up the timing light and start the engine. At idle with vacuum cannister disconnected, you should be about 14 degrees BTDC. Shine the light on the degree wheel. If so, blip the throttle a few times to 3200 and see where the pointer points. If it hits the desired numbers (36-38 degrees), you're ok. If not, you might have to add more initial timing or recurve your advance.

[Silverback51]

I bought a Weber this Sunday. It only pops when I ignite it.




Sorry Jim, couldn't help myself.

[TINNMANN]

Depending on your cam you may have to start with more advance IE. I have a fairly large cam ( 610 lift) and my base is set at 18 deg. total 34 all in at 3000 rpm vac disconnected. By doing that the motor is able to burn off the fuel rather than dumping it into the exhaust which can cause backfires or pops. The thing to watch for is too much advance because you won't be able to hear if the motor is knocking. You may have to recurve the dizzy to get the desired amount of advance in by about 3000 rpm just be sure that you disconnect and plug the vac advance and plug it before setting it up. If you have to buy a timing light spend the extra to get the dial back digital with tach it will make life much simpler. If you are running a vac advance I chose to use the timed port so at a idle there is no advance to the timing because as you add more base timing you could get to a point that kickback could happen.
Cheers Greg

[patrickt]

Jim, you can do this job yourself. First, read this to learn about the different type of timings: http://www.gofastforless.com/ignition/advance.htm and then watch this video: http://www.videojug.com/webvideo/how...iming-on-a-car and then set your total amount of timing at, say, 3500RPM. One point that I'll add is don't turn the distributor when you have the RPMs up at 3500. Instead, watch the timing under your light at 3500RPM and then let the engine slow back down to idle, turn the distributor a little bit, and then rev it back up to 3500RPM to see if you have it set correctly.

[Steve Bisson]

Jim,

Timing is a relative easy thing to accomplish. As mentioned initial should be 12 to 14 degrees with a total of 32 to 34 in at 3,000-3,200rpm.
Let me know if you need a hand.

[1blackbb66]

Jim,

I sent you a PM

Ray

[race-it]

Thanks to everyone. Silverback, Could you give me the dimensions of your weber to see if I have enough hood clearance!!!!!!!!!!!

[Andrew Teal]

Jim,
I well loan you my dail back timing gun. Is the powder coating place out by you still open, Kens, as I call the # no answer. I might get over this week.

Andy

[race-it]

Andy, Kens is about a mile from me. I did not use him because I had white pipes and he was relucant to do white. I went to performance coatings in Auburn. The other work I saw from him looked good.

Jim

[race-it]

I brought #1 piston up to top of cylinder. "O" Mark on damper lined up with
top strait edge of pointer that said "time". With idle set a 700 RPM, damper was 36 to 38. Should have said 12 to 14. I moved plug wires back and forth one hole to see if that would help. Engine would not run in either changed position. I pulled distributer and moved one slot, same thing. Is my pointer wrong. Engine runs good but pointer lines up at 36 to 38. What do you think is wrong. With a dial timing light do you have to mess with the damper setting?
Jim

[patrickt]

Originally Posted by race-it

What do you think is wrong?

Do you by any chance have an MSD ignition box?

[jwd]

Jim

If it is running well enough to drive, bring it over and we'll straighten this timing thing out in a few minutes.

Jim (TOO)

[jhv48]

Originally Posted by race-it

I brought #1 piston up to top of cylinder. "O" Mark on damper lined up with
top strait edge of pointer that said "time". With idle set a 700 RPM, damper was 36 to 38. Should have said 12 to 14. I moved plug wires back and forth one hole to see if that would help. Engine would not run in either changed position. I pulled distributer and moved one slot, same thing. Is my pointer wrong. Engine runs good but pointer lines up at 36 to 38. What do you think is wrong. With a dial timing light do you have to mess with the damper setting?
Jim

Did you undo the vacuum line to the distributor and plug the hole first?

When you revved it a little, did the number get larger. If not, your timing light is measuring total advance.

[Steve Bisson]

Ditto on plugging the vacuum hose.

[DAVID GAGNARD]

Originally Posted by patrickt

Do you by any chance have an MSD ignition box?

If you have an MSD or any other multi-spark ignition boxe, your timing light will "read" each time the # 1 plug fires.....or in the case of an MSD box with your engine idling, you'll "read" 3 times the actual timing becuase of the three sparks per cycle...........

Not all timing lights do this, but I bought a new "digital" timing light a few weeks ago and it reads triple at idle, at 3000 rpms,it reads the exact correct timing I have in my motor............on the box it specifically said "compatible with multi-sparks ignitions", one reason I bought it!!!!!!!!!!!!!!!!!!!!

When I first built the motor I was using a Ford Durapsark distributor and ignition box and once I had my base/total timing where I wanted it, I marked the distributor flange and the block lightly with a small chisel,that way if I have to remove the distributor and re-install it, I know exactly where it goes with #1 at TDC......but my timing light says its at 30 degress instead of 10 degrees where it should be, exactly 3 times the real timing value, rev it up and after 2000 or so rpms, MSD will only fire once per cycle and my timing goes to 32 degrees total timing............

Not all timing lights will do this, but most will...........

David

[jwd]

My timing light is a Sears "Penske" from 1970 and it reads perfectly with a MSD. Come on guy's, this isn't rocket science.

Jim

[DAVID GAGNARD]

Originally Posted by jwd

My timing light is a Sears "Penske" from 1970 and it reads perfectly with a MSD. Come on guy's, this isn't rocket science.

Jim

My old Sears timing light from the early 70's worked perfectly with my MSD right up till a few weeks ago when checking the timing and I accidently let the positive clip touch the positive side of the coil, evidently it's only good for 12 volts and not 40,000+, that's when I bought a new/improved digital timing light thats not half as good as my old Sears one............

David

[race-it]

To answer question's,

I do have an MSD Box.
My distributor does not use vacuum. My distributor is a modified Ford distributor converted to electronic ignition that came with the 302.

Jim