This is getting frustrating...new 445 reluctant to start.

[My427stang]

The whistling carb is odd, but not unheard of, assuming you don't just have a 3/8 vacuum line unhooked, wouldn't be the first guy to accidentally miss one under the rear of the carb.

Good test on the intake ground test, assuming you had one lead to the negative post of the battery.  Checking the head isn't that important through, I would be checking distributor body to intake, or distributor body to neg battery post to verify that when the distributor wanted to collapse the coil field, it can.

Let us know how the checklist goes, and as goofy as it sounds, enjoy following it.  Don't treat that checklist as a hurry up and do, take your time, make sure everything you look at you understand, and enjoy the troubleshooting, it's the best way to discover a problem

[Yellow Truck]

Ross, I printed out the steps so I can follow them and make notes.

I noted I hadn't been systematic in the testing plug wires because I had thought I had a bad #1 wire, so I checked it and a couple of others. No question time to settle in and work this progressively.

[Yellow Truck]

Following the check down list -

First I pulled the wires off and measured resistance from the inside of the cap to the plug end (might as well follow the electron path as far as possible) - the results when measured by the length varied from 41.4 to 44.8 ohms per foot. I think that rules out a fault with the wires, although there may be a problem with the wire to plug connection since it was not tested. I will test that before I am done.

Second I pulled the plugs - pictures below. Number 8 seemed a little wetter than the others, but they all show evidence they were firing. They all look rich to me. The mark on the top of #1 is because I dropped it.

I'm looking to borrow a compression tester today, if I can't I'll buy one.

[My427stang]

For some reason I cannot see pics at work.  I'll look when I get home.

Don't worry about them looking rich if they are all firing, we know it isn't running well, it would be surprising if the plugs looked good.  Again, I can't see them, but the thing I will look for is if they are too far gone to trust for continued troubleshooting because they are fouled.

Disregard much of what I say until I get home, but did the truck backfire at all when you were trying to get it running, or did you go inside the carb for any reason?

[Yellow Truck]

With these plugs it has not backfired. It did with the Autolites that were in it before (when it would not start). So far it is running rich and not as sharp in the throttle response as when we first got it to fire and ran it around the block.

I shortened all my plug wires today (purely aesthetic reasons) and I'll fire it tomorrow and advance the timing as it was set at 10-11 degrees. I will also check total timing.

I need to take off all the pulleys to test TDC, and I don't have access to a compression tester and I don't want to buy one, so for the moment I'll skip those two. I'm pretty sure on TDC given it is a new balancer and we were pretty fastidious putting it together (checked it several times).

I'll check the grounds before I fire it again, especially the distributor.

[ScotiaFE]

Any chance you have the rockers a tad too tight?

[My427stang]

With these plugs it has not backfired. It did with the Autolites that were in it before (when it would not start). So far it is running rich and not as sharp in the throttle response as when we first got it to fire and ran it around the block.

I shortened all my plug wires today (purely aesthetic reasons) and I'll fire it tomorrow and advance the timing as it was set at 10-11 degrees. I will also check total timing.

I need to take off all the pulleys to test TDC, and I don't have access to a compression tester and I don't want to buy one, so for the moment I'll skip those two. I'm pretty sure on TDC given it is a new balancer and we were pretty fastidious putting it together (checked it several times).

I'll check the grounds before I fire it again, especially the distributor.

OK so the reason I asked if it backfired was because I was wondering if the power valve was damaged, however,half those plugs look like they weren't firing.

There is absolutely no reason a stock set of Autolites would cause a backfire.  There are more strokers out there running 3924s than you can shake a stick at

If it were mine, I would pull the coil wire and crank it with the coil wire about 3/4 inch from the intake.  The spark should be sharp and blue.  If it is, I'd put a fresh set of Autolites in it, and assume you happened to fix what was causing the first backfire.  If it is not, I would look at the ignition, those plugs are not doing OK at all

If it still ran rich, I would bet on a bad powervalve

[Barry_R]

This is all repetitive - but worth it sometimes.  I follow the same list when things go off the rails here.

Those plugs look swimming rich for unleaded.  No question that we have a problem.  I am not a big fan of the fine wire plugs in a hot rod.  Just get a set (another set?) of 3924 Autolites - we run them in every single non-race engine here and they work just fine. 

Just stick a piece of rod in number one hole and rotate the engine around to verify number one/TDC on the pointer - no need for perfect - we're just checking for "close enough".  With all new stuff it will also be fine unless the pointer got goofed up somehow or the wrong one got installed.  There are a couple unusual oddball ones "out there" but odds are really against you having one.

Fire it up and get the idle timing to 16-18 degrees.  Don't worry about WOT timing right now.  We just want to get the idle & low speed stuff sorted.  We can play with advance curves later on.

With the timing up at 16-18 you should be able to set the carb to baseline throttle position and idle mixture screw setting as discussed earlier - throttle just cracked all around and 3/4-1 turn out from bottomed on mixture screws.  Does it respond to the mixture screws?

If it won't play nice at idle at this point there is something wrong with either carb, ignition - or ?

Look for and eliminate every possible vacuum leak - carb front, carb back, carb side, intake runners, PCV, power brakes - anything hooked to vacuum should be removed and capped so we eliminate outside influences.  You should not need sealer on a carb gasket.

I wish you were closer - on the dyno I sometimes stab in an MSD "ready to run" and a known good carb just to eliminate variables when trouble presents itself.

[Yellow Truck]

Howie - I followed T&D and Barry's instructions, and we went from one turn in being just snugged (could still turn them) to one more turn. Curious, how would that make it behave the way it is?

Ross - if the vacuum is actually 6 inches that may cause some problems since the power valve is a 6.5. I need to play with the idle and idle mix to see. To do that I thought I'd set the initial timing. I did that tonight - just started it and ran it to temp and then set the idle up to 14 degrees. I think I will move it up again tomorrow as recommended by you and Barry. I had my brother run the engine to 3,000 while I checked it and the total timing was around 41 degrees. Idle sped up a fair bit when I increased the advance, but it didn't really smooth out. My brother checked the exhaust and it was clear.

Before I start it tomorrow I'll disconnect the brake booster, PCV and distributor advance. I'll also check it for leaks as best I can. For clarity, I was not saying the Autolites caused the backfire, I thought your question was related to the current plugs (you clarified that you were thinking about the power valve). I didn't switch to the NGKs, that was the guys that got it to start for me - they switched them because once they got a good blue spark they still couldn't get it to start even after cleaning the plugs.

I have NOT been inside the carb since we got it running the first time, but I did remove it and open the secondary butterfly valve a fraction.

Last comment on these plugs - I haven't looked at a lot, but I thought all the plugs looked like they were showing carbon from burning too rich. Which ones do you think look like they were not firing?

Barry - you are right - it is a long way to your shop. I will start tomorrow with disconnecting all the vacuum draws and check for leaks. I may try and rig up a home smoke machine. Luckily I am a cigar smoker!

If I'm satisfied with that I will pull the plugs and try and get it to TDC. I have checked it several times as we put it together and finally before we started it to make sure we had the distributor clocked. I'll check the grounds again at the same time.

Then I'll start it, advance it to 16, and then start adjusting the mixture to see what it does to idle and vacuum. And then I'll report back.

One last question for you guys - new set of Autolite 3924s before I try and start it again?

[machoneman]

Yes, new plugs indeed!

[ScotiaFE]

If the rockers are holding the valves open even just a smidge
it will cause the engine to perform exactly like you describe.
Hard to start, low on power, runs rough.
Even the odd whistling from the carb.

[ScotiaFE]

On the next set of plugs put some anti seize on them.

[My427stang]

Don't get caught up in the PV is 6.5 and vacuum is 6.0 worry, I am talking about a failed PV.  Which may have happened when if backfired initially.

At idle, if the primaries are closed, the PV cannot provide fuel unless it is ruptured, then it dumps fuel into the chamber behind it

As far as which plug looks bad, well, only #2 sort of looks like it's firing, the others all look like they are intermittently firing at best

Regardless, like Barry, I am not fond of the fine wire plugs in a carbed engine, but if it were tuned right, they would likely do fine.  In this case, I am not sure you can get it running correctly with them in that condition

At this point, I would want to see if it has a fat juicy blue spark off the coil wire , and I also wonder what you changed other than the plugs to stop the backfire.

ON EDIT - Just to clarify

- the wrong PV, when off idle and on the main circuit, may be too rich to the tune of about 4-8 jet sizes, but the engine won't be too unhappy.  The comparison of idle vacuum to PV size is just a starting point

-a failed PV allows gas to follow a different route and just bathes the intake once the engine starts.  Its a completely different situation. 

I would get a fresh set of 3924s, I would also check for a blue spark off the coil wire, and then if the spark is good, and you cannot adjust the carb or it's still blubbering at idle, I'd consider pulling the PV and see if it ruptured.  If it did, I would replace it with another 6.5

[ScotiaFE]

If I was standing in front of the truck I would pull off the covers
and adjust the valves.
Bring the rocker adjuster down to just touch and then one full turn and lock it down.

[Yellow Truck]

Thanks guys. Time for a run to the parts store for some plugs.

BTW, it starts just fine right now.

Howie, if you look at the initial start video - the carb was a mess but we got the idle smoothed out. I suspected our problem at that time was we had the idle screw turned to far to keep it running and we were into the transition slot - we turned the mixture screws all the way in and it didn't alter the idle at all.

After that initial start I couldn't get it to start until we put in new plugs.