Have you done this? I know you said you re calibrated the tach but try a total disconnect. I have had 2 different tachs do this to me, i disconnect them and boom it fires.
I pulled all the plugs yesterday. All were dry. Attached each plug to it's wire one at a time and set it on the engine to check spark. Each had spark. As far as the carb, pulling back on the linkage gives you a good solid squirt of fuel. No fuel leakage.
I will give it a try and see if that works. I keep thinking it has to be something with the MSD box but the fact it has good spark
then it should fire even if the carb mainjets are plugged for some odd reason, the single full squirt and good spark, should get it to fire for a split second. Can't do a static timing test without a points dist...but you can at least see if something jumped; pull number 1 plug out and get someone to bump the starter a bit to get compression building there, then move the damper a bit by hand, to line up the pointer to 6-10 degrees BTDC, then look at rotor to see if it is pointing at number 1 wire in cap. This may sound dumb, but does it sound like it has compression? I can tell, but if you can't, test the compression, or if you don't have a gauge, test each hole with your finger while someone cranks. It should blow your finger out no matter how hard you push.
One other problem I had with my MSD box, but it was the total opposite of your problem was that I failed to put in the little diode in the alternator wiring, the damn motor wouldn't shut off!
I pulled #1 plug and put a piece of plastic in the hole. I then turned it over by hand and when the timing mark gets to about the 11-11:30 position and starts the compression stroke it popped the plastic right out and the valves remain closed until the timing mark passes the pointer. The rotor was pointing at #1. That's why this baffles me so much. Air, fuel, spark, timing, compression are all there.
Every once in a while there's one of these type threads. They aren't magical or mystical machines they are mechanical. When the magic and mysticism play a role it's due to the mechanic's methods. ^^^ remember that You've missed something or what you are observing isn't what you think it is.
Suck, sqish, bang, blow....... Sounds like you squished, went past the timing mark then the valves opened?? Maybe I'm reading your post wrong with the 11:30 deal? Where's your timing tab located? 2:00?
I know this will sound stupid but I believe the tach needle being eratic is the give-a-way, something is wrong with the battery. I had a similiar experience with a MSD. I put in a new battery and the problem was resolved. I thought it sounded stupid too but it worked.
the marks should go way past the pointer before the exhaust valve starts to open. You are going to have to go way back to basics. Start with piston stop test and verify your timing marks. Why? Because there's a bunch if different covers and balancers that don't match and the rubber in the balancer slips. If you assume the marks are correct when they aren't your timing light will be telling you stories. Google piston stop and there will be lots of info. Then run a compression test, why? Cause it takes 8 mins and eliminates all the internals as culprits. Reset/ check your distributor . Why ? Because you've apparently missed something and that's needing eliminated too. And you now have verified engine TDC marks.
Let me go down the list of what I have done so far Checked for fuel--good squirt when moving throttle, fuel in tank, no leaks, good pump Good spark all the way down to the plug tips--new plugs & coil replacing new plugs & coil, old plugs gas fouled from running rich/numerous starting attempts confirmed timing mark is on 0 degrees when piston is at TDC on compression stroke confirmed this 3 times using piston stop along with removing valve cover to confirm valves were closed on comp stroke. Checked all valve movement. removed plugs and squirted oil in cylinders, turn engine over for about 30 seconds with plugs out Checked timing at least 3 times. rotor points at #1 when timing mark at 0 on timing tab checked adv/ret by moving the dist one tooth each direction Checked to make sure timing was not 180 off All wire connections are good. Tach went crazy just before problems started. Had to reset tach to 8 cyl because when it went crazy it was reading 1000 rpm's higher than actual no vacuum leaks The engine has several hours of running time with no problems. All parts were brand new incl stroker kit, heads, intake, carb, dist, coil, msd, plugs,wires,exhaust, cam, lifters, etc. It was running fine just before the tach problem occured. I started with the basics and worked out from there since no matter how complex the engine combo is you have to have air,fuel,fire. My next step is to pull the tach wire from msd and retry as suggested starting fluid check batt connections/battery as suggested I really appreciate all the input on this and welcome any other suggestions you may have.
I have a buddy with an 6AL MSD box in a 56 Ford truck that had the same problem. It ended up being the ignition control module in the distributor. He would have spark and then go to drive it and it would die and not start. Get it back home and check spark and fuel, and everything looked fine again. He sent the MSD box in to checked and was fine. He replaced the ICM in the distributor and has been driving it to work ever since ..... And he actually got the replacement at Auto Zone for a lot less than the MSD. Might be something to look at next? So many projects..so little time
I can see why you're leaning toward an ignition problem. But have you done either a compression test or a cranking vacuum test?
I say its an ignition problem. Disconnect the tach, see what happens. If you're confident enough, drop in another HEI distributor and see what it does. I think that everyone has a spare HEI and stock points type distributor laying around, but I could be wrong. Bob
I'm in Springfield, I think I have a spare 6AL box but I think I'd swap a HEI or old points dist in there and see if that works. Did you do a leak down or compression test to make sure it actually has enough compresssion to run?
I dont know what your skill level is so please dont take offense to the posts about being 180 out Im just trying to make sure without a Doubt that it is in time. The timing tab can line up at tdc on the compression stroke or tdc right before the intake stroke. I also remember something about the timing marks on the 400 crank being different than the 350 so you might want to put in a piston stop and rotate the engine one direction until it bumps, put a mark on the balancer that corrisponds with the zero on the tab then rotate it back the other direction until it bumps and put a mark there in line with the zero on the tab. Now centered between the two marks would be TDC. Its a simple thing you can check.
I was just giving you a hard time about the 180 thing. I was actually thinking the same thing about the timing mark. The only drawback is the fact that the car was running fine when everything went down. Just for the heck of it I did drop it in 180 out to see. No fire, backfire or sputter. I will add that to the list of things to try.
If you have a degree wheel you might want to throw that on as well and just double check the cam timing to make sure it didnt jump for some odd reason. Just do it the same way you would if degreeing in the cam. By any chance did it start acting up after you goosed it a couple of times?? Then again that would throw the rotor button out of position....
while out hunting, one might SEE tracks ....tracks don't make (insert animal here) coyotes... coyotes make tracks ah never mind
Ok little more coffee in me now, think he means on the right track, but going overboard with the degree wheel??
The problem started after an erratic tach reading. 1) Disconnect the tach. Wouldn't be the first time a tach caused a problem. 2) Put a battery charger on the battery, you want to be sure its fully charged after all this screwing around. 3) Start it like a cold motor, the temps have dropped a bunch in the last few days/week here in IL. Hate to think is not starting simply because its not getting enough gas for the cold motor to start. Cold motors require more gas to start. My thoughts are 1) tach problem or 2) fuel problem, either too much or too little. I think you have beat up the ignition enough I don't believe that is your problem. Gene
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