Carl in LA

Hello:

SEE MY UPDATE AT THE BOTTOM - GOOD NEWS!

The 383 rebuild is back in the car and everything is hooked up - won't start... checked many things, twice, and the suspect is a weak spark... very thin little spark on number one plug and even then it appears intermitent... What causes the spark to be so weak that it won't ignite the cold, brand new engine???

This is on a '76 with the HEI system.

Other factors... starter turns new engine but sounds like heck (does the new ring gear need a break-in???), Went through all the charge in the car battery trying to get it to hit, jumped a second battery... went through that one too... bummer.

Whos got a clue to this situation??? :)


[Modified by Carl in LA, 7:22 PM 12/30/2001]


[Modified by Carl in LA, 5:26 PM 1/1/2002]

63Banshee

Check your engine and battery grounds.

Carl in LA

scraped all that new paint off the block at the attachment point and retightened the ground strap from the engine to the frame (at the motor mount)... Battery ground was not touched during rebuild. Smaller ground was reattached to trans shell at lowest passenger side bolt... Keep thinking.

mountainmotor

The starter needs shimmed .The shims correct the depth of the starter drive gear and the flywheel when engaged.

Was the distributor in good working order when you began the project?

427V8

Bad spark;
Check your battery, check and clean your battery terminal connections

Noisy starter, It probably needs to be shimmed, it's engaging too deep into the ringgear.

Nomad78SA

Is the battery wire connector tight in the distributor cap and make sure the prong it is snapping into did not push up when you connected it. Also check to see if the 4 coil screws are tight holding it down under the distributor cap. I have seen both of these problems on HEI systems.
Neil in Tenn

Carl in LA

Man... when you guys come to the rescue you don't mess around...
I will check the condition of the connections... seems reasonable as to why it would not work now... of more so, works, but not good enough...

Feedback.. the HEI system did run before the rebuild. I do not know how well it ran because of all the other problems the engine had... I do remember a miss at idle.

About the starter... the original setup did not require shims... but that was on a 160k mile car... The new ring gear just came off the mill and has sharp edges on each tooth. I shimmed it down with one of the "Help" parts kits you get at Kragen and it still hung... added a washer to each bolt and it did better... I believe the spindle would retract if the engine would ever catch on and release the pressure from the starter.

But... that has yet to happen.

I did test the continuity of the coil and it is 0 ohms... tested the trigger and it is to spec... 550 ohms... The Haynes manual says you have to take the module to Chevy to have them test it... I bet it would be cheaper just to replace it than test it! The thing that bugs me is the intermittent observence of the spark... Why would you see spark for the first few passes and not see any for a few passes and then see another spark... wierd???

The Haynes manual says I should see a fat blue spark... I am not even close to that right now. :confused:

I'm sure you can imagine how bad I want to hear that 383 rumble!

Vetterodder

Unless you've soaked the plugs, start up is the least taxing part of an ignition system's duty and, because you are getting spark, I think your problem may be elsewhere. Are the plugs wet? Repeated attempts may have fouled all of them. Does it do anything? Cough? Backfire? The engine needs fuel, spark, and compression in order to fire. Assuming that you have compression in at least one cyl, even a weak spark will give some response if you have fuel unless the plugs are completely fouled.

Carl in LA

I thought the same thing and I did have the number one plug out repeadly all day when checking TDC to ensure the timing was at zero for an initial start up... No "serious" gas on the plug... when I pulled the plug I did get vapor from the cylinder but the top of the piston was also dry.

Not even a hint of a hit... no cough, kick, nothing.

I stood there doing that chant over and over... fuel, air, compression, and proper ignition... fuel is getting into the system (visible squirts from the pump), air... air cleaner off...holding the choke plate open, compression... held my thumb on the spark plug hole to test for the compression stroke to TDC... its got plenty, ignition... weak spark - not consistent (when checking the number one cylinder).

I have another clue... I had my timing light hooked up and ready to go and the strength of the spark (I'm seeing) would not even trigger the flash on the timing light!

63Banshee

I was thinking of the battery terminal and connection rather then the cable itself. I have a feeling that the issue is elsewhere though.

Chris@VetteFinders

Why not try a new coil?

Carl in LA

I recall that Autozone can test electical gear... perhaps they can test the distributor (along with the coil) to pinpoint where the breakdown is ocuring.

Isn't that the way it always is... spend a ton of money on the rebuild, pull the engine, spend day cleaning, painting, and reassymbling... only to be held back by a smaller problem!

And all this before I start bringing the 200 R4 up to speed (for those of you that don't know... Bowtie Overdrives is very strict on their startup procedure to ensure the warranty).

7Bob3

If the starater is working it's a safe bet the motor is grounded. Before you buy a new module, run a jump wire from the battery + to the distributor. The inboard wires from the module to the coil are correct?

Chris@VetteFinders

Yep, did a total frame-off only to think I was going to have to replace the engine a couple weeks after. Turned out to only be a bad exhaust gasket.

Chris@VetteFinders

Any luck?

2ND77

The new ring gear is most likely not the same as the old one. You are going to have to play with shims to find the right set up for the starter.

As for the weak spark.....if you have good 12 volts at the coil/distributer, then it has to be a componet or connection there or between there and the plugs. Have you checked the plug wires yet? How about the dist. cap? Seem cracked ones lose alot of spark. Is the rotor button on right? I know its simple, but sometimes the simple things get over looked. I would start there or look for a bad connection. Maybe take it all apart and put it back together again making sure all connections are good. If your ignition started the car before, it should do it now too.

Ron

Carl in LA

Honestly the car ran like crap and would hardly start before the rebuild. When it did run it had a solid miss at idle that was suspect... I believe the higher compression, slower cranking, extremely weak - non existant spark is what kept the engine from cranking on Sunday. The coil was tested for continuity and it passed but the manual said to also test the module at the Chevy Dealer... I will likely skip that and go to AutoZone for whatever tests they can do.

I read on a post from MIKER that the coil will be destroyed if the tach filter wire goes to ground... not impossible that I did this in some manner - with the key on, crossing terminals under the cap with the screwdriver??? I did note that the wire to the filter is really worn. My tach did serious flucuations right after startup in the past. I see in that same post that Robzr says he just disconnected his filter with no ill effects. I may do that for the start-up just to keep making progress.

MIKER also posted about a late model Chevy PU ministarter to turn the big 383... his has one more point of compression than mine (9.2) so it may not be that critical.

The coworkers at the office said they have seen weakend spark from a failing capacitor and a failing module.

My next stop is the AutoZone and I may come home with a new module and capacitor or even a whole new distributor (the stock one is 160k miles).

I also believe the LARS recurve is in order... Either his or one from the local speed shop. I really want this ****** to haul - I also want to tune the carb with a fuel air mix tester... In short - I want it dead on for stop light to stop light and freeway onramp (scary) power!

I'm not depressed but I am anxious to hear it run! I still have a few more days of attaching transmission linkages and trans cooler connections before this rebuild is a done deal.

BTW - When I'm at the Zone I'm going to pick up a can of starting fluid just to help the process along!

Here is the link to my rebuild picture page - Hope you got DSL because I left the pictures really big!
Http://www.geocities.com/carlsvacati...neRebuild.html

Carl in LA

What a difference a trip to AutoZone can make...

Went over and picked up a new coil, module, and capacitor... hooked em up and boom... a few cranks and a few false starts twisting the distributor and it lites up like a super nova! Plenty of smoke from all the new paint and a few wierd noises (like the one from the smog pump) but no startup disasters. Sucker made 70psi oil pressure and held at 200 degrees with the Griffin and the Flexilites during the cam break-in run.

Next - Onto the transmission start up.

Chris@VetteFinders

Heh, see, it is sometimes the small things. :cheers:

427V8

WhoooHoooo! :cheers: :cheers: :cheers: