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Rebuilt engine starting problems

A

AZ75K5

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Hopefully you guys can help me out. I have searched the various forums, but am still stumped. I just finished wiring up the ignition/starting circuit on my newly rebuilt 406SBC (from a builder at Phoenix Engine). Anyways, long story short...after priming the oil pump, and carb float bowls, and setting the HEI dizzy...I cant get it to start up. :crazy: Im sure the dizzy is NOT 180* out because it is a D.U.I. with a clear cap, so the rotor/pointer is easily seen. As the engine is turning over, all Im getting is backfiring out of the exhaust and the carb as well...sometimes flames too through the carb. The carb is freshly rebuilt too and the plugs are wet, so there isnt a fuel delivery issue. Im using 91 octane gas (needed for the 10.5:1 compression) too. The only thing I havent made sure of is that there is a good spark, because I didnt have a buddy around to help out. However, I can turn my HEI ignition on and off in the cab, and with it off...the engine just turns over...when I turn the HEI circuit on, it definitely sounds like its trying, but nothing is happening. Its frustrating and especially cause I gotta try and respect the neighbors...I cant sit out there trying over and over with constant back fire. Any help is greatly appreciated.:bow:

Thanks

p.s. Pauly, if u read this...u should PM me and come over to help me with this thing...Im in Mesa too. I will hook u up with beer, or pizza or money or whatever.
 
To be honest, I am relying on the info that the builder told me. He said that the #1 piston was at TDC compression and ready to install the dizzy. If that is really something that sounds like could be the problem I can pull the valve covers off tomorrow and verify. I read some other posts about putting your thumb over the hole, etc...but thats tough when u dont have someone else helping. Are you thinking that the crankshaft was 180* out? Like that the #1 piston was on its exhaust stroke or something? That sounds like it would make sense. I guess I should have checked for myself before setting the dizzy :doah: . I wish that I had built the engine myself, becuase that way I would have known exactly what was done to it and that no corners were cut.
 
It's REAL easy to get the dist. 180* out. I read up on it a million times here and swore it was not gonna happen to me when I istalled my new crate 350. Sure enough, it was 180* out when I tried firig it.
 
But Im confused about the dist being 180* out because I can see through the clear cap and see that the rotor pointer is pointing at the #1 plug wire when I initially set it. The only thing I can figure is that the #1 piston was in fact NOT at TDC compression (even though the builder assured me it was when he delivered the engine). I appeciate att the help on this though, and all signs make it seem like something is definitely off...I just really dont think its the dizzy, again because I can see the rotor pointer through the cleap cap:confused:
 
Easy check... get the rotor pointed at #1 on the distributor. Now take out the #1 cylinder sparkplug. You should be able to slip a thin screwdriver or wood dowel into the hole and feel the top of the piston. Also, the timing mark on the harmonic balancer should be lined up with the 0 degree mark at that point.

Just looking at the rotor pointing to #1 doesn't really prove anything. You need the cylinder at TDC at the same time.
 
Is there anyway that even if the piston is at TDC and the dizzy pointer is in the proper place...that the piston may in fact be on either an intake or exhaust stroke? Or is the only way to determine that is to do either a "blow out" test or removing the valve cover to check that both valves are closed?
 
even if the #1 piston is at tdc and the dist is pointing at #1 it can still be 180 out remember your dist is driven by your cam which makes 1 rev for every two the crank makes you need to make sure its on a compression stroke (both valves closed). as far as your problem def sounds like timing
 
the only other thing i can think of is if the rockers are adjusted to tight causing your valves to stay open. if you think it might be 180 out bring it to tdc and flip the dist 180 from where it is (or switch the wires 4 places to test it)
 
Awesome help you guys have given me. I cant wait to dive in tomorrow and see if this will do the trick. Ive been at this project for about a year and Im finally almost done. Just gotta iron out the kinks. As far as setting final timing with the HEI (after I get it running)...do I have to wait until after the 2000rpm cam break in to set it, so the engine can stabilize at normal idle rpms...or can I set it even during cam break in?
 
it can be set during cam break in. what specs did your builder give you for timing settings and at what rpm
 
When I did mine i lined up the the timing mark to 0 and pulled the valve cover off to confirm. after thats all said and done just set the dizzy to number one. If you think it is 180 out then just turn the dizzy 180* and it should work.

I never thought i would ever have trouble doing this but ive tried all the ways and this seems to be the one way to do it with less chances of screwing it up..

hope you get it running sound like its gonna be a good running motor.
 
No other way that I know of. I don't think it makes any difference though. I'm pretty sure the only time the #1 piston is TDC and the timing mark lines up (and the rotor is pointing to #1) is on the compression stroke.

We just went through a similar situation with my son's 72 K5. We had other issues to deal with but first problem we had was exactly as you describe, backfiring and flames out the carb. The dizzy was not the issue although we did verify TDC and rotor pointing to #1. We had two plug wires reversed, it's an easy mistake to make... go back and double/triple check that you have the right wires going to the right places. It is 18436572 clockwise around the dizzy
 
He never told me exactly. I know...theres plenty of things about the whole thing that is making me wonder about his work. Anyways, I tried to look it up at the Comp Cams website, but found no real timing info...just a bit on whether or not to degree the cam and how its done. According to other people in here, 8*BTDC seems to be a good number for the aftermarket HEI guys. I was going to give Davis Unified Ignition (dizzy builder) a call to see what they have to say. My truck is going to be an offroad only, low RPM(usually) truck if that affects anything.
 
jager remember the piston is on tdc on the exaust stroke as well as the compression stroke thus a 4 stroke engine on a two stroke youd be correct. (sorry if that came accross snotty not trying to be)
 
8 btdc center sounds about right. just fire it up and let it idle at about 750rpm for a min with the vac advance disconnected and set it with a timing light then break in the cam. you dont wanna run it for long w?the timing way out of wack
 
2High4U said:
When I did mine i lined up the the timing mark to 0 and pulled the valve cover off to confirm. after thats all said and done just set the dizzy to number one. If you think it is 180 out then just turn the dizzy 180* and it should work.

I never thought i would ever have trouble doing this but ive tried all the ways and this seems to be the one way to do it with less chances of screwing it up..

hope you get it running sound like its gonna be a good running motor.
Click to expand...

I sure hope this motor is good. The builder bored it .40 over from stock and with the piston/rod combo he used along with the matched intake runners...he said it should push 450hp and about 430ft/lbs. I guess we will see. Im just so anxious to get it done and out on the trail to start havin some fum with all you fellow K5ers. Hopefully there will be another meet and greet coming up.
 
gmtech954 said:
8 btdc center sounds about right. just fire it up and let it idle at about 750rpm for a min with the vac advance disconnected and set it with a timing light then break in the cam. you dont wanna run it for long w?the timing way out of wack
Click to expand...

Cool. Thx for all your help. I will let u know tomorrow night how it goes. I got a buddy whos gonna come over and help me out to watch the timing light while I adjust the dizzy, etc.
 
gmtech954 said:
jager remember the piston is on tdc on the exaust stroke as well as the compression stroke thus a 4 stroke engine on a two stroke youd be correct. (sorry if that came accross snotty not trying to be)
Click to expand...

no problem... I was just thinking that the dizzy would not be pointing at #1 wire when the #1 cylinder was at TDC on the exhaust stroke. But..it's been awhile since I had an engine apart...
 
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