hey guys, I know there's a ton of posts on this, but I wanted to seek some advice on my own build. 454HO twin s366, MSD 6AL-2, C&S carb... just starting to get this running, within 30sec of idling at 1800rpm during warm-up my headers are glowing. Timing is at 0 degrees and my AFR are 14.3-14.8... I know this is slightly rich, but didn't think it was bad enough to cause this. Any thoughts?

 

Timing is way retarded .

lock the timing at 34 degrees and pull it back in boost only .

And thats not rich at all .

 

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So. Took the dizzy out to lock it out and start my timing curve with the box and found this.

 

Holly crap ....... lol

 

I had a few choice other words... not sure how this happens? The cap and rotor are brand new from MSD for a GM HEI.. the rotor only goes on one way... any words of wisdom? Also going to change the oil, its reeking of gas.

 

Also... since I haven't driven this yet, mostly because I want to make sure I don't blow it up because it seems like I'm very close to that... How do I know what RPM to start pulling timing from? The truck hasn't been under any load yet and hasn't made any boost, mostly idle-2500rpms

 

6530 box ?

Use a 3bar MAP sensor and do a boost timing curve .

 

Im not a big block guy , but you should be able to run 32 to 34 degrees until boost .

I run a 9:1 sbc and I run 40 degrees out of boost ........ idle , all the way to boost .

 

Also , I would think about getting rid of the HEI and get the right coil for that box .

 

Everything blown385 said x2

 

I think you guys are both right. I spoke with MSD and apparently I should have switched the bushing that's in the cap and rotor to change the tolerance in the contact, along with moving the ground to a better spot on the block.

I need to do some more research on the boost timing curve because I don't even have a reference point where to start.

Thirdly, could this cause unburnt fuel to get in the oil and cause the header glow? Or should I be looking further into it?

 

very likely. Zero degrees timing doesnt give the engine any time to complete the burn.
And with gasoline, the leaner the mixture at cruise, the more timing it needs to complete the burn because the fuel particles are farther apart. Most stock cammed factory engines these days with modern high efficiency combustion chambers will idle at 15-20 deg and jump into the 30s just off idle. Most at lean cruise 14.7-15.0 will have 45-50 deg. advance. That being said, BBC and most old style combustion chambers in performance applications or larger cam will like 25-30 on average idle timing. Most will still like lots of timing at lean cruise.
But mid 30s should work for idle and all driving conditions until boost.

 

So... pulled the distributor, locked it out. Put it back in, connected everything. It will not start, attempted to and it had a massive backfire out of one cylinder... took the cap off, brought it up on TDC and I was right on the money. Bent the tong up to make sure it has good contact with the coil. Everything looks perfect. Connected the box to the laptop, no errors or codes and had a consistent 12.4v when starting. Check for spark, had spark in all 8 plugs.. I've moved the dizzy all the way advanced and work it back retarded, only popping once out the tail pipe, other than that, little pops out the carb...

Fee free to get your nerd on and teach me...

 

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Its probably 180 degrees out.

Did the engine move at all , or did the distributor drop right back in ? Rotor facing the same direction ?

If nothing moved, then double , and triple , check the wires and fire order .

Also use a timing light while cranking to see if its firing at 34 degrees .

 

Motor moved while i was fooling around with the ignition, but I brought it back around on top dead center, distributor dropped right in with the rotor pointing at #1

I'm also nervous turning this thing over because of how violent the backfire was.

 

The engine would have to go around twice for it to be right . Not once . The engine turns twice for one rotation of the rotor

You should use the boost retard not run retard . Alot of guys use the run retard to pull timing under 500rpm for a "start retard "

Get a 3bar MAP sensor ....... and you have to go into the menu and select the proper sensor .

 

The MAP sensor setting have three choices .

15 psia is 1 bar
30 psia is 2 bar
45 psia is 3bar

Default setting is 15

 

Yea, I brought it back up on the compression stroke, pulled the first plug and connected the pressure gauge... I'm going to order a map sensor tonight, but I'm still stumped.

 

Double check the firing order and wires . Then check them again . lol