# Misfire on newly built butler motor



## 1967pontiac400 (Dec 10, 2020)

Hey guys, 

Long time no chat, I hope everyone is well and had a great Christmas!

My old 400 was experiencing some major compression issues and needed a rebuild. Fast forward 8 months, I ordered a new motor and trimmings from butler and have it installed and (almost) running. 

*Engine overview:*

69' 428 block stroked to 461
Edlebrock aluminum round port heads, ported
Hydraulic roller/cam/lifters (1.5 rocker arms)
Butler/comp 8021 cam
Continuing to run my 65' tripower =-)
Points ignition
*
Issue:*

So I went for the first fire the other day and it ran great for a few seconds, noticed a fuel leak at the carb so I shut down, cleaned up and went for a restart. The engine on restart ran terribly, sounded like a misfire. After playing around for a while I went to pull the plugs and wires to see what's going on. I'll attach the pics below, but basically it looks like 7 and possibly even 5 were not firing at all, which explains the sound. 

When I pulled the wires the electrode broke right off and stayed on plug 7, so I'm hoping I just have some tired old wires, ordered up a new set due in tomorrow. I reset the engine to TDC and re-did the distributor set-up to get it right on cap wire plug for number 1. I also threw in new plugs as well just to be sure. 

Is there anything else I might be overlooking that could have caused such an issue on a freshly built engine? The rockers all looked okay so a valve did not drop or anything crazy like that. The only thing I can think of if I just never got the timing close enough on initial start-up but I'm not 100% certain. 

Thanks for the help and support as always!


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## Boomstick (Sep 13, 2021)

Personally, I'd ditch the points and go with HEI. I run the pertronics and couldn't be happier...


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## lust4speed (Jul 5, 2019)

5 and 7 definitely were not firing -- and all plugs show that carb is running way rich. Possibly just not enough run time to have the electric choke pull off before taking the plugs out. You can always ohm out the wires, and I'd be satisfied with any needle movement and not worry much right now about ohms per foot or anything. Any continuity from one end of the wire to the other will be good enough for getting around the block.

A good tip is to use your timing light on every plug wire right down at the sparkplug while engine is running. You are not checking timing or anything and are just observing the flashing light. A bad wire won't have the light flashing at all or you might see the flashing drop out every now and then. Between the continuity test and using the timing light you will know if voltage is making it from one end of the plug wire to the other.

I also notice the numbering on the shop towel and want to verify that despite the sequence that you do identify #1 plug at the front driver side of the engine. Had a friend that thought #2 was #1 and that led to some strange timing problems for him until we got him straight.


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## Jared (Apr 19, 2013)

Is it possible you had those two wires crossed?


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## BearGFR (Aug 25, 2008)

Having those two wires pull apart is a big clue. I'm betting the new set will correct that. When removing wires, you pull on the plug boot and not on the wire, right? I usually put some dielectric grease on the plug porcelain to help keep the boot from sticking. 

Bear


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## geeteeohguy (Feb 2, 2008)

Boomstick said:


> Personally, I'd ditch the points and go with HEI. I run the pertronics and couldn't be happier...


This has zero to do with the problem and conversion to pertronics could actually make things worse. 

To me, it looks like the plugs are not getting fuel, but with a carbureted car, that isn't happening unless there's a sock stuck in the intake runner. 
I would replace the wires and verify the firing order. 5 and 7 can get crossed easily and in a 18436572 firing order, can cross-fire if routed too closely.


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## Scott06 (May 6, 2020)

Agreed start with wires. An HEI distributor won't fit a tripower manifold , dist is too big in diameter.
also thinking two plugs wires may be swapped. Dont recall which two I did, i think 2&4, actually would idle ok, just a slight pop out exhaust when accelerating.


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## PontiacJim (Dec 29, 2012)

Scott06 said:


> Agreed start with wires. An HEI distributor won't fit a tripower manifold , dist is too big in diameter.
> also thinking two plugs wires may be swapped. Dont recall which two I did, i think 2&4, actually would idle ok, just a slight pop out exhaust when accelerating.


Electronic distributors are a personal choice, but points will certainly do the job. Make sure you have a name brand set. If the flat spring that holds the points closed is not up to original specs, the points will not be held firmly on the distributor cam and can bounce as RPM's increase and you can have firing issues.

Since you have the E-heads, you may want to go with a "hotter" spark plug which will burn the air/fuel mixture better. I would contact Butler IF they did not recommend a plug/heat range for your build.

Other than that, do as has been recommended with the wires and check firing order. Make sure your mechanical and vacuum advances are working correctly.


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## 1967pontiac400 (Dec 10, 2020)

Thanks for the feedback, here's what I've done, will re-attempt tomorrow:

New plugs, wires, cap and rotor. Can't be too sure. 

I'm sure and checked that I did not make a silly mistake like cross any wires to mix-up my odd and even banks, however, a cross fire is possible, so I'll give the 5 and 7 wires a little extra separation. 

I also am running special plugs from Butler, gapped for points.

HEI would be cool but that's not worth losing the tripower for (won't fit on the tripower manifold), but electronic ignition will be in the future for sure.


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## geeteeohguy (Feb 2, 2008)

If you had access to an old school oscilloscope, you could see in two seconds if it was an open wire, bad dist cam, fuel, etc. Another thing I've seen a couple of times but it's not common: the dist. shaft can get some play and lobes can wear. If the 5 and 7 lobes are worn the ignition would be weak or none on those two cylinders. Very unlikely, but very easy to check with a feeler guage.


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## 1967pontiac400 (Dec 10, 2020)

Update:

It turns out the voltage I was stealing from my coil for my electric cchoke was causing my problems. Once I moved that to another 12v source the problems immeditley went away, something was causing issues or interference stealing power from the coil. I should have known better, silly mistake!


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## RMTZ67 (Mar 12, 2011)

Hmmmm, that's where I got my choke hooked up and it seems to take forever for the engine to be able to warm up and not misfire. Gonna move it and see what happens. Just go to figure where to put it. 🤔 fuse box is a little clustered with Amp, Dakota gauges, after market bluetooth system.


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## Scott06 (May 6, 2020)

Ok so it was dropping voltage to plus side of coil. Great i love it when it is a simple solution!


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## 1967pontiac400 (Dec 10, 2020)

Yes, beats all of the headaches from the not so simple ones =-).

RMTZ, if your car is anything like mine you will be running a whole lot better once you relocate that. I went through the firewall to the radio power wire which provides 12v when the engines on. That restriction wire (if you're still on points" cuts voltage down so your choke is probably opening more slowly as a result of that too.


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## RMTZ67 (Mar 12, 2011)

1967pontiac400 said:


> Yes, beats all of the headaches from the not so simple ones =-).
> 
> RMTZ, if your car is anything like mine you will be running a whole lot better once you relocate that. I went through the firewall to the radio power wire which provides 12v when the engines on. That restriction wire (if you're still on points" cuts voltage down so your choke is probably opening more slowly as a result of that too.


Going to pick up some wire today.


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## Scott06 (May 6, 2020)

RMTZ67 said:


> Going to pick up some wire today.


there will be unused blade terminals on fuse box you can easily access just need one that is powered when ignition is on . Would also recommend a inline fuse


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## Baaad65 (Aug 29, 2019)

Went through the same terror on my new to me Butler motor but mine was because of the wiring harness that wasn't listed as for points only, hooking to the MSD R2R didn't work so nice. And my other carb had an electric choke but I ran it into the box to keyed power. Here's what it sounds like running on 9 volts, and if look close you can see most of my hair scattered about 😉 running on 9 volts


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## geeteeohguy (Feb 2, 2008)

I've never run an electric choke on any of my GTO's over the years and have never had an issue with the stock GM components. I do realize that a lot of you gents are dealing with cars that have been 'worked on' over the years and have original parts missing or not really available. Thanks OP for the follow-up. It will be interesting to see if the other plugs burn cleaner now that you have the correct coil voltage.


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## 67ventwindow (Mar 3, 2020)

Holley
INSTALLATION INSTRUCTIONS FOR ELECTRIC CHOKE KITS 

WARNING: Correct polarity must be observed when connecting the electric choke wires. Connecting the (+) lead to
ground and the (-) lead to a 12V source will result in a direct short and could cause a fire. The 12V source
selected should be fused. If not, an inline fuse rated at 10 amps should be installed 

WARNING: Connecting the choke cap to the ignition coil will result in unacceptable choke operation. This could
cause engine misfiring (resulting in possible engine damage). DO NOT connect the choke wire to the coil!


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