Need help with rebuild

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Hooligan111

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We have rebuilt a slant six 225 for a 1964 Dart. We're done with the rebuild but can't get it to start. It'll rumble like it's going to start but won't maintain and stay running. We have spark, timing is set (and double and triple checked), distributor is new, starter works well. The guy that helped me with the rebuild is very good at working on cars and has rebuilt many engines but this is his first slant six.

We're at a loss as to what could be preventing this engine from running. What else could we be missing? What are we missing?

Thanks.
 
Not really a "slant six issue". Sounds like a general "any gas engine" issue, so shouldn't stump the guy.

Check for a strong spark using an in-line spark tester. Harbor Freight has a real cheap one that works OK. With spark and good compression (you did check?), it should run on starter fluid. Just keep spraying shots down the carb. I did that long ago for a girl w/ a VW Jetta w/ Bosch Jetronic (not a slant!). Ran fine as long as I kept squirting starter fluid, and she didn't see understand why she couldn't drive home like that (with me under the hood?). Her fuel pump had failed.

What carburetor do you have? We know all about them here. The choke needs to be tightly closed when cranking, then pop open slightly by the "choke pull-off" or "unloader" so it doesn't die rich. Those often have a torn diaphragm.
 
In addition to Bill's commnet son the choke....Can yo pelase answer some troubleshooting questions?

- Can you better describe "rumble like it's going to start but won't maintain and stay running" ?
- Does it run for any length of time at all?
- Does it start but then stop running when the key is released from START to RUN?
- If it runs in the RUN position for any length of time, does it just die out? If so, suddenly or gradually?
- How did you set the ignition timing?
- Is this a points distributor? If so, is the points maximum gap at .018 to .021?
- Have you run a pressure check on the fuel pressure to the carb?
- Is there any fuel dripping down the throat of the carb after it tries to run?
- How did you test for spark? Testing across a spark plug gap is NOT an adequate way to test spark. The spark has to be able jump at least a 1/4" gap in open air to fire a compressed fuel/air mixture in the engine.
- Have a you checked the plugs for carbon fouling?
- Was the cam timing set with the crank and cam sprockets perfectly dot-to-dot?
 
nm9stheham said:
...
- How did you test for spark? Testing across a spark plug gap is NOT an adequate way to test spark. The spark has to be able jump at least a 1/4" gap in open air to fire a compressed fuel/air mixture in the engine.
...
Excellent point and a common error. It is easy to throw a spark at 1 atm. You can see sparks jump many feet in a vacuum chamber. I have tested automotive systems and they can throw a spark 1" in the air. At max cylinder pressure (~150 psig), which occurs at low rpm and WOT (and when cranking), the spark plug gap might be too large to allow a spark. I had that issue with my 1996 2.4L, when accelerating on a highway on-ramp. It would start mis-firing. I lowered the gap from factory ~0.060" to 0.050" and no more problems. That was a Chrysler TSB for the turbo versions (turbo gives even higher cylinder pressure).
Click to expand...
Click to expand...
 
Vacuum leak? I recently tried to start my race motor for the first time. Hard vto start, and would stall. Forgot to cap the vacuum port on the number six intake runner. DUH
 
check the firing order of plug wires. fill the carb fuel bowl with gas and it will run for about 10 seconds with a bad fuel pump
 
Hey Marco
Its a slanty
With a full bowl It might run a minute and a half,off choke.

OP, If you think or believe its a no gas issue,Fill the bowl through the bowl-vent as Marco mentioned.Then try this; splash a tablespoon or a bit less of gas down the carb, wait a half a minute, FLOOR the pedal, then hit it. If it fires up, back out of the throttle, and bring the rpm down to under 1000rpm. Then slowly bring it down closer to idle, while somebody sets the timing. And then let it idle.And a final timing check.

But I still think the timing is late. Are you very sure the dizzy is not out 180*?
 
It's been a week since it was originally posted with no further input form the OP.... have to wonder if it is out driving around now?
 
Still not running. Work has been crazy and I'm waiting for my buddy with more knowledge about what we've tried to come over. I'll respond later this morning.
 
Work has been insane. I appreciate all the responses about our issues. After going to Good Guys in Columbus and talking to many people we think we have the issue down to the ignition. We changed out the ignition to a Mopar one with the ballast resister but continued to have wiring issues. We spoke to someone at MSD and they suggested adding the street fire box. He said this would clean up our wiring issues. We plan on finishing this tomorrow afternoon. If anyone has suggestions on the wiring of this I could use the help.

Thanks,

Ralph
 
If the dist. is a tooth off can give you all kinds of headaches. Are you sure you're on the correct tooth?
 
Your problem could be so many different possibilities. If it won't start with starter fluid, but sputters, I would check timing, ignition and valves.
When I rebuilt my slant some years ago, I had 2 different problems which prevented the initial startup. I had the wrong year harmonic balancer which showed the timing as correct, but was actually off by about 60*. Also, I got platinum plugs which fouled way too easily and, with a new 4 bbl, that happened almost immediately.
Keep us posted and good luck!
 
Hooligan111 said:
Work has been insane. I appreciate all the responses about our issues. After going to Good Guys in Columbus and talking to many people we think we have the issue down to the ignition. We changed out the ignition to a Mopar one with the ballast resister but continued to have wiring issues. We spoke to someone at MSD and they suggested adding the street fire box. He said this would clean up our wiring issues. We plan on finishing this tomorrow afternoon. If anyone has suggestions on the wiring of this I could use the help.

Thanks,

Ralph
Click to expand...

WOW,a bunch of strangers who have never laid eyes on,listened to,touched, or
smelled your vehicle decided it was ign,?AndyZ is rite,and what you need is ONE
person who can diag. that thing for you, not twenty.The guy at MSD is just trying
to sell you product,and the wiring sugg. are in the instr.s,which is his job after all.
Double check the basics,did you mix timing cover/dampers w/another eng.,if you
verify TDC's 1&6 are on w/ the marks aligned,recheck valve lash isn't too tite,it's
not the same spec if cam is perf. replacement(i.e."purpleshaft")the spec. is way
looser. I know you just reblt it,but do a comp. check anyway,and be sure the batt.
is fresh and fully charged,and use a booster as you try this thing repeatedly.If
you are checking the timing cranking & it's OK and the marks R on,spark strength
is next,a spare plug w/the grd. electrode cut just B4 the bend is good enuff. if it
can jump that it will start a car.As others have said,this is basic eng. stuff,let us
know what you find, fresh fuel in eng.& the above items OK means fire so....:coffee2:
 
are you sure the valves are adjusted properly, not to tight.
 
Killer6 said:
,it's not the same spec if cam is perf. replacement(i.e."purpleshaft")the spec. is way looser.
Click to expand...

Good info on all that, especially the MSD guys advice. I'd trust most salesmen 'bout as far as you can throw 'em. I quoted the info above, cause to be more 'universal' I guess it should be worded 'lash the cam to whatever the manufacture suggests'. My OCG 819 lashes at .010 and .012, at stock specs it runs horrible. Carry on.:burnout:
 
SPARK, COMPRESSION, and FUEL


In addition to some great stuff above,

SPARK AND SPARK AT THE RIGHT TIME

1....Never take anything for granted. ASSUME the gas in the car is too old or contaminated. See if it will fire on a shot of fresh fuel or starter fluid "down the carb.

2...See 1 above. Never assume the timing is right until you CHECK. Is there ANY possibility the cam timing is off? There is a procedure in the shop manuals to check this. If not you can estimate intake valve opening cycle and check it

3....See 1 above. CHECK the timing marks. I don't know how bad slants are, but some v8s have had issues with the dampener ring slipping, making the marks innacurate. Use a piston stop

3....THEN SET your timing. You can check timing with a light "on the starter." I would set it at least 5* adavanced, that is 5 BTDC or a bit more.

Otherwise, STATIC time it. Pull no1 plug. Stick your finger in, or compression gauge. Bump the engine til you feel compression. You may need to go 'round a couple times to "get" what you are looking for. STOP when compression 'just starts.'

Now bring the engine around to WHERE you want timing, say, 5--8 BTDC. now look at the distributor. The rotor should just be "coming to" the no1 plug tower. You will have to move the dist. body to adjust the points opening / or reluctor position. Adjust FROM retard, moving towards advance, to set the points "just open." If electronic, set so the reluctor is centered in the pickup core. "Lean towards" more advanced.

4....Use a multimeter. Check your coil + terminal cranking voltage. Should be "same as battery" and at least 10.5V Check your spark out of the coil tower. CRANK USING THE KEY not by jumpering the starter relay. You should have a good hot 3/8--1/2" long spark. use a wire core wire to check, not a resistor wire

5....NOW!!! You have checked cam timing!!! You have set and checked the timing marks!!! You have set / checked ignition timing and you have good spark

COMPRESSION

6....CHECK the valve lash setting if they are adjustable. CHECK the compression.

FUEL

7.....Use a small shot teaspoon? or so of KNOWN FRESH fuel down the carb

At this point there is no reason on earth why this engine will not fire, and run for a few seconds

8.....Once you GET to the point above, if it won't STAY runnning, time to check fuel supply, IE tank, line, pump, and maybe the carb is gummed up.
 
It was the ignition set up. We bought a MSD Street Fire and ran it with the electronic MOPAR distributor and it runs great. I appreciate all the responses and apologize for the delay in getting back to everyone.
 
that is great. glad it was not major. enjoy!
 
wonderful,now you can enjoy cruising time,if it's not raining constantly like
it has been here lol!!
 
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