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1946 PONT 6 L HEAD SURGING, MISS, BK FIRE


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skyguyd
Novice

Apr 3, 2014, 8:34 PM

Post #1 of 12 (1425 views)
post icon 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

I HAVE COMPRESSION TEST OF 120 TO 95 @ CRANKING. NEW PLUGS, WIRES, CAP, ROTOR, POINTS, FUEL PUMP VACUUM TEST OF 18/20 FAIRLY SMOOTH READING, AND REBUILT CARB CORRECT # FOR YR AND ENG PER MANUAL. I HAVE ONLY CHECKED VALVE CLEAR ON ONE CYLINDER.@ .014. I DON'T HAVE HOW TO MOVE ON TO ALL OTHER CYLINDERS. NO INFO IN MANUAL. IT KIND OF SOUNDS AS IF THE WIRES ARE IN THE WRONG ORDER, BUT CHECKED AND RECHECKED. FIRING ORDER ON BLOCK WITH COUNTER CLOCKWISE ROTATION OF ROTOR. PULL WIRES OFF PLUGS WHILE RUNNING AND LITTLE CHANGE NOTICED. CKED CYLINDER PRESSER IN ORDER OF FIRE/ORDER AND SEEMS CORRECT. WRONG CRANK?? NOT FOUND. ('crazy') I HAVEN'T WORKED ON THIS TYPE OF ENGINE FOR OVER 50 YRS, BUT THAT SHOULDN'T CAUSE ME TO GO STUPID. HELP!!!! DON ALSO NEW TO POSTING. NOT SURE HOW TO KNOW IF I GET A REPLY OR WHAT EITHER.


Discretesignals
Ultimate Carjunky / Moderator
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Apr 4, 2014, 4:29 AM

Post #2 of 12 (1395 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

Not sure what compression is supposed to be on that engine, but that is low and seems inconsistent. 95 psi isn't enough to support combustion.





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skyguyd
Novice

Apr 4, 2014, 4:54 PM

Post #3 of 12 (1372 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

THANKS FOR THE REPLY, I HAVE HEARD THAT BEFORE FROM A QUOTE VETTE MECH. I HAD A SMALL BLOCK CHEVY IN A BOAT. 2 OF THE CYL. ONLY HAD 60 PSI. WHEN I TOLD HIM THAT HE SAID IT WON'T RUN WITH ANY CYLINDERS WITH THAT LOW OF COMPRESSION. IT RAN SMOOTH. ONLY WAY YOU COULD TELL WITHOUT DOING A COMPRESSION TEST WAS IF YOU COULD HEAR THE EXHAUST CLEARLY AND YOU COULD HEAR THE HISS OF THOSE 2 CYLINDERS DON


Discretesignals
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Apr 4, 2014, 5:00 PM

Post #4 of 12 (1371 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

With low and inconsistent compression numbers you'll never get the engine to run right. You could rebuild carbs and replace ignition parts all day long, but you'll be throwing money into the wind.





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Tom Greenleaf
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Apr 6, 2014, 5:19 AM

Post #5 of 12 (1357 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

Compression is too low. Check valve timing for this.
Vacuum fuel pump (on top makes vacuum) means nothing but intake manifold vacuum about can't be that high with compression that low,


T



Tom Greenleaf
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Apr 6, 2014, 7:34 AM

Post #6 of 12 (1349 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

New post so you should get a notice of a reply made.


This smacks of a jumped timing chain. Without taking anything apart you can just turn crank bolt and watch how far it turns back and forth before distributor rotor turns which shouldn't be much.


You have some compression so it can't be snapped but off probably a few teeth which would cause all heck to not behave, low compression on all cylinders.


I don't trust your test results either so use another compression gauge if you can. There's a slight maybe you can remove fuel pump and see or feel the timing chain? Sorry it's a bit old for even me!


T



Hammer Time
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Apr 6, 2014, 9:21 AM

Post #7 of 12 (1341 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

Timing chain?

Did they even have an overhead valve engine in '46



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Apr 6, 2014, 9:52 AM

Post #8 of 12 (1334 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

I'm stuck HT. I need to know just what is in this thing and finding confused info.


A timing gear is listed with a chain but bet not correct. This engine should look a lot like this.........

Hmmm - Flat head. Pontiac Division. Near sure Chev made an OHV 'SIX' at least by 1948 and can't know just two years earlier and still searching it out, Tom



Hammer Time
Ultimate Carjunky / Moderator
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Apr 6, 2014, 10:01 AM

Post #9 of 12 (1330 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

I believe the 235 inline went into production cars in 1953.

That would have been the first OHV in production GM vehicles.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



skyguyd
Novice

Apr 7, 2014, 6:36 PM

Post #10 of 12 (1317 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

THANKS FOR YOUR REPLY. NOT TRYING TO MAKE IT RUN SMOOTH. TRYING TO GET IT TO, NOT RUN LIKE IT HAD A SUPER CHARGER. BUT, THANKS FOR THE INPUT.


skyguyd
Novice

Apr 7, 2014, 6:42 PM

Post #11 of 12 (1315 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In

I HAD A 36 BUICK WHICH HAD A STRAIGHT 8 WITH OVER HEAD VALVES. MY MANUAL FOR THE PONTIAC 46 SAYS BOTH THE 6 AND 8 WERE FLAT HEAD L ENGINES. I ALSO THINK MY 39 CHEVY WAS AN OH 6, BUT NOT TOO SURE. SLYGUYD


Discretesignals
Ultimate Carjunky / Moderator
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Apr 7, 2014, 6:45 PM

Post #12 of 12 (1313 views)
Re: 1946 PONT 6 L HEAD SURGING, MISS, BK FIRE Sign In


Quote
NOT TRYING TO MAKE IT RUN SMOOTH


Ok, so you want it to run like a piece of crap and not have any power what so ever? To each their own I guess.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.






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