Re: 1936 - standard 8 - spitting up through carb
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Forum Ambassador
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As time goes by and cars require less and less maintenance, we tend to forget just what a good comprehensive tune-up consisted of. You started a tune-up, my suggestion is to complete it; check manifold vacuum, compression, fuel pump pressure and volume, valve adjustment, check timing chain slack, check intake manifold gaskets for leaks, function of the heat riser valve, and all the other little things associated with a good comprehensive tune-up. You may get a quick clue from the compression and manifold vacuum readings.
While you're at it, remove the air filter, hold the choke open if necessary, and with the engine running above an idle, is gasoline leaving both main jets at more or less equal streams? While it doesn't match your symptom, as long as you're there check the accelerator pump action. Somewhere in the course of the above you'll find your problem and as an added plus of doing a full tune-up, you should now have thousands of miles of worry-free driving ahead of you.
Posted on: 2019/7/5 15:43
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Hi,
As an update, I ran a compression check and here are the results: Cyl #1: 130 psi - holds steady Cyl #2: 130 psi - holds steady Cyl #3: 130 psi - holds steady Cyl #4: 130 psi - holds steady Cyl #5: 50 psi - holds steady Cyl #6: 30 psi - pressure drops and I can hear it 'puffing' through the carburetor. Cyl #7: 30 psi - pressure drops and I can hear some 'puffing' through the carburetor. Cyl #8: 130 psi - holds steady. So now I know something but I literally have less than 500 miles on this engine since it was rebuilt about 6 years ago. Where do I go from here? Check the valve adjustment? That is my next inclination. Thank you, Crin
Posted on: 2019/7/5 17:36
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Re: 1936 - standard 8 - spitting up through carb
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Forum Ambassador
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Sure, check the valve clearances. Hot clearance specs are 0.004" intake and 0.006" exhaust. With any hot clearance at all, valve seats integrity may be suspect.
Not that it necessarily applies to your problem, but was the cylinder head was retorqued several times after the rebuild until it no longer needed tightening?
Posted on: 2019/7/5 17:46
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Sticking valves
Posted on: 2019/7/6 4:59
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Hi Crin,
I went through this with my 6 cylinder and it turned out to be the head gasket. I am not a mechanic, but the way you describe the 2 cylinders with bad compression and say you can hear 'puffing' through the carburetor makes me wonder if that is your problem. I did not have oil in my antifreeze or vice versa, but compression was leaking from one cylinder on the compression stroke, through to the cylinder with open valves beside it and back out the intake. When you say there are very few miles on the engine, I would sure think that would be a good place to start. Initially, I thought the head just needed retorqued once, after one heat cycle, but as Dave (Owen_Dyneto) stipulates, the head nuts must be chased until they no longer need torquing. I'm willing to bet there are lots of Packard heads out there that are not at 'max-torque'! Chris
Posted on: 2019/7/6 19:02
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'If you think you can, or you think you can't - you're right!' Henry Ford.
1939 Packard Six, Model 1700 |
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Thank you all for your input. As I'm piecing this all together it has dawned on me that I have been seeing this odd looking 'foam' of sorts in the radiator. I'm willing to bet it all on the head gasket. And now the more I think of it I only torqued the head down once after I got it back from the machine shop. I'm also thinking that maybe I should add another washer on the bottom of those acorn nuts - maybe they're bottoming out on the stud making the torque reading not really mean what it should.
Well now the next question - should I go with Olson's gaskets for a head gasket or do you all recommend another vendor? Is there another vendor for that matter? Thanks again for the help. I'll take a head gasket over a stuck valve - I think... -Crin
Posted on: 2019/7/6 21:10
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Hi,
One more question for you all. I saw this in one of the online manuals regarding cylinder head tightening (please see the attached picture). It mentions using a specific torque wrench and apply 150-160 as indicated on that wrench. My little engineering brain is telling me those numbers are in-lbs. I just want to verify that with you all. I would imagine 150 ft-lbs would torque the stud clear off the block. Thanks, Crin Attach file: (58.70 KB)
Posted on: 2019/7/6 21:36
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Re: 1936 - standard 8 - spitting up through carb
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Forum Ambassador
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Those are arbitrary units, neither ft-lbs nor inch-lbs. 60 ft-lbs would correspond to 720 inch-lbs.
Posted on: 2019/7/6 21:43
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Re: 1936 - standard 8 - spitting up through carb
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Home away from home
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Hmmm... So if I have a modern day torque wrench, what would I need to torque the head nuts to?
Thanks Crin
Posted on: 2019/7/6 22:58
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