Tom hodkin Posted April 24, 2019 Share Posted April 24, 2019 I’m new to this car so please help me. I did a compression test and have 70-80 psi per cylinder. The guy who had it before installed a different distributor and down draft Rochester carb fed with a electric fuel pump. I just can not get it to run correctly. Plugs show too much fuel black sooty looking. Any help you can give will be appreciated. I’m vacationing this week going to Carlyle swap meet this week. Hope to meet some of you guys there.. thanks in advance. Link to comment Share on other sites More sharing options...
Hubert_25-25 Posted April 24, 2019 Share Posted April 24, 2019 Tom, That is pretty good compression. These cars are 4.5 to 1 compression ratio. Modern cars are 8 to 1 or better. A vacuum gauge reading on the intake manifold should be 13-14 mm Hg and steady. Distributor changes are common as Buick used pot metal on the housing. A change to the distributor should not really effect the car like a change in the carburetor or the condition of the carburetor. Hugh Link to comment Share on other sites More sharing options...
Spinneyhill Posted April 25, 2019 Share Posted April 25, 2019 Gauge reading should be about 68 p.s.i. assuming about 80% volumetric efficiency in your engine and 4.5:1 compression ratio. Higher values may mean the head has been planed. The formula is here: Link to comment Share on other sites More sharing options...
Morgan Wright Posted April 25, 2019 Share Posted April 25, 2019 Is this the formula? (14.7 x .8 x 4.51.3 ) - 14.7 I can't do 4.51.3 in my head Link to comment Share on other sites More sharing options...
Larry Schramm Posted April 25, 2019 Share Posted April 25, 2019 I would guess that the electric fuel pump could be the problem. You should have maybe 1-2 psi at the carb. More than that you could be over running the carb/float with fuel causing the car to run rich. Just a thought. Link to comment Share on other sites More sharing options...
Spinneyhill Posted April 25, 2019 Share Posted April 25, 2019 (edited) 15 hours ago, Morgan Wright said: Is this the formula? (14.7 x .8 x 4.51.3 ) - 14.7 I can't do 4.51.3 in my head Yes. 4.51.3 is damned hard in one's head. In my first life, before calculators, I would have done it with reference to Chamber's seven figure log tables, or maybe on my slide rule. Edited April 25, 2019 by Spinneyhill (see edit history) 1 Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted April 25, 2019 Share Posted April 25, 2019 Do you have a fuel regulator incorporated into the system and know the flow rate of the pump ? I had this same issue on my 40 Ford when I installed an electric pump to do away with vapor lock. I just had to decrease the pressure a 1/2 pound. Link to comment Share on other sites More sharing options...
Morgan Wright Posted April 26, 2019 Share Posted April 26, 2019 On 4/25/2019 at 6:07 AM, Spinneyhill said: Yes. 4.51.3 is damned hard in one's head. In my first life, before calculators, I would have done it with reference to Chamber's seven figure log tables, or maybe on my slide rule. Don't knock slide rules......we got men to the moon on slide rules. Link to comment Share on other sites More sharing options...
dracenroc Posted April 26, 2019 Share Posted April 26, 2019 Tom, book says 80 pounds for a 28' master, don't know the engine specs of a '26 master but with your 70-80 psi your compression should be ok. Link to comment Share on other sites More sharing options...
Morgan Wright Posted April 27, 2019 Share Posted April 27, 2019 What does the book say for a model E-49? Link to comment Share on other sites More sharing options...
Larry Schramm Posted April 27, 2019 Share Posted April 27, 2019 (edited) I still have my slide rule that was my Dad's in college. I used it through high school and the first couple of years of college. It is a K&E brand. Edited April 27, 2019 by Larry Schramm (see edit history) 2 Link to comment Share on other sites More sharing options...
dracenroc Posted April 27, 2019 Share Posted April 27, 2019 1 hour ago, Morgan Wright said: What does the book say for a model E-49? Don't know, the pressure for the '28 standard is given as 93 pounds Link to comment Share on other sites More sharing options...
Buicknutty Posted April 28, 2019 Share Posted April 28, 2019 On 4/26/2019 at 9:11 PM, Larry Schramm said: I still have my slide rule that was my Dad's in college. I still have the one my Dad used to. Tried to give it to my son, who was about 16 at the time, and told him it was his Grandfather's computer. He just looked at me like I had turned into an alien. Sorry, not trying to hijack your thread! Keith 1 1 Link to comment Share on other sites More sharing options...
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