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Buick36-49

1936 Buick Special - 233 rod adjustment

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Hi All

Nice weather is on it’s way! Time to dust off them off and polish em up!

I am thinking that I am going to re-adjust the bottom end of my 1936 Buick Special Series 40 with a 233 cubic inch (3.8L) connecting rods. I think they maybe loose on the crank. While running the engine good and warmed up, I took off the oil pan just to “see” what they looked like. I noticed that they move very freely on the crank (end play). Also, there is a slight knock on acceleration. With the heavy oil the knock sound is less audible and reduces when warming.

This time I’m going to use a plastigage to measure the clearance between the rod and crank. All roods are Babbitt bearings and have brass shims. I want to gain at least 10 to 15 more pounds of oil pressure (hot). I am running SAE 40 weight with on quart of Lucas stabilizer and only have 29 lbs hot at 45mph and about 13 pounds idle hot.

Any suggestions? Otherwise I just wanted to post my next project.

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Have you checked the oil pressure relief valve for operation? Thirteen pounds at idle hot seems acceptable to me, but 29 lbs at 45 mph might be a little low.

Terry

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Hi Terry, yeah, I did, in fact I had a spare pump in which I stretched the spring and got more cold pressure, but hot about the same. The book calls for 45lbs @ 45mph

Thanks

Robert

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These are out of a Buick Special 40 Series

You may want to check the mains also.

Do not set the clearance less then .001 per inch of crank.

A 2 1/2 inch crank say, would have .002-50 Minumim clearance, and or not over Plus one more .000-50 thousandths.

Herm.

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Edited by herm111 (see edit history)

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[ATTACH=CONFIG]248180[/ATTACH][ATTACH=CONFIG]248178[/ATTACH][ATTACH=CONFIG]248183[/ATTACH][ATTACH=CONFIG]248181[/ATTACH][ATTACH=CONFIG]248179[/ATTACH][ATTACH=CONFIG]248177[/ATTACH][ATTACH=CONFIG]248184[/ATTACH][ATTACH=CONFIG]248182[/ATTACH]

These are out of a Buick Special 40 Series

You may want to check the mains also.

Do not set the clearance less then .001 per inch of crank.

A 2 1/2 inch crank say, would have .002-50 Minumim clearance, and or not over Plus one more .000-50 thousandths.

Herm.

Thanks Herm,

Interesting. I never done this before, but will learn how to do it. I know for a fact that this engine has brass shims (multi layers). Some are thinker than others.

I want to get the know out and increase hot pressure.

Robert

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