Morgan Wright

1918 E-49 starter/generator restoration job

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I dropped piston 5 today and what a mess. The amount of carbon jammed in the rings and ring grooves was unbelievable. The carbon was all loose due to all the solvents I used to untick the engine, ranging from acetone and brake fluid mix, toluene and ATF mix, carb cleaner, brake cleaner, but the carbon was stuck UNDER the rings. I wish I took a pic before I wiped it off but I'll take a pic when I drop the next piston.

 

I thought cleaning out the carbon would fix the problem with the rings, but I found out the rings were extremely worn down, by measuring the ring gap. I will show you next post.

 

Here is the bore. Clean, smooth, no gouging. This pic also answers the question of whether valves can drop into the cylinder.

DSCN2686.JPG

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Posted (edited)

I put one of the rings into the cylinder to see the gap. It's supposed to go by the rule of 0.004 for every inch of bore, so a 3  3/8 bore would be 0.014. But the Buick manual says no less than 0.030. Look at the pic, the gap was 0.120!!!!! These rings are shot!!!!!!!!!!!!!!!!!!!!!!!!!!

RingGAP.jpg

Edited by Morgan Wright (see edit history)

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6 minutes ago, DonMicheletti said:

Are you going to pull the other pistons too?

 

What is the ring side clearance?

 

Yeah, I'm doing all the pistons, might as well do it right. 

 

The ring side clearance............The diameter of the rings when fully compressed to zero gap is 3.32 inches but the diameter of the piston skirt is 3.36. The ring fully expanded by its spring pressure is 3.40 but the gap is huge at that point, when you compress the ring to the same diameter of the piston, the gap is .11 that is terrible.

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Dave at Otto machine told me that end clearance on my 1922 should be between15 and 50 thousands.    I too have 3 3/8 bore.

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Morgan,

I mean the side clearance between the ring and its grove.  Are the groves OK?

 

The .120" end gap is huge.

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6 hours ago, DonMicheletti said:

Morgan,

I mean the side clearance between the ring and its grove.  Are the groves OK?

 

The .120" end gap is huge.

 

Makes you think that piston 5 was being carried along by the other pistons, like 5 guys on a work crew and the 6th guy is Bernie Sanders.

  • Haha 2

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The amount of carbon you removed pointed to a ring issue.

 

The nice thing about these engines is that valve guide wear is not a contributor to oil consumption nor carbon.

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