Restart the rebuild

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4spdragtop

4spdragtop

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I havent done anything other than gather more parts in 3 years. For some of those 3 years it only had a tarp thrown over top. Altho it was well oiled/stored I wasnt confident that it was clean. I decided to remove pistons, clean and reinstall.
I decided to test fit cam and measured #1 lobe lift. 0.333" intake, 0.330" exhaust. Spec is 0.331" Call it good with my lousy measuring skills.
Cam spun nice, no binding.
Test fit new MP distributor drive gear # P3690715. Good there too.
Test fit lifter in every bore, seems good there too.
The next step is to double chk piston rings. Everything seemed within spec, but the proper orientation is in question.
#'s on box 40787-30, 2m694-030.
Also inspect #7 rod journal, bearing appears to have an issue.
Oh ya, measured depth of oil gallery plug with wooden skewer, approx 7 1/2", good there.

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Best of luck my friend. I'm in worse shape that you..............
 
#7 will just have more oil floating around the main! Weird having a pit like that though. And scratches. Was your crank turned?
Good luck on the build Steve.
 
Thanks George, yes crank was machined. I'll scour over the bearings pretty good to make sure.
gdrill said:
#7 will just have more oil floating around the main! Weird having a pit like that though. And scratches. Was your crank turned?
Good luck on the build Steve.
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Since you already had the pistons in, did you come up with a static compression ratio for your build? Did you get the chambers cc'd?
 
Morning Troy, I did cc them, I'll look for the numbers. Heres where i started my build, the 1st 7 1/2 pages are fodder with me trying to decide what direction to go in engine wise lol.
CFD244 said:
Since you already had the pistons in, did you come up with a static compression ratio for your build? Did you get the chambers cc'd?
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I'm a certified weld inspector and that pit, although it is not a weld, reminds me of a slag inclusion in a stick weld. I wonder if it isn't just some casting slag that happened to be right there and got exposed when it was machined because there isn't a gouge leading up to it?
 
Thanks, I noticed a few other "pieces of interest". I think it's a cleanliness issue. I ordered 2 more bearings CB-481 P-20 locally, should be here in the morning. I'll plasti gauge the new ones. Can plastigauge get "old"? I've heard older stuff might not "read" correctly?
ACME SS said:
I'm a certified weld inspector and that pit, although it is not a weld, reminds me of a slag inclusion in a stick weld. I wonder if it isn't just some casting slag that happened to be right there and got exposed when it was machined because there isn't a gouge leading up to it?
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I believe plastigage can get old and I say that because I had some at work that would easily break. That said, when I purchased new it seemed to be good for several years.
 
So I removed the top 2 piston rings. Those were the ones that were confusing. In my initial thread, it was decided that the top ring had the dot, and the 2nd ring in fact labelled "TOP" was the 2nd ring.
When both were installed they both were within spec. It just seems real weird to me that the one labelled "TOP"is the 2nd ring.
Both are 5/64.

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Check all your lifters to make sure they have a crown.

Easy way is to place the cam end of two of them back to back and make sure they rock and are not sitting against each other flat.

Also be sure to check your cam to make sure there is no casting flash on a lobe sitting up proud of the machined surface.

Once the short block is together, mark each lifter at the top with a marker, then spin the engine over. Each lifter should rotate in its bore the same amount when the engine is rotated.

If one or more isnt rotating dont go any further until it is fixed or it will wipe out a cam lobe.
 
Good points, thanks! So took a complete piston into local machine shop. He confirmed the proper location, the dot is top ring, facing up. And the ring labelled "TOP" is 2nd ring with TOP up. So good news, I said I'm fine with buying a new set, but he said no need.
So I'll continue cleaning and check the lifters, all specs were good previous, so I'll plastigauge the 3 new bearings tomorrow.
Should I look at removing main caps for inspection? Everything was well lubed properly when installed, but finding what I did on 3 rod bearings has me wondering?
Thanks.
mgoblue9798 said:
Check all your lifters to make sure they have a crown.

Easy way is to place the cam end of two of them back to back and make sure they rock and are not sitting against each other flat.

Also be sure to check your cam to make sure there is no casting flash on a lobe sitting up proud of the machined surface.

Once the short block is together, mark each lifter at the top with a marker, then spin the engine over. Each lifter should rotate in its bore the same amount when the engine is rotated.

If one or more isnt rotating dont go any further until it is fixed or it will wipe out a cam lobe.
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So looking forward to you getting this puppy perking Steve. Thanks for the update.
 
4spdragtop said:
Good points, thanks! So took a complete piston into local machine shop. He confirmed the proper location, the dot is top ring, facing up. And the ring labelled "TOP" is 2nd ring with TOP up. So good news, I said I'm fine with buying a new set, but he said no need.
So I'll continue cleaning and check the lifters, all specs were good previous, so I'll plastigauge the 3 new bearings tomorrow.
Should I look at removing main caps for inspection? Everything was well lubed properly when installed, but finding what I did on 3 rod bearings has me wondering?
Thanks.
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No harm in checking your work if you have any questions. Much easier to deal with it now then after it is in the car.

Also if you haven't degreed the cam I would do so. I used to install them "dot to dot" on a stockish rebuild, but parts quality is so bad that there are numerous reports of cams being ground wrong and timing gears that are not machined properly.

Just isn't worth taking a chance imo on something that could have you chasing your tail trying to get a good tune after the engine is installed.
 
I'm thinking top means cylinder head side, not slot position but I could be wrong. The taper on the inside top is designed to take combustion gas pressure and apply an outward sealing force. We rebuilt Quincy compressors at the nuke plant I used to work at and they described that in their manual and in Quincy's case, they had the dot on the top. They called the dot a "pip". I don't know why one ring would have a pip and the other say top unless maybe that is supposed to be the top ring for that set?
 
Apparently the reason the "dot" is the top ring is because its moly ring. Apparently they always go top. 2nd ring should say "UP", not "TOP" in my opinion.
ACME SS said:
I'm thinking top means cylinder head side, not slot position but I could be wrong. The taper on the inside top is designed to take combustion gas pressure and apply an outward sealing force. We rebuilt Quincy compressors at the nuke plant I used to work at and they described that in their manual and in Quincy's case, they had the dot on the top. They called the dot a "pip". I don't know why one ring would have a pip and the other say top unless maybe that is supposed to be the top ring for that set?
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Not trying to muddy the waters here, but I read somewhere (probably here) that the chamfers on the compression rings.........IIRC Top ring the chamfer faces up, and the chamfer faces down on the second ring. Something to look into?
 
Thanks Troy, I had read the same thing and mentioned it, but if I remember correctly, in the situation you described is when there are reverse torsional rings involved and apparantly these arent, or the 2nd one isnt anyway.
CFD244 said:
Not trying to muddy the waters here, but I read somewhere (probably here) that the chamfers on the compression rings.........IIRC Top ring the chamfer faces up, and the chamfer faces down on the second ring. Something to look into?
Click to expand...
 
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