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Replacing Piston Rings......HELP Please.


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#1 Phlebmaster

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Posted 28 May 2008 - 11:50 AM

As you may have seen in my "phlebmaster's 620 evolution" thread, I have done the top end of my motor and the timing components. Now I still have to replace the piston rings....she smokes. :mad: I was rushed to get her on the road because my family car bit the dust.... :(

OK...now I have seen some of the other threads about rebuilding the engine and I still have a question. First, can this be done without taking the motor out? Second, can this be done without taking out the crankshaft? If yes to #1 then the second answer is obvious. :lol:

I want to do it right, but here is what I was thinking. I was going to pull the head, pull the cross bar so I can pull the pan, then I planned on loostening the rods starting with #1 and pushing the piston up and out. Then I would hone the cylinder of course, replace the rings and using a piston ring compressor, push the piston back down into the cylinder. Then reassemble the rod to the crankshaft. What else would I need to replace?

Please tell me if I am missing a step here with what I plan to do....

Thanks again guys..:D
Thanks, Aaron
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#2 ]2eDeYe

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Posted 28 May 2008 - 12:00 PM

Yes to both questions. You'll want to pull your crossmember to get the oilpan out of the way.

Check the cylinders for out-of-round (if they are out of spec get the block machined, you'll have to pull it out of the truck for that) and make sure you gap your rings before you install them onto the pistons. Double check the indexing of the ring gap before you install the pistons.

These procedures are shown in your service manual.

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620 KA24 Motor Mount Swap Brackets

1977 620 KingCab Deluxe KA24DE Swap - Refresh and cleanup
1978 620 kingcab 4x4 - KA24E SAS w/Dana 44 front and Toyota rear

1967 RL411 Station Wagon

 

Whenever I think that I'm out of my mind for putting this much time and money into an old Datsun, all I have to do is look some of your threads to know that I'm not nearly as whack as you are.

You're going to skin a few knuckles, stand up too fast and bump your head, hunt around the floor for the nuts and bolts you dropped, invent a few new cuss words and when you're finished you'll say "That wasn't so hard after all!"


#3 Phlebmaster

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Posted 28 May 2008 - 01:38 PM

Thanks Redeye!! :cool:

I have never ventured this far into a motor before so I have to ask some seemingly basic questions. What do you mean by gapping the piston rings before I install them on the piston??:o I will read, read, read.. my service manual. :D
I know that I must make sure the ring gaps(spaces) are not right on top of eachother.

Do I need a special tool to complete this project? Other than the ring compressor, honing tool, and torque wrench, and the measuring tools?
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
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To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!

#4 ]2eDeYe

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Posted 28 May 2008 - 02:34 PM

To gap the rings you just need a gap set (same set you use to adjust the valves) and a file.

Set the ring into the newly honed bore and check the end gap clearance with your gap set and file if neccesary. If the gap is to big, odds are the bore is out of spec.

The rest of the tools you have listed will do the trick for install :)

Smokin' Joe's House of Datto's

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Member- *Japanese Trucking Association*

**DATSUN FAQ** ~ If ya know it, post it ~ If ya don't know it, learn it ~

ratsun.net rising sun stickers                     ratsun business cards order thread

620 KA24 Motor Mount Swap Brackets

1977 620 KingCab Deluxe KA24DE Swap - Refresh and cleanup
1978 620 kingcab 4x4 - KA24E SAS w/Dana 44 front and Toyota rear

1967 RL411 Station Wagon

 

Whenever I think that I'm out of my mind for putting this much time and money into an old Datsun, all I have to do is look some of your threads to know that I'm not nearly as whack as you are.

You're going to skin a few knuckles, stand up too fast and bump your head, hunt around the floor for the nuts and bolts you dropped, invent a few new cuss words and when you're finished you'll say "That wasn't so hard after all!"


#5 hang_510

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Posted 28 May 2008 - 03:43 PM

im gonna try this method for the first time... real soon :blink:


yeah, crossbar=crossmember

"I can spend time working on the Dattos, or wasting money at the strip club. You make the call." :D


I'll put on chain mail and a dirt bike tire jock strap and drive it!!!!!


#6 Phlebmaster

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Posted 28 May 2008 - 03:45 PM

2eDeYe;61113']To gap the rings you just need a gap set (same set you use to adjust the valves) and a file.

Set the ring into the newly honed bore and check the end gap clearance with your gap set and file if neccesary. If the gap is to big, odds are the bore is out of spec.

The rest of the tools you have listed will do the trick for install :)


Ohh....that makes sense...LOL :D I understand now.

Thanks!
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
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#7 Phlebmaster

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Posted 28 May 2008 - 03:48 PM

im gonna try this method for the first time... real soon :blink:


yeah, crossbar=crossmember


Go for it!! Let us know how you do it. I will post pics of the whole thing and keep everyone updated so I can help out the next fella who wants to try this.

crossbar=thingamajig that was put in your way so you can't get the pan off...:lol:
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
MY_YOUTUBE_VIDEOS :D
To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!

#8 datsunaholic

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Posted 29 May 2008 - 07:16 AM

While it's certainly possible I do have to mention that honing the cylinders with the crank in place isn't such a good idea. You'll get cutting oil and grit all over and in the main bearings, which won't promote optimal bearing life.

You will have to pull the timing cover and chain anyway, because I believe you will need to roll the engine over to remove and install the rods. I'ts POSSIBLE you might be able to get the rods on/off with it static, but I wouldn't count on that. Well, you'll know when you try- I mean, I managed to change the main bearings on my L20B without removing the crank, so a lot more is possible than some folks think.
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#9 Phlebmaster

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Posted 29 May 2008 - 08:32 AM

While it's certainly possible I do have to mention that honing the cylinders with the crank in place isn't such a good idea. You'll get cutting oil and grit all over and in the main bearings, which won't promote optimal bearing life.

You will have to pull the timing cover and chain anyway, because I believe you will need to roll the engine over to remove and install the rods. I'ts POSSIBLE you might be able to get the rods on/off with it static, but I wouldn't count on that. Well, you'll know when you try- I mean, I managed to change the main bearings on my L20B without removing the crank, so a lot more is possible than some folks think.


Thanks for the tips....I will make sure I cover those vital bearings with plastic or something to prevent damage. And I will be buying a timing cover gasket kit too. I know that the rings come in standard, .020, .030 sizes. Would I only use the larger sizes if my cylinder was bored over to .020 or .030? Or will this be determined by how much wear I have on my cylinder walls? :D

I know...measure it:rolleyes:, but I was hoping to have all of the parts when I get started and not have to wait until I pull the motor apart to order those rings. I hate waiting!! :lol:
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
MY_YOUTUBE_VIDEOS :D
To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!

#10 ]2eDeYe

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Posted 29 May 2008 - 09:41 AM

Yep, measure first. Then you'll know if you need to overbore and also what rings you will need.

Smokin' Joe's House of Datto's

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Member- *Japanese Trucking Association*

**DATSUN FAQ** ~ If ya know it, post it ~ If ya don't know it, learn it ~

ratsun.net rising sun stickers                     ratsun business cards order thread

620 KA24 Motor Mount Swap Brackets

1977 620 KingCab Deluxe KA24DE Swap - Refresh and cleanup
1978 620 kingcab 4x4 - KA24E SAS w/Dana 44 front and Toyota rear

1967 RL411 Station Wagon

 

Whenever I think that I'm out of my mind for putting this much time and money into an old Datsun, all I have to do is look some of your threads to know that I'm not nearly as whack as you are.

You're going to skin a few knuckles, stand up too fast and bump your head, hunt around the floor for the nuts and bolts you dropped, invent a few new cuss words and when you're finished you'll say "That wasn't so hard after all!"


#11 hang_510

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Posted 29 May 2008 - 10:36 AM

Yep, measure first.

and measure twice.
if its that worn, youll need new pistons, etc...


im pulling the crank to replace the bearings during my work, clean up should be effective.
just hoping i dont have to bore it...otherwise i wont be saving anything.
trying to accomplish it in 1 day too :blink:

"I can spend time working on the Dattos, or wasting money at the strip club. You make the call." :D


I'll put on chain mail and a dirt bike tire jock strap and drive it!!!!!


#12 Phlebmaster

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Posted 29 May 2008 - 11:11 AM

Brian,

Would you please take pics and post them here so I can see what you do??

PLEEEEEEZE :D

Thanks
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
MY_YOUTUBE_VIDEOS :D
To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!

#13 hang_510

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Posted 29 May 2008 - 11:17 AM

thats the plan...but for some reason i always forget my camera for the important times :cursing:

"I can spend time working on the Dattos, or wasting money at the strip club. You make the call." :D


I'll put on chain mail and a dirt bike tire jock strap and drive it!!!!!


#14 datzenmike

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Posted 29 May 2008 - 05:38 PM

Thanks for the tips....I will make sure I cover those vital bearings with plastic or something to prevent damage. And I will be buying a timing cover gasket kit too. I know that the rings come in standard, .020, .030 sizes. Would I only use the larger sizes if my cylinder was bored over to .020 or .030? Or will this be determined by how much wear I have on my cylinder walls? :D

I know...measure it:rolleyes:, but I was hoping to have all of the parts when I get started and not have to wait until I pull the motor apart to order those rings. I hate waiting!! :lol:


The pistons, old or new, have to fit snugly in the bore, something like 1 to 1.5 thousandths of an inch. Once this bore diameter is exceeded by wear, it has to be re-bored to match a new oversize piston and ring set. You cannot use the old pistons with a larger ring set to make up for bore wear. The rings won't be properly supported by the piston and the piston will rattle around in the loose fitting bore.

A block is always bored to match the piston diameter. Each piston is carefully measured and the bore calculated and only then is it bored.

Having said all this... It's quite possible that the rings can be worn out, yet the bore is still within specs. So yes a cylinder hone to rough it up so the rings will 'wear in' should do it. Place each ring in the bore and push down in about an inch with an inverted piston to position it properly and measure the small gap. Top ring gaps are approximately 0.016", second rings are 0.12" and so on. Top rings have a larger gap because they are closer to the top and get much hotter and expand more than the next ones down. Ring gap on a worn bore will likely be bigger than too small.
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#15 flyerdan

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Posted 29 May 2008 - 07:02 PM

One thing that I haven't seen anyone mention is the need for a ridge reamer to shave off the ridge. It doesn't take much of a ridge to keep a ringed piston from coming out, especially since you'll pretty much be pushing up on them with a stick of some sort.
Another thing that is covered in every repair manual but bears repeating is to put a piece of rubber tubing over the rod bolts before installing the assembly to avoid putting a big ol' scratch on that shiny crank journal.

#16 datzenmike

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Posted 29 May 2008 - 07:49 PM

Used one back in the early '70s on my slant six. The thing with newer cars vs. the '50s and '60s is you don't seem to get as much ridge on them. I don't think I'm imagining this. I've pulled lots of L and Z series engines apart and hardly any ridge on them. Better design and materials maybe.

Know what you mean though. Forcing the ring over the ridge risks breaking the ring lands.
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#17 Phlebmaster

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Posted 30 May 2008 - 03:47 AM

I will have one on the ready just in case.....but I did not feel more than a slight variation in the cylinder wall at the top......Very slight.

But better safe than sorry I'm sure. :D I can't wait to get started!!

My next question then....does anyone local have one I could borrow for this project? Oh...and that funny looking ring expander tool and grove cleaning tool??
:cool:
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
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To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!

#18 hang_510

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Posted 30 May 2008 - 11:42 AM

autozone may rent it...
i have a huge assortment of dentals tool for groovin'

thats the plan...

no longer the plan, i wanna paint the block/eng bay so its coming out...

"I can spend time working on the Dattos, or wasting money at the strip club. You make the call." :D


I'll put on chain mail and a dirt bike tire jock strap and drive it!!!!!


#19 datzenmike

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Posted 30 May 2008 - 04:11 PM

I will have one on the ready just in case.....but I did not feel more than a slight variation in the cylinder wall at the top......Very slight.

But better safe than sorry I'm sure. :D I can't wait to get started!!

My next question then....does anyone local have one I could borrow for this project? Oh...and that funny looking ring expander tool and grove cleaning tool??
:cool:


You can use a piece of broken ring to clean the groove too. Just do NOT gouge it or remove any metal from the ring land. A small wire wheel maybe would work too, but use a soft metal like brass. There are two longitudinal slots behind the oil control rings. Be sure they are clear. Think of the oil rings as squeegees wiping the oil off the cylinder walls. This oil needs a path back to the crank case.
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#20 Phlebmaster

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Posted 30 May 2008 - 04:16 PM

Got it! I have a dremmel tool with some soft wire wheels. :D

I have a friend who will lend me his "re-ring-ing kit" :lol: So I will have all the right tools to get it done.

Thanks some more! :cool:
Thanks, Aaron
Life is about making dreams come true, stop dreaming and make life happen. ;)
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To keep an opened mind- speculation is devine.
Assumptions always lead to a dead end!