Author Topic: Questions..Piston Pin removal and crankcase high pressure clean  (Read 4303 times)

matt

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It has finally arrived!!


I took delivery of a new Jkson 8/1 and I am now stripping it down to clean it out as per George's CD. (and Quinn's excellent kit engine report).

I have to say that despite hours of reading and studying the CS design, nothing prepared me for the the great sense of satisfaction when I first took off the inspection cover and beheld that massive crank and con-rod!!! ;D ;D ;D.

WOW.  This is some seriously heavy duty powerplant!!

The sump was pretty clean and the crank case internal paint job supurb....but there was a little grit on top of the piston and on the Head Gasket. Also a tiny amount of scoring from grit inside an otherwise shiny new Big-End bearing. Also a slight horizontal scratch on the crank journal which I will polish out using the "shoe-lace" method.

I am not taking any further chances on grit so I am completely tearing it down to clean, and now I have come across 2 issues that I need advise on......


1....
How do I remove the piston pin? That thing is sure in there tight !!!

2.......
George says to high pressure water clean the inside of the crankcase. Will this actually remove the paint? ( my crankcase is finished in red oxide undercoat type paint)
Or should I use the Quinn method of a 24 hour "Drain-o" bath.
(I wonder what he did with the drain-o water mix when he was finished???).

It is just that the paint job looks so darnn smooth.
I have poked around and have found no sand pockets at all. Am I beeing fooled by the smooth paint?
If a water blasting will remove it I will do that. The "acid" bath at this stage is not really an option for me.


Other than the over use of body filler, I am pleasantly suprised that the machiening of the case/block/head seems pretty good and better than I expected.

Thanks in advance for any advise

Matt


jimdunne

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #1 on: April 28, 2008, 03:13:31 PM »
Hello Matt,
Contrary to what has been stated earlier here, the blocks are painted on the inside to insure that there are no seeps/leaks of oil to the outside through porous cast iron, NOT to cover sand.

It works, and is a low-cost, low-tech solution.

I just wiped mine down and it came out fine. Also, you don't have to remove the pin, just slide the piston and rod out as an assembly.




ronmar

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #2 on: April 28, 2008, 04:02:17 PM »
Hello Matt,
Contrary to what has been stated earlier here, the blocks are painted on the inside to insure that there are no seeps/leaks of oil to the outside through porous cast iron, NOT to cover sand.

It works, and is a low-cost, low-tech solution.

I just wiped mine down and it came out fine. Also, you don't have to remove the pin, just slide the piston and rod out as an assembly.

Jim

   Sealing the porus cast iron metal is the justification behind the paint, unfortunatly if the case was not properly cleaned before the application of that paint, it may have trapped sand behind the paint.  Paint is not very strong.  It gains it's strength by the bond with the surface material.  If the surface material that it is bonded to, like sand, is not itself bonded to the cast iron, it can come off in big flakes, and release the sand it is hideing into the case...

Not only did I find sand in my case, I found a rather large area, covered with sand and NO paint at all.  The upper surface of the sump tip-out section where the oil fill hatch was on the original lister singles had a large area of attached sand.  You can't see this area, and the only way I found it was by feel.  Once the rod, cylinder and piston are out of the way, I could look at part of the area with a inspection mirror.  It was a real bear to reach and clean, which is why it wasn't done properly in the first place... 

I found the most sand in the cylinder water passages.  Once I pressed the liner out, and started clenaing up the coolant passages, I found it caked to the casting all over the place. 

Ron




« Last Edit: April 28, 2008, 08:20:44 PM by ronmar »
PS 6/1 - ST-5.

MacGyver

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #3 on: April 28, 2008, 04:05:55 PM »
My JKson 6/1 had PLENTY of sand well hidden under the paint. A good fat teaspoonful total.

Take a pointy instrument and really poke around at that paint. Any lumps or irregularities in the paint need to be poked at to see what's there. Sometimes it's just a bump in the iron, sometimes it's a painted lump of sand. Especially check in corners and in the sump area. Mine had a lot of sand stuck to the roof of the sump in the hardest to reach places.  I also found a small amount of sand in the head, in the intake and exhaust ports and inside the combustion chamber.

Maybe yours doesn't have any sand. Or maybe like mine it just doesn't have any *obvious* sand.
Be diligent about the sand thing. I was surprised how much mine had once I started really looking for it.

I doubt that pressure washing will remove much of the paint. The lye bath does a great job on the paint and body filler. I didn't do my block, but I did soak some of the smaller parts and all the painted nuts and bolts in lye to remove the paint.

I heated my piston up in the oven to about 300F and the pin pressed out fairly easily.

Congratulations on your new toy!
Steve

JKson (PS) 6/1 'roid & ST 7.5

matt

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #4 on: April 28, 2008, 11:59:20 PM »
Hello Matt,
Contrary to what has been stated earlier here, the blocks are painted on the inside to insure that there are no seeps/leaks of oil to the outside through porous cast iron, NOT to cover sand.

It works, and is a low-cost, low-tech solution.

I just wiped mine down and it came out fine. Also, you don't have to remove the pin, just slide the piston and rod out as an assembly.

Jim

   Sealing the porus cast iron metal is the justification behind the paint, unfortunatly if the case was not properly cleaned before the application of that paint, it may have trapped sand behind the paint.  Paint is not very strong.  It gains it's strength by the bond with the surface material.  If the surface material that it is bonded to, like sand, is not itself bonded to the cast iron, it can come off in big flakes, and release the sand it is hideing into the case...

Not only did I find sand in my case, I found a rather large area, covered with sand and NO paint at all.  The upper surface of the sump tip-out section where the oil fill hatch was on the original lister singles had a large area of attached sand.  You can't see this area, and the only way I found it was by feel.  Once the rod, cylinder and piston are out of the way, I could look at part of the area with a inspection mirror.  It was a real bear to reach and clean, which is why it wasn't done properly in the first place... 

I found the most sand in the cylinder water passages.  Once I pressed the liner out, and started clenaing up the coolant passages, I found it caked to the casting all over the place. 

Ron








Wow I didn't even think of checking under the top of the lower sump...thanks for the tip Ron. I haven'y yet removed the cylinder liner but i have had a look and feel and it seems to be quite sandy in the block.

MacGyver, what did you do to the crankcase to ensure there was no more sand under the paint than already found ?
How did you press out the piston pin when hot? Is that 300deg Farenheight or Celcius?

Maybe a step by step guide...."Pin removal for Dummies"   (because I am one) :D


Thanks all for the well wishes,

Matt

MacGyver

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #5 on: April 29, 2008, 12:39:21 AM »
MacGyver, what did you do to the crankcase to ensure there was no more sand under the paint than already found ?

I'm not at all sure that there's no more sand hiding under paint...
But I was quite thorough with my pick, and I *hope* there's no more.
I think the only way to be 100% sure is to chemically strip *all* the pant off.

Quote
How did you press out the piston pin when hot? Is that 300deg Farenheight or Celcius?

300F.
I have a wooden V-block I cut out of a piece of 4x4. (made it years ago for just this type of event. I laid the piston in it and and drove the pin out with a big brass rod and a hammer. Once the assembly was hot I didn't have to whack it hard. Just tapped it gently out. Reassembly is similar but even easier, because if you start with a hot piston and a cold pin it will just push in by hand *if* you move fast and get the pin all the way in place before the temperatures equalize.
A hydraulic press would be better, but I sold mine years ago rather than move it yet again..

Don't forget to scrub that piston good when the pin, rod, and rings are off. Mine had quite a lot of grit under the top of the piston.

Steve

JKson (PS) 6/1 'roid & ST 7.5

matt

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Re: Questions..Piston Pin removal and crankcase high pressure clean
« Reply #6 on: April 29, 2008, 03:20:51 AM »
Thnks for the info MacGyver ;D ;D ;D

I will have a go at making a v-block out of 4x4 like yours and heating it up.


Did you find sand in the hard to access top of the lower sump like Ron?

Matt