L28 full rebuild assembly

[Av8ferg]

Thanks guys. Moving forward!
So, I’ve read about people weighing the piston assemblies but don’t have the details or what the benefits are. Smother running engine? I guess you find the lightest assembly and find a place to remove material from the others the get close to the lightest? I don’t want to remove the rod from the piston because I don’t have the tools to properly set the pin back in, so not sure if you have to do that. Didn’t really follow railroad tie process you mentioned


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[Mark Maras]

 If you don't want to separate the rods from the pistons, weigh the assemblies. It's not as good as weighing items separately but it will give you more info. 

[Patcon]

That kanga link that was posted recently has some good info. One video was balancing piston assemblies

[Captain Obvious]

Is the cheapo HF scale good enough to do the weight matching? Mine has resolution down to 1g (in theory). I have no idea how accurate it is on an absolute reading, but it ought to be reasonably good at relative (comparative) measurements.

You don't care much about the absolute number... You just want to see if they're all the same.

 

[Av8ferg]

Thanks, now I feel compelled to weigh my assemblies and see where they are. Ordering a scale from Amazon now that is accurate within .5 grams.
Home Built By Jeff posted a video of him balancing his pistons assemblies. He did it with pistons connected to rods. Down the rabbit hole I go.


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[240260280]

How to increase resolution:

[siteunseen]

I ground the weight off the skinny side of the rods with a die grinder. Up and down both sides until they weighed.

[Av8ferg]

Just ordered a scale with a .1g accuracy on Amazon for $16.99

https://www.amazon.com/gp/aw/d/B07MP1Y746?ref=ppx_pt2_mob_b_prod_image

Don’t think I’ll be able to trim the skinny end of the rods while attached so whatever differences I find will come off the caps I guess.


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[Patcon]

You really want to balance the pistons separately if you are going to do it. The rods should be balanced big end and little end. If you are going to do it, I would have the shop separate them for you then heat and reassemble when done. Fairly inexpensive to have done. If you're going to spend the time, might as well do it the best way possible

You could probably come up with a way to separate them at home. a couple of sockets and a C clamp or something but you need to heat the small end to reassemble them.

Edited December 7, 2019 by Patcon

[Av8ferg]

Well, as you guys know I’ve been cleaning pistons all week. Like many of you, I have a case of OCD and I cannot let things not just okay. I know it’s not necessary to clean the underside of the pistons immaculately but I couldn’t leave them nasty looking. It would bother me to leave them like that. Like when Steve Jobs asked his engineers when looking at the iPhone prototype he asked what the screws were made of. When they told him normal steel he wasn’t happy and wanted them to be stainless steel. They said “no one will ever know and it would be more expensive”. He responded “ I don’t care...I will know” That’s the story I was told not sure if it factual but it makes my point.

So I’ve been cleaning the inside of the pistons...if you think the top is hard it’s worse under due to tight crannies and grooves. I’ve experimented with a lot of products this week. Here’s my rating on their ability to remove carbon residue. Scale is 1-10. 10 is best (this isn’t Asia where #1 is best)

 

WD-40 = 5/10

Acetone = 6/10

Mineral Spirits = 2/10

Sea foam 2/10

Carb Cleaner 8/10

Purple Power 9/10

 

I had a bottle of purple power on my shelf already. Said, what the heck let me try it. Sprayed it on the underside of the piston and walked away for 10 mins. Came back and there was a black puddle under the piston. This stuff is amazing. No scrubbing, no wire brush or scotch brite. Wipe clean with a shop towel and hit with a blast of carb cleaner and....boom spotless!!!

Check it out below.

10 min soak and 5 min to wipe clean and hit with carb cleaner .

 

Unbelievable!!

 

 

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[240260280]

Ultrasonic works nice too but your purple beats it.  Nice info! Thanks!

 

 

[Captain Obvious]

I pulled my ultrasonic off the shelf a couple days ago to see if it was large enough to fit the piston top inside to clean the ring grooves, and it's not only large enough for that, but it's actually large enough to accept an entire piston AND rod.

Sounds like I should get myself a bottle of Purple Power as my cleaner liquid for the US!