Kroil

J

jerryinid

New member
Mm
I have read many of your post and I have enjoyed all of them, but it seems like there is allways more questions than answers. So my latest question has to do with the use of kroil for freeing rusted pistons. I have a donner 392 out of a loadstar that I was/am going to put in another loadstar, however I made the mistake of exposing the engine to a north idaho winter with out cover. I then let the engine sit for a year before starting to tear it down. Was I surprized and disappointed. Currently, I have 4 of the pistons out and 2 that have been soaking in marvel mystery oil for at least a week. I have read the hype and success of kroil and just wanted to know what your experience ,if any, has been. I am determined to bring this engine back to life one way or another.
The engine appears to be in almost stock condition. The 4 cyl. That I have removed pistons from have mic out at 4.125 after honing and rust removal. The rod journels that are exposed mic out at 2.373. And there was/is no ring ridge on any of the cyls.
Any comment or suggestion would certainly be appreciated

jerry
 
I definitely feel that kroil is superior to any other form of "penetrant" on the market!

I recently had to do some spring u-bolt removal as described in this thread:

http://www.forums.IHPartsAmerica.com/readers-rides/2945-beaters-third-life.html

As you can see those u-bolts on the d70 axle are really rusty! So I used a power wire brush to buff as much of the threads as I could access. Then doped with kroil. Everything broke loose but was still too difficult to remove without ruining threads.

I noticed that the kroil has a very high "solvent" action and it nearly completely evaporates after about an hour of exposure to the atmosphere, leaving hardly any oily residue at all! So I next used some "breakfree" lube which is the best I think for stainless steel actions on automatic pistols and applied, you could see the penetrating action of that stuff also as it migrated into the threads. Then I applied the kroil again,...that combo was the magic bullet dude!

So you might try a similar concoction!

I'd busted out many engines just as bad as you describe, you will waste the pistons anyway. But if you can get all the rods free so the crank can be removed, then apply the dope and start "vibrating" the piston domes with a large drift and hammer, you will set up a much better penetrating action.

Along with that trick, I normally use the gas axe to heat the piston dome also, then as it cools keep applying dope, the heats creates a wicking action that draws the penetrant into the piston ring/cylinder seizure zone.

Above all else, this takes a great deal of patience and manipulation, normally over several days of back and forth! My focus is to always save the block and crank (and rods) if possible). Replacement pistons are not an issue to obtain, and the block will have to be bored again anyway (most likely but maybe not)!

By the way, my former father-in-law who I've always regarded as a true mentor for helping me develop my car/truck fixxin' skills, swore by the use of controlled application of heat, along with water as the penetrant!!! His theory was the heat "excited" the metals, and that water will penterate through anything and start slipping the corrosion bond. I've seen him go through the same struggle as you using heat/water to finally create some movement, then that allowed of his favorite penetrating oil, old-fashioned "3-in-1"!
 
This subject came up recently over on bp...yeah, I know, I know. Anyway, one of the posters, c/p'd the results of a field test conducted by some outfit that took the top 5 commercially available lubricants and applied them to stuck fasteners and then measured the amount of torque necessary to break them loose. I don't recall all the specific controls, but all the bolt stock exhibited identical corrosion charcteristics. I imagine they employed a standard soak duration of x amount of hours across the board. Kroil came in a close 2nd. 1st place went to a 50/50 mix of atf and acetone.
 
I think that I will give it a try. Will order a gallon tomorrow and see what happens when it gets here. In the mean time I will continue soaking with marvel mystery oil and will try scoutboys 50/50 solution. Will keep you posted with the results

jerry
 
As noted in the previos post, I tried scoutboy 74's suggestion. A 50/50 mixture of acetone and atf. It did not work for me even with multiple applications. In my opinion, the reason it did not work is that the evaperation rate of the acetone left just atf after a day or two. So I order a gallon of kroil which I received this week and have started the "soaking" process in the remaining cylinders.
I don't doubt the success that others have had with the 50/50 mixture, but what I found was that they were removing bolts that were rusted as opposed to pistons that are rusted in a cylinder. Hope the kroil helps

jerry
 
I agree with ya jerry! There are certain applications of any shop chemical which work better than others.

And the kroil when used on say a exposed bolt thread will evaporate overnite also, though it does leave a lubricant residue.

We're going to be looking at the penetrant produced by swepco in the future, we think it May be somewhat of a magic bullet kinda deal. I used my latest find,...the stuff supplied by marc recently on axle u-bolts and found it to be equivalent for that use to kroil, but not better and it evaporates much faster. The active ingredient in it is mek.
 
This is a follow up on my experience with kroil and stuck pistons. It has been almost six weeks since I poured kroil in two of the cylinders and to date there is no visible change. I talked with the rep from kroil and his only comment was have patience. I informed him that patience equates to time and at 73 I don't have much left. In his defense, he did offer to refund my money. So where do we go from here, continue to let it soak and hopefully that it will free the pistons shortly.

Jerry
 
You are well past the "give it time" stage jerry! And I face the same kinda tickin' clock challenge you do!

What I'm thinkin' ya got here is two types of corrosion and both are present in this situation.

The aluminum pistons have reacted with the cast iron rings and the cast iron cylinder walls. And the cast iron rings have reacted with the cast iron cylinder walls.

If you see any evidence of what I call "white rust" (the results of water sitting with the aluminum and cast iron, then that condition is worse than plain old rust.

Since the ring groove area of the piston is reduced in diameter significantly as compared to the skirt area, water can just lay in there and pool over time, while both forms of corrosion start working.

The kroil is acting on the "red rust"...but not on the "white rust" if ya follow my drift.

You are now at the point of resorting to plan c. That involves a homebrew chemical mix and heat (from a propane torch, not an oxy-acetylene rig).

Try and set the engine so that both of the frozen piston crowns are parallel with the shop floor and pointing up. Hopefully there is some cylinder volume showing below the deck which will form a sort of "cup" area.

Inna quart plastic container (butter tub, tupperware, coffee can, etc., pour in two tablespoons of plain old table salt. Then add one cup of plain white vinegar and attempt to dissolve the salt, it will to a degree but not fully. Then add two cups of boiling water and stir in until the salt is dissolved. Pour that mix down into the cup above the piston crown and let it sit about two hours...no more!

Then drain out the mix or sop it up with rags. The shit is not toxic to ya and won't hurt anything but will surface rust anything it hits pretty quickly. The idea is to have this stuff penetrate the corrosion which the water /vinegar does very readily, more so than any oil will. It also chemically "converts" the white rust.

Next I'd quickly hit it with a shot of atf or even kroil, just wet it good, not pool it. The light up the propane torch and start heating the piston crown. Smoke will start up quickly and maybe a bit of flame so take proper precautions for that, but it will not flair up like gasoline or kerosene! Get the piston crown real hot (aluminum becomes plastic around 1100*f but the oxide on the surface has a higher melting point) so you will never see the base metal start to become molten like steel does. We only wanna elevate the piston crown temp to around 500*f momentarily, that helps the "action" of the penetrant product.

Then using a hardwood block and abouta 3lb. Hammer, start whacking on the piston crown and see what happens then. Yes, you will waste the piston but it's already wasted. You "might" damage the rod and journal, but that's the cost of getting the motor apart. After removing the heat, dose it with the kroil again while it's hot.

If this works, be real proud ya lernt new stuff at yore age. If it don't work, then we'll discuss plan d.
 
I have gone to plan g as in give up. The cost is going to exceed any return including satisfaction. I bought the donner loadstar for the 392 and 5 speed for my loadstar, which I only put about 3-5 miles on per year. Haven't even had it out on the road for three years. So I will stick with my 304 and 4 speed and when I do have to use it to haul gravel I will put up with the lack of power. The truck is 1966 with only 80,000 miles. Just getting broke in. Thanks for your advice and help
jerry
 
Mm
well, I didn't give up, I just went to a bigger hammer and got lucky. I took off all the main caps and reinstalled two of them so there was approximatley 1/2 inch between the cap and the crank. Then with the aid of a 4' pipe and a 1' plate on top of the pipe we use a large sledge hammer and froced the pistons downward in their cylinders until the crank bottom out on the caps. We then took the caps off and there was enough play/movement that allowed us to get the last two rod caps off which in turn allowed the crank to be removed. Once the crank was out the, removing the pistons aws a lot easier. Hopefully ther are two pictures attached which show the condition of the last four. Currently they are soaking in a pan of kroil to see if the rings will break loose. Maybe there is hope after all
 

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All it takes is lots of time and different battle plans!

Those rods are candidates for having rebuilt by the machine shop. The pistons and pins are history, no way they can ever be used! The pins are "press fit" and are normally r&r'd by the machine shops with the aid of some jigs and tooling (and a special "heater" used on the piston if needed). The pins will be badly etched from corrosion and are scrap.

The rods are worth having a machine shop analyze/rebuild, we can't get new ones any longer.
 
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