My first post on the new site!
I’m disassembling a motor that’s been left outside for 10 years.
The bores are rusted badly, and the pistons are well stuck. I tried removing the big end cap, and driving the piston up or down, but they didn’t move.
I assume for a rebuild the pistons would have to be broken up to get them out. How might this be done? Or maybe torches?
Does anyone have an idea?
Thanks,
Rob
I dealt with the same thing with an XK140 engine my brother found abandoned in a field. Quite a trick getting the split pins out of the rod nuts when you can’t turn the crankshaft.
Anyway I presume you have the crankshaft out already.
Clean out all the rust you can reach in the bores.
You are right to assume you sacrifice the pistons to save the block.
But first try soaking the piston tops with PB Blaster or Kroil or kerosene or diesel fuel for a month or two. Then try a propane torch and ice for a few thermocycles. Don’t hurry, this may take another month. Dry ice or liquid nitrogen is even colder but dangerous to work with.
If you’ve tried all that, the last thing is to cut the pistons apart in a milling machine.
Hi Rob
One method I’ve used as a last resort, is to chain drill out the piston crown. A 3.4 XK I stripped once, had pistons so siezed that even a twenty five ton press wouldn’t move two of them! After reverting to the drilling out method, they both came out after a sharp clout with a big hammer and a stout piece of wood!
Thank you both, I’ll let you know how I make out.
Cheers,
Rob
Has anyone ever considered whether using an ultrasonic bath cleaner might work in this context?
These are small capacity baths into which you can place dirty fuel injectors or what have you, and then use an appropriate solvent to work itself at the internal and external surfaces using high frequency vibration. What I would envisage is that you dismantle one of these machines, extend the wiring to the vibrating platform/disc (which normally attaches to the base of the bath) and attach it to the stuck cylinder. Effectively, you’d be massaging in the PBblaster into every tiny micropore. Another alternative might be to look at a product like Evaporust, which is a chelating agent - once it attaches itself to rust, it takes it up into solution to free the remaining rusty surface to be chemically attacked by the next wave of solution.
I haven’t particularly thought about what state that leaves the remaining liners/block in. Others can chime in. This may give you one more attempt at the job before brute force inevitably takes over.
kind regards
Marek
So your idea is to put the vibrator down in the cylinder on top of the piston and fill the top with penetrating oil. Intriguing idea, if anybody tries it let us know if it works.
Here is the website for Evaporust.
I also found:
http://www.orisonmarketing.com/evapo-rust.html
I noticed in the testimonials there are a couple of shots of somebody using this stuff on his E-type body, and somebody derusting motorcycle carbs that had stuck parts and the parts came apart.
Again let us know if this works.
Rob, Marek,
I use an ultrasonic bath quite a bit, not just for bits from the car, but also for clocks and watches. It is excellent for removing dirt, oils, and surface contaminants (like Brasso or wax) but it would need to be a pretty powerful unit to remove rust.
Generally speaking, the thinner the fluid, the more effective the US cleaning is. I normally just use water, sometimes with soap, sometimes with citric acid. I also sometimes use solvents (Alcohol or terpentine), but they evaporate very quickly!
With a thin fluid like evaporust, or hammerite rust remover (aqueous citric acid) you would aid in circulation if you just put one of those mist generators down each bore and immersed it in the solution. It wouldn’t have enough power to remove the rust itself, but it would probably help keep fresh fluid at the surfaces where it is needed.
Here is a place that sells transducers and driver units: https://www.steminc.com/PZT/en/ if you want to make a larger bath - I would say a pair of 100W bolt on transducers with a suitable driver would make a kitchen sink sized cleaning bath. But be aware, although you end up using water as your cleaning fluid the noise the things make is a lot more annoying than a solvent based cleaning tank.
And the cat will give you a look like he has just been shot with a machine gun and shoot out of the kitchen/garage at warp speed when you turn it on.
kind regards
Marek
Greetings All,
Rob, I ended up taking a 3/4" thick plate of steel and mimicking the stud pattern, along with drilling a clearance hole and welding a fine thread 1" nut to the center of the plate.
The fitting of the plate necessitates 4 pipe nipples of equal length to space it high enough for a cylindrical aluminum piece that has been machined to engage the piston around the dome.
A piece of 1" fine thread rod, with a nut welded on one end.
This whole thing, when tightened and locked up allows you to use the 1" rod to drive the piston out the bottom. Crank has to be out obviously.
Liberal use of PB Blaster helps.
Had one that was really bad, and wanted to save the block. I thermally cycled it using a small hot water heater and a zone pump on a timer. Took over a month, but once hooked up, just had to check on it occasionally.
Contact me if interested, I may be able to put my hands on the fixture.
Yes, aware the stud could break, but having access to a sinker EDM I wasn’t worried.