Re: Honing Cylinder

Basswood Thu Aug 27, 2020 4:03 am

Iceberg wrote:I have heard several thoughts on the matter.

I have a #4 cylinder that was running awesome and now it is too tight for a piston. It will allow the piston to go up and down however the friction is too high. I have tried several pistons and they all run the same in the cylinder so I believe the friction is only in the cylinder. Since it is an original #4 and was majorly kicking but before. I would like to salvage it if at all possible.

What is a way to nicely hone a cylinder that is too tight by a fraction of a thousandth or something like this one.

Scotch bright with thinner? Steel wool? Other secret remedy?

Thanks for the expert advice in advance.

Iceberg

Geesh I haven't had to much problem with tight pistons, just loose ones. Raise the octane (higher nitro) and higher compression and I guarantee you, it loosen right up in no time.. Laughing

Bob

balogh Thu Aug 27, 2020 6:07 am

Darren,

I am also happier with tight cylinders than with loose ones. My first solution would be to use the de-varnisher brush sold by Bernie...I have never tried, but cold grease remover sprays used in the kitchen to remove caked grease from ovens etc. should also act fine, without mechanically torturing the cylinder wall like de-varnisher brush does... maybe now that we talk about it, I will give it a try...

Iceberg Fri Aug 28, 2020 8:02 am

Ken Cook wrote: When I have this issue, I have a piece of tubing that fits inside the skirt of the piston. I wrap masking tape as needed around the tubing to obtain a tight fit into the skirt. Clean the cylinder free of oil and crud. I insert the piston upside down into the cylinder. I use Brasso or even Happich Simichrome as a lapping compound. I only use a little and begin to move the piston up and down in a screw like fashion. Don't just move it up or down as it travels but turn it while doing so. Spend a bit of time at the bottom of the cylinder. This keeps the drag low.I then place the piston into the cylinder the correct way and do the same but don't bring the piston up to top dead. Keep it lower in the bore by at least a 1/8". Then clean everything well in hot soapy water and dry it well. The piston should stick in the cylinder at TDC and fall out when you tap it.

Hi Ken
I did this with the tube over the connecting rod and tucked into the skirt with masking tape to tighten it. I used my Dremel polishing paste. Fought it for 10-15 minutes and it did loosen a bit. There was no bur or tightness around the ports. Just the lower half below the ports. After this I actually used a polishing pad that fit the cylinder in my Dremel for a few seconds with the paste in the lower 1/3 of the cylinder below the ports. Guess what? Cylinder is back to its screaming self again!! Why would only the lower half get so incredibly tight? The upper was still ok.

Thanks
Darren

**Cribbs74** Fri Aug 28, 2020 11:28 am

Is the cylinder in question a thin or thick wall?

Iceberg Fri Aug 28, 2020 12:03 pm

Hi Cribbs
Thin wall one. Older one .

Thanks
Iceberg

happydad Fri Aug 28, 2020 1:04 pm

Iceberg wrote:Hi Cribbs
Thin wall one. Older one .

Thanks
Iceberg

Iceberg: you may have a slight twist in the cylinder, which makes it out of round. Oliver Twist , I call it.

A team effort, but you figured it out. Clapping

Happydad

Iceberg Fri Aug 28, 2020 1:20 pm

Yes makes sense about the twist. Wow took me all up about 2 hours to hone the twist out of it. Must have just been a thousandth or something. Super little.

Took for run this morning and was tipping almost at 20k again. I'm a happy camper today!!

Thanks all
Ice

Sponsored content