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DIY Piston Ring Compressor

 

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Today I want to share a quick tip with those of you who are working on your own engines but just can’t justify buying a set of piston ring compressors. It’s entirely possible to make a perfectly good ring compressor from materials you can get at the hardware store. All you need is some plumber’s pipe hanging tape and a hose clamp that is sized according to your cylinder bore.

To construct a DIY ring compressor from plumber's pipe hanger tape you will need to determine the length of tape required. This is easily done using the following equation for calculating the circumference of a circle.

Length of Tape Required = Piston Diameter x π (Pi)

When the tape is wrapped around the piston tightly, the final length may need to be reduced slightly so that the ends don’t butt together. Once the tape has been cut to length, make sure whichever side of the tape will be contacting the rings is smooth and free of little plastic burrs that could catch the rings.

Simply lube up the tape, tighten down the hose clamp, and you are in business.

ring compressor.JPG

Do you have a tip that makes compressing rings easier or cheaper? If so, leave a comment below!

- Paul

If you enjoyed this tip and want access to more like it, check out my book, The Four Stroke Dirt Bike Engine Building Handbook. On the fence about the book? Check out what other riders are saying: Thumper Talk Review

Available at:

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Not cheaper but worth the price. Worm gear clamps tighten unevenly, constant tension claps are stronger and tighten all the way around. You can get them from Hydraulic supply shops or truck, heavy equipment parts places. Turbo-intercooler clamps would be good too.  

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Meh...you do not need great tightness or strength in a ring compressor.  It still needs to be able to slip to work the jug back on.....

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I've had really good luck using zip ties. OTOH, your idea looks like it would be a lot easier hold rings and slip jug on.

Edited by ballisticexchris

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On 3/1/2017 at 9:11 PM, kevvyd said:

Meh...you do not need great tightness or strength in a ring compressor.  It still needs to be able to slip to work the jug back on.....

http://www.hoseclampkings.com/Cat-51-1-109/t-bolt-small-spring-3-4-band-zinc-plated-screw.htm

This is the kind of clamp I mean, the advantage is not just that it is stronger but squeezes evenly without the pinch points of worm gear clamps. They are also less likely to strip when tightening and loosening. 

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On 3/4/2017 at 1:52 PM, agave248 said:

What do you think Paul?

Personally, I've not had any problems with uneven tightening or the worm gear stripping the band using the method I've presented, however, that does not mean it is the only method. The point of this article was to present an option and allow folks to weigh in with other ideas and tips and expand the topic from there. I think the clamp you've proposed would work equally well and gives everyone another avenue to pursue. To your point it's possible the T-bolt clamp you've suggested would be a better solution for applications where the ring tension is high. 

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I tried it last night a 250 2t.  It did not work well for me and I just ended up using my fingers.  

What happens is the first ring goes in to the bore, and the second ring would come out of the hose clamp, hit the bevel on the bottom of the cylinder, and then force itself out the bottom.  I ended up doing it the old fashioned way; my fingers.  

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I should add that the best thing I have found is to suspend the cylinder a few inches above the crank (hands free) and using both hands bring the piston up to the bore and work the rings in with my fingers. 

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On 3/9/2017 at 4:00 PM, crypto666 said:

I tried it last night a 250 2t.  It did not work well for me and I just ended up using my fingers.  

What happens is the first ring goes in to the bore, and the second ring would come out of the hose clamp, hit the bevel on the bottom of the cylinder, and then force itself out the bottom.  I ended up doing it the old fashioned way; my fingers.  

Did you incorporate the pipe hanger tape when you tried or just a hose clamp? 

Also, for a two-stroke I agree using your fingers is the easiest way. The method I've outlined is more useful when dealing with oil control rings.

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Yes, it was a 2t.  I didn't have the actual pipe strap, but I did have some plastic strap that should have been just as good or better.  

Ironically, I did a 4t recently as well, and it was easier to do by hand than the 2t, and I didn't bother with suspending the cylinder either.  I think it all depends on the chamfer on the bottom of the bore.

My problem with the hose clamp is I just couldn't make the transition from the clamp to the bore without the ring without the ring hitting the chamfer and forcing it downward.  

I think ring compressors work better on v engine where you are pushing the piston down from the top and the there isn't a chamfer.  

 

 

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