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+--- Thread: making piston ring compressor (/showthread.php?tid=6094)
RE: making piston ring compressor - Howard Wright - 09-05-2021
Hi Jon
If you are going to buy a ring compressor for an A7 it will probably be best to buy a set for motorcycles. Car ring compressors are generally too big! I found a cheap eBay set quite adequate although I could probably do with two sets when trying to join the crankcase to block when all the pistons are attached.
Cheers
Howard
RE: making piston ring compressor - Bob Kneale - 09-05-2021
Unable to find my compressor on one occasion (I'd lent it to someone), I made up a very serviceable arrangement from a piece of rainwater pipe and a couple of jubilee clips. It was so successful that I have never bothered with anything else on an Austin Seven. If you use lots of oil on fitting,there is little or no risk of filling the bores with PVC shavings.
I wrote it up for the Cornwall Club Focus magazine February 2020 edition. (image attached). Written under my 'non de plume'!
RE: making piston ring compressor - Roland Alcock - 09-05-2021
I was once loaned this and it worked brilliantly. Unfortunately the owner of it is no longer with us, but I believe he brought it home from Longbridge.
It’s a simple cantilever construction.
I would love to find another one.
Roly
RE: making piston ring compressor - Bob Culver - 09-05-2021
The observations above about the Companion should also apply to the Williams Specials books.
My father and self forever on various makes used simple home made sheet metal clamps with flanges double thickness, folded out and closed with a nut and bolt. Unfortunately many tin plate cans are now corrugated so have to select. Dont use galvanised iron as some coating scrapes off
RE: making piston ring compressor - Duncan Grimmond - 10-05-2021
I do like the simplicity of that clamp, I'm just going to the workshop and I may be some time...
RE: making piston ring compressor - Ian McGowan - 10-05-2021
I bought clamps almost identical to the cantilever one about 12 years ago from FW Thornton.
Classic Engine Parts | Vintage Engine Parts | FW Thornton
RE: making piston ring compressor - John Mason - 10-05-2021
JonE. Perhaps a little late but the type of compressor Ruairidh has outlined. You need two as you have to do two together then the other two again together. I think it is a bit risky myself and prefer to drop the sump and gauze and undo the big ends so that on re assembly I can put all the pistons in the bores, replace the block and then reconnect the bid ends. I think what it really is that I haven’t got the bottle to try the other method. I recall years back in the 60s motor cycle mechanics did it all the time with twin cylinder engines.
John Mason.
RE: making piston ring compressor - JohnD - 10-05-2021
Piston ring compressor! Thats all a bit posh, just work them in with your fingers and a wooden chapping device!
RE: making piston ring compressor - Robert Leigh - 10-05-2021
Some years ago I did a hints and tips session in the pits at a Silverstone 750 meeting. I showed how to fit a piston in an A7 block without a compressor. Someone was so surprised that he said 'Do that again' so I did. Many years before that on a 750 trip through Switzerland Chris Baggaley broke a kingpin and a crankshaft on the same day. At the end of the day there was social gathering at the local garage, and talking to the staff they willingly volunteered the workshop for the remadial works. There were so many crowded around Chris's works that I stood back so that I would not get in the way, but at some point engine work stopped, so I asked Reg Nice why. He said someone's gone back to the camp site for a ring compressor, so I took my clean sweatshirt off and showed them how to do it without. I was surprised that noone else of the many people there was aware of the technique. The bevel on the bottom of the bore makes it easy, so long as your finger nails are strong enough to compress the rings.
RE: making piston ring compressor - Andy Bennett - 10-05-2021
Quick question probably for R.
The ebay compressor link says 62mm diameter upwards.
Given that this is some 4-6mm larger than the A7 piston, does that matter as it sounds like it wouldn't compress the rings into the grooves, or am I overthinking the precision here?
Andy