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MG Midget and Sprite Technical - Honing cylinders in the car - an idea

Good afternoon all, an idea for you good folks to think about:-

Fitting my new rings shortly and as no rebore is required (only 1 thou of wear but knackered rings), I will be honing the bores in the car. This prospect was filling me with dread - grit in the bearings, crank, cam and dist. drive etc. etc.

Measured the bores and found the bottom 1 1/2" never touches the rings, so if I could seal the bottoms of the cylinders, I could hone (using a flexi-hone), brush and clean with no muck getting through to the moving bits.

Found a metal jam jar lid (just under 70mm dia. and 8mm deep) stuck rubber ridged self-adhesive draught excluder round the circumference, lightly oiled and bingo, it slid nicely down to the bottom. With a 20mm wedge between the top of the big end journal and the underside of my new seal, it will not travel down any further.

When honed and cleaned etc, just push it up from below and remove, leaving the cylinder free of the nasty bits, they would all be in the lid!

Clearly, I will tape the journals and cover the crank and cam just in case, however, feels like a good idea to me - what do you people think?

Regards, Tony

Tony G

Patent it!

If you also grease the bore around the edge of the lid seal, then this will also trap any swarf and bring it up with the lid when you remove it upwards.
Guy

And if you used a magnet on a stick, you could pull it back up the bore to avoid it tilting and the magnet would attract the swarf.

Bernie.
b higginson

Good idea, you test it and report back.
Alex G Matla

I think it sounds a good idea but if the bores aren't scored, does it really need honing? Weren't you going to try those CORD rings anyway?
Guy

Hi, thanks for your positive comments.
Guy, the engineer who did the unleaded works, thought Cords were good but rather agressive and would only accelerate the time for a full rebore. The rings were all poor, particularly the oil control, which had an end gap of over 50 thou. He reckoned the rings were pumping oil rather than scraping it.
He thought a good set of rings and a light hone to bed them in was all that was required. He is lending me his flex-hone for that.
No idea why the rings had worn so badly, when the bores had only worn 1 thou. in 50k miles.
The rings fitted (2nd and 3rd compression) were not tapered as spec. so wrong rings may have been put in at some time in the past.
Regards, Tony
Tony G

Ah. Useful then to have an experienced engineer on hand who can look at it and advise first hand, as it were.
Guy

This thread was discussed on 11/12/2011

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