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MG MGA - Smoking MGA / MGB pistons

Hi,

Well, I've finally solved the smoking MGA saga...

I put it up on the MG Enthusiasts Website, but here's the summary.

I finally got a ball micrometer and measured the cylinders. Here's the sad news..

Cylinder #1 Cylinder #2 Cylinder #3 Cylinder #4

3.0050 3.0050 3.0060 3.0040


It appears that when I gave the pistons to the "machinists" last year, they never checked the sizes and only honed the cylinders. I'm now wondering if the old pistons were some weird size that the PO stuck in.

However, standard MGB pistons for a 3 main bearing engine are 3.160 ". so I should be able to bore this block out to 3.160 " and stick in std MGB pistons. I'm assuming that the connecting rods, etc will all be Ok.

Any comments ?

Thanks,

Duncan
DA MacFarlane

Hi Duncan. Sent you an email. GLenn
Glenn

Yes you can do this with the 1600 and go straight to 1800cc. Watch the cr though as you won't want to exceed about 9:1 to avoid knock and run on with 92 octane fuel.
Iain MacKintosh

Iain, if he attends to deburring the combustion chambers, he should be able to run it on 89 octane at 9:1

I find that 92 will support 10:1 if the timing is spot on, otherwise you need 94.
Bill Spohn

I'm surprised Bill but that would be a bonus and I suppose the final proof will be when this motor is back up and running. I looks like making quite a difference to the MGA though. Next questions will be higher ratio diff, overdrive and then how to stop the thing!!
Iain MacKintosh

This thread was discussed between 16/02/2006 and 17/02/2006

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This thread is from the archive. The Live MG MGA BBS is active now.