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MG MGA - 1622 pistons in mga 1600 engine

I have been searching for flat top pstons for my Standard MGA 1600. Cannot find them. Would like to increase compression from 8.3:1 to 9:1.
Bore size is a bit less than +0.30 oversize. So I could fit 1622 Pistons with +0.20 after reboring engine block. Additionally would have to ream out conrods to fit the 1622 Piston bolts.

Has anyone experience with this upgrade ?

Alternatively: Where can I find 1600 0,030 flat top Pistons (NOT the 1622 flat top Pistons) ??

Thanks for any advice in advance !
H. P. Meyen

Yes, you can fit the 1622 pistons.

A better alternative for rods might be sourcing a set from an Austin A60 from Britain - should not be too hard to find.
Bill Spohn

In case it is of any use my "1600" has MkII flat top pistons and MkII con-rods with a 1600 crankshaft. The flat-tops were fitted to help the compression ratio after I discovered it was fitted with a 1967 MGB head with its larger combustion chambers. It does not like 95 octane fuel but needs and really performs on 98 octane and the richer RO needles.
My engine is now +0.060" on the MkII bore so there appears to be plenty of spare metal in the 1600 block.

Dear Bill, dear Pete

thanks so much for your responses. In the meantime I was able to acquire 1622 +0.020 Pistons and could manage to get a set of used Austin A60 conrods in UK. Conrods will arrive soon.

I did not purchase new 1622 conrods since they seem ? to have more width ? at the big ends, which would have forced me in regrinding them as well.

Anyway "Octogonal Thanks" to the international help I was lucky to experience in this community !

H. P. Meyen

FYI When you get your new to you rods make sure you check your rod to crank clearance. Over the years as rods get to be rebuilt several times over they do grind a bit off of each side just to line them up. That is what happened to mine.When I measured the side clearance,which is something like .008 to .012,I must have pushed the feeler gauge until it touched the crank thus measuring the bearing shell to crank clearance because now after all the machining over the years the rods were narrower than the bearing. When driving it 1K the shells then wore down and started making a knocking sound. On tear down the actual rod clearance varied from .030 to .040. I went thru alot of used 15 and 1600 rods at University Motors looking for ones that had not been ground down to useless. Also found out that crank re-grinders can get careless too and take a few extra thousands off of each crank cheek increasing the clearance too.
gary starr

This thread was discussed between 30/03/2018 and 05/04/2018

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