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MG MGA - connecting rods & pistons

happy new year to all perchased 1960 mga 1600 barn find not running started a compleat frame up last year doing eng. rebuild over this winter . as soon as i opened the eng. i new i had somthing special flat top pistons twin cam connecting rods and a hi out put oil pump plus a hi lift cam. stage 3 eng? the head had been worked on too polished ect. my problem is this i cant find any twin cam pistons and standard 1600 pistons wont fit to the twin cam rods. need to find twin cam pistons or a set of 1600 rods. can any one out there help !!!!! cheers mike
mike

Mike, When I rebuilt my 1600 some years back, the local speed shop did all the machine work. They sourced most of the parts but I got the pistons from one of the ususal suspects. They could have supplied either cast or forged pistons maded to order. As I recall, they were comparable in cost to the ones I purchased. however it would have taken about a month to have made.

I would think this could still be done. Since they were 1600 pistons, my guess is that if you found twinkie pistons, they would probably be more expensive that custom made pistons.

Chuck
Chuck Schaefer

Mike- My experence in finding rods was rough.1500 rods can be used,don't know if they are the same part # tho. I'm sure others will know.My problem was that when rods are rebuilt they remove material from the side of the big end to true them up.My 1600 had .040 over pistons so it had been worked on before.By the time my crank was ground and my rods reconditioned I had up to .040 side clearance between rod and crank.Factory clearance is .008 to .012. Found another set of rods, but still had up to .026 clearance.On my original rods the thinist one, measured across the big end was 1.195 and on the replacement rods the thickest was 1.218.Never able to find out what size a new one was. Ended up having crank welded and remachined and now are at .008 to .010. Anyway I think as long as the crank and rods you have are good it would be better to get pistons.Maybe Bob West could help if someone here could get you his address.
gary starr

Mike,
Are you rebuilding a OHV engine or TC (Twin cam)engine?
Pritty sure you can't just cut the tops off TC pistons and make them fit.
There is a picture of all the pistons in this doc I put together on page 14 and rods on page 13.

http://freespace.virgin.net/marka.hester/MGATwinCamTuningGuideAddenda2005v0.3.doc

what do you existing pistons look like ?

Cheers <MARK>
Mark Hester

Mark is correct - Twincam pistons would be useless to you.

It was a period tuning thing to use full floating wrist pin Twincam rods with flat top pistons. These special pistons are no longer available unless you have them custom made.

Best bet is to revert to regular MGA rods and sell the Twincam bits to fund the restoration. You don't really need them on ther street anyway.
Bill Spohn

Mike,

Give up on the idea of flat top pistons too, they give a bad squish pattern and force the gasses out towards the head gasket more.
"Lots of people" buy them and then have a small dish machined into they anyway.
Alternately have the block face milled and then get standard pistons and machine them down a little also, which you may find is what has happened in your case.
Not sure what the total height of the block is, but I'm sure you can find out by asking someone to measure a 1600 block for you anyway.

What are the part numbers on your TC rods also? Should be the same as in that doc of mine above.
Carrillo rods are much better again if you don't like the standard one's.
Your twin cam rods should fetch a good price anyway.

Cheers <MARK>
Mark Hester

thanks for the info every one it would seem that i have AEH 642 AEH 644 connecting rods and 12H173 flat top pistons 9.25:1 ratio. i may have found a set of replacement pistons nos. waiting to here back. plan 2 replace the small end bushing in the connecting rod shorten the wrist pin and cut grooves for cir clips in standard pistons. thats my thinking at this time. your comments would be appreciated. cheers mike
mike

I could be wrong, but I seem to recall reading that all 1600s had flat top pistons. Was it he 1622s? Am I mis-remembering?
Marvin Deupree

Hi, Good luck with your quest for the correct pistons for your 1600 - Bob West mentioned above (acknowledged expert on all types of MGAs) is at Haverlands Farm, Hardwick Road, Pontefract, West Yorkshire, WF8 3DL (UK Phone 01977 703828) Cheers Cam
C Cunningham

This thread was discussed between 03/01/2006 and 07/01/2006

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