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Which Pistons to go with?

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KLUTZ

KLUTZ

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Evening,
First, off topic, where would I find the serial # on the Transmision?
As for the engine. With the pistons needing replacing, and the valves while I am at it, what would be the best way to go after having it honed out? It is an 1800 from a 741/2 MGB GT. There is a great shop in my town for the stuff I won't attempt, so whatever size pistons I would get, I would let them know. I am far from an expert with this, but I would assume one would need a bigger piston after the cleanup? And would a bigger piston create more power?
Thanks
Paul
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[ 04-20-2004: Message edited by: KLUTZ ]</p>
 
I went with Moss 8:75:1 pistons in my '74. And I suggest getting the smallest size overbore you can get away with. I did 20 over on my engine. AE brand is good.
 
Paul,
Very nice looking car & great pic.

Actually it depends on bore condition. Honing is just used for superficial bore finishing/conditioning. If the cylinders are worn enough to need new pistons, the block will be bored & then honed to the finished size.

Any "good" shop will insist on having the new pistons in hand before boring & fitting the cylinder bores to the individual pistons. The shop will need to measure the bores to determine how much oversize the pistons need to be before ordering the pistons. The minimum overbore that will totally clean up & straighten the bores should be used. Maybe .010" over, possibly more. Take their advice. The piston maker should specify the piston to cylinder clearance to be used.

As mentioned, using higher compression pistons will increase power some. The power gain from larger bores alone would be insignificant. David K. gives good advice on pistons & compression ratio.
D
 
GREAT LOOKING CAR!!!

I agree with all the above. Take the block down to the shop and have them check it out and they will tell you if it needs boreing. They can also sell you the correct size pistons and rings. They will also clean it up so it will be like a new block which will be much nicer for you to handle. Take the crank also and have it checked for wear and possible turning and oversized bearings. Also have them check the head for cracks and do a valve grind and check the seats etc.

[ 04-21-2004: Message edited by: mrbassman ]</p>
 
Has anyone on this forum taken pictures of progress while doing a rebuild on their engines, from start to finish? What I mean is, Is there a web site with this information. I would really like to have a visual to lead me in the right direction.
I have seen Dr. Doolins tape on Ebay. Is it of any help?
Thanks
Paul
 
Dr Doolin is very good, it will be alot of help. and when your machine shop tells you what size pistons to get check with Brittek They are very very good. also don't overbore more than you have to just because you can. The power gain is insignificant and you may want to do it again someday
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Chuck Cougill:
Dr Doolin is very good, it will be alot of help. and when your machine shop tells you what size pistons to get check with Brittek They are very very good.<hr></blockquote>

I looked at the Brittek site yesterday, and was wondering if they ship to Canada, or if there was a place similar in Canada to save on the exchange and shipping costs.
I will probably call tomorow to get some Info.
 
Factory manual recomends "high test" gas for my '72 B, and they mean it. If you go too high with the compression you will have to diddle around with the timing to cut out detonation (pinging) and be right back where you were when you started, power wise. Bob
 
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