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 Posted: Apr 8, 2020 12:11AM
 Edited:  Apr 8, 2020 12:14AM
TK
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AU
Offset grinding a 1505 is fine. Here is Matt "Madmatt" Read having a go in a 1510cc with offset ground crank in Targa Tasmania. The 'experts' said that it wouldn't last!!!!! https://www.youtube.com/watch?v=D6KB4A-0adg Save the block. Just go the next size up. If you can pick the the difference between them I'd like to see dyno figures, is it worth it?.

EDIT: I think that he mean 521 rods. Also if you want 'cheap' ARP rod bolts use Ford Big Block bolts, two sets for the cheaper price of one!!!!

 Posted: Apr 7, 2020 08:05PM
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US
Hi all, the 1505 cranks lacked the bigger counterweights of the later, better A+ type, so that's the deal with those big heavy rod caps. I have used the A+ rods with 1505 cranks, and let's face it, a 1275 is not a smooth engine to begin with, so they work fine. Have you ever noticed the FLYWHEEL from an Austin America? No that isn't a 1 ton truck brake drum!! I would NOT use those clumsy rods on a 6232 crank however, nor would I bother with the S type with 3/8th" rod bolts. The A+ uses unusual 11/32" rod bolts so the rods can fit down the bore with the 1.75" rod journals of the A and A+. Don't grind the crank down... it's cast and would be considerably weaker with 1 5/8th" rod journals.

Don't worry about "saving" the block. A good 1380 overbore will last the rest of most of our lives! And if you do blow up a standard or .020" or whatever overbore, it will just as likely destroy it as the 1380! You already have pistons so go for it! Still the easiest and most reliable way to make power.... displacement! I offset bore the two Middle cylinders outward .010" each, and Cometic makes their gaskets to this spec... I gave it to them. They call it the Mini Mania Offset spec. I think MED uses the same one if you buy Cometic MLS gaskets from them...

Oh, I have two sets of 621 rods with ARP 3/8" bolts for S or Inline as I pretty much build full race units with multi-web cranks and straight rods now (that use a Toyota bearing). Also two standard size very nice inline (Sprite/Midget)1275 crankshafts if anyone is looking during this time of... well. lots of time for projects! [email protected]

 Posted: Apr 5, 2020 05:44PM
TK
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AU
If your block is only at 020 please do not bore it to 1380. Go 030 or 040.

 Posted: Apr 5, 2020 04:32PM
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US
Quote:
Originally Posted by dogscarf
Somethingnew71,  I may take you up on that.  I am still trying to figure out what I am going to do.  My engine is at .020, but has some slight rust and marks on the cylinders.  I do not know if they will hone out.  Also, my engine builder says he cannot offset bore.  I may just go with .020 or .040.  Do you need any Mini parts for a trade for the rods?

Dogscarf
When I did my 1380 my machinist didn't have the capability either - so we had it offset indexed on a bridgeport and then overbored and honed.  but then this was at least 30 years ago in Kansas City.  The last two I had done was after we moved to the Atlanta area say around 2003 - the had all computer controlled and no problem offset boring to 1380.

 Posted: Apr 5, 2020 08:28AM
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US
Quote:
Originally Posted by dogscarf
Somethingnew71,  I may take you up on that.  I am still trying to figure out what I am going to do.  My engine is at .020, but has some slight rust and marks on the cylinders.  I do not know if they will hone out.  Also, my engine builder says he cannot offset bore.  I may just go with .020 or .040.  Do you need any Mini parts for a trade for the rods?

Dogscarf

Sounds good just let me know. I don't need anything at the moment. Just trying to recoup some costs on my supercharged build. If you decide to pull the trigger on the rods shoot me an email - [email protected]

 

Happy to try and work something out with ya.

 Posted: Apr 5, 2020 08:20AM
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Somethingnew71,  I may take you up on that.  I am still trying to figure out what I am going to do.  My engine is at .020, but has some slight rust and marks on the cylinders.  I do not know if they will hone out.  Also, my engine builder says he cannot offset bore.  I may just go with .020 or .040.  Do you need any Mini parts for a trade for the rods?

Dogscarf

 Posted: Mar 30, 2020 06:44PM
TK
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AU
https://www.ebay.co.uk/itm/MINI-COOPER-1275-A-CONRODS-MG-METRO-ROVER-ENGINE-TURBO-1300-RACE-RALLY/264683965156?hash=item3da064cae4:g:KjkAAOSwkktc7GAN

 Posted: Mar 30, 2020 09:05AM
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US


Heres a photo of them

 Posted: Mar 28, 2020 08:18AM
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US
Hey, I have some A+ rods in great shape for sale if you want them. It appears most places that actually have them in stock have them for sale for around 250-300 for a set of 4. If you want them I'll do $200 shipped anywhere in the USA.

 Posted: Mar 27, 2020 09:57AM
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US
Quote:
Originally Posted by dogscarf
There are some inexpensive Chinese rods on the market.  I don't know if they are any good though.  I could lighten my heavy rods but that is a lot of grinding involved.

Dogscarf
 I wouldn't use the Chinese I beams in a High Horsepower (800+) V8 Build,
    Just by my local machinist experience with a Hemi + Chinese rods that stretched and wrecked a motor... But that was his guidance. after the motor blew it came to him He identified the stretch in the mains.

Neat reading and seeing this type of conversatoin.... Not many building specality 'big' motors these days and chatting about it... Its hard to understand and keep up being a 'newb" in speciality builds.

 Posted: Mar 27, 2020 06:31AM
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US
Quote:
Originally Posted by dogscarf
Fellow Minioids,  I have a set of 73.5mm pistons and I want to build a 1380.  My block is a 1275 GT block as near as I can tell.  It does have an A+ crank though, CAM6232 with  1.75 mains.  The crank is perfect.  I also have a 1505 crank that needs turning.  Question, can I turn either crank down to 1.62 to fit Cooper S rods.  I have two sets of rods and they are the heaviest with the wights on the bottoms.  I would like to ditch them or use a lighter rod and not have to turn the CAM6232 crank to 1.62.  Thoughts?

Dogscarf
1965 Mini Cooper
1967 Mini Cooper S
1968 Mini Cooper S mk2
Some 30 years ago I was working on that same goal of building a 1380.  Read Vizard, offset bore, use the 11 studs - with only 9  they tend to blow out at the ends.  I had my machinist lighten that heavy rod - but that was then.  After running it for over 10 years I came into an abundance of the 1505 cranks ( read that as I worked out a deal to buy 7 Austin America core units - but they could only come up with 4 ), had the 1505 offset ground to 1.625" giving me a stroked 1380 so around 1430.  If you are using 'S rods with the 1505 crank I believe Vizard was saying have the rod narrowed to fit - my machinist widened the crank journal to fit.  

 Posted: Mar 26, 2020 07:45PM
 Edited:  Mar 27, 2020 04:51PM
TK
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AU
If you're staying the with stock stroke I'd use Innocenti Rods. Remember to offset bore the block. If you're going to offset grind the crank for more CC's then use 521s or 625s. Stay away from the 177s.

 Posted: Mar 26, 2020 06:26PM
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CA
Also need to check on what pistons you have, wrist pin styles.
Bruce

 Posted: Mar 26, 2020 05:55PM
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There are some inexpensive Chinese rods on the market.  I don't know if they are any good though.  I could lighten my heavy rods but that is a lot of grinding involved.

Dogscarf

 Posted: Mar 26, 2020 02:22PM
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US
Good choice... go with rods over cutting a crank further.

what about I Beam rods?  

 Posted: Mar 26, 2020 01:54PM
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Workinprogress,  I guess that I could lighten the heavy rods, but I have plenty of projects.  If someone has A+ rods for sale I would be interested.  

Dogscarf

 Posted: Mar 26, 2020 01:39PM
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CA
You do not need S rods to build your 1380, only reason is that you can get lighter rods to help it spin faster. A or A# rods are fine, if you want just upgrade the bolts and you can also lighten them some as well if home bored like many of us right now. 

 Posted: Mar 26, 2020 12:46PM
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Fellow Minioids,  I have a set of 73.5mm pistons and I want to build a 1380.  My block is a 1275 GT block as near as I can tell.  It does have an A+ crank though, CAM6232 with  1.75 mains.  The crank is perfect.  I also have a 1505 crank that needs turning.  Question, can I turn either crank down to 1.62 to fit Cooper S rods.  I have two sets of rods and they are the heaviest with the wights on the bottoms.  I would like to ditch them or use a lighter rod and not have to turn the CAM6232 crank to 1.62.  Thoughts?

Dogscarf
1965 Mini Cooper
1967 Mini Cooper S
1968 Mini Cooper S mk2