Or if the block is good just hone and re-ring it, drive it around for a bit then you've got heaps of money saved for you new motor. For an inbetween motor i just hone it unless it NEEDS a rebore.

just my 2 cents

Bah if its only for 6 months, give it a hone and re-ring it. A motor that's been re ringed can last for ages!! Much longer than 6 months.

Save your money for the big bore engine.

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68 Mini
70 Moke

ha,,, when i was about 14 years old, i re-built a std-ish small bore donk, but i just cleaned up the ring lands, stuck a set of new oil rings in (cause dad had piles of new "loose" rings in stock,,, ah those were the days ) & fumbled around dads workshop picking out good looking 2nd hand compression rings from other 2nd hand pistons,,, grabbed good looking 2nd hand bearings & oil pump & shoved it back together, cost me diddly squat,,, i put it into a little roundy van & sold it off cause my race mini donk was almost finished by that stage.

Year & years later i ran into the fella that bought it & he was happy as a pig in mud as it went really well & was still going really well

just thought i`d share one of my early "Bung it together" storys

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

i would do that, but i want the twin cam engine to be a 1360 or 80 so i need a 1275 block for that..

thanks for your help everyone, i might go down on monday and ask if i can get away with just a hone,

cheers

sean

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Potato

im about to order some rings and shell bearings for the engine.

what size bearings should i order.. the measurments off the crank (ie the surface the bearing rubs against) are (in mm)

centre main and two end bearings: 44.2mm

con rod - crank bearings: 41.0 (all 4)

and what rings should i get for my pistons which measure 64.5mm accross the top..

i dont know weather any of this is standard and sorry if they mean nothing.. hope someone can translate my lack of measuring talent

cheers

sean

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Potato

your machine shop should be doing the measuring, I usually get mine to do the ordering too -

because the bearings are measured oversize in thousandths, you need to calculate the size

measure it, convert that to inches, then refer to your workshop manual, see if it's the same, then see what the oversizes are etc. etc.

get the machine shop to do it...

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did I tell you that I won a trophy?

im not having anything done other then the block honing so he wont know what anything else is ground to. i would reuse my shell bearings but im not sure if theyre overworn as a couple have some darker patches on them

if it helps my pistons have d19 508 stamped on the edge ot them. they measure 2.54inches across.

the standard measurements in the australian mini manual are

main bearings - 44.4

and for the conrod - 41.2

so its had 0.2 mm taken off both.. whats that in inches 0.0078

so from that.. what shell bearings do i need, or am i on the wrong planet?

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Potato

The first standard regrind undersize is -.010" (0.25mm near enuff). If your measurements are accurate, it is a WORN std crank and definitely needs a regrind.
Measure all the journals at 2 points 90° to each other- ie vertical and horizontal. More than .001" ovality and it needs a regrind anyway.
I just rebuilt an A+ 1275, and the crank had .007" wear on all the big end journals...

you must use bearing shells to suit the crank size it was ground to.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

remeasured in inches and got 1.61 all round on the 4 conrod faces and 1.73 on the front centre and rear bearings.. my verniers dont go into .000 but roughly speaking they are .01 smaller on the conrod part and .02 smaller on the mains

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Potato

.010 is 10 thou, .020 is 20 thou - it's a lot when you can't measure it accurately

if a machine shop is doing the honing, just take the crank in and ask them to measure it - you can buy the bits, but the measurement has gotta be spot on

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did I tell you that I won a trophy?

Also ask them if it needs a linish or a regrind. They know what to look for and have real micrometers, not verniers...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

meeni,.,, Please just take the thing to your local engine reconditioning shop,,, get them to measure it all for you & they will let you know what is good & what isn`t, & also let you know what to do & what not to do

ok?

It`s easy to stuff things right up by yourself,,, it`s better that you let them stuff it up for you Kidding,,, just kidding

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

yeah thats fine.. il take it tomorrow, im just trying to learn.

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Potato

that's cool - but learn the right way - get the guy at the machine shop to show you what he does

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did I tell you that I won a trophy?