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Big end and main bearing sizes


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hello again obviously went ahead and brought this gauge to measure the crank diameter etc on my engine rebuild........



http://www.ebay.co.uk/itm/Linear-electronic-digital-outside-micrometer-25-50-/321539792529?pt=UK_Measuring_Tools_Levels&hash=item4add43de91



now its a case of how to set it, I presume you set it with the little 25mm block you get with it, so it would be closing the gap as much as possible, then putting the little 25mm block you get with it once the block is in and holding you set the gauge to 25mm then take the 25mm block out and take it from there when measuring the crankshaft journals? Thanks Pat


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it will tel you how to exactly in your book you got with it make sure when calibrating her that the contact points are clear of any oills etc etc and yes you use the 25mm extension to calibrate and lock her till the next calibrate

take really good care of the calibrate pin dont ever drop it and dont scratch it

Edited by 5e colin
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I do mate I have the 0.25 acl bearings from the other crank and still have the standard bearings from the crank I'm using but them ones are not oem ones, I was gonna use the telescopic gauges to measure inside the rod bores then put that in the micrometer and use the micro meter on all crank journals but there is a 25mm gap on that micrometer hence why I wasn't sure if you set it on the micrometer gauge 25mm, then wind it back to the measurements I need mate

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yep thats the way to do it i just mentioned it to try on the bearings so you get the hang of it with the clicks at the end and if the measurements are the same every time etc etc

set the tumbler to zero open the locking valve then measure the 25mm unit relock her and make sure if the tumbler is still on zero then you should be good to go

just read the book of it might be small bit diferent on your 1 ???

Edited by 5e colin
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Hello gang this is interesting on the measurements

I now KNOW I need std mk 1 for the main bearings.

On the big end bearings (rods)

I'm getting different sizes to the chart above as it says 43. Something where mine are

From cambelt size

Big end 1 39.989mm

Big end 2 39.985mm

Big end 3 39.986mm

Big end 4 39.987mm

So of course there all very near each other but there not in the 43's as it says in the chart above with the big end diameter.

I'm guessing you have to measure the inside of the rod bore to get the 43. What you need?

Thanks guys (what a pain in the ass)

Pat

Edited by patman
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measure the holes like i said before from block mains and the conrod then the crank journals aaal off them mains and big write them down on paper so i can have a look at them on ere

also there is no way them mains are all nr 1 remeasure them

From cambelt size crank

Big end 1 39.989mm crank journal ( outer )..... / cap hole ( inner ) 42.990 to 43.050 ???? somewhere

Big end 2 39.985mm crank journal ( outer )..... / cap hole ( inner )

Big end 3 39.986mm crank journal ( outer )..... / cap hole ( inner )

Big end 4 39.987mm crank journal ( outer )..... / cap hole ( inner )

then you do the exact same for mains inner and outer size !!!!!!!!

Edited by 5e colin
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My local engineer shop Phil decided to round it all off in hundreds not thousands so he was rounding off the mains to 47mm and the big ends to 40mm

Hence why I am in this postion now as he oh had the gauges what deal in hundreds not thousands

Sorry for the late reply Colin in the end gave it to a very good mechanic friend who's dealt with this stuff before, he texted me at the end of the day quickly to say all the rod holes measured up were all inbetween 43.000mm-43.007mm as gave him the 3 std bearing options for big ends 👍

Edited by patman
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^^^^^ no mate your getting it wrong !!!!!! the crank lobes/journals FOR the conrods is around 40mm BUT the conrods themselves are around 43mm this equals to 3mm and 1.5mm for each bearing cup/half

but you have to measure this in thousands

have a read tru the whole thread so u will see wa tools u need

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So patman you just had your bearings done in a nut shell would you just advise to take to someone who has the right mesure tools and get them to do it?

I am hoping I can do them with head still on. Been told to remove sump and crank get it reground and polished and same guy can make up the bearings to suit.

That sound right?

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Colin has nailed it mate it is a pain in the ass I know stripping things down, I would like Colin said check everything and take head off, I got another issue at the moment on the main caps they are numbered obviously 1-5 I know the arrow points to the cambelt side but I can't remember if number 1 starts at the cambelt side or the fly wheel/gearbox side? What a pain

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