i`d love to have any old std 1275 engines too Greg,,, absolutely!!!

& Ty i don`t believe so,,, as far as i`ve been lead to believe they are all done once final machining was completed on each item they would balance each item (be it crank or pulley or flywheel etc) seperately... everything being made in rather large batches.

that`s why they are "rarely" perfect but they were not too bad all the same

however,, you would "Now-&-Then" get a sooper-dooper smooooooth donk & the guys back then would call them a "freak" engine because they would rev & rev high & rev smooth.

some 1100cc donks (totally std & from the factory unopened before) would race against 1275s (again unopened & still factory stock std) & the 1100 would actually keep up with the 1275 everywhere,,, Now i was in the scene back then (young but still right in the middle of it all) & i was witness to this many a time,,,

But my thoughts with this scenario are that they were fairly poorly built 1275 donks racing against quite a well built & balanced 1100...

"sometimes",,, just "sometimes" the factory would be ar$ey & get a few engines pretty bloody right , where everything just fell into place as an almost blueprinted donk,,, these donks were of course quite quick & smooth ,,, just that they didn`t hit the nail on the head all the time with every engine,,, quite the opposite actaally... most are just "so=so"

edit--> spelling

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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 think you guys are actually agreeing in many ways?

1) If the engine is a known quantity and does not vibrate badly, you could save some money and not balance it.

2) If it is unknown give some thought to balancing it to avoid spending on a rebuild to end up with a vibrating mess.

3) Talk to your engine builder and get some advice based on their assessment of how it runs prior to a rebuild or on assessment of the internals.

4) There is no hard or fast rule around balancing and an assessment has to be made around budget and the raw product.

For me the big difference is Matt is selling a product and he balances to ensure a standard is met, regardless of the raw product (which is unknown to him). Greg makes a good point that you can save some dollars you don't have if you have a good unit to begin with, which I also agree with.

I think the golden rule is discuss balancing with your engine builder in relation to your engine (particularly if you are on a tight budget).

Well you can cut that ^&%$ out now, nobody wants to hear reason in a schlong measuring contest...

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http://www.mini-hb.co.nz

Sorry! I forgot to mention I have a Doctorate in Mechanical Engineering with 50 years experience!

Just on this balancing thing.....If the entire assembly, shaft, balancer, flywheel ect is dynamically balanced (which I'm assuming done in similar way as wheel and tyre) is there any noticeable improvement over having it statically balanced.

I would agree with that reasoning.
I do feel for the bloke who wrote the original thread. Sorry to have your thread go so sideways.You have bought Vizards book which I think is a great idea. It will pay to read it well, at least you will have a basic understanding of what you are looking to do. If anything it will help you to decipher the advice you wish to keep and that which you wish to disregard.
Good luck
G.

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1970 Cooper S ex-Bathurst & ATCC
1964 Austin Cooper S ex-Group C race car
1967 Morris Cooper S ex-Group B
1962 Mini Speed sports sedan
1968-71 ex-Peter Manton Shell car

I actually thought it was a good debate on all sides, it got everyone thinking and goes to show we are all passionate about these cars and helping one another! Both Greg and Matt raised things I would not have thought of, keep sharing your good ideas guys!

OK, I am a bit nervous asking this question after reading the past 5 pages but here it goes.

I too am looking at rebuilding my 1275 engine, I have/will be purchasing a SC12, manifold, HIF44 (Ben '92' kit). As far as I know the engine is stock as they come but will be pulling the engine down to rebuild it so I know what is inside of it.

My question is if I want to do this and not spend a stupid amount of money (budget is yet to be decided) what are the 'upgrades' I should be looking at starting with the 'absolute essentials' to the 'it would be nice'.

I am not after a race engine but rather a weekend warrior.

I see that their are many on here that have a mile of experience please share your ideas and pointers.

Thanks

ok,,, to be sensible & seeing as you`re talking about supercharging,,, then decent quality pistons are not a silly thing to spend money on, right--> everyone agree???

that`s not hard to understand right?

ok,,, so (in my opinion) if you have a large journal assy,,, then flick the con-rods & get some A+ rods... again in my books that`s a no-brainer

I would fit a decent quality (new MED or similar quality) harmonic balancer

I`d fit a lighter flywheel & a heavy clutch... pretty simple & understandable so far??? everyone agree???

are we all keeping up so far???

make sure your crank is not cracked & have it ground/hardened/balanced/ground/linished as necessary.

the block-> INspect, inspect & inspect--> it thoroughly,,, first for any cracks , or bore porosity... & if it`s all good then bore it out as necessary & run a tap through all the threads & pull all the gallery plugs out (water & oil) & clean clean clean & lube it all up straight away so it doesn`t rust while you`re building it.

all good so far everyone???

well,,, now,,, cyl head is where it`s all breathing through so get someone well-experienced with working mini cyl heads to wave a magic wand (die-grinder) over that (don`t have to go stoopid on it either),,,, & then match it with a forced-induction cam to suit.

are we all still on the same page???

now get all that rotating/reciprocating mass (((that`s been purchased from all corners of the globe or played with by all sorts of different & un-known people over the years))))--> BALANCED

makes sure you over-haul your gearbox, drop gears/brgs etc,,, & i would fit a Quaiffe type diff myself,,, but maybe at least a 4-pin

I "Dummy-up" all my engines a couple of times (sometimes more) catching all sorts of stoopid things in the process so i suggest you do the same (i use a plastic gudgeon pin & other silly special tools to do so),,, cc-ing equipment is a must (measuring volumes of chambers & such) again maybe contact a reputable performance engine builder for some help here to make sure your compression ratio isnt too high (or too low)

bung it all together with slightly larger/greater clearances than the manual says (see a reputable performance engine builder for some suggestions in this dept)

"MAKE": the lower crank thrusts have about 10-15thou more clearance than the uppers, leaving the uppers to do all the work.

shall i continue??? or are we all happy at that???

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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.

Miniman, I follow your post.

I will PM you.

If anyone else has ideas please post.

Thanks

Is it possiable to staticly balance a rotating item I know you can balance the pistons on a scale so they weigh all the same and palance the rods so they all weigh the same in the same spots but how would you balance a crank or flywheel without spinning it (like a wheel).
Back to your question MG Rocket, I think if each item is say 1% out, by the time they are all bolted together and (in worst case sinaro) each 1% is in the "wrong" alignment once it's all spinning then you'll realy notice the less than perfect static balancing method. I imagin it would be about the same as a factory build, like Matt said some engines that 1% out of balance lines up perfectly in some engines and the result is the "freak" engine, but some (the majority) would not be as good as a dynamicly balanced assembly.

On the balancing topic;
Is it true that the Bathurst winning Cooper S, 13C, the mechanics took around four or so S engines striped them down and checked the weights/balance of all the internals and re-assembled 13C's engine as 'the best' balanced of the lot, same as a "freak" engine
It was still built with factory standard parts as they came frome the factory so it still complied with the race rules. Or is this an old rumer?

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Respect mine and I'll respect yours.

You `could' statically balance a crank the same way they do big grinding wheels on crank grinding machines:
Sit it on 2 level knife edges and if it don't move, it's in balance.
But...
A crank could be dynamically way out of balance (heavy 1 side at one end and the same amount opposite at the other end) and pass this test.
So dynamic balancing of cranks is far better.

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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.

I have come across a cam that i thought would be suitable for my rebuild, can anyone provide some feedback on the specs and let me know if it is worth looking at.

Specs are as follows;

Crow cam grind (740 l/c 108 ) on to a 1/2" lobe, spider drive, BMC 'A' Series camshaft. (Never been used since it has been ground)

Specs read inlet duration as 280 and exhaust as 287 degrees with 108 degrees lobe centres. (.266" lift)


Advice please

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1977 Leyland Mini Clubman 1275cc - In the process of supercharging! Any adice is welcome