120 replies to this topic

[1977 Loud_Mini]

I have a 1380cc engine and wanted to get the crank balanced with the flywheel, clutch and crank pulley so went to my local engine centre to ask if they can do it and how much. Well i was told that i didn't need it balanced and they kept saying 'what do you want to prove' so i said i'm building a 1380cc engine. When replied to him saying i didn't need it balanced i said even with an ultralight flywheel and clutch backplate he just laughed and looked around. Anyway they then went on to say i would need the pistons and conrods balanced aswell with the crank and that it would be very expensive, £255 plus VAT to be exact. I'm sure it's not ment to be that much. They also said i would need an oil scraper and someone else came in saying something about a dry sump. He also went on to say that it would be dangerous to drive as when approaching a slight slope it will have no pull all because the crank has been balanced, so basically i just left after that as it was too expensive and i may as well get it done by a proper engine builders because it sounded like they didn't know a thing regarding a dry sump?

Evan.

[mini93]

you cant dry sump a transvers a-series engine! if they are trying to give you advise like that your better off not giving them your custom.

you dont need piston etc balanced when you have the crank but of course it always helps and for them to say you dont need anything balancing, thats very short sighted of them. What have you had done to the crank? any wedging, lightening etc?

[AndyMiniMad.]

Im also running a 1380 and asked the very same question of a local engine services company. I was quoted £276 for balancing the crank, flywheel, pistons and rods, Ive decided it will be fine without any balancing as im not a race driver and the mini will be road use only, I might get it up to 7000 revs once in a while but mostly 5000- 6000 will be my max. Ive not had any work done to my crank that woud mean it needs balancing anyway.

Edited by AndyMiniMad., 02 November 2010 - 06:26 PM.

[danrock101]

lol walk away

[MRA]

Interesting next time tell them they should be on comedy hour.........

Total rubbish, a well balanced A series will not give you much in extra power if at all or extra revs for that matter, but it will feel smoother and as such should also last longer due to lower wear

Ge tit done properely if you want it done, don't worry about dry sumping, that is just rubbish

Name and shame the company that treats any cusomer in such a manner (

[samsfern]

take it else where if thats the attitude you got, id have put them in their place and told them id take it elsewhere as they dont know what their on about. You cant dry sump a transverse a series, ive seen inline a series engines dry sumped though. As for struggling up hills, if the crank is lighter it will have less momentum to keep it turning, so youll have to drop a gear or two.

[mini93]

it would be dangerous to drive as when approaching a slight slope it will have no pull all because the crank has been balanced

say whaaaaaat?? lmao!

[1977 Loud_Mini]

Yeah i'm not going there again. Any ideas why i would need an oil scraper?
The crank has been reground +10 and apparantely balanced but i'm going to get an ultralight flywheel and thats why i would have thought it would make sense to get it balanced. I said to the place that it will be smoother at higher revs. Anyway it's called K.L. Engine centre, my dad has delt with them before but perhaps he saw me (only 18 years old) and thought i don't want to serve him as he kept saying 'what are you trying to prove'.

[AndyMiniMad.]

Dont go back... Bunch of idiots, I also have a lightweight flywheel, although not the ultralight as my cam is a bit on the lumpy side. And as ive said I didnt get it all balanced. It runs fine. Picks up great and really takes off when it comes on cam. Well it did for a while untill it decided to eat my gearbox case, But thats another story...

Edited by AndyMiniMad., 02 November 2010 - 07:19 PM.

[TopCatCustom]

Your new engine builder friend sounds like he doesn't know the difference between an A series and a K series, how can they tell you you dont need your new engine balanced but say you need a dry sump?!?!?!?!!?!

Every engine needs to be balanced- but every engine IS balanced in the factory- though with older engines often to a fairly poor tolerance, but will still be fine for road use. As said a properly balanced engine will run smoother, but a proper balance involves every moving part- so pistons and conrods too.

You can balance your pistons and conrods yourself, there will probably be a "how to" on google (easier than me trying to explain) with an accurate set of small scales. A good balancer will probably want one piston-conrod assembly if you have balanced them yourself as they will put weights equal to them on the crank to simulate the pistons etc when spinning it up. This is true with a multi plane crankshaft (I've been living in V8 world lately) so it may not apply to a flat plane mini crank!

edit:
A crank oil scraper will regain maybe 1 horsepower at a lot of revvs, great on a race engine! As said before the engine shouldn't really need balancing but it will be nicer if it is done.

All that aside- why are they turning down business? Surely they should be saying you definately need it all balanced or it will explode lol

Edited by C4NN0N, 02 November 2010 - 07:37 PM.

[1977 Loud_Mini]

AndyMiniMad: I've got a 296 SP cam so will be quite lumpy at idle i'd imagine with the flywheel combo. I read about your gearbox casing trouble you had, hope it all goes well from now on

C4NNON: It seemed to me as if he didn't know what he was talking about. So mine should be ok for road use without getting it balanced. As the previous owner of the engine told me that when the new (still new) mains etc and regrind was done that the crank had been balanced so i'm hoping it'll be ok as suggested by the comments on here.

[valve bounce]

they sound like a bunch of idiots to be fair, when i had my block bored i got all the moving parts balanced (crank, flywheel, clutch, bottom pulley, conrods and pistons) and the engine runs alot smoother that the previouse one and the cost? £45inc vat

[1977 Loud_Mini]

they sound like a bunch of idiots to be fair, when i had my block bored i got all the moving parts balanced (crank, flywheel, clutch, bottom pulley, conrods and pistons) and the engine runs alot smoother that the previouse one and the cost? £45inc vat

£45 seems cheap for all that balancing. Where abouts did you take your crank etc to?

[bmcecosse]

In a way - they were right - although the 'dry sump' thing is obviously a leg-pull. A 1380 engine is not going to be a 'revver' - so the balancing is not as important as it is say on a 970 or 1071 (or even a 1275) where balancing lets you run the engine at higher revs to pump more air = more power without breaking the crank. On a 1380 the power will be limited by the head - so there is no point revving it high! And also - it is really not worth just balancing the rotating parts unless you also balance the reciprocating parts (pistons and rods) (and also check/correct the piston heights and the combustion chamber volumes!) - so again in a way they were giving you fair advice. They probably meant a 'centre oil pick-up' - also good advice.
My advice - just build up the engine and run it - and don't go beyond 6000 rpm. It will be fine!

[1977 Loud_Mini]

In a way - they were right - although the 'dry sump' thing is obviously a leg-pull. A 1380 engine is not going to be a 'revver' - so the balancing is not as important as it is say on a 970 or 1071 (or even a 1275) where balancing lets you run the engine at higher revs to pump more air = more power without breaking the crank. On a 1380 the power will be limited by the head - so there is no point revving it high! And also - it is really not worth just balancing the rotating parts unless you also balance the reciprocating parts (pistons and rods) (and also check/correct the piston heights and the combustion chamber volumes!) - so again in a way they were giving you fair advice. They probably meant a 'centre oil pick-up' - also good advice.
My advice - just build up the engine and run it - and don't go beyond 6000 rpm. It will be fine!

Thanks for the help. Is 6000rpm the absolute limit for a standard reground crank then as i will be running a fairly revvy camshaft and with no rev counter will be a little tricky to stick to that.