Cranks
Turbo Mini Forums

How many people are running a standard crank just with a centre main strap? Would you recommend them for a build what will be pushing 160bhp to 180bhp?

That's all I ran

What bhp was you running nick? If I have it balanced and looked at you recon it will be fine?

I was running around 200 bananas, just a balanced std crank with a centre main strap.

If you're not revving it high then you may as well spend the money elsewhere

Okay mate sound, thanks a lot 👍

These day's unless planning to regularly spin big RPM I probably wouldn't even bother with the strap.

My engine only has one in because the block's cap had been machined for one before I used it.

If something is worth doing, it's worth doing half of.

Depends on what you are calling standard. I think balancing would be a good idea.

I went for wedged, balanced and hardened. With a strap. But the car is a small bore and it loves to rev.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I'll be using a standard A+ crank and at some point may occasionally push it close to those sort of power levels. Only crank mod is cross-drilled mains to make sure the big-ends see as much oil as possible.

Whatever you use, it's important to polish the journals if needed and check the crank is straight... But does anyone know a sensible run-out limit?

How many of you get the flywheel / clutch balanced on the crank and also get the rods and pistons balanced? After a lot of testing I'm definitely of the opinion that getting just the crank balanced (even if it's better than the factory balance) is of little use, since most of the imbalances come from elsewhere.

Edited by PhilR on 28th Jul, 2015.

And what about them liquid filled vibration dampers? Do they work.?

you can do anything if you set your mind to it...
i rather blow it up winning than keep it together losing.

finish date set for project 1... march 2018

Personally on any engine I'd get it wedged to improve counter weighting and heat treated to make it last ages. Cross drilled if aiming for the 8k+ region but some reckon that it is not needed at all.

Would you notice much difference on a weekend/trackday turbo mini having a lightened balanced etc crank, reving to say 7k tops?

I was going to get it wedged, crossdrillied, cleaned up and balanced, but now just thinking maybe to just get it balanced with the flywheel etc. As it's not high reving.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

I've not built a turbo a series yet, but lighting the rotating parts improves performance hugely.

Balancing Pistons, rods (end to end) then dynamically balancing the crank, flywheel clutch, bottom pulley has two big benefits.

Firstly the engine runs much more smoothly across all revs. And secondly there is less stress on individual parts due to the balancing.

My 1293 engine ran a 285 cam and although the exhaust note sounded a rough as a bag of nails running off am, the engine was very drivable off cam.

The difference balancing had was like the difference between a 850 or 998 and a 1275!

The other part of balancing is making sure the compression ratios are the same in all cylinders.

Regarding the oil filled bottom pulleys most modern engine use them and don't balance the crankshafts as it's much cheaper for them.

But from our applications the oil filled damper pulleys will damp over a wider harmonic range. They are pretty expensive though, so if you re not revving it hard a lot, then I would balance all the rotating parts and run a standard pulley, that is in good condition. Fitting a pulley with a worn out rubber in it is asking for trouble. The a+ pulley is not like th s pulley where the rubber isolator could be replaced.

In the 286 engine it ran regularly up at 7k and up to 8 on occasions with the standard pulley but balanced.

New project will be a screamer, so en40b crank and oil filled bottom pulley.

The other thing to think about is flywheel, I am not familar with the uprated veto ones, but the pre verso flywheels can fail at sustained high rpm, if lightened. Lighting the flywheel improves engine acceleration, but also makes it much easier to stall. And sometimes requires a higher idle speed.

Nathan

having the whole rotating assembley ballenced is a must and money worth spending.