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Hi
I got this crankshaft in my Volvo b230 engine 90mm stroke. and I got some vibration at 3500 rpm. I wonder if this crankshaft need a ATI damper ???

now it's a aluminium from KL racing

Do anybody know the name of this chrankshaft

Get rid of that solid alu pulley ASAP.

Check the crank balance.
And check the pulley balance to.
An aluminum pulley is not optimum but it works.
I use them on my engines even if I would prefer a damper.

Erland

Do you think it is a issue That the crankshaft not have so many Contra Weights. Like a b23 Chank

The crank is in balance

Do you know if it if I should bay a ATI damper from another car.
From which car Do it fit best. I know I much customise it to fit properly.

Maybe a supra ???

Probably a Honda or another 4 cylinder car so that it is tuned for a 4 cylinder.
Have you had your crank balanced?
A guy here in Sweden had an aluminum hub that was severely out of balance.
He said 60 grams but not at what radius.
O have never had an issue with the aluminum hubs and I do track racing and dyno testing.
I have revved my engine to 8700 rpm without problems.
And my engine lasted for 4 years on the track and dyno without problems.

Erland

I would get a damper..mail ATI and ask for advice.
My common sence says there must be a reason why nearly every engine has a harmonic balancer from factory.

Honda and opel cracks oilpumps and damages bearings without balancer. I have heard 6cyl volvos snap cranks.

Just my thoughts. I have never been brave enough to start downgrading my engines

Mertz skrev:Do you think it is a issue That the crankshaft not have so many Contra Weights. Like a b23 Chank

The crank is in balance

Do you know if it if I should bay a ATI damper from another car.
From which car Do it fit best. I know I much customise it to fit properly.

Maybe a supra ???

Counter weights need to be on both sides of the piston/rod if you want to use light weight pulley and flywheel. (most important at high revs)

With this type of crank you should aim for heavy pulley/flywheel, this will help you to keep bearings in good condition at high revs and also help you from vibration issues at lower revs.

A fluid damper must be designed for a similar crank, if not, it will not help as much as you need.

Seems like some other comments did not reed what you wrote since they tell you to check crank balance (as you already told it was in balance)

3500 rpm is nothing. If there is problems at so low engine speed, I would measure vibrations.

I would guess that crank eigen frequency (torsional) is higher than 3500 1/ min (57 Hz).

You are right about 3500rpm is nothing.
We could make this discussion very long for no reason at all, it is not only torsional problems but also the problem of bending the shaft.
Bending will occur when piston/rod tries to escape through the head and the crank will go the oher direction. All of the forces will need to follow the big end crank pin until it reaches the main bearing and the next counterweight. On B230 the pin is relatively thin (49mm) and this will easily take a little "flexing" (especially when stroked to 90mm)....

More heavy wheels in both ends will help to keep it more straight.

I am not saying this must be the actual problem, but it is not a good idea anyway to try and race an engine when the wheights and crank-type is in mismatch. It is just a few months since i saw a customer with similar crank destroying his 1+4 piston by head-contact at revlimit 8000 (standard B230 crank easily take 9000-10000 rpm)

I am totally convinced about he fact that if he had scrapped the light-wheight flywheel and alu-pully, his car was still running.......

Also, i think a standard B230 could like the alu-pulley but im nut 100%, the standard 230 shaft is one of the best casted shaft that i heard of (if i did not know it was casted i would take it for forged, since it works so fine)

why not use the original damper?

Thanks for all the good answers I’ve bought a ATI damper from kl racing

Do they have an ATI damper for Volvo?

Erland

The only one i found on KL's website is the one that fits 2jz.

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I have a custom hub for a eco tech ati damper from ftt racing for my b230.
But I know one drifting guy that broke 2-3 crankshafts, then put on a sr20 ati super damper and never broke a crank again 8500rpm 700hp.

under abut 8000-8300 rpm you should be ok like it is.

2 order vibrations at 3500rpm is normal on a 4 cylinder engine and is not harmful to the engine. to get rid of it you need balans shaft but is not for the engine its more for the driver.

what HP? boost level? max rpm? approx piston, flywheel and rod weight? automatic converters is good.

mvh jens