TWIMCAM BOY wrote:dont even think about puttin them in!!!! i had them in my vr4/starion engine and it spat out the bearing and cracked the block so i had too rebuild the engine that engine cost me big $$$ wasn t happy not too mention it was 3000kms old and still on run in tune! TAKE THEN OUT
It's hard to tell what happen's after a chain reaction.
But thanks for all the input guys, the engine builder who before worked for mitsubishi proposed ralliart shafts which are lighter, Im considering leaving them in, he has tuned before stroke engines, one from a mate which so far has had no problems and likes his work.
i have just had my engine built and i went for the removal of the 1 shaft. however i strongly recomend not removing the right hand shaft the runs off the oil pump, insted have the weights machined off it and cut it down so its just a bit longer than the bearing half way along the block.
The reason for this is the oil pump has 2 gears inside it, 1 is the drive gear and the other is the driven, if you remove the shafts altogether the driven gear has only one bearing supporting it and therefore can move and distort the bearing housing and flog out your oil pump. By leaving the shaft in you support this gear and avoid any oil pump probs.
as for sealing the unused bearings in the removed shaft a plug needs to be made for an interferance fit and the bearing half way along the block and simply be spun 90 deg out to seal off the oil feed then peened in place.
on doing this i recomend that the engine be balanced on a digital blancing machine, most good high performance workshops should these because of the acurracy they have as apposed to older manual style blancers.
my engine had all new forged internals and it still took nearly 2 weeks to balance it but i'm wanting a 7500 rpm limit.
boost = the replacement for displacement
<<<PIGS can fly
I don't think the bearing inside the engine needs to be rotated, I see this recommendation on a lot of balance shaft elimination guides but when I went to do it I realised there is no oil hole in that bearing, it's solid. The oil passes through the balance shaft from the front bearing to get to the rear bearing, not through a channel in the block or bearing.
yer...... is it ok then to leave in the shafts but take away the belt 4 them...
coz thats wat we did when we rebuilt the motor coz there not spining then.....
The shaft on the oil filter side can have the belt removed
and left alone, then do what ever you have too with the other
someone go and count the oil pump drive gear
and divide that by the driven gear tooth count and
maybe that will be the counter shaft ratio (sounds right) :? :? ???????????
by pulling off the small belt in the timing case your only stopping one shaft from spinning.This is going to render the balance shaft system useless. If mitsubishi could have made it work with one shaft then why did they put 2 in there. Its either remove one and machine the other or leave them alone if you want your engine and your gear box input shaft bearing to have a longer life.
boost = the replacement for displacement
<<<PIGS can fly
I stroked my VR4 engine and re-used the balance shafts. They have to be modified so they dont hit the larger crank.
I was in 2 minds on to use them or not. My dyno tuner said to get rid of them they are only there for NVH. The engine builder wanted to use them, he said they are there for a reason and to re-use them. I was told if i didn't use them the rear of the crank can snap of where the flywheel bolts up, aparently it is common.
I have completed 3 race meetings and 2 practice days at Barbagello and have never had a problem.
Oh NOW I see there is a little more about these shafts
I might have to find out, as there are two very good
arguments for and against useing them.
I have never heard of them priventing crank shaft failure :?
I`ll take a guess and say that this would be possible but
can anyone say if the removal would make these engines
any more likelly to fail ????.
tri26t wrote:Oh NOW I see there is a little more about these shafts
I might have to find out, as there are two very good
arguments for and against useing them.
I have never heard of them priventing crank shaft failure :?
I`ll take a guess and say that this would be possible but
can anyone say if the removal would make these engines
any more likelly to fail ????.
I was advised not to remove them on a Stroker engine, I wasn't prepared to take the risk, so i used them. Im still not convinced that they are esential. If i was building a 2ltr and not a stroker i would have removed them!
I still had the engine fully balanced from the crank pully to the clutch.
you know Im thinking bout this balance shaft thing
and have this nagging feeling that the WEIGHTS of the shafts
would be calculated against the original crank/piston/rod collective
weight and there for the vibrations would happen ether more ???...or...??? less ...??? than usual after stroking
or changing pistons or rod weight
is the weight calculated with fly wheel ?,harmonic balancer ?,
or is it just about the CRANK ??????????????
The crank can be balanced all by itself. Its not like a V8 with all that bob-weight tom foolery. As long as its balanced and your reciprocating mass is equal from cylinder to cylinder you're good, no matter what stroke.
The balance shafts really are just for NHV and are not related to "balance" of the engine. Get rid of them.. at 9,000rpm they're at an F1 18,000rpm. That's what I did on my 2.4L with no regrets.
