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Engine Balancing - Do all Pressure Plates for engine's whole life span?
bajachris88 - July 25th, 2013 at 03:58 PM

Hi gents,

Just contimplating pressure plates before purchase and bottom end balance.

Do I really need to buy all the pressure plates i'd expect to go through over the duration of the engines entire lifespan to be balanced with the flywheel/bottom end?

Or can the balancer technician in the future balance the new pressure plate to the flywheel by taking note of how the original one behaves on the flywheel during rotating on his/her jig in due time?

For the kennedy pressure plates, it makes a difference if i can get away with just 1 for the moment. Difference between $230 USD to $430 USD! I'm getting from aircooled.net as they check their hardware before shipping out, and I hear kennedy's QA isn't perfect so want a seller with the knack for detail.

Thanks in advance,
Chris


1916baja - July 25th, 2013 at 04:30 PM

Geez dude, rod sells them for about $180! Put it this way, daves engine on his drag buggy was balanced with the old pressure plate, he then got a new pressure plate a year later not balanced and it made no difference. Shit man, choose the right pressure plate and it should last as long as the rest of the engine surely!


matberry - July 25th, 2013 at 06:25 PM

Your hardly going to know by feel Mick, if you did it's soooo far out of balance it should be in the bin.

It comes down to your balancer. I use Crankshaft Engineering and they can repeat the balance job on new components as they have jigs to do so. Not all shops do so beware, some even only balance the complete assembly and not progressively so as soon as anything is removed your balance job is history. Even the torque sequence of fitting the clutch pressure plate can effect the balance.


1916baja - July 25th, 2013 at 07:02 PM

I just remember past engines that were not balanced and how rough they ran compared to the well balanced engines we use now. I was just pointing out that it didn't make enough difference to notice it.... We use crankshaft engineering also. My gear will be there next week!


bajachris88 - July 25th, 2013 at 09:47 PM

Thanks guys, so i take it in the future i can just take a new pressure plate to a reputable mob to get balanced, and if the assembly is balanced with each component individually it should be ok?

I'm thinking of getting a 1700lb kennedy, and when stage 2 (turbo fitting) is finished, then upgrade to 2100lb. I could just get 2100lb PP straight up instead, but want to see how the trans holds up first. Don't want to break it in the dirt away from civilisation/tow trucks so always what that little bit of slip when dumping hard. Was thinking a cushionlock disc would compliment nicely.


dangerous - July 26th, 2013 at 07:49 AM

The important point about clutch balancing is LOCATION.
Because of its mass, even .001" or .002" can equate to a large imbalance.

Same goes for flywheels, but you would hope that it locates firmly on a true running crank!

The ideal situation is to have it balanced with the crank and flywheel that you are going to use,
but in a worst case scenario (SP),
if, at a later date you need another pressure plate balanced,
you should remove your flywheel and tell the balancer that it has been done,
and so they should be able to sort the deal out on a special mandrel, or another crankshaft.

Now the only issue with that deal,
is that there is no way to determine if the mandrel is the same as your crankshaft,
as far as centreline is concerned,
but at least you can be sure that it will be better than a guess.

Clutch and flywheel imbalance is a major cause of case damage at the forward main tunnel,
due to ill fitting pressure plate location(loose).
If it does not fit precisely, it should be pinned at the time of balancing.


bajachris88 - July 26th, 2013 at 08:00 PM

Thanks Dave!

Well i'll get a single plate then. I won't be seeing 9 or 10k rpm but would like to redline freely at 6k without guilt or remorse :lol:

When the time comes for replacement, i'll take the flywheel then and try my luck :)