I am replacing the pressure plate and disc in my truck. And I will face the flywheel. But, I have a flywheel from a turbo engine and it weighs in at 24 lbs, whereas, the present n/a flywheel weighs in at 33 lbs.

I think that acceleration would be improved at the expense of low speed smoothness and stall speed. I wonder why Isuzu reduced the weight for the turbo engine.

So, do any of you have any thoughts re this weighty issue? <img src="/forums/images/graemlins/wink.gif" alt="" />

Paul

Paul, I do not know the answer to your question, but I offer these thoughts for you to consider.

1. Are these engines balanced internally or externally? If external then a change of the front pulleys may be required that match the turbo flywheel?

2. In theory, changing the flywheel weight could change the torque range and this may change fueling requirements of the IP in that range.

3. There maybe a relationship between a lighter flywheel and turbo response??

Was it NCDiesel that just had a engine balanced? If so maybe he can contact the person that balanced his engine for some more information.

crossbones

That was indeed me.

The flywheel and pressure plate are balanced as a unit to itself only - like a car tire. It is not balanced in relation to other components. This is because a balanced flywheel will have a net affect of zero to the engine, in terms of out-of-phase inertial forces. In other words, if the the flywheel/PP is balanced until itself, then all is well and you can feel free to bolt it to any engine.

Just make very sure the mating surfaces of the flange and flywheel hub are clean and dry. Also bolt it to the crankshaft with an opposed/star pattern, like you are supposed to do with a wheel. These things will help ensure that the flywheel's plane of rotation is exactly perpendicular to the crankshafts axis of rotation.

The reciprocating parts like the pistons and crankshaft are balanced separately and I believe that is done statically but I have never seen that done. All my work is done by Golden Shamrock Machine shop in Winston-Salem, NC. However, any full service autmotice machine shop could do this for you.

NCDiesel

Hey guys--

Thanks for the input. Now I will need to decide.

Paul

That's funny- I have a N/A flywheel that I was going to put in my Trooper. I need a turbo flywheel. Jerry LeMond said that they were interchangable- I never even considered that they might not weight the same. I know that in racecars the flywheels are as light as they can get by with to reduce the rpm's faster when downshifting in the curves.

MAybe the same theory applies here.


Jesse

HEY PAUL I JUST CHECKED SOME OF THE PT NO,S AND THE PICKUPS AND THE TROOPER WITH THE TURBO HAD THE SAME FLYWHEEL AND THEY ARE NEUTRAL BALANCED, MEANING THEY HAVE AN INTERNAL BALANCE FOR THE ENG, AND THE NON TURBO FLYWHEEL IS FOR SOME REASON ABOUT 10 LBS HEAVIER, BUT IS ALSO NEUTRAL BALANCED , IF I HAD MY CHOICE I WOULD DEFINATELY USE THE LIGHT WEIGHT WHEEL ESP IN YOUR CASE OF THE PICKUP , AS YOU SHOULDN,T NEED THE OFF LINE ENERGY FROM THE HEAVY STOCK FLYWHEEL, SEEMS STANGE THAT THEY DIDN,T USE THE HEAVY FLYWHEEL IN THE TROOPER BECAUSE OF THE LARGE AMOUNT OF ADDITIONAL WEIGHT OF THE VEH, EVEN THOUGH THEY WILL BOTH INTERCHANGE AND THEY BOTH USE THE SAME CLUTCH AND PRESSURE PLATE ASSY, ONE THING ALLSO THERE WAS 2 DIFF, FRONT HARMONIC BALANCER ASSY, FOR THE TURBO ENG ONE WITH A.C. AND ONE WITH OUT , I WAS TOLD THAT THEY WERE BALANCED IN SUCH A WAY THAT WHEN THE A.C COMP WAS ENGAGED THE HARMONICS CREATED BY THE A.C. COMP WOULD BE CANCELLED BY THE DIFF OF THE BALANCE IN THE DAMPNER, HOWEVER YOU COULD USE THE A.C. DAMPNER ON A NON A.C. EQUIPPED ENG , GUESS WHAT WHEN YOU ORDER A FRONT DAMPNER NOW BOTH THE OLD NO,S SUPPERCED TO ONE NO, AND IT IS THE A.C. BALANCED NO , WHEATHER IT IS FOR A.C. OR NOT SO IT EVEIDENTLY WAS NOT A BIG BALANCE PROB, LIKE IT WAS FIRST THOUGHT, ONLY ONE NO. AVAILABLE NOW , AND IT COMES WITH A NEW HUB, CAN,T BUY THE HUB BY ITSELF, OR THE ENERTIA RING (PULLY) BY ITSELF, I HAVE HEARD SPENCERS DSL RUN AND THAT THING IS REALLY SMOOTH RUNNING, I JUST FINISHED UP AN ENG FOR A CUST, WHICH WAS A 2.2 C223 WITH A NON TURBO CRANK BUT WITH TURBO RODS AND PISTONS , AND A SMALL FLYWHEEL , IT IS AN AUTMATIC TRANS AND THIS THING REALLY IDOLS SMOOTH, THE MAN THAT OWNS IT SAYS THE ORIG, ENG NEVER IDELED LIKE THAT, AND IT SURE DIDN,T PULL THE HILLS OF NORTH GA LIKE IT DOES , AND HE IS GETTING 26-28 MPG WITH 4.11 GEARS AND A 3 SPD AUTOMATIC STOCK DSL CONVERTOR WITH A STALL SPD OF ABOUT 1600 RPM , FROM A DEAD STOP IT ACCELS ABOUT LIKE A NON TURBO , BUT AT ABOUT 20MPH WHEN THE BOOST COMES UP MAN THAT THING REALLY TAKES OFF, AND I SET IT TO A MAX OF 12 LBS WITH A 2.5 IN, EX ALL THE WAY FROM THE TURBO BACK THRU THE MUFF AND OUT , BETWEEN SHIFTS THE BOOST WILL DROP ABOUT 2-3 LBS AND HANG RIGHT IN THERE , I CAN,T READ THE GAGE ANY CLOSER THAN THAT, EGT DROPPED FROM 1050 F TO LESS THAN 800 ON HARD PULL IN SEC, GEAR AS SOON AS IT HITS 3RD THE TEMP SETTLES RIGHT DOWN , I THINK THE EXHAUST MADE MORE DIFF IN THE TEMP THAN I WAS EXPECTING , NOW WHEN THE TURBO STARTS TO SPOOL UP YOU CAN HEAR IT START TO WHISTLE A LITTLE BIT WHERE WITH THE STOCK 1 5/8 PIPE IT JUST FELT STRANGLED , THAT WAS A TOUGH FIT TO GET THE 2.5 PIPE IN UP BY THE STARTER AND UNDER THE TURBO OUTLET JERRY

Could it be that lighter flywheels are used in turbo-charged engines to improve rpm response when the turbo spins-up?

Just a thought - no idea if it is valid

NCDiesel

HEY SPENCER ,I THNIK THAT MAY HAVE BEEN THEIR REASONING OR AT LEAST SOME OF IT ,BUT AT THE SAME TIME I THINK THAT THE HEAVY FLYWHEEL WOULD MAYBE HAVE ELIMINATED SOME OF THE OVER REV PROB, THAT THEY WOULD EXPERIENCE AT ABOUT 4000 RPM, I HAVE SEEN THOSE ENG HIT 48-4900 RPM AND THE GOV IN THE PUMP COULD NOT REACT FAST ENOUGH TO PULL THEM BACK UNLESS YOU WERE IN 2ND OR 3RD GEAR ,IN 1ST GEAR THE TROOPER IS EASY TO MAKE GO UP TO NEAR 5OOO RPM, YET THE PICKUPS WAS ALLMOST IMPOSSIABLE TO DO IT ,, 4.55 IN THE TROOPER, AND 4.11 IN THE PICKUPS , THAT WAS THE MAIN REASON THE 87 TROOPER WENT TO 4.11 GEARS IN THE TURBO DSL ONLY , TO HELP HOLD THE RPM DOWN, RED LINE ON THOSE ENGS TURBO OR NON IS SUPPOSSED TO BE SET AT 4200 RPM JERRY