trapt350z

iTrader: (7)

the shop i am having my motor build done at called me and said when they tried to balance with my pauter rods that the crank would shoot out of the machine with the formula they were using unless he added weight to the crank.

now my main question is...anyone who had their crank balanced...

did the shop have to add or subtract weight to the crank for balancing?

Z1 Performance

iTrader: (564)

not sure how you add weight to a crank...shaving weight, sure, that's what you use the counterweights for

they should be putting the rods on a scale, taking the lightest one, and shaving the rest to match that lightest unit.

jerryd87

iTrader: (4)

you can add weight alot of shops do it, mayby not for the vq but its pretty popular in the v8 world you drill a hole in the side of the counterweight instead of the bottom and replace it with an alloy know as mallory which is a super dense metal and iirc weights about twice as much as the material you remove

trapt350z

iTrader: (7)

yeah he balanced the pistons and rods to match in weight, and I asked him to balance the crank but apparently the consensus is that the crank should be balanced already...which is good news for me because now i can get on with my build...thanks

blAk mAx

should the oem crank always be balanced when changing to aftermarket rods & pistons?

trapt350z

iTrader: (7)

10-12-2011, 08:58 AM ....... maybe shoulda checked the date on the last post -_______-...been fully built and boosted for quite some time now hahaha

trapt350z

iTrader: (7)

but to answer your question...its only like 90$ to have it race balanced but our stock cranks come fully balanced from factory so its not neccesary

jerryd87

iTrader: (4)

definitely not true, pauter rods are much heavier then factory and piston weights will be different also. when i have mine balanced they had to add mallory(heavy metal used to add weight to the crank) and 3 or 4 spots and took metal away in several other spots. dont do it and its gona be a time bomb

blAk mAx

i have eagle rods and wiseco pistons ready to put in. a long with a list of things the machine shop wants $200 to balance the crankshaft and the piston rings may need to be shaved and it will cost more if i want that done..

jerryd87

iTrader: (4)

ring end gap set should be the part of any blueprinting process otherwise when they expand they could cause the piston ring lands to chip off and ruin the engine. balancing for anything going over 5500 rpms imo is a must.

blAk mAx

didnt expect the process to be over 1k

jerryd87

iTrader: (4)

that is pretty expensive but it depends on the area your in, for instance on oahu they charge $45 per cylinder for bore and hone without a torque plate, yet back home in ohio i could get it done for $15 a cylinder with torque plate.

blAk mAx

Can the crank and rods/piston be balanced at the same time. As in I assembly then take it to be balanced? I ordered a piston and rod set wouldn't the rings already be the correct size and not need " sanding"?

jerryd87

iTrader: (4)

no lol the crank is balanced by placing it in a machine and spinning it after entering the weight info into the computer for the piston, bearing, and rod weights. pistons are balanced by finding the lightest one and taking material off until they all match. rods are balanced by weighing each end independently and again doing the same as the piston. no its impossible to order the "correct size" for the rings. different pistons have different piston to wall clearances, the manufacturing process has +/- limits, the pistons have +/- limits for manufacturing. pretty much every single engine will require a different amount of filing(if the machine shop is sanding then run away it should be done using a ring grinder.) the only rings you will not need to file fit is gapless which arnt made for the vq35.

if your trying to cheap out your engines gona blow period

blAk mAx

Just trying to see what I can do to adjust the machine shops new quote that doubled. I started buying parts based on the estimate he gave me. Came out to be better than buying a built block. But now im going see if z1 can help me with returning what I bought and getting a built block

Andrei

iTrader: (7)

It's always best to check but aren't Pauter rods already weight balanced by Pauter? Doesn't the same go for aftermarket pistons?

jerryd87

iTrader: (4)

mine where not perfect, its usually a + or - thing as well, they will usually be close but not perfect and the shop should be charging if it actually needs done or not and it still dosnt address the crank since balancing is done as a rotating assembly that SHOULD include rods, pistons, crank, flywheel, and crank pulley(unless its a fluidamper)

johnwigs

Can I get a Like button??? The trick to keeping a modified VQ running for a long time is in the details!!! Yes your car will run without weight matching and balancing... but not for long! I also grind down all the corners on every single part of the engine (remove heat risers) and remove the casting flash in places that Nissan couldn't be bothered to do at the factory... details that don't reflect on dyno graphs but reflect on engines that outlive their owners driving skill and live life in second and third chassis!!!

Andrei

iTrader: (7)

^Agreed but you need to post some pictures. Especially of the heat risers because I never saw any. Maybe you're referring to stress risers?

Andrei

iTrader: (7)

They should be weight balanced for $1k. They should also specify main bearing sizes according to the journal sizes of a new OEM crank assuming all new OEM cranks are identical.