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Wiseco Pistons, orientation in block

PostPosted: 06 May 2007 0:06
by MLMFLCN
Hello,

I am installing a set of Wiseco Pro-Tru in my 440. Simple question, but just don't want to screw this up. Should the notched part of the piston be toward the "outer block", or up towards the lifter valley? To me it looks like it should be toward the lifter valley. I have attached two pictures, showing the Number 1 cylinder. Image 1335 is towards what I am calling the "outer block" and image 1334 is towards the lifter valley. Thanks for your help.

PostPosted: 06 May 2007 7:40
by christer
I found this pic in the book Big-Block Mopar performance.

PostPosted: 06 May 2007 10:17
by MLMFLCN
Thanks Christer, that's what I was hoping for. Now I can keep moving.

:D

PostPosted: 06 May 2007 11:27
by Eddie
just make sure the connecting rod orientation is followed. The bearings will be a little offset if used with a full radius crankshaft. If you get it backwards the crankshaft wont turn freely by hand as the rods and pistons are turned over following insertion in the bore. So the rods must be installed with the bearing off set towards the neighboring rod i.e.#1 cylinder is offset rearward, #2 forward and so on. Good Luck, those Wiseco are nice arent' they.

PostPosted: 09 May 2007 0:27
by MLMFLCN
Thanks for the tips on the rods, I was certain that each bearing offset was facing their neighbor. Is this strictly for oiling purposes?

This is my first assembly from scratch. The machine shop balanced my cast crank, and consequently showed measurements on each piston/rod assembly. The weights were written on the underside of the pistons, anywhere from 625.5 to 626.3. I tried to follow the numbering of the rods 1 - 8, but certain rods were not marked well. If the oiling holes are lined up, how critical is the weight factor in terms of the overall balancing / performance? The entire assembly spins very easily (it should my garage floor was covered with oil) and with 6 pistons installed, I could still spin the engine by just pulling on the crank throws. It only takes limited effort on the harmonic balancer bolt, and doesn't seem to bind anywhere.

Any other tips before I start on the heads?

I am certain I will be back. I have mildly worked 452's and Harland Sharp roller rockers. Should be fun....

Thanks again for all the help, this website is the best tool in my toolbox!!

PostPosted: 09 May 2007 12:27
by Eddie
The offset is for clearance with the chamfered bearings that must be used with a radiused crankshaft. The factory bigblock cranks are all grooved at the ends. The only crankshaft,(s), I am aware of that were radiused from the factory were the Maximum Wedge 413, 426 engines from 62-64 and the Mighty 426 Hemi Head engines all the rest used the grooved cranks. If it spins as freely as you say then you must have the rods in the proper orientation. The small "slits" on the stock rods are for cylinder wall oiling. Most performance rods omit this feature because they tend to overoil the cylinder walls. :thumbsup:

PostPosted: 09 May 2007 12:29
by Eddie
[quote="airfuelEddie"]The offset is for clearance with the chamfered bearings that must be used with a radiused crankshaft. The factory bigblock cranks are all grooved at the ends of the rod journals. The only crankshaft,(s), I am aware of that were radiused from the factory were the Maximum Wedge 413, 426 engines from 62-64 and the Mighty 426 Hemi Head engines all the rest used the grooved cranks. If it spins as freely as you say then you must have the rods in the proper orientation. The small "slits" on the stock rods are for cylinder wall oiling. Most performance rods omit this feature because they tend to overoil the cylinder walls. Keep us posted. I love engine tech and buildups :thumbsup:

PostPosted: 09 May 2007 14:03
by MLMFLCN
Thanks Eddie. :thumbsup:

Any thoughts on the weights?

balance

PostPosted: 10 May 2007 0:28
by itsfred
i was told by a very good machinist/racer that as long as the balance is close you are good. due to the fact that you cannot control the amount of oil splashing around under there and whats hanging onto the pistons and rods. we are talking grams here not so much ounces.
so from what i saw with your numbers you are good.
fred

PostPosted: 10 May 2007 0:41
by MLMFLCN
Thanks Fred!

PostPosted: 10 May 2007 7:19
by dave-r
Balancing a crank is an art not a science. :lol:

It seems a bit "subjective" to me because in real life you can only balance at one particular rpm.