Main gridle or crank scraper?

[91DSMdave]

I've done some searching, but i cant seem to find my answer. I have been looking at the Jay Racing billet main caps, with the Kiggly Racing main girdle. From what i can see, the girdle provides potential for more power, by connecting all the main caps together. The crank scraper is supposed to remove rotating mass from the crankshaft by eliminating the windage cloud of oil caused by the rotation of the crank. which should i choose? Can i use both?

 

[1991GSXAWD]

If this is going to be a "race only" engine than you will benefit installing these parts to get the last ounce of HP and durability out of it.

 

[bjones18]

There are alot of high-horsepower v8s without a "girdle" cap. My understanding is lateral bolts into the caps are a geat way to tie caps into the block, but I'm not sure if this is possible on our blocks. While "main girdles" may offer some strength advantage, I think they are designed more to reduce the vibration modes of the block. This enables engine designers to reduce noise. On a alternate thought, I have heard of race teams trying to run long head bolts straight though to the mains to keep the block together.

While I haven't seen the girdle you mention, if you think about the vertical & rotational forces coming from the pistons & rods, I do not see "bridge" supports from other mains providing much vertical support. Now, if your mains are flopping around like flexing potato-chips at 1950Hz... tying the mains together with a girdle may increase this "potato-chip" mode to say... 2800Hz where for instance it might not interact with a crank mode at 1953Hz. (frequencies in this example have been changed to protect the innocent :^)

 

[firefighter]

Main girdle and the caps from jay racing are not a bad thing. Depending on your application it could be a waste of money or money well spent. If you are really going to build a high horsepower high Rpm engine(around 1000 hp 8500 rpm) get them.For a street driven Race ready car you are wasting your money.Put in ARP studs with Main bearing cap alignment dowels you will end up with a pretty good bottom end. Get a crank scrapper from Isharra Johnson.I got and it,s a real nice peice , it's well made.The scrapper helps to keep the oil off of the crank reduceing rotating mass also the oil will run cooler (better heat dissapation). You will pickup HP as well.