need tips for making power on ka24de, scca it legal

[all stock]

hey guys, spun a bearing on the short block, so it's time for a rebuild. i've pretty much done everything allowable on the head, which isn't much. bronze valve guides, and 1" port matching, .025" mill

the pistons are going to be 1mm os, must be same weight, relatively oem.
the rings are unrestricted. what advantages are there with rings?
planning on rebalancing everything. i can blueprint too, but not really in my budget

can we make the bearings and rings loose to make a bit more power?

things i can and can't do:
http://www.scca.org/documents/Club%20Rules/ImprovedTouring.pdf

[BigVinnie]

hey guys, spun a bearing on the short block, so it's time for a rebuild. i've pretty much done everything allowable on the head, which isn't much. bronze valve guides, and 1" port matching, .025" mill

the pistons are going to be 1mm os, must be same weight, relatively oem.
the rings are unrestricted. what advantages are there with rings?
planning on rebalancing everything. i can blueprint too, but not really in my budget

can we make the bearings and rings loose to make a bit more power?

things i can and can't do:
http://www.scca.org/documents/Club%20Rules/ImprovedTouring.pdf

What you want is more rev out of the bottom end. Too much harmonic stress from its half weighted crank. GT3 class drills the harmonic dampener bolt through to journal 1, this prevents the crank snout from snapping at high rev. It also heps to increase dampening.

Also make sure to drill oil holes through each journal of the KA crank (snout journal, and center main journal).

If you are using the DE bottom end you want to replace the girdlemain, with individual main caps that are used on the DE truck blocks that frees up some rotation and rev.

Looking for pistons that are relatively to that of OEM look into clevite.

[burnsauto]

What you want is more rev out of the bottom end. Too much harmonic stress from its half weighted crank. GT3 class drills the harmonic dampener bolt through to journal 1, this prevents the crank snout from snapping at high rev. It also heps to increase dampening.

Also make sure to drill oil holes through each journal of the KA crank.

If you are using the DE bottom end you want to replace the girdlemain, with individual main caps that are used on the DE truck blocks that frees up some rotation and rev.

Looking for pistons that are relatively to that of OEM look into clevite.

in reference to the main caps off the de truck blocks. are they in any way stronger than girdlemain? also....i would need to measure for bearing clearances after i made the cap switch, correct? any help would be appreciated.

[BigVinnie]

in reference to the main caps off the de truck blocks. are they in any way stronger than girdlemain? also....i would need to measure for bearing clearances after i made the cap switch, correct? any help would be appreciated.

Not only stronger but it allows each journal to become independent.
Yes you need to measure for bearing clearance and tolerance.

[all stock]

thanks for the tips.

i'm not sure i would be allowed this in Improved Touring, however. out of curiousity tho, how much higher can you rev with the main caps and bolt drilled.

i'm assuming you guys are running windage trays or a scraper?

[BigVinnie]

thanks for the tips.

i'm not sure i would be allowed this in Improved Touring, however. out of curiousity tho, how much higher can you rev with the main caps and bolt drilled.

i'm assuming you guys are running windage trays or a scraper?

Everything I mentioned is strictly OEM (clevite pistons are made to OEM spec) and is usable for your scca class. You can modify stock as long as it isn't replaced with an aftermarket that is rated other than OEM. The clevite pistons can come with stock or oversize, but the ring dpths and clearance are all designed to OEM spec so they are usable for your class.
I didn't know exactly what the improved rev is just with the main cap modification, but I do know with the use of the dampener bolt drilled to journal 1,and the main caps being used as a combination, rev can get as high as 7800RPM. I wouldn't recomend that rev without replacement of OEM JDM spec CA18det retainers, and springs. On the stock retainers and springs I wouldn't exceed rev over 7300, just to be on the safe side.
If you are using the 91-94 intake manifold remove the scv's they reduce intake flow at high rpm, although they make good torque numbers for low end, due to high intake velocity at low rpm. Also use the 240/248.

You can also port and hone the intake manifold a 1mm port/hone makesmajor improvement on the KA.
http://i27.photobucket.com/albums/c166/BigVinnie/coolantpassage.jpg
http://i27.photobucket.com/albums/c166/BigVinnie/extrudeimpefection5.jpg
BEFORE
http://i27.photobucket.com/albums/c166/BigVinnie/MMcheck2.jpg
AFTER
http://i27.photobucket.com/albums/c166/BigVinnie/MMcheck1.jpg
http://i27.photobucket.com/albums/c166/BigVinnie/intakemanifoldpic6.jpg

Idon't know if you can use an SAFC to modify the ecu but if you do the N60 MAF shows upto a 5 HP gain when compared to the stock G60 or G70 MAF. An N60 is OEM atleast for a Nissan Maxima

[all stock]

only allowed to port match the manifold and head up to 1" into.


i'm allowed a maximum os piston of 1.00mm or .040" over. it needs to be OEM shape, size and weight, except for the oversize. does anyone know of a good brand? rings too.

[BigVinnie]

only allowed to port match the manifold and head up to 1" into.


i'm allowed a maximum os piston of 1.00mm or .040" over. it needs to be OEM shape, size and weight, except for the oversize. does anyone know of a good brand? rings too.


The clevit pistons are "all stock" in weight, and bore, even ring placement, and there dirt cheap. Wiseco's and super techs are no where near what you want.
Believe me dude I'm all stock, and still street legal.
Your good to go.
You can port match 1" into, that doesn't mean you can't polish the crap out of it.
Or you can always go ebay...... http://cgi.ebay.com/ebaymotors/ENGINE-REBUILD-KIT-NISSAN-2-4-91-94-KA24DE-240SX-DOHC_W0QQitemZ260141183443QQcmdZViewItem

[tacotacotaco]

why not go sohc pistons?

[98s14inaz]

This is a great thread. I never knew that about the girdle mains etc. I will definitely do some of this stuff on my next ka build. Thanks

[LigouriRd]

why not go sohc pistons?
Not stock, since they are different size and shape from the model year of the car. They will raise the compression ratio, doubtful that anyone would tear down the motor to inspect it, cept maybe on a national level, but its still cheating.

[S14DB]

98-01 Altima pistons have slightly stronger ringlands. There was a design change to help prevent oil blowby which was common on the 93-97 models as they approached higher mileage. I would expect though that any auto parts retailer will carry OTC no name pistons for all 93-01 models and they will not be any better than the older OE units would be. In other words, buy the newer OE pistons from the dealer or go big.

They look damn near identical. You would have to measure the ring lands to see the difference. Being OE KA pistons you can play the they are OE stock KA parts game.