Thought on Spec and Cometic?

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Caveit77777
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Joined: Sat Nov 07, 2009 7:02 pm
Car: 1996 240sx SE

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Alright a few questions. First off I just ordered the spec stage 3 clutch for the ka from frsport a few days ago. I did a few searches AFTER i bought it and apparently these things were crapping out anywhere from 2 days-1 month of use, buuuut this was all back in 2003-2004. Was wondering is this still the case now?

Also I'd like to buy the cometic hg/arp headstud combo off of frsport because they have a decent price if you buy them together. I'm just wondering if 90mm x .040 is alright for my head even though stock bore is 89mm and mine isn't bored at all. It does have arias 8.8:1 pistons though. Then i started hearing cometic gaskets are only a c-hair better than the oem ones and they're known to blow easy?


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neverlift
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my buddy just put a vg together and it was pissing on day one, it stopped but still wtf now he is scared to beat his motor and its fully built down to crank balancing ffs.
my ebay gasket does decent lol evergreen and arps baby. Holds 7psi daily, handles the rough launch control. Its seen more boost than some cometics will ever see...about 3~4K miles on rebuild/hg

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biggie
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Car: '16 Q70L/'14 Q60S Vert/'19 Armada/'09 FX35
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Haven't heard of any issues with Spec in the last few years. I've had a couple Spec stage 2 clutches and no issues with them.

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Caveit77777
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Car: 1996 240sx SE

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Alright well fr sport offers up to .040 thickness for headgaskets but I'm thinking I should step up the thickness? Will this help at all? I plan on running a t3/t4 at a little more than 1 bar.

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neverlift
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folks do a bar on stock block/head gaskets.. but increasing the thickness will help reduce compression(minimal) and that not a bad thing for boost. IMHO cometic use a thick one and trq it down good with arps. But again I have an ebay gasket I paid 5 bux for it local cause an n/a guy was scared of it hehe

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2FourTee
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Joined: Thu Oct 28, 2004 4:16 pm
Car: 96 240sx - Supercharged ka24de

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Lots of people have complained about cometic, but that's because they don't do it the correct way. To seal properly, the cometic needs a very smooth and flat surface. That's because there isn't as much "crush" occurring when you torque down a cometic headgasket compared to say, a fel-pro. A cometic requires a much smoother surface than your typical machine shop will give you if you don't actually specify what you want. Cometic specifies a surface of 50 RA or better.

If you haven't had the head and block both re-surfaced (along with both the upper and lower front cover) and you're not looking for much more than 400 hp, I'd go with the fel-pro. If you're going for big power and both the head and block have been resurfaced PROPERLY, then use the cometic. Cometic actually specifies to install the gasket dry, but from what I have read on here, a lot of people use the copper spray prior to installing. SO far, I haven't heard anything negative about using the copper spray, so that's what I'll probably do as well. Use ARP head studs, and you're final torque specs need to be more than the factory 60ft/lbs. They need to be 80ft/lbs.

Installed correctly, it's a pretty bulletproof gasket.

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D-UNIT
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Car: a 91' S13 (15.014 @ 94.56mph NA) KA-T

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actually according to ARP the nut and stud design technically doubles the clamp load. They recommend 40ft/lbs for the head studs which would effiectively be 80ft/lbs! So 80ft/lbs would be 160ft/lbs!!! I torque mine to 45ft/lbs. I just couldn't bring myself to do only 40. No problems so far 3500 miles , 15-17psi.

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2FourTee
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Car: 96 240sx - Supercharged ka24de

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Well, a lot of people on ka-t.org and other various forums have posted of using a final torque of around 80 ft/lbs. Hell, the factory specs call for 60-65 ft/lbs.

http://www.ka-t.org/forums/viewtopic.php?t=42243
Tighten the head studs in the order below.
Lightly apply ARP Moly lube to both sides of the washers and on the end of stud.
This is from JGS's website for ARP torquing specs. Stock specs are basically the same. (For cometic just add a #8 and torque them to 80 lb-ft)
1. Torque studs to 25 lb-ft.
2. Then to 45 lb-ft.
3. Then to 55 lb-ft.
4. Loosen all studs IN ORDER (NOT the tightening order, use the loosening order mentioned earlier in the thread).
5.Torque to 25 lb-ft.
6. Then to 45 lb-ft.
7. And finally to 60 lb-ft.
Here are several other threads where people mention final torque specs around 80 ft/lbs:
torque-specs-when-replacing-head-gasket ... 18681.html
http://forums2.freshalloy.com/showthread.php?t=121175
http://www.ka-t.org/forums/viewtopic.ph ... =arp+++lbs
http://www.ka-t.org/forums/viewtopic.ph ... =arp+++lbs

I definitely wouldn't go LESS than OEM with ARP studs. That doesn't make a bit of sense. And my machinist, who has been building engines for 30 years, agrees.

Maybe you're confusing it with the rod bolt torque specs, which are around 45 ft/lbs, I believe.

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D-UNIT
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Joined: Mon Jun 23, 2003 10:37 pm
Car: a 91' S13 (15.014 @ 94.56mph NA) KA-T

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Hmmm... maybe you're right. It has been a while. hee. But anyhoo I specificly remember that because the studs thread into the block and nuts thread onto the studs , that makes the actual torque values double up. That is the beauty of running studs. I'll go look at my notes (not! didn't take any haha) I think I only torqued the rods to 25ft/lbs! Well I don't wanna be spreading misinformation so I'll get back to you on that. I guess overtorqueing is not as bad as undertorqueing!

amerjarrah
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Joined: Fri Oct 15, 2010 1:31 pm
Car: white 91 s13 coupe

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i'm interested in the result?

did you need to retorque 'em to 80?

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slikklogic
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Car: 99 honda civic 1.8T!
95 240sx base/se
Location: north central NJ

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dam i hope there clutches are good.i have the spec stage 3 in my garage waiting for install now


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