First KA-T build, question/issue

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First KA-T build, question/issue

Postby shftqikr » Wed Sep 07, 2016 6:16 pm

Hello Everyone,

I've been browsing for some time while putting my '90 ka-t together and have my first real question. I've been searching for a couple of days, but have no real answer yet on this. I am trying to find a more performance oriented head gasket for my sohc ka-t project. I have stock internals on all fresh machine work for the head and block. I am using the CXracing turbo kit which seems o be working fine at this point. I started engine up after build held rev at 2500rpm per builder's guide to seating the new rings correctly. I took the car up on the highway for a total of 2 miles, never running it hard. boost is set low at 7psi, but feels extremely smooth in operation. The issue is this, after all of 33 miles on the build, I took the car up to 5000rpm in 3rd gear 1 time, and at the end of this short pull I had a stuttering engine, and the tell tale cloud of white smoke so thick that the road behind me could not be seen. It smoked like this for the 1/2 ile ride home (watching the temp gauge the whole time), and used up all the coolant. I first checked compression which was solid a 155 on 3 cylinders, but only 120psi on #3. I added coolant, and cranked engine with no plugs in it, and of course out shot coolant from plug 3's home. I have not yet pulled it apart, but I guessing this is either a gasket blowout, or crack in head. It is held with ARP studs torqued at 70, so I don't think that is the issue. If there is a better gasket out there can someone please point me in the right direcrtion. I have already read about the mod of the dohc cometic but I'd rather have something made for this engine.
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Re: First KA-T build, question/issue

Postby SIL8D » Sun Oct 02, 2016 5:20 pm

any luck on this ?
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Re: First KA-T build, question/issue

Postby shftqikr » Tue Oct 11, 2016 8:18 pm

Yes, and no. I ended up replacing the head gasket as it was obvious that it was blown. I used a felpro replacement this time with the ARP studs. Torqued with atp lube to the needed 70ftlbs. This lasted much longer, but when I put the DSM 450cc's in with resistor, turned up to 10psi and tuned to 11.2 afr through the rpm band above 40% throttle....it lasted about 60 miles and blew again. Now on a hunt for a better head gasket option. The cars like a top at 7psi, and ran well with hard pull when I upped it to 10psi, just back to a blown gasket issue.
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Re: First KA-T build, question/issue

Postby BigLoukaT » Thu Oct 13, 2016 5:10 pm

What are you tuning with?

Does not seem normal at all to blow at 10psi. I have beaten my 200k mile sohc relentlessly for 5 years at 8psi so it seems that you have a mechanical fault with your specific engine
1990 S13
Boosted single slammer
MS DIYPNP

npx from 240sxforums wrote:i figure from my very limited knowledge about the 240 and under the hood about cars in general i would follow the sr20det trend.
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Re: First KA-T build, question/issue

Postby shftqikr » Sat Jan 14, 2017 12:34 pm

Hello again,
Sorry I let this die for awhile, life took a front seat to fun for awhile. So to catch back up, I have not yet taken it apart from the new blown gasket, but to answer your question, i am only using the SAFC 2 with an LC2WB right now. I am going to ditch that option for a Jim Wolf tuned ECU and 740cc injectors. This way I am ready from a fueling stand point to turn this thing up after I figure out why I keep blowing HG's. I agree with you about it not being normal to blow gaskets like this. This is a fresh rebuild, with all fresh timing and needed parts. So the surface is level, so not sure why this keeps blowing. I also beat the hell out of another engine I ave in my DSM, that has 150k and I run 30psi on a never opened engine with no issues. Just wondering if this is something that is seen on the KA24E engine hen using just a felpro head gasket.
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Re: First KA-T build, question/issue

Postby Crack240 » Wed Feb 01, 2017 5:09 am

I've boosted a few stock sohc engines and was able to take them up to 13 psi reliably. I don't see why your having head gasket failure. It must be an imperfection in the mating surface. Even my semi bukit motor with 22psi didn't have any head gasket failures
89 Ka24e-t
completely stock
49k miles
550cc injectors
z32maf
GSP.50 trim
38mm WG
10 psi
260wtq
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Re: First KA-T build, question/issue

Postby adamky » Sat Feb 04, 2017 12:51 pm

Do you have a way to monitor knock? And did you retard your base timing at all? You HAVE to do this with a SAFC. I've personally known of two people who blew KAs this way. You've either got too much timing causing knock, or some kind of defect in the head and/or block.
Wiseco/Eagle, JWT S1 cams, BC valve springs, PT5857, ID1700 injectors, SR20DET ECU w/ Nismotronic, etc, etc...
--> YouTube channel --> my build thread
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Re: First KA-T build, question/issue

Postby shftqikr » Fri Feb 24, 2017 6:25 pm

OK, update. I pulled the head, and as I thought it blew the gasket at cylinder 2 and 4. Both spots blew through to the water jackets.Thanks also for the ideas, I believe the issue is the timing not being pulled at the distributor. It was running great at 8psi, so I went to 10psi and it blew within 60mi. I used another felpro with copper spray on each side this time. I am back at wastegate pressure of 8psi, and have put 800 miles on it with a few heavy pulls. All is running well. I do not have any way to watch knock as I do on my other cars. Is there a way to add this feature to the SOHC? I plan on having JIM WOLF flash a DOHC ecu so that I can run 740cc injectors. This should handle timing and fuel needs up to the end of stock internals. I will be putting on my N62 maf at that time as well. I'd really like to turn this up to the limits of the stock maf, but am not sure how much base timing to pull to keep things safe. I've been searching for sometime now, but have seen no solid answers on this. How did you get up to 13psi and not pop the gasket? Any help would be great.
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Re: First KA-T build, question/issue

Postby shftqikr » Fri Feb 24, 2017 6:29 pm

OK, update. I pulled the head, and as I thought it blew the gasket at cylinder 2 and 4. Both spots blew through to the water jackets.Thanks also for the ideas, I believe the issue is the timing not being pulled at the distributor. It was running great at 8psi, so I went to 10psi and it blew within 60mi. I used another felpro with copper spray on each side this time. I am back at wastegate pressure of 8psi, and have put 800 miles on it with a few heavy pulls. All is running well. I do not have any way to watch knock as I do on my other cars. Is there a way to add this feature to the SOHC? I plan on having JIM WOLF flash a DOHC ecu so that I can run 740cc injectors. This should handle timing and fuel needs up to the end of stock internals. I will be putting on my N62 maf at that time as well. I'd really like to turn this up to the limits of the stock maf, but am not sure how much base timing to pull to keep things safe. I've been searching for sometime now, but have seen no solid answers on this. How did you get up to 13psi and not pop the gasket? Any help would be great. In the pic you can see burn marks on the gasket right where the gasket blew.
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Re: First KA-T build, question/issue

Postby adamky » Mon Feb 27, 2017 11:01 pm

What type of knock detection to you use on your other vehicles? You can make some DIY knock detection for tuning for fairly cheap. Search for "knock ears" or "detonation cans".

I like having a visual warning of some sort since I often have my stereo blaring. Even if detonation got bad enough to hear, I wouldn[t hear it over the stereo. I used a TurboXS knock light for years but it was very basic and I never felt that I could trust it.

So when it died a while back, I purchased a knock warning gauge off of eBay called the "Lil Knock Meter": http://www.ebay.com/itm/Knock-sensor-ga ... 35?vxp=mtr. Here's their website: http://www.insaneimportperformance.com/. It's actually a fairly cool little device that looks to have lots of potential when setup correctly. There is configuration software for it that allows you to change sensitivity, noise threshold, time, etc. It has both digital and analog out signals to use for logging the knock level. I've played with the settings and you really can tune the thing a lot more than anything I've seen from any other companies, and it's fairly inexpensive.

It also has an audio output so you can plug headphones directly into it. However, I wasn't happy with the sound quality and volume I was getting out of it so I also have a Y-splitter that I run into a cheap personal sound amplifier. I can then split this signal using a Y-cable and either listen via headphones while simultaneously recording the sound via my laptop. OR... I have a standard headphone input jack on the front of my Kenwood head unit that allows me to play the engine noise through my car stereo. With the windows up and the stereo cranked up, this is a great way to allow both the driver and the tuner/passenger to listen for knock in real time.
Wiseco/Eagle, JWT S1 cams, BC valve springs, PT5857, ID1700 injectors, SR20DET ECU w/ Nismotronic, etc, etc...
--> YouTube channel --> my build thread
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