Now here is were it gets bad. It was probably 9:30 or so when i decided to do two more runs then call it a night. The first run i did was an ok 14.7. I decided since i was doing my last run i would do a burnout in the box since i had not done one all night. So i did my burnout and that is when i pulled my best time. So i pull the car around to park it and watch others run for the rest of the night. When i pulled into a spot next to a car i hear this metal on metal contact.... ....i was hoping it was my exhaust since i sounded like it was coming from under the car. So i get under it and shake a few things but nothing makes the sound. I pop the hood and give it a little rev and it follows the rpms. I shut it down and go watch other cars run for 20-30 minutes. So i get back and check all my fluids and they are ok. So i start her up and here the horrible sound that is a rod knock on #4. Then i start to limp my way home. I guess on a good note i did make it home (45min drive). On the way home it didnt make any noises or act weird at all. It only seems to do it at idle. I was boosted for 2 years with no major problems until now.

Thank god its not my daily any more.

So i am going to rip her apart and see whats up. I plan on keeping the same crank and rod if they are not damaged. I have a quick question though. What would cause it to spin a rod bearing? Streched rod bolt? I was shifting at 6K. If a rod bolt is the cause of it i am going to get arp rod bolts if you can for the stock rods and throw some new rings and ACL bearings in it while i'm in there. I rebuilt this motor 15K ago (stock rebuild) so i guess i got some use out of it. I used a ebay rebuild kit at the time too ....how ever i later learned that it was the same rebuild kit TopHat sold. ......Ebay bearings (ITM)....FTL

Modified by nelson8708 at 6:44 AM 7/19/2008

Modified by nelson8708 at 8:23 AM 7/19/2008

Megan Racing Parts supplier.Among many more companies Act, hks, b&m, sparco,msd,etc. hotrod6000000@yahoo.com
KA-T why settle for anything less?

I'm pretty much going to throw it up on jack stands and if everything looks ok under it then i am going to go ahead and start unbolting the tranny and what not.

Quote, originally posted by Florida240sx »

Sure it's a bearing not timing chain? Wishful thinking

My S14 does that. You can heat that bish' doing it's thing at idle, but if you bump up the rpm's, it goes away. I guess the oil pressure tightens it up. Or that's a sign of a bad oil pump.. who knows'. lol

But yeah, hope it's nothing bad. And the fact that you drove it home without a hitch, is a good thing.

Now that you're going to tear it down, put some fortified guts in that puppy!

If it happens only at idle, maybe it's a valve thing? You sure it's not coming from the top of the motor? Just throwing it out there.

"I'm no prince, and I can't lay the stars at your feet,
But I got this old car, and she's pretty tough to beat..."
Wings For Wheels, by Bruce Springsteen

Time for a rebuild!

Brand new Borg Warner S258 ---> http://forums.nicoclub.com/zerothread?id=354932

NIB Ferrea 1mm oversize ka24de valves 4 a KA ---> http://forums.nicoclub.com/zerothread?id=363557

New sparco sliders/rail for a s14 --> EMAIL ME

I had that issue...I had knock...then I had a hole in the block. In fact 3 years later that same engine with the hole is still under the hood...lol.

My buddie (also sohc) thought he had a lifter seize on him but coutinued to drive the car for about a week or two. It was a rod knock and the motor ended up seizing in his drive way after a drive home from work. So he drove it for about 1.5-2 weeks after hearing the initial rod knock.

http://tinypic.com/player.php?v=285b7o&s=4

I have a high volume 280zx oil pump so i dont think it was a pressure or volume problem. The only thing i can think of being a lube problem is that it was a 95 degree day. During my last run when it happend it had cooled down to probably 86 degrees. I was running 10w30 (only had 800 miles on the oil that was in the engine though).

You got an oil pressure gage? Hows the OP?

damn nelson at least you got it home man

so what was your best time?

----------------------------------
r.i.p. Lee
09/01/89~09/28/06

Quote, originally posted by nelson8708 »

I went to the track today. I got there about 6pm and did runs all the way till 10pm. I got 16 runs in ...I probably did three runs back to back then took a half hour break or so. I was on 5psi, bald street tires, welded diff. For the first 6 runs or so i couldn't get a decent launch. Were talking 2.4 to 2.6 60's. I was launching around 3K since that is what i launch at on the street but i would spin like crazy on the street and i was bogging on the track. I kept upping my laucnch rpms and when i got around 4K it didnt bog as much any more. Towards the end of the night i was launching at 4,200rpm and was cutting 2.2 60's. I think i can get it a little lower if i were to lauch around 4,500. My best time of the night was a 14.6@97 with the 2.2 60'.

Yeah i was happy that i atleast made it home.

You don't run the car hard when it is cold do you?

1992 Nissan 240sx KA24DE-Turbo: The "Showcar"
Stock internals
532whp/486ft.lbs-30psi
12.6@122.3mph-22psi
http://ka-t.org/cory_b.php

No i never beat on the car when its cold. I wait for it to atleast get up to 160-170 degrees. I believe i read on moto tune usa that beating on a motor that is not fully warmed up is one of the main causes of engine failure. When i pull it i will find out whether or not its the flywheel bolts backing out or not. I did use red lock tite when i installed them but, that doesnt mean they didnt back out. When i pull it i plan on spot welding what i can in the engine bay as well as maybe cleaning up a few wires.

Do you think it could of been the fact that i was running too light of engine oil (10w30 on a 92 degree day)? I am thinking 10w-40 or maybe 20w50 depending on my clearences if it turns out that i have to replace my bearings.

Quote, originally posted by Ghost518 »

guy near me has a junkyard turbo setup KA SOHC on his 90. his best was 14.4 @ 95. im very glad to see people arent throwing these motors out. nothing wrong with sohc.

Yeah...I ran a 15.2@92 on my t25/smic setup. My clutch was already going so i didnt launch it and ran a 2.7 60' when i was at the track with that setup.

I think i could of ran a 14.5 or 14.4 (new setup) if i had launched a little higher. I was getting nervous when i was having to launch around 4K even though i was still bogging. I think the sweet spot would be 4.5K and then i would be able to cut a sub 2.0 60'. Plus i had pulled to much timing on that tune. I pulled enough timing for 8psi since i though i would be running that but, i was only on 5psi because the mafs maxed out. So with a little timing put back in and a higher launch rpm i think i could of gotten a little better time.

I am starting to think it might be the clutch like nissan fanatic said. I had to start the car today to turn it around in the garage to get it ready to pull the motor next weekend and when i stated it...it was fine and didnt make any noises. Once it warmed up a little the noise came back but it wasnt loud. I have noticed that it only does it on the down rev and because that i think it might be a wrist pin / piston issue. It does have ebay pistons in it after all. My tig teacher gave me the hint that it might be wrist pin related. He does a lot of welding for a sprint car team and he and his son use to race go karts so he knows a bad sound when he hears it, But he said that only wrist pins make the noise on the down rev and if i had spun a bearing it should do it all the time. I am still going to pull the tranny this weekend to check the clutch and if it turns out everything is ok then i will pull the motor but, probably not the same weekend. Since i still have to pull the bottom end a part to get the pistons / wrist pins out for inspection i am going to go a head and put some ACL bearing in there. If it turn out the pistons have some issues then the stockers will be going back in.

P.S.

Does any one know where i can go look at some diamond star racing wheels?

EDIT: New videos

http://tinypic.com/usermedia.p...3D%3D

http://tinypic.com/usermedia.p...3D%3D

Modified by nelson8708 at 6:03 AM 8/4/2008

BTW, OEM used pistons > ebay pistons any day of the week. Not trying to be an ***, i just cant believe you used ebay pistons over OEM.

Really curious now to see if its a wrist pin thats failed/failing. Good info from your shop teacher about knock on the down rev knock. Hes right about the rod knock noise, if it was that, you would hear it all the time.

King bearings

of

ACL bearings

I would just go with tried, true, and damn cheap. ACL, 45 shipped for rods/mains, done.

I run ebay pistons bro, @75 bux shipped I will eat them if I have to, honestly the quality was as good or better than a local parts shop rings were not the best...

clevite main and rod bearing for 3x$ been reused once now....

I'd pull the tranny, I experienced a strange noise I knew was my motor being pwnt, it turned ou to be 2 flywheel bolts backing out, and another time 2 pressure plate bolts..... thread lock ftl hell speaking of two's I believe my overheating is solved but now my slave cyl is dead and leaking fvckin nissan

well tyten up and let us know

If i cant get ahold of a cherry picker then i will pull the tranny though.

It could come out looking like this:

You'll have to extract six of these little bitches if your flywheel shears off.

If it is a clutch issue, you should be able to feel/hear a change when you depress the clutch. Or you can just wait until your car is immobile and the car sounds like a sport bike when the throttle is depressed.

FAIL

Yea, I had a naughty word in the url. Censorship reflects a society's lack of confidence in itself.

P.S.

I also found out that one of my couplers had a decent size hole in it so i might have ran faster if it wasnt for that. I will have some pics of it and the motor being pulled tomorrow night.

Quote, originally posted by nelson8708 »

I dont think i have the power to sheer off bolts but maybe because of having ot launch so high, one may have come loose. I dont know yet but, will find out tomorrow since i got a cherry picker today but, forgot to get a chain while i was there .... P.S. I also found out that one of my couplers had a decent size hole in it so i might have ran faster if it wasnt for that. I will have some pics of it and the motor being pulled tomorrow night.

You don't necessarily shear off bolts from too much power. It is typically a clamping issue. Basically, bolts are supposed to operate in a single vector. All they are supposed to do is clamp two surfaces together, and the coefficient of friction, area and clamp load should dictate how much force can be applied. If the bolts back out, then you have a problem. A lot of things can come into play here. If any of the three are compromised, then you could have a failure. Three easy problems could be improperly torqued bolts (no lubricant on the threads, damaged threads), lubricant on the flywheel/crankshaft mating surface, or warped surfaces. Once one of them is compromised, it is a matter of time/frequency. The bolts could probably hold a constant 300ft/lbs of direct force. But alternating force will kill them quickly. This could be related to the theory of an impact wrench vs a breaker bar. Whether or not we feel it, our drivetrain undergoes the same stress that bolts/sockets/extensions undergo when being used with an impact gun. The engine simply exerts these forces at a much higher frequency. At 7000rpm, the entire driveline is seeing the resulting force in sine wave form at 233.3 Hz, and the amplitude can be described using cylinder pressure*area of the piston top. You could then use that force value times .1574803ft to see what torque is being made by each cylinder.

Most of that is way over my head but, i get the just of it and i know that clamping force is what holds it together. I got the engine out and its not the clutch or flywheel. I was susprised to see that the flywheel on has two hot spots on it. I figured that it would be a little more burnt since i had a slipping issue last year with it but, it held up great at the track.

So its defintally internal and i suspect it to be the piston / wrist pin. I have to get one of my buddies over here to take my other engine out of my stand that is in the barn so i can use it on the one in the garage. I want to start tearing it apart tonight so i can see what i need to order so i will be ready to reassemble next weekend. I will try to get a few pics up tonight.

I drained the oil and the magnetic drain plug looked like it did on the first oil change when i was breaking it in. I pulled as much as i could apart to night and got it in my engine stand but, i dont have a puller so i couldn't pull the crank pulley off so i had to stop there. I screwed up the crank pulley when i tried to use a pry bar and hammer on it ...but, its no big deal. I will just get the pulley off the short block i got a couple weeks ago. Tomorrow my goal is to have the the entire engine apart so i can see what i need to order. I got my stock pistons out of my barn so they are going back in. I am going to use the rings off the pistons that are in there and give the block a light hone so they can re-seat. I believe you did that a while ago cory and didnt have any problems with blow-by because of it.

Also, do you guys think it would be ok to delete the coolant lines going to the upper part of the intake manifold? I want to delete them for a cleaner look. Do you see any problems with this? I know its common for people to cut the throttle body out of the loop but, i haven't seen it done with the intake manifold. Does the coolant heat up the intake manifold to engine temp or does it keep it cooler than if i was to not run the coolant line?

I couldn't sleep anyway so i decided to pull the rest of it apart. I dont see anything that would cause the knocking sound it made. You guys did watch the vids right? I'm not hearing $hit and I? The rod bearings look fine. Better than the main bearings do. Do the shinny spot on the main bearing mean the crank and bearing came into contact? The crank is fine. No scratches or anything on it. You can drag your finger nail across it and it is smooth. Everything was tight when i pulled it a part. The only thing i see is that the side of one of the rods looks like it came into contact with some thing. I checked the block and there is nothing else it could have touched. It might have been like that when i rebuilt it the first time.....i dont remember. At this point i dont know what to do. Do i just put new bearing in it and see what happens? The small little pieces of metal that was on the magnetic drain plug had to come from some where.

You sure that the wrist pins are O.K? Still floating in the groove?

What about your timing chain/tensioners?'

How do your cylinder walls look?

Check your rod bolts to make sure they havnt stretched.

How big were the metal shavings? Was it powdered metal or little chunks?

IDK i dont like the idea of putting it all back together without figuring out what was the cause of that noise/metal.

Yeah all the wrist pins and still floating and none have excessive play as far as i can tell but, the stock pistons are still going back in with a light hone. The timing chain and tensioners look fine. I havent got a close look at the cylinder walls yet but, i will today. If the rod bolts had stretched then that particular rod nut would be looser than the others when i pulled it apart but, i have a caliper so i can compare them real quick. The metal shavings were more powder than anything. When i wiped off the magnet is just looked like black grease. There were a few tiny slivers but, nothing bigger than the normal engine break in size.

Yeah believe me i dont want to put it back together and have the same problem agian....that would be terms to sell the car and buy another honda. ....i was actually thinking a rx7 FC since i dont think that will become a bandwagon car because people are scared of what they dont know and that is rotory power.