sohc ka24 quick question

[driftiteasy0113]

my track car has a sohc ka,whenever i start it up i makes like a small knocking noise until it warms up.when its warm the sound is eliminated. i heard it might have something to do with the valves but i dont remember.does anyone have an opinion?

[JP240SX]

Check the timing chain tensioner or the chain guide, I had the same problem...

[Vegascorbin]

Yep, Time for a Timning Chain job. Not too bad though Took us 3-4 hours and about $135 for parts at Autozone. 2 gears, guides, tensioner, chain, gasket stuff.

[driftiteasy0113]

i just replaced the timing chain though??anything else it could be?

[olsonator$13]

well if ur sure its not the chain, and if the sound seems to be coming from the top end, it could very well be rocker(s). since theyr hydraulic they hav to be filled with oil for them to work right so if thers a screwy one and its not keeping the oil in it, it will make a knocking noise for a bit until there is oil reaching it, then itll fill up and stop making noise. tht might be it and ive dealt with the same stuf in my sohc. but the rockers should hold their oil unless its been sitting for a while. hope this helps you out some.

[FRnIsmO]

have the same issue, only when start up for 3 seconds and when i drive hard, knocking starts and wont go away until i let the car sit for a day without driving...makes me look down at my car when i drive around clicking under the hood...saw a diy on general tech but sounded kinda hard...the hydrolic lifter you say??? dont have much tech exp. but i do mod. work on car...does it seem that's it and could it really be a diy job?

[driftiteasy0113]

how can you tell if the rocker arm is bad anyways??

[FRnIsmO]

good question, it just seems like the symptoms are the same is there any smoke when you stomp the pedal right after starting?
Modified by FRnIsmO at 10:00 AM 7/1/2008

[driftiteasy0113]

ya actually there is a little

[FRnIsmO]

im not expert but sounds like it's the hydrolic lifter, and if it was the valve, it would always tick...now the question is, can someone do it themselves...there's a walk threw on this under tech but it seems pritty hard...did anyone do it themselves?

[Vegascorbin]

If it was me I would pull the head and send it to a machine shop and ask them to replace the rockers and the valve seals and true the head. Might cost a few $$ but that would be the correct fix.

Or as long as the noise goes away quickly then I would just turn the radio up louder for hte first few minutes. Wouldn't hear it then

[FRnIsmO]

does anyone know if this problem leads to anything bigger? if it's just a matter of start up noise, i can live with that till i make up my mind as too what to swap.

[olsonator$13]

well my sohc will do it most of the time but the head does get the oil it needs and itll shutup. im pretty sure its a tad expensive to replace all the rockers with new ones and i believe they only come in sets. if u really want u cud use junkyard ones but of course u may jus be getting more defective ones. i dnt think it will harm anything for the short time tht it "knocks". the best cure i found is jus to run the car. before i pull out of my driveway i can jus run the car at about 4 grand for maybe 15-20 seconds and once i let it go bak to idle it wont be making any noise. as far as replacing them: ive seen some procedures in the factory service manual tht say u can take the rocker(s) off and let them soak in oil for a little while(straight upright or on their side so the air goes to the top of the "bleeder hole" at the top) another thing to keep in mind..dnt let the rockers sit on their side or upside down without being in oil otherwise air will get in and oil can leak out causing the hydraulic properties to be defective.(wow tht sounded professional ) i think when i had my head disassembled at the shop air got in some fo them or oil leaked out so when i first ran my motor it was clicking and knocking in the head pretty hardcore. what i did: i had some donor parts. i took the valve cover off, and pressed down and jiggled each rocker. i found one tht was not stiff (stiffness=filled with oil, working right) i took the rocker assembly off(in this case it was the intake side, take out the 10mm bolts tht go through the rocker "rod" and cam caps) and its pretty simple just slide each rocker off until you get to the one thts sketchy, replace it with a new one, put it back together, bolt the rocker assemply back on (factory torgue calls for like 30ft lbs. on those 10mmbolts and **be sure theres no oil in the thread holes or else when u bolt it back down it will press the threads right off and ull have a stripped hole!!***.i learned tht the hard way. its best to really loosen all of them on both sides and torgue them back down to sequence so everything is uniform. put ur valve cover back on, run the car for a bit at idle and see where ur at. the sound should go away after just a few minutes at idle max. if it doesnt then repeat the process. i had to about three times to get all of them taken care of, it still does tap a bit but it goes away and truley the problem is not that significant. but sohcs are also known for timing chain problems too as mentioned above^^

i think this is the best way to diagnose a rocker problem.sry for the length but i want to help you all out some and share what i've learned from working on this thing. also excuse the occasional use of cheesy language hahahope this helps out!

[FRnIsmO]

hey, thanks alot man

[driftiteasy0113]

thank you very much for the feedback friend.i think i got something to do this weekend now

[mechman900]

Couple questions: How many miles on your car? Do you have an oil pressure gauge? If you don't have one, I would get one and check the oil pressure after the car is warmed up. I had some similar noises on startup (even after replacing the timing chain, etc) and I ended up losing my engine 10 minutes into a track session. Turns out the oil pump was on the weak side and the stress of the track killed it quickly, even though during normal daily driving it seemed perfectly fine. The oil pump on the SOHC motor is easy to change if it is weak, much easier than changing the motor! Hope this helps.

[yotik]

hey that sounds like the same problem i had. knock while it warms up. then if you change to synthetic it wont do it for a while. about 2months later the timing chain went out. i wish i would have been on the forum last march

[driftiteasy0113]

it has 150 sum thousand miles on it,but it has a freshly rebuilt head.you think i may need a new oil pump?

[olsonator$13]

just a little update, the owner of a tuning shop whos pretty experienced with nissans said that a way to stop the rockers from making noise is to throw in some 20w-50. im still in the break in stage on my rebuilt sohc so im still using mineral and i had some 20w-50 around and i drained out sum of my oil and made a 50-50 mix of my reg. 5w-30 and the 20w-50. im gona see how this goes and when i eventually go synthetic ill use 20w-50...it may be worth a try ya know.

[driftiteasy0113]

fo sho, let us know how it goes bro

[240sxbuffy]

KNOCK OR TIC BIG DIFFERENCE TIC IS LIFTERS KNOCK MOST LIKELY COMMING FROM LOWER HALF OF ENGINE? HOW IS OIL PSI? WHEN ITS KNOCK IN PULL PLUG WIRES ONE AT A TIME IF NOISE GOES AWAY REPLACE THE CRANK AND BEARINGS

[olsonator$13]

it seemed to be okay for a bit then for sum reason, (prlly because i had a ****ty beaten on camshaft thats gotten retarded hot) (dramatic music) i broke my camshaft in two pieces when i was practically at idle. i had a spare so i swapped it out real quick and its been fine. the oil is workin okay i guess, no noticable difference yet, and if i have bad noise i have sum extra rockers and i just replace them real quick. i dont have an oil pressure gauge but im def. thinking about investing in one. theres a thread on here sumwhere and sum guy took apart the rockers and explained pretty in depth about how they fail and what to look for. he knows alot more about it then i do. i googled sumthin like "sohc KA24E rocker arms" and got a result from here. new oil pump is def. not a bad idea tho.