CherryNova

I had my Ka24de rebuilt in august and I'm still having problems.

>The idle drops to around 400ish when i hit the brakes, but then jumps back up to 800ish when i release. (I'm thinking vaccuum leak, but im not too sure)

>I have no low end power. I can slam the gas and get no response; until around 3500 rpms, then it actually moves..

>I burn through around a quart of oil every week or so, and i'm going through gas too fast. $20 used to get me around 215-235 miles, but now im getting 125 for $20.

Someone please off this poor little girl some advice

I'm not sure if it matters, but I have s13 cams, with an s14 head, on an s13 block.. lol

speedfiend

Well hello, nice to see a girl getting her hands dirty and working on her own stuff.
As for your problems, the rpm issues sounds like a grounding problem to me. These cars are old and the grounds become insufficient. Do you notice the same problem when you turn your lights on?

As for the loss of power and extreme oil consumption, it sounds to me like who ever rebuilt your motor for you messed up the piston to cylinder wall clearances. With to much clearance you will experience a large amount of blow by and power loss, more noticeable in the lower rpms. The power loss could also be from the cams being out of time. You should check the cam timing especially since you have a mixed setup.

Hope this helps and good luck getting things straightened out.
Cameron

rebornS14

sounds like you need to fix your oil leak. change o2 sensor. get a new IACV.

89redzenki

Sounds like whoever rebuilt your engine did a crappy job. I would first off check your compression and go from there bad rings can pretty much account for all your symptoms. If your compression is good check your ignition timing and for vacuum leaks. Hope this helps

DreamN

Take your car back to where ever that engine was rebuilt.

The funky idle could definitely be from a vacuum leak. Check the hose that goes into the brake booster for tears as that would be most likely to cause that issue upon braking in my opinion. Though, do check other hoses for leaks as well.

Have you done a compression check? Is your CEL on? With the type of issues you're describing I would expect some codes to be showing up.

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CherryNova

i <3 working on my car. and i'll look into the grounding suggestion. I do have problems with my lights sometimes. and i think that you may be on to something there with messed up walls/cylinders. the first guy who "tried" to rebuild my motor, didnt measure the rings and had the valves hitting the pistons.
I had the second, Good guy,(who got her up and running finally) recheck the timing - cams and chains - and said everything was fine..

CherryNova

I was told that my compression was around 140 at each cylinder.. i dont know if thats good or bad..

and reborns14, whats a IACV? and idid fix the oil leak. I have a bright yellow block for that reason

and my check engine light isn't on.

89redzenki

Did the new guy replace the valves and machine the seats if not you could have valves not seating correctly. Do a cylinder leakdown test

89redzenki

140 is really bad for a rebuilt engine should be more like 160 to 170

CherryNova

the valves were not replaced, and i doubt that the seats were machined, (im not sure what that is). i do know that the head went to the machine shop to get checked and to have the deck shaved..

CherryNova

i thought 140 was really low. that's what it was at before i had it rebuilt, and that's poring smoke with bad piston ring... I really don't know too much about cars, I'm still learning alot.

89redzenki

If you had valves hitting the pistons 90% of the time they need to be replaced. The valve seats are the part of the head the valve seals against if the valve is damaged it usually will damage this surface as well.

CherryNova

its very small dents, but the guy who rebuilt said it was nothing to worry about. as for valve seats, ill have to ask him.

89redzenki

Okay But that still sounds really suspect to me it does not take much to keep valves from sealing. From what i have this is what it sounds like to me. Original engine builder totallly didnt know what he was doing cylinder issues also did not set the cam timing correctly. Sounds like the second guy just reset the timing and got it running. Sounds like you need to either go through that engine again no telling what else that first guy did incorrectly Ie ring gap bearing clearances ect. Hope this helps i hate that people will act like they know what they are doin and take advantage of less knowlegable people just to make a buck. Gives good mechanics a bad name.

rebornS14

IACV = Idle Air Control Valve.

qoute from nismo shop westcovina,
"IACV on Nissan motors are notorious for going bad, getting stuck closed or open thus creating an irratic idle and incorrect fuel mixtures."

speedfiend

Yeah I hate to say it but the grounding issue that I suggested seems like the least of your concerns with this motor. If the valves were hitting the pistons then I can almost gaurantee you the valves are probably bent to some extent. The pitting in the valves and seats is NO good. You will definately need a valve job done to remove the pitting otherwise you will never get a good seal between valve and head.

In all honesty with the problems your having and with the issues that have already happened, ie. valves to piston contact, I would suggest you completely tear the motor back down and start over. And this time you need to find a REPUTABLE mechanic that can do the work. Ask around and talk to some other people that have built motors and see where they have had their work done. Its very sad to see but looks to me like you have been burned not once but twice on this motor. Sorry and goodluck with getting things squared away. Let me know if you have any other questions.
Cameron

89redzenki

Dude did you just copy my post word for word lol

speedfiend

Sorry didnt read all the posts just the reply she posted to my suggestions. But yeah pretty much on the same page haha.

To the OP good luck and let us know what you find if you do end up tearing the motor back down.
Cameron

CherryNova

Thanks for everything guys. I really appreciate all the help and suggestions..

plusONETEN

as people above said, if your valves hit the pistons, they are probably bent.

the pistions themselves might be OK though. you COULD try swapping on a new head and seeing if that fixes the problem. i say that because KA parts are relatively cheap and you might be able to find a complete DE head for cheaper than it would be to replace all the individual valves. you would also get the peroper s14 cams that way...

i've never heard about putting s13 cams in an s14 either...


and just because pressing the brake affects idle doesnt mean that there is necissarily a problem with a vacuum leak. my rpms drop about 100rpm on my honda if im stopped and go from light brake pressure to heavy brake pressure. theres air moving between the mainfold and the brake booster whenever you press the pedal, so that will affect the engine.

however, if you press the brake hard and keep it there, the idle should come back up withn a second or two, as the air should have completed moving... if it stays low as the wording your first post indicated i would suspect a leak...

plusONETEN

oh, and also if your battery is weak, your idle will drop just because the brake lights are on and the alternator is putting more resistance on the engine.

but again, the idle should come back up after the initial 'shock' of the unexpected extra load