Hesitation, Bogging, Won't Rev, Weird noises

[gogeeta13]

Well, micah and I finally got the "new" KA running. Turns out we had the timing out of whack it ended up being like 230* off. So yeah

Now it is running really rough, it can barely idle and stumbles to say running. When you give it gas, the idle drops then starts climbing very very very slowly. The horsepower is completely dead, the car can barely bring its revs up to accelerate, at WOT it can climb to about 4k but doesnt really build any actual power. It hesitates to do just about anything.

Things we have tried:
Fresh gas
Working MAF
Idle screw
EGR junk
spark plugs
wires
injectors
Throttle body clean
cat is not clogged
o2 sensor should be fine
new dizzy cap
new rotor
new plugs
just plain driving around in it for like an hour, nothing improved.


In addition to that, the valves/timing chain/whatever is noisy as fuck, the engine makes tons of fucking clanking sounds and is ultra fucking bad sounding. I removed the upper chain guide under the valvecover and the other one behind the front cover on the side of the upper chain(the nissan recall one)


Any ideas, please let me know.

[F3600]

massive air leak in your intake system.... check for that im pretty sure its that

[orion::S14]

Did you change the cams for any reason? Or maybe have all the valve "buckets" out of the head? Why is this a "new" KA...?

I've had a KA do the same thing...and it was all related to valve shims being too tight on a few valves, and very loose on others.

Too tight = Valves not closing fully, so HORRIBLE idle and driveability.

Too loose = Loud clanking, b/c the cam lobe was slapping the shim on every rotation.

Solution:

With the motor warm, check the clearance between the base lobe and the shim...should be between .013" and .016". I found some that were too tight to get even a .005" feeler gauge in, and other that were +.025"...wrote down which ones were too tight, and which were too loose...pulled the cams, swapped the shims, and voila! Perfect idle, power is back, etc..

A quick way to check is if the compression is bad...I knew I had a good bottom end, and a resurfaced, cleaned, and good head...with a new HG. So bad compresison pointed me to the valves...

Hope that's it... - Brian

[gogeeta13]

I just picked up a compression tester. I will post results shortly.

I shouldn't have any air leaks, everything is plugged and such.

The cams weren't out. It is "new" in that the motor that came in the car was shot, I got a KA that was pulled from an Auto coupe with 100k miles. It was supposedly a good running motor when pulled. It sat for 6 months before I bought it. When pulled, the seller swears it had no valvetrain noises or anything. I took out the chain guide from the valvecover and the chain guide from the front cover(apprently this is even a recall by nissan, so I doubt I did anything wrong?).

I will have to find my set of feeler guages and check shim clearances too.

Thanks Brian and F3600!

[orion::S14]

Yep, guide removal is a Nissan recall.

If the top end hasn't been taken apart, chances are the shims are fine. But if you got a motor with unkown origin, who knows...

Let us know what happens with the compression test.

- Brian

[gogeeta13]

Compression 1-2-3-4
165-159-159-155
Progressively dropping probably as the engine cooled down and oil settled away to teh oil pan or something.

The Noises are one thing...why the hell won't thing thing rev, and why does it bog and hesitate?

[gogeeta13]

any ideas?

[orion::S14]

Huh...dunno.

Probably not vlve shims, as you didn't take apart the top end, and the compression numbers look OK.

Timing is definitely at 20*...???

- Brian

[gogeeta13]

Yeah, I used a timing light...

Unless there is some sort of electronic advance or something I need to disable to do the timing?

[aznpoopy]

20 degrees = the notch all the way to the right. besides that, there's nothing particularly special about the timing on a ka24.

you mentioned its making terrible horrible noises. how about a better description of the noise / where its coming from?

sorry to hear ur engine is still running bad.

[gogeeta13]

It is commign from the front of the engine. Probably the timing chain. I am thinking that the guides I removed may have been keeping the noise down by taking the impact of the chain instead of the alluminum head?

Also, could excessive valvetrain noise cause false knock sensor readings causing the engien to run in a safe mode with less power.



the notch all the way to the right? Shit, I thought it was the 2nd from the right....

[osal]

did u fix ur problem??...sorry for bumpin this up but i m having same problem

[cotbu]

Omega Bumping..... send a pm to the TS linking his\her thread