New World Datsuns...

So my car developed a noise tonight. Can not tell where it it is coming from. LZ21 long rod, dogleg 5 speed.

First we went through and replaced the spark plugs, cap & rotor, coil, and re-set the timing, since it all needed done anyway. Still makes the noise. Checked the oil "Just in case" it was dry. Which is weird since it was just full yesterday and I only drove 40 minutes today. After filling the oil up the noise so I thought quieted down, but once I started driving again it was still there.

I was thinking maybe a rod/main bearing? But the weird thing is when I drive, the car still has tons of power and goes down the road smoothly, it's just awful to listen to the noise, so I tried to stay out of it as much as possible. I noticed it will be louder and more consistent in low gears, once I hit 4th it will stop making it sometimes, depending on how much gas you give it in 4th or 5th makes it louder or quieter. Give it just barley any gas and it will get louder, give it more gas and hold it there and it wont make the noise at all. Every time I shift it makes a odd clunk sound as well. This all got me thinking transmission is having a problem?

Really lost here, any help is appreciated! 2 videos below, best I could do in a crunch. Click them to play...

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Did you pull the VC and see if a rocker came loose, lash pad came off ?

Do you hear the noise more when you go around a corner ? This will make a rod bearing get louder.

when you give it gas and it got louder then hold the pedal in place, makes it sound like you got a bearing going out.

Ni10 wrote:Did you pull the VC and see if a rocker came loose, lash pad came off ?

Do you hear the noise more when you go around a corner ? This will make a rod bearing get louder.

when you give it gas and it got louder then hold the pedal in place, makes it sound like you got a bearing going out.

This,

Where did the oil leak from?
Has a slight sound of a stuck valve




Sorry to hear this draynor

Does the noise change with engine RPMs?

Find out where that oil went!!

Never pulled the VC. need to get a gasket. Valves do need to be done.

It kinda changes with rpm. Low rpms it will be louder, higher rpms especially in 4th-5th it won't really be there.

If it was a bearing wouldn't the car be significantly slower? Cause it is still just as fast as it was before the noise. Pulls nice and easy, if you can get past listening to it.

Well "H5WAGON" and I adjusted the valves today. After the first adjustment noise sounded a little louder, then we tried again and it kinda sounded like it quieted down, but it's some what herd to tell, next to a busy street lol. Adjusted one more time, then 5 or so minutes later it started making another ticking sound. Now it always does it even at idle, never really did it at idle before. We determined both noises are coming from the top end. We ran it with out the valve cover, and nothing looked like it was shaking or anything.

Anybody have idea what in the head could be making this noise?

I know you can't tell much from a video, but here is another with the "New" clicking sound. On video it kinda sounds like a exhaust leak, but it's not...


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[quote="Draynor"] We ran it with out the valve cover.
quote]
wow, it sounds worse then before.
When you ran it without the VC, was their plenty of oil on the cam/rockers ?

and just wondering, no disrespect but wut did you set the exhaust / intake at and was it hot or cold when you did the valve adjustment.

have you got a oil pressure gauge ?

Sticky valve?

It may be slightly sticky,and when running the spring does not have the force to push it closed?
Had something similar happen, when checking the valve train when not running,it looked good,after many on offs with the vavlve cover, I finally saw the culprit

510freak wrote:Sticky valve?

It may be slightly sticky,and when running the spring does not have the force to push it closed?
Had soemthing similar happen, when checking the valve train when not running,it looked good,after many on offs with the vavlve cover, I finally saw the culprit

wouldn't a compression test tell you if it was a sticky valve ? OR even a vacuum tester.


wonder if a valve spring/s is weak, just a thought.

Ni10 wrote:

510freak wrote:Sticky valve?

It may be slightly sticky,and when running the spring does not have the force to push it closed?
Had soemthing similar happen, when checking the valve train when not running,it looked good,after many on offs with the vavlve cover, I finally saw the culprit

wouldn't a compression test tell you if it was a sticky valve ? OR even a vacuum tester.


wonder if a valve spring/s is weak, just a thought.

It was pretty intermitent, as in one of those pull your hair out problems,compression was in par
It ended up being a weak spring yes

I was going to go buy a pressure gauge today.

There was plenty of oil up there when we ran it without VC. Had to put towels down everywhere lol.

We set them warm, intake: .010 & Exhaust: .012

I am thinking I need to get the pressure gauge, check that. Then probably will need to take the head off to clean whatever might be clogging it.

We also changed to KA pump out for the L16 pump to see if that was the issue. Seemed louder after....So the KA pump was probably working fine.

And Derek engine was warm when we set them.

that exhaust is WAY wrong. .010 and .012

Laecaon wrote:that exhaust is WAY wrong. .010 and .012

This is what we set it at...

Ok, thats just not what Derek wrote...

Yeah I told him .010 and 2 ....He forgot the 1

Whoops

Alright! Got a compression test done tonight. Going to do the oil pressure tomorrow.

#1: 182
#2: 186
#3: 175 - Came in at 170 the first time.
#4: 190

Pretty good numbers. Made some phone calls and did some thinking. The old pistons in this block, before we rebuilt it, On 3 of them the valves hit. After some more thinking and looking back at pics #3 piston had the biggest gash in it from the valves out of all of them. Just so happens that number 3 cylinder is getting the lowest compression too. So we're thinking maybe the valve is bent...

Only had little time today to check things out, and no one around to start car and such.

But I did find/fix a problem.

So went to put the oil pressure gauge I bought in. Took the old sender out and no oil came out of the hole, hmmm. Hooked up the gauge anyway and it showed no pressure. So stuck a screwdriver in there to see if it was clogged or something, nope, it just stops. Then remembered the screw we put in a hole just above the sender cause oil was coming out of it, I thought before this was the sender hole, but everyone else thought otherwise.

So I put the sender in there, oil light goes off, yeah! Then hooked up the gauge, and it reads 50psi at idle. I think that fixes my oil pressure problem! [:D] [:D] [:D]

Went ahead and took the head off. I have a car to borrow for a while, so I thought might as well check everything out. Taking it apart tomorrow...

The #2 pistons is pretty clean compared to the others. A bronze color.

Also one of the valves has some grinding around the area it touches. The cam also has some grind marks as well. All pictured below.

























You can see the grinding around the valve area here.

























You can see the grinding on the cam here, also the head has some marks too...