Head is knocking and small BHG

[Fletch124]

Last week my car developed a small knock that was very unnoticable unless you were next to a wall and on the gas and you could barely hear it then. 2 days go by and it starts getting worse and worse until i stopped driving it yesterday. It was about normal maybe alittle louder than it initially started yesterday going to work. All was fine going from work to school. But when i was going home I got off the freeway and it was LOUD. I was only 2 miles from my house so I just said screw it ill just make it home.

I pulled the valve covers off and checked the lash. Lash was actually a tiny bit tighter than spec. I did a compression check (valve covers off, dead cold, WOT, .017 Ross forged pistons, cranking motor on a low battery) I did 2 tests per cylinder.

#1 90psi
#2 95psi
#3 ~87psi
#4 ~87psi
#5 80-85psi
#6 85psi

I completed a compression check a month ago and the lowest cylinder was 145psi.

I really do believe that the knocking is coming from the head, when i pull the oil cap off the sound changes. The car ran low on oil once a year ago, since then i've been super anal about oil level always being over the full mark.

Found some brown milkshake starting to clog up the nipples on the valve covers and free standing water inside a hose for my catch can. The bottom of the oil cap is coated in brown milkshake.

Discuss. HELP!

Also contemplating a 2jzgte swap.

 

[92TealSupra]

Last week my car developed a small knock that was very unnoticable unless you were next to a wall and on the gas and you could barely hear it then. 2 days go by and it starts getting worse and worse until i stopped driving it yesterday. It was about normal maybe alittle louder than it initially started yesterday going to work. All was fine going from work to school. But when i was going home I got off the freeway and it was LOUD. I was only 2 miles from my house so I just said screw it ill just make it home.

I pulled the valve covers off and checked the lash. Lash was actually a tiny bit tighter than spec. I did a compression check (valve covers off, dead cold, WOT, .017 Ross forged pistons, cranking motor on a low battery) I did 2 tests per cylinder.

#1 90psi
#2 95psi
#3 ~87psi
#4 ~87psi
#5 80-85psi
#6 85psi

I completed a compression check a month ago and the lowest cylinder was 145psi.

I really do believe that the knocking is coming from the head, when i pull the oil cap off the sound changes. The car ran low on oil once a year ago, since then i've been super anal about oil level always being over the full mark.

Found some brown milkshake starting to clog up the nipples on the valve covers and free standing water inside a hose for my catch can. The bottom of the oil cap is coated in brown milkshake.

Discuss. HELP!

Also contemplating a 2jzgte swap.

Well you do know hearing that noise differently when removing the oil cap doesn't exactly mean it's coming from the head. Now don't get me wrong it's possible. Those number are very low though, and I will say it is going to be getting worse. I am sure it is very possible it's your head gasket.Noise travels very well through motors, if I were you get a " stethoscope " and find out exactly where your noise is coming from. If you said the lash was a little tight why not adjust it to the correct spec? Also if you do have a BHG that is a sign of problems, start your car and see if the coolant bubbles, also you can get a tester, the dye tester and see if the gas changes the color. Any more question just shoot.

 

[Fletch124]

Yea your correct it could be a rod knock.. unfortunately. I know its not a bad BHG because my oil hasnt reached the state of white milkshake, its still a dark brown. But if you look close enough you can tell there is some water thoroughly mixed in.

What to do?????? Rebuild or 2j swap?

 

[92TealSupra]

Well, previously you stated you did run oil low in the motor before. I know you hate to hear this " but it only takes once " You might have wore it enough to start a snow ball effect, which means things could have progressed from that. I know when oil gets low on the 7m- motor you can have rod knock occur. Like I said if you can basically get a stethoscope and check that for verification.

[ Also does this noise always there, or does it go off and on ] Rod knock most of the time, prier experiences always stays with you. It seems like after you have done some more work to figure out what may be, or what is wrong, you may want to pull the motor. ( I would not suggest running it much longer, if I were you I would try to save as many internals as possible)

But yes, good luck and let me know as soon as you learn of anything or find out some information.

 

[Fletch124]

It ran low actually well well over a year ago, probably atleast 1.5 years ago. Since then I havent had one problem with knock.

The sound is consistent at idle, but if you rev it, theres a very small rpm range where it completely disappears. Its rev dependent aswell, higher the rev faster the knock.

 

[92TealSupra]

It ran low actually well well over a year ago, probably atleast 1.5 years ago. Since then I havent had one problem with knock.

The sound is consistent at idle, but if you rev it, theres a very small rpm range where it completely disappears. Its rev dependent aswell, higher the rev faster the knock.

I am wondering if you have a point where the vibration from the motor counter acts the noise at that certain rpm. Now as you stated, it's RPM dependent, which is not that great. Have you lost any performance out of the car, or do you lose anything while you drive it? have you test drove the car lately or is it basically sitting after this noise occurred?

 

[Poodles]

Can you FEEL it? Mine was really bad though (trash a bearing from losing all your oil at 120mph and it's going to be bad).

Video is in order I think as it's hard to really tell.

Your compression results are HORRID. You're going to have to pull stuff apart anyway, wouldn't be hard to pull the engine start tearing it down to really know what you're dealing with. With compression that bad something is seriously fucked anyway...

 

[Fletch124]

I am wondering if you have a point where the vibration from the motor counter acts the noise at that certain rpm. Now as you stated, it's RPM dependent, which is not that great. Have you lost any performance out of the car, or do you lose anything while you drive it? have you test drove the car lately or is it basically sitting after this noise occurred?

Now that you say that I do remember on the freeway heading home the car had a few very small hick-ups but enough to notice the engine lose tons of power while cruising then come back online.

Can you FEEL it? Mine was really bad though (trash a bearing from losing all your oil at 120mph and it's going to be bad).

Video is in order I think as it's hard to really tell.

Your compression results are HORRID. You're going to have to pull stuff apart anyway, wouldn't be hard to pull the engine start tearing it down to really know what you're dealing with. With compression that bad something is seriously fucked anyway...

Thing though is im not missing any oil at all, still full.

Ill try to get a video but I dont have any good camcorders.

Yea I dont know what happened, last month my lowest number was 145psi. That number was a result of the motor only sitting for 30minutes after driving it.

WHAT TO DO???

 

[92TealSupra]

Well your number prove there is a progression losing compression in your cylinders, and I find it seemingly weird that your coolant is not a milkshake color by now. i am very curious as to where the compression leak is coming from now. You will have to tear down the whole motor now, there really is not a thing you can do to prevent that now, but I hope nothing major has gone wrong that may cost in some huge $$.

One quick thing do you have a MGH, or stock? If so check what torque it was at, also did you ever re torque your head?
Good luck.

 

[CyFi6]

First off, you need a fully charged battery when doing a compression test, if youre cranking slow you are going to get wrong readings. Try adding a tiny bit of oil to the cylinder next time before doing the compression test and report how much the pressure jumps.

About the knock, sounds to me like a combonation of running low on oil previously and getting coolant into the crankcase caused your bearings to slowly wear out. If its knocking, its knocking, you just cant deny that. If you think its knocking from the head it could be the piston smacking the head because the bearing is worn out and the conrod is all oblong now giving it that extra clearance to travel farther up.

 

[Fletch124]

Well your number prove there is a progression losing compression in your cylinders, and I find it seemingly weird that your coolant is not a milkshake color by now. i am very curious as to where the compression leak is coming from now. You will have to tear down the whole motor now, there really is not a thing you can do to prevent that now, but I hope nothing major has gone wrong that may cost in some huge $$.

One quick thing do you have a MGH, or stock? If so check what torque it was at, also did you ever re torque your head?
Good luck.

Can you FEEL it? Mine was really bad though (trash a bearing from losing all your oil at 120mph and it's going to be bad).

Video is in order I think as it's hard to really tell.

Your compression results are HORRID. You're going to have to pull stuff apart anyway, wouldn't be hard to pull the engine start tearing it down to really know what you're dealing with. With compression that bad something is seriously fucked anyway...

I've almost got the motor out. I bought an Na 2jz from an Sc300 a few months ago... :naughty:

First off, you need a fully charged battery when doing a compression test, if youre cranking slow you are going to get wrong readings. Try adding a tiny bit of oil to the cylinder next time before doing the compression test and report how much the pressure jumps.

About the knock, sounds to me like a combonation of running low on oil previously and getting coolant into the crankcase caused your bearings to slowly wear out. If its knocking, its knocking, you just cant deny that. If you think its knocking from the head it could be the piston smacking the head because the bearing is worn out and the conrod is all oblong now giving it that extra clearance to travel farther up.

Too late now, motor is almost out of the car.

I'll get it torn down and let you guys know.

 

[randandrawson@v]

yea, check compression with a full battery, and all plugs out. wot.
the oil trick will show dead rings (if it comp comes up with oil vs dry)

mine is knocking right now from the cam caps.
about 2500 rpms it makes a hellish noise.
am in the process of tightening them up and re-engineering the oil up top.
I would think if it was coming from the top though, your valve clearances would open up, as the cam gets pushed higher on the dead caps.

If the valves are tight, maybe you burt one, but not all the way around I would not think.

put a mechanical pressure gage on it, will tell if the knock is in the bottom for sure.

 

[Poodles]

Never heard of the cams making a knocking sound...