!jz knocking sound

[te72]

Issue: Hearing a slight knocking sound at low rpm, initially on cold startup, goes away when warm or has been warm.

Details: 89 Supra, 1jz, BC 264 cams, solid chromoly mounts, oil always kept ~1qt over 'full' on dipstick.

Thoughts: My first thought was of course, "oh shit, rod knock.". However, the fact that it goes away after about a minute of running, and usually only happens after it's sat overnight makes me really question that. I had a 7m with RK, and that was entirely different feeling/sounding. Fabricator who made my mounts suggests that they *could* have loosened up a bit, and cautioned me that that I may hear sounds like rod knock, since there's nothing cushioning the vibrations like normal mounts do...

Any ideas guys?

 

[te72]

Bit of an update: I'm really starting to lean toward exhaust leak where the down pipe meets the test pipe. Damn cheap ass ebay y-pipes have some real fitment issues... Gonna see if I can't tighten that up better somehow, or find a culprit elsewhere, I'm off Thursday, so I'll get to it then hopefully.

 

[geartech]

You know my 1JZGTE does the exact same thing. Thought it was a rod knock also but it doesn't fit the rules. Only does it cold for a min. maybe. Only after it has sat overnight.
I've been trying to find some information about oil pressure on these motors.
What does you're oil pressure run at idle and cruise? also max oil pressure.

 

[Supradupra.com]

I am pretty sure this dull knocking sound when cold is a trait of the 1j. I have seen a few threads on this now & cetainly any 1j I have come across & the ones here all have the exact same trait, a dull knock when cold which vanishes. I really don't think it's anything to worry about.

I'll have to get some oil press readings from mine when I run it next too.

I always found it odd the 1j revs so high from cold, seems unnatural to do such a thing.

 

[gennro]

Mine does the same thing also and I am running solid motor mounts and it goes away after about 5mins. Oil pressure running 5w-40 at idle is around 19 to 20psi when the engine is about 185 to 195 degrees F.

 

[TripleC]

My oil Pressure on my 1J is around 50 to 75 when i start it up.It stays around 75 while driving but It will also go as high as 95 on less then avarage acceleration. After about 1.5 minutes when its warms up my gauge reads 20 at idel and to 50 at full boost WOT

 

[RacerXJ220]

If the serpentine belt tensioner is bad, it will make that sound when cold.

 

[Jayhall]

Before I had to rebuild my 1J it would almost sound like a diesel in the morning when I started it cold. It always went away once the motor got some warmth to it and I always had oil pressure so I never looked to much into fixing it.

 

[oowee623]

ive had this same issue since september of 2008. knocking noise at cold start, 20 psi oil pressure at warmed up idle. i ignored it until yesterday when i started to hear it while on a 100 drive round trip, which finally threw a rod when i nearly got home.

 

[te72]

What does you're oil pressure run at idle and cruise? also max oil pressure.

Unfortunately, I still don't have a functioning oil pressure gauge. It is definitely on my list of priorities though. For what it's worth, as of October, it had all new gaskets, and pretty sure it doesn't burn any oil.

I always found it odd the 1j revs so high from cold, seems unnatural to do such a thing.

Could you perhaps elaborate on what you mean about it revving high from cold? I don't rev mine past 3k until it warms up, and try my very best to keep it out of boost until it's at least 80*C (176*F).

Mine does the same thing also and I am running solid motor mounts and it goes away after about 5mins. Oil pressure running 5w-40 at idle is around 19 to 20psi when the engine is about 185 to 195 degrees F.

I believe I am running the same oil as you too, the Rotella Synthetic 5w-40? When I was running the Rotella 15w-40, it never burned a drop. Checked my oil after a 2000+ mile road trip on the 5w-40, and it hadn't burned any, but last time I checked it, it seemed about 1/2qt lower than where I normally keep it... Does the 5w-40 burn off easier perhaps?

If the serpentine belt tensioner is bad, it will make that sound when cold.

Interesting... how can you tell if it's bad? Loose belt? I'm trying to figure out how that sound would disappear when it's warmed... I believe the tensioner is a spring based unit, correct? I guess that would explain it.

Before I had to rebuild my 1J it would almost sound like a diesel in the morning when I started it cold. It always went away once the motor got some warmth to it and I always had oil pressure so I never looked to much into fixing it.

Fortunately mine doesn't sound that bad, but that is reassuring to hear.

ive had this same issue since september of 2008. knocking noise at cold start, 20 psi oil pressure at warmed up idle. i ignored it until yesterday when i started to hear it while on a 100 drive round trip, which finally threw a rod when i nearly got home.

Ouch... sorry to hear that man. Still, that motor gave you nearly 2 years of service, that's not all that bad for a turbo Supra, at least in my experience.


Thanks for all the replies guys, I wasn't expecting much after the second day after posting this. I look today and it appears I'm not alone here. Oddly enough, this thud/knocking sound has only recently came up. If it had done this from day 1, I never really would have even thought to question it, but it's only started in the last month or two... since the y-pipe install. Anyone else have any experience with this 1j noise or symptom?

 

[te72]

Oh, and also, the knocking sound only really happens between 1000-2000rpm. After 2000, even if it is still cold, it smooths out too much to hear.

 

[gennro]

Yeah I am running Rotell T Syn 5w-40. It is possible since it is a thinner oil.

 

[geartech]

I was starting to think the same thing about the 1j, It could be piston slap but it dosent really sound like it.
My oil pressure is about 25 at idle hot but seems to never go above 45-50 on the gauge hot. I need to put a mechanical gauge on it to verify its accurate though.
If it is wonder if it could be a bad pressure reg spring or valve in the pump?

 

[7Matt-GE]

i can say this...its a high day in hell when any supra motor will piston slap. are you an Auto or manual?

 

[te72]

Well, it's been cold lately... and Wyoming is about as close to hell as a Supra can get, so...

All my cars are manual. Why might that matter?

 

[92TealSupra]

What he means revving from cold is the idle when you first start it. I noticed when i started the one I did build it was a ticking sound, not really a knocking anyone agree or?

Discuss.

 

[geartech]

O.k put a mechanical guage on her. Now I feel much better. Idles with 50-55 psi. goes to 85-90 at 2500-3000 rpm.
Looks like I need a new sender unit.
Knock when started cold dosen't bother me as much now knowing I have good oil pressure. 40 psi max scared me. But it never went below 20psi hot at idle.

 

[steve1479]

Yea dude it's a common thing, I'm up in Canada and even during our summer months I will always get it on cold start up's (over night) goes away about a minute after running.

I'm running German Castrol 0W-30 weight.

 

[te72]

What he means revving from cold is the idle when you first start it. I noticed when i started the one I did build it was a ticking sound, not really a knocking anyone agree or?

Discuss.

Ahh, my idle control valve was sticking for the longest time, so my idle is kept steady at about 1000-1100 by cracking the throttle body open via a set screw on the cruise control bracket. Throttle response got a lot better when I did that too, no slack in the actual throttle bracket anymore. Even better news, my IACV seems to have started to cooperate again, the idle doesn't droop at stops like it used to, almost always stays above 700.

As for your ticking, I think mine does a little bit as well. We got the valve shims within spec when we put the cams in, but haven't rechecked or readjusted them since. It's possible they may be a little on the loose side of spec now?

On the subject of the knock that we hear though, I'm not very worried about it now, but am curious as to what actually *causes* it. Like I said, this wasn't a day 1 sound, it's only started happening in the last 3 months. The three to four months before that, I don't think I ever heard that sound...

 

[steve1479]

I think it has to do with some sort of valve train component rather being cold or not properly lubricated during cold start. If it goes away after a minute then it rather:

1. Became properly lubricated

OR

2. Heated up

Iunno, just my .02