This baffles me to no end

[doradox]

The charts are the same in both FSMs. What am I missing?

When I lived in Tucson (30 years) I always ran 10W-30 in my daily driver Zs. Probably close to a couple hundred thousand miles between my 2 73s.

Steve

[sblake01]

I really don't think Tucson has much, if anything on where I live heat wise. We were at 100+ most of last week and that's fairly typical here this time of year. That chart says (to me) that any of the oils listed in the top two arrows as well as 80W-90, 90, or 140 gear lube would be acceptable in that type of climate. I ran 80W-90 gear lube because it does get below 40 here in the colder monts. I've had no lubrication related problems with either of them.

Edited September 7, 2010 by sblake01

[Z train]

I really don't think Tucson has much, if anything on where I live heat wise. We were at 100+ most of last week and that's fairly typical here this time of year. That chart says (to me) that any of the oils listed in the top two arrows as well as 80W-90, 90, or 140 gear lube would be acceptable in that type of climate. I ran 80W-90 gear lube because it does get below 40 here in the colder monts. I've had no lubrication related problems with either of them.

We've been +100 for the past three months.Yesterday it was 112 at Gila Bend.A few weeks back it hit 120.Tucson is always about 10 degrees cooler.And for Ca,you're 90 weight selection would be correct.

But in any event,the oil weight isn't the issue here.Everyone here is scratching their heads over this noise.

[Diseazd]

I agree with doradox.....Check the harmonic balancer. If it's not torqued properly,your crank pulley will rock on the woodruff key (been there done that). This causes all kinds of noises that sound like it's coming from the chain and camshaft. Mine was caused by the use of a Nismo aftermarket crank bolt and washer that wasn't suited to the stock damper (Thanks MSA and Nismo for not pointing that out).It didn't allow the slinger,worm gear and crank sprocket to lock up tight. The chain noise was only between 1500 and 2500 rpm (sounded like what you described). I don't in a million years think that a different viscosity oil is responsible for your noise. If someone installed a new chain and tensioner, make sure they didn't use that aftermarket Nismo crank bolt and washer.....if not, check the torque on the stock bolt.

[Pomorza]

I agree with doradox.....Check the harmonic balancer. If it's not torqued properly,your crank pulley will rock on the woodruff key (been there done that). This causes all kinds of noises that sound like it's coming from the chain and camshaft. Mine was caused by the use of a Nismo aftermarket crank bolt and washer that wasn't suited to the stock damper (Thanks MSA and Nismo for not pointing that out).It didn't allow the slinger,worm gear and crank sprocket to lock up tight. The chain noise was only between 1500 and 2500 rpm (sounded like what you described). I don't in a million years think that a different viscosity oil is responsible for your noise. If someone installed a new chain and tensioner, make sure they didn't use that aftermarket Nismo crank bolt and washer.....if not, check the torque on the stock bolt.

While I agree with everything everyone here has said the issue is still why it went away and came back. If it was in fact the harmonic balancer or the cam chain/gear or tensioner how would running a thinner grade oil make the noise go way? And if it was something mechanical how did running sea foma through the intake make the noise diminish and finally go away?

The harmonic balancer is tightened to 100 ft lbs or torque by two different wrenches twice. The cam gear is tightened to ~40 ft lbs again by two difference wrenches twice. I did the timing chain with the help of Z train and I'm positive that we did it right. I've checked and rechecked the cam and chain. It has a bit of play (the chain) but not enough to make the noise I'm hearing.

I'll try to make a video tomorrow afternoon (2pm Arizona time) and post it here. From there I can only hope that someone has heard the noise before. At the moment I'm planning on switching back to 10W40 and running another treatment of sea foam and see where it went from there.

For reference. The noise occurs using Valvoline 20W50 VR1 oil and a Fram TG filter. (and it is NOT the filter as I've run both Wix and higher end filters with no change). When I used mobile 5000 10W40 the noise did occur but went away after some seafoaming action. There's a post here someplace about this same noise. I can find it if that is needed.

Jan

[doradox]

While I agree with everything everyone here has said the issue is still why it went away and came back. If it was in fact the harmonic balancer or the cam chain/gear or tensioner how would running a thinner grade oil make the noise go way? And if it was something mechanical how did running sea foma through the intake make the noise diminish and finally go away?

Jan

The oil pump is driven by the gear on the crank. Thicker oil is harder to pump so that gear is under a different load than with thinner oil. Also the timing chain tensioner works off of oil pressure. When all the vibrations in the crank, cam, timing chain, etc. line up just right a small change like that can cause odd things to happen. However, if the balancer is tight and your timing chain is right like you say then it's a moot point.

Steve

[Pomorza]

is the video. It is a rather poor quality but about 6 seconds in you can hear the sound I'm talking about. I'm sorry I don't have a very good camera so this is as good as I can do it. You can hear it also everytime I release the throttle.

Jan

Edited September 8, 2010 by Pomorza

[Darrel]

You say you run 20-50 because the manual says to, it ALSO says you can run 10-30 or 10-40 at those temps.

So why run 20-50 when 10-30 0r 10-40 can do? Since it does get up to 120, then i would run the 10-40.

Even though I'm in denver, I run 10-30 year round in all my vehicles.

[Z train]

You say you run 20-50 because the manual says to, it ALSO says you can run 10-30 or 10-40 at those temps.

So why run 20-50 when 10-30 0r 10-40 can do? Since it does get up to 120, then i would run the 10-40.

Even though I'm in denver, I run 10-30 year round in all my vehicles.

Ya don't run 10/30 in a 250,000 mile motor that lives in temps exceeding 100 degrees for months at a stretch.

The balancer is tight as Jan stated.

Sitting in the pool last night talking with my machinist,we were discussing this little "issue"he trggiering a long lost fact filed away somewhere.If i remember right,the tensioner is fed off of the number one main(or somewhere in the vicinity.It is POSSIBLE that a piece of gasket or some other debris(not sludge) has entered the passage feeding the tensioner.This MIGHT explain the problem.

[Diseazd]

Did the engine make the noise before the new chain and tensioner was installed?

[Z train]

No-but he was running only 10/40 then.

[Pomorza]

No-but he was running only 10/40 then.

That's not true. The sound was there before we changed the chain. That was our number one reason for changing it was that we thought (and with the amount of stretch it had rightly) that I had chain slap.

Jan

Edited September 8, 2010 by Pomorza