INTJ

I was responding in kind 50 wt will make it quiet, but would be retarded.

INDYMAC

The valvetrain flutter on start-up has been apparent over the years for me too, even after a valve adjustment. I was able to quiet the noise with some different oil brands, but after the advent of SM oils, no joy from an oil standpoint. What works the best for me since then has been Marvel Mystery Oil added to the fuel. I use the recommended dosage (4ozs/10 gallons) and it works great. After a tank or two, you will notice a big difference in the sound of your engine at start-up.

2007 Zx-10

Interesting, why would MMO (which is essentially a detergent) reduce valvetrain noise? Not sure it would help in my case, because I only have 10k miles, and the oil has been changed three times in that period, so I doubt carbon build up is an issue. Like I said before, it would be interesting for me to test drive a new car and compare noise levels.

INDYMAC

My engine started the annoying valvetrain flutter/clatter earlier than yours did. It went away after I changed the OEM oil fill at 3300 miles to group III oils rated SL. But came back when the SM oils came on the market. MMO is a UCL for the most part when added to the fuel. I suspect it to be a very mild solvent at best. On my G35, it added 200ppm of Phosphorus to a back to back UOA. Phosphorus is one of the metals that API dictated a reduction in for SM oils. Maybe there is a correlation?

2007 Zx-10

Would be interesting to see a UOA with MMO. Alot of RX-7 owners use it to remove carbon deposits from the apex/corner seals, I used it for awhile in my FD (with the original engine) and vacuum levels at idle definitely increased. However, MMO contains solvent, there is little question about that, and this post reflects my general thoughts about it

http://www.bobistheoilguy.com/forums/ubbth...051250&fpart=11

[QUOTE]If you use a good oil you should not need to use a solvent in your engine. Think about it, there is many places in your engine that don

WarrenW

Mine sounds clangy, sort of like a diesel until it's warmed up. I showed it to the service tech when it was pretty new, maybe around 3 to 5k mi and he said that's normal. Could be because it's an aluminum engine. I'm at 128,580 mi now and so far no problems (knocks on wood).

2007 Zx-10

You mean it had a similar noise level at only 3k?

INDYMAC

Sorry, I don't have any personal experience using MMO in the sump, just the fuel to eliminate the valvetrain noises on start-up. I thought that was what you were looking for. I guess I misread your post.

WarrenW

Until it's warm. It sounds what I call 'clangy' til then. But like I saw 128K+ mi and no problem so far.

2007 Zx-10

Yeah I think it's normal.

Indy, yes I was referring to pre-mix (I've never heard of MMO being added directly to the sump), the residual solvent would find it's way into your oil either way.