I've become pretty attached to MMO use since trying it after first visiting this site some time ago. I notice quieter idling and quicker starts. However, I've always been curious about its affect on engine cleanliness, as this is the formost reason generally cited to support its use.
I recently completed some preventive work on my daily driver ('89 BMW 325i) which involved removing the intake manifold to replace a variety of wear items in that part of the engine bay, and was very interested to see the condition of the valves and the intake.
First I'll mention that this engine is known for having problems with intake valve desposits. The particular cause doesn't seem to be known, but when the cars were new BMW dealers spent a lot of time and money repairing cars under warranty by blasting the valves with walnut shells to clean them, sometimes repeatedly on the same car. It's enough of a concern that it was among the reasons I started using MMO in the first place.
Anyway, I was very pleased to find that most of the intake valves in my (12v straight six) engine were pretty much spotless. These all had a clean, slightly shiny appearance, and were in fact actually visibly coated with a light layer of shiny reflective oil, clearly the MMO itself as no other source of any such substance seems possible.
The valves that were not perfectly clean all had some very light carbon deposits of the sort that I've seen routinely on intake valves in the past, with an important exception. The covering layer was very thin, it covered only a few parts of the valve, and most importantly the pattern formed by the deposits looked very much like the final residual remains you'd expect to see in an incomplete cleaning process. In other words, if you clean any stubborn deposit from any surface, you see a characteristic appearance develop as clean areas emerge between remaining areas of deposit, then enlarge as the deposit areas shrink. It is different from what you see when the deposit is actually forming. This is the type of pattern I was looking at.
My belief is that the valves did have carbon deposits in the recent past, and that MMO has indeed removed the majority of those deposits and is continuing to remove the rest. The engine has just under 240,000 miles on it, and I've been using MMO for perhaps the last 8,000 or so.
Here, then, is a list of beneficial results that I believe can be attributed to MMO with a fairly high degree of confidence:
- Quieter running. I interpret this to be the result of a cushioning effect on the valves and possibly the top piston ring (compression ring).
- Quicker starting. Speculation I've read is that this is due to MMO maintaining cleanliness of the spark plug electrodes. Sounds reasonable to me.
- Intake valve cleanliness. I'm now a believer. Among other things this removes one source of driveability problems, and very likely extends the life of valve guides, valve seats, valves and possibly valve guide seals.
FWIW I've been using the stuff pretty religiously at the recommended dose of 4oz per ten gallons of gasoline in the tank. A clattery idle reminds me pretty quickly when I forget to add a dose.
- Glenn
I recently completed some preventive work on my daily driver ('89 BMW 325i) which involved removing the intake manifold to replace a variety of wear items in that part of the engine bay, and was very interested to see the condition of the valves and the intake.
First I'll mention that this engine is known for having problems with intake valve desposits. The particular cause doesn't seem to be known, but when the cars were new BMW dealers spent a lot of time and money repairing cars under warranty by blasting the valves with walnut shells to clean them, sometimes repeatedly on the same car. It's enough of a concern that it was among the reasons I started using MMO in the first place.
Anyway, I was very pleased to find that most of the intake valves in my (12v straight six) engine were pretty much spotless. These all had a clean, slightly shiny appearance, and were in fact actually visibly coated with a light layer of shiny reflective oil, clearly the MMO itself as no other source of any such substance seems possible.
The valves that were not perfectly clean all had some very light carbon deposits of the sort that I've seen routinely on intake valves in the past, with an important exception. The covering layer was very thin, it covered only a few parts of the valve, and most importantly the pattern formed by the deposits looked very much like the final residual remains you'd expect to see in an incomplete cleaning process. In other words, if you clean any stubborn deposit from any surface, you see a characteristic appearance develop as clean areas emerge between remaining areas of deposit, then enlarge as the deposit areas shrink. It is different from what you see when the deposit is actually forming. This is the type of pattern I was looking at.
My belief is that the valves did have carbon deposits in the recent past, and that MMO has indeed removed the majority of those deposits and is continuing to remove the rest. The engine has just under 240,000 miles on it, and I've been using MMO for perhaps the last 8,000 or so.
Here, then, is a list of beneficial results that I believe can be attributed to MMO with a fairly high degree of confidence:
- Quieter running. I interpret this to be the result of a cushioning effect on the valves and possibly the top piston ring (compression ring).
- Quicker starting. Speculation I've read is that this is due to MMO maintaining cleanliness of the spark plug electrodes. Sounds reasonable to me.
- Intake valve cleanliness. I'm now a believer. Among other things this removes one source of driveability problems, and very likely extends the life of valve guides, valve seats, valves and possibly valve guide seals.
FWIW I've been using the stuff pretty religiously at the recommended dose of 4oz per ten gallons of gasoline in the tank. A clattery idle reminds me pretty quickly when I forget to add a dose.
- Glenn
