LUBRICANTS. BASIC WHATS AND WHYS.

[Matthewf/Norbert/TuiDog]

whilst diesel spec engine oil may be ok in some older engines (in fact it has great ep additives!) i would not recommend it for new motors as it contains more detergents etc which may wash or glaze the bores

andrew with regard to engine oil filters it's great you are getting a flame/spark arrestor type. however the K&N cotton oil charged type are fairly hard on engines as they let more hard contaminates through relative to the thicker foam type oil charged filters, this is shown in the amount of hard contaminates present in the oil which generate wear debris. given the relatively low hours we do, at the end of the day we would probably not see the accelerated wear as a failure, plus the k&n breath well (hold them up to the light, you can see through them )

to run your boat without a filter, well that's just criminal 

 

[Peter.]

Good call Matthew. The K&N debate has always been a great one. The particulate pass-thru always is greatest when they are cleanest (the holes are clearest). When dirty they seem to operate better Funny that.

[wildrj]

K&N cotton oil charged type are fairly hard on engines as they let more hard contaminates through relative to the thicker foam type oil charged filters,

[/quote]

Bloody sight less than current arrangement!!

[Matthewf/Norbert/TuiDog]

Bloody sight less than current arrangement!!

so your saying you were a criminal  (no filter!)

[wildrj]

so your saying you were a criminal  (no filter!)

No Matt, your words.
The fact is that if I run a normal air filter, I am a criminal, because regulations require a spark arrestor.
Hefty whack over the knuckles to get caught not running one.
Now I can stop dust etc AND sparks.

Get back to work, Matt- you must have something to do other than harrass me!

[Matthewf/Norbert/TuiDog]

always time to dig at a taswegian 

[mako]

Found a link for further reading http://www.bobistheoilguy.com/ cool bearing wear analysis page.

[Peter.]

Lately there was an extreemly interesting question asked regarding cam wear relating to synthetics and mineral lubricants. To give a precis of the problem is this: Commercial Big Block "Eating" cam lobes with a Name brand synthetic but stopping that when changed to a well known mineral lubricant. By the way, these engines use heavy valve springs to overcome the inertia of a bulky valve train at the RPM's they run at. Hence the load on the lifters is VERY high.. We are not referring to wild-grind cams here.
Grade: 20W-50
API Rating: SL
This problem also occurs with many older engines running flat tappet style cams. The additive, that was always added to stop wear in this area, has been reduced/deleted from many of the latest lubricants. Hence the necessity to keep a watch on tappet clearances. If they start to increase, at a faster-than-usual rate, the cam lobes may well be on the way out. Even hydraulic lifters can only take up so much wear. OHC engines appear to miss out on this happening.
With full synthetic lubricants, one must realise that the additive packages used are very expensive and are not the same as mineral oils. Therefore, only the minimum quantities are used, and for normal engines, this is more than adaquit. But we are not talking about a normal engine here with reference to the valve train.
The  Mineral oil, as per the one used here, has a small amount of Extreem pressure additive included as the cost of making that a part of the additive package is minor. That has saved the day.
If one was wanting to use a synthetic, then a Race version would have probably saved the day too. But these are expensive  and racers will pay for this without question. For a commercial operator, this is not an option.
Race lubricants have lots of trick ingredients but they also have a downside. They are not intended to stay in service for an extended period as their detergent package is minimal. It is NOT recommended they be used in extended drain interval situations.
In a situation, as outlined here, ask what is best suggestion first before getting burnt. Unfortunately, it is often hard to get a genuine answer as most reps etc have no idea what you are on about. Sadly, this is the norm these days.

[wildrj]

Solution "B"- Use a roller camshaft.

Also avoid long periods of idling.

[wildrj]

By the way, these engines use heavy valve springs to overcome the inertia of a bulky valve train at the RPM's they run at. Hence the load on the lifters is VERY high.. We are not referring to wild-grind cams here.

What sort of RPM?
I'd have thought 4500rpm or so would be absolute max for a commercial boat running a big block.
At this, spring pressures shouldn't need to be that high.
Might pay to go for lighter springs, take the load off the valvetrain and maybe save some fuel as well.

[Peter.]

And another small tip that may be useful:
When running grease-packed bearings at higher speeds (in excess of 5000 rpm), experiment with the quantity of grease in the bearing. A 10 percent change in the quantity of grease can drastically affect the amount of heat generated by the bearing (even as much as 40F depending on how close to optimum you are). If there is too much grease for the bearing to push out to surrounding pockets, the bearing will heat up quickly.

Often the optimum amount of grease is less than what you might think. Be sure to provide a sufficient run-in period for the bearing to position the grease before exposing it to full-time duty

[Peter.]

If you are driving an older classic muscle car or hot rod that has an engine with a flat tappet camshaft, you should be aware of the fact that today's "SM" rated motor oils contain much lower levels of anti-scuff additive called "ZDDP" (Zinc Dialkyl Dithio Phosphate). The level of ZDDP in current motor oils has been reduced to no more than 0.08% phosphorus to extend the life of the catalytic converter. Phosphorus can contaminate the catalyst over time if the engine uses oil, causing an increase in tailpipe emissions.

The lower ZDDP content is not harmful to late model engines with roller lifters or followers because the loads are much lower on the camshaft lobes. But on pushrod engines with flat tappet cams, the level of ZDDP may be inadequate to prevent cam lobe and lifter wear. In some cases, cam failures have occurred in as little as a few thousand miles of driving! This is even more of a risk in engines if stiffer valve springs and/or higher lift rocker arms are used. The oil needs to be about 80 degrees celcius or above to get the zinc anti wear additive activated, at low temperature the zinc antiwear additives are not fully activated .

To avoid such problems, you should add a ZDDP additive to the crankcase, or use an oil that meets the previous "SL" service rating, or use diesel motor oil or racing oil that contains adequate levels of ZDDP to protect the camshaft and lifters.

If you are installing a new camshaft in the engine, be sure to use the cam manufacturers assembly lube and follow the recommended break-in procedure. But you will still need to add ZDDP to the crankcase or use an oil that contains adequate levels of ZDDP for continued protection.