8V92 STARTING

[Woody]

Is there a 12V portion of this engine.

Went to the storage garage to give her the weekly run, turned on the 24V (but not the 12) and almost ground the batteries down with no start up.

Turned on the 12V and she fired right up.

Whats the connection?

[Jon Wehrenberg]

Woody,

The 12 volt is for the DDEC. It gets the power for the brains that control the engine from the 12 volt.

[JIM CHALOUPKA]

Woody, something good may have come from your experience with the 24V, 12V issue.
Awhile back there were several posts on worn cam lobes and followers and talk about pre-lubing.
One idea was that someone said to crank the engine over several times but without starting it to get the proverbial juices flowing. The suggested idea did not work as the engine starts immediately, as everyone knows, but ah ha you have come up with the answer for those guys that want to pre -lube!

TURN OFF THE 12V and crank away!!!!!!!!!

JIM

[Jon Wehrenberg]

So what you are suggesting Jim is that cranking but not starting doesn't eat as much metal as starting?

The idea behind a pre-lube is to replace oil which has drained from bearing surfaces on the crank and cam and other areas lubed via oil pressure as opposed to splash lubing.

[Coloradobus]

Woody, Your dilemma got me thinking. So, went out after dinner to start the bus..........dead. From the manual, states there is a jumper box to connect jumper cables battery charger to it, but nothing appears in the rear side compartment that looks like the diagrams in the manuals. Anyone have an idea/ JON? where to jump the bus from. Turned on the 2 breakers, and turned the key, made sure the "rear start' was on "Front" and nothing when twisting the key. No beepers, guages unmoving. From our Beaver Manual, it states there is a chassis battery charger. Apparently, its not there, inoperable, or faulty. Hmmmm. It has always started, but this time the coach has sat for 2 1/2 months. Our previous coach, I KNEW I needed to run every 3 weeks, but with an 8V-92, I thought we would not have this trouble.

[gmcbuffalo]

Jim and Chris
Beaver's design is that the inverter charger is wired to charge the chassis batteries while charging the house batteries. Do you have any switches off in the house battery compartment?
GregM

[JIM CHALOUPKA]

So what you are suggesting Jim is that cranking but not starting doesn't eat as much metal as starting?

The idea behind a pre-lube is to replace oil which has drained from bearing surfaces on the crank and cam and other areas lubed via oil pressure as opposed to splash lubing.

Not suggesting that at all, just voicing how to go about it if you think that is the case. Some did. I don't.

JIM

[dale farley]

Considering Jim's and Jon's comments, it does make you wonder how there is any benefit in our generators turning over 1-2 revolutions each time before they are allowed to start. Maybe they have a a special technology that instantly pumps enough oil to lube the bearings in only those 1 or 2 revolutions?

[Jon Wehrenberg]

I am far from an expert on engine wear, but in aviation it seems the engines that are used often, such as in a daily training environment almost always reach or exceed the recommended time for overhauls.

The engines that sit for long periods appear to be the engines that have a premature failure.

I read somewhere that the oil that provides the lubrication between surfaces eventually drains from between those surfaces thus allowing metal to metal contact and greater wear. That makes sense to me so if a motor is going to sit for long periods between uses it would seem some form of pre-lubrication would restore the lubricating oil to those surfaces such as between the bearings and the crank and cam and anywhere else pressure lubrication reaches.

But nobody has ever quantified how much wear actually takes place so that we can get an indication of if our engines for example will only go 500,000 miles instead of 1,000,000 or if the generators will only go 15,000 hours instead of 30,000 hours. Before I add pre-lubrication to the list of things I have to lay awake thinking about I guess I would like to see data that compels me to add it to my list of worries. Since our engines seem to have positive displacement oil pumps it is likely oil is hitting the bearings within seconds of the start of rotation so it is probably OK to accept so wear given that it is likely to be a miniscule amount.

[Woody]

A wise old Detroit Diesel mechanic at their Lodi NJ shop told me that this engine (8V92) especially must be started every week and run hard at least once a month or-------