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Running Pre-Mix

Posted: Tue Dec 16, 2008 6:25 pm
by gear-ed
How do folks feel about running pre-mix? I found that I can reduce smoke by running AMSOIL Saber at 80:1 ratio. Truck runs fine, very little smoke, and no carbon fouling.....Comments????

Re: Running Pre-Mix

Posted: Tue Dec 16, 2008 9:36 pm
by Idahopaul
I dont know how much the ratio needs reduced for using the synthetic oil. I would still be afraid of going above 50:1 myself. but you can always keep an eye on the plugs to see if your mix is right. they should be a chocolate brown on the ceramic insulator, but check them after a hard run and no idle time before shutting it down to get an accurate color.

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 5:28 am
by Jimny
Well I have found that premix is NOT the way to go, it is sooooooo much better to use the CCI system, if you keep your oil/tank clean then it will give you a lifetime of service. The pumps don't wear out (well I have seen some that was so dirty it stripped the gears), they just get dirty and can't distribute the oil correctly.

80:1 isn't enough, with premixing your LJ should be smoking.

With the CCI it will produce minimal smoke, sometimes unnoticeable.

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 7:31 am
by Suzy
Jimny, you state that premix is not the way to go and that it should run smokey if you do, but you don't say why. Premix is standard in so many applications why would it not be good here ?

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 11:00 am
by stevec
I think premix is okay for short periods of time, but I wouldn't use it as a permanent fix. Based on the oil consumption of the CCI system, the ratio is about 30:1 which is a lot of oil (most nowadays use 40 or 50:1). Also, the CCI system distributes the oil where it needs to go (4 or 5X as much to the cylinder walls as to the crankshaft), whereas with premix, there is only oil where there is gas. The result is that engines running on (30:1) premix will wear faster than engines using the CCI system. With the oil mixed in with the gas, I would expect higher deposits in the engine as well.

If you need to use premix, mix it at 30:1; even with synthetic oil, I wouldn't change the ratio.

Jimny did a writeup on cleaning your pump: http://www.lj10.com/howto/cciscleaning/" onclick="window.open(this.href);return false;

When I bought my RHD a few years ago, the pump wasn't working properly. I took it off, and found that a prior owner had taken it apart, and had not put it back together properly. :?

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 11:06 am
by Ruby
stevec wrote: Also, the CCI system distributes the oil where it needs to go (4 or 5X as much to the cylinder walls as to the crankshaft), whereas with premix, there is only oil where there is gas. The result is that engines running on (30:1) premix will wear faster than engines using the CCI system.
That makes total sence, never thought about it that way.

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 11:34 am
by Jimny
I actually was going to state why (pretty much the way Steve said it) but I got in a hurry (inturupted by a phone call) and forgot finish it out, but what Steve said is why.


I also was going to say I use 30:1 that is what I recomend to people when the put a rebuilt engine back into thier LJ and the first five gallons should be 30:1, sure after the pump starts doing it's thing it will smoke but it will be well lube for five gallons.

Re: Running Pre-Mix

Posted: Wed Dec 17, 2008 9:28 pm
by Suzy
OK that is interesting. Where exactly does the CCI iject the oil ?

JG

Re: Running Pre-Mix

Posted: Thu Dec 18, 2008 6:10 am
by Jimny
There are two inlets on the side of the jug about a 1/4 of the way up, and two inlets at the bottom of the crankcase, the oil is delivered four times more to the cylinder walls then it is to the crankshaft.

The oil "pump" actually is a regulator, when the piston is going up in the engine it will suck in oil both at the crankcase inlets and the jug inlets then when the piston is going down there are check balls in the oil lines that keep the oil from being pushed back into the pump etc...

Inside the pump it has a round part (no clue what you would call it) that turns and is driviven by the crank (just like the distributor) that has four holes in it and the two holes for the cylinders are larger then the two holes for the crankcase, therefore the different quantity of oil. At first glance the holes look the same size but under a magnifying glass you could tell the difference.


I did an experiment a while back where I took the reservoir feed line off and hooked another reservoir up to a pump on a running LJ, the original oil was clear and on the second reservoir it was the blue oil and watched when the oil was going through the clear lines going to the engine and watched how much more faster the lines to the cylinders were going then to the crankcase, it was kind of interesting to watch.


http://www.lj10.com/lj20service/pg55.htm" onclick="window.open(this.href);return false;

Re: Running Pre-Mix

Posted: Fri Dec 19, 2008 11:00 pm
by Idahopaul
so then the round part you speak of is a valve, and the pumping action is done with engine vacuum and check balls along with this metering valve?

Re: Running Pre-Mix

Posted: Sat Dec 20, 2008 12:25 am
by Myers
gear-ed wrote:How do folks feel about running pre-mix? I found that I can reduce smoke by running AMSOIL Saber at 80:1 ratio. Truck runs fine, very little smoke, and no carbon fouling.....Comments????
Coasting and premix
If using premix only, the amount of oil getting to the engine depends on the position of the throttle. Thus, coasting with the tranny in gear and your foot off of the gas is not wise. Although the engine may be turning very high rpm, the amount of oil getting to the engine will be the same as if it were at idle speed. However, a properly working CCI system delivers oil according to both throttle position and engine rpm.

Coming down the long and steep trails at the Cooke City meet, there were times when the engine was turning very fast rpm even though I was hard on both the foot brakes and hand brake. Under these conditions, the CCI system was still providing adequate lubrication. With premix the engine would have been very short of lubrication.