gm 8.1 engine

randallb wrote:
As the engine manufacturers started using light tension ring packages to reduce rotational loss there was a slight increase in oil consumption and the best way out of this situation was to issue a statement about miles/quart. One of the major American manufacturers started looking in to oil consumption very seriously when their warranty claims started to increase dramatically. The most prevalent cause of increased oil consumption was the use of different oil suppliers or going to Econo Lube and then Jiffy Lube and then the local independent because of price. This company then ran a long term test, mileage and chemical analysis, and came to the conclusion that switching from one oil to another had a definite impact on increased oil consumption and the reason was the difference in additive packages. The chemical analysis found that the additive packages used by different oil companies would actually "fight" each other and the oil consumption increased dramatically. During the test the most interesting observation was the decrease in consumption after 2 to 3 oil changes when using the same oil. I personally experienced this 6 to 7 months after reading this study when I changed from a Pennzoil product to Kendall D-3 at my shop. A large number of customers complained of increased oil consumption which then decreased dramatically with the next oil change. Modern science, what an amazing headache at times.
Randy

Can you provide a link to that study???

As the engine manufacturers started using light tension ring packages to reduce rotational loss there was a slight increase in oil consumption and the best way out of this situation was to issue a statement about miles/quart. One of the major American manufacturers started looking in to oil consumption very seriously when their warranty claims started to increase dramatically. The most prevalent cause of increased oil consumption was the use of different oil suppliers or going to Econo Lube and then Jiffy Lube and then the local independent because of price. This company then ran a long term test, mileage and chemical analysis, and came to the conclusion that switching from one oil to another had a definite impact on increased oil consumption and the reason was the difference in additive packages. The chemical analysis found that the additive packages used by different oil companies would actually "fight" each other and the oil consumption increased dramatically. During the test the most interesting observation was the decrease in consumption after 2 to 3 oil changes when using the same oil. I personally experienced this 6 to 7 months after reading this study when I changed from a Pennzoil product to Kendall D-3 at my shop. A large number of customers complained of increased oil consumption which then decreased dramatically with the next oil change. Modern science, what an amazing headache at times.
Randy

Whether there's an old style valve in the crankcase breather hose or not, all modern engines require a Positive Crankcase Valve (PCV) system to control emissions. You cannot allow positive crankcase pressure waves to chuff into the atmosphere (containing hydrocarbons). Modern engine design incorporates the PCV into the valve cover or intake manifold design. These are sophisticated designs that create air/oil separation before routing the gases into the intake, but like all engineering endeavors they don't always work in the real world as the appear on paper.

I'm not saying there's a flaw in the Vortec 8.1 breather, just saying. Early Vortecs were known to have an issue with the intake manifold gaskets (there's a Technical Bulletin) that can cause oil consumption, but it was addressed with different gaskets and bolts IIRC,

My mistake. Yes some of the older moldel 8.1,s do have the pcv valve. I believe the 30 valve Ford V-10 does not.
Detroit Likes to keep things as confusing as possible to prevent us DIY types from maintaining our vehicles on or own.

harold1946 wrote:

RLS7201 wrote:

harold1946 wrote:
The 8.1 does not have a PCV valve.

Harold,

Not denying the accuracy of you statement.
But trying to understand how the crankcase is ventilated on a 8.1 with out a PCV valve.
What new technology is incorporated in the engine to remove crankcase pressure? Just trying to increase my knowledge.

Thanks
Richard

Most fuel-injected engines use a PCV system which recirculates crankcase gasses back through the air intake and into the combustion chamber, and then pass through the exhaust system into the catalytic converter where the gasses are burned up, eliminating the need for the valve.
Do a search for "engines without pcv valve" and you will find a full explination.

Thanks Harold,

By "most", you must mean most General Motors products. I find that Ford & Fiat (Chrysler) are still using PCV Valves.
I also found that some 8.1 do use a PCV Valve. Gosh, why can't they keep it simple?

Richard

Not a 8.1, but my last gas chassis coach had the 454 engine. Purchased new in 2000 and traded in 2008, operated for 84,000 miles. That thing used one quart of oil per 1,000 miles from day one until it was traded.

Per GM specs, that was on the low end of acceptable, but was not cause for alarm.

In the overall scheme of things I guess I can say that I spent about $300 for make up oil over eight years. Didn't break the bank or blow the engine, so all was good.

Martin,

Go to irv2.com and post on the Workhorse Chassis Forum section. You will get great answers there. I drove 4000 miles in 2011 and only had to add 1/4 qt near the end of the trip. Not sure if this is actually normal or not. I am not a mechanic, but do believe that most engines will use/lose/burn some oil over time.

Happy Trails! :W

Darryl

It is just a orifice that meters flow, does the same thing, with a different name. I made the same error calling it a pvc valve.

RLS7201 wrote:

harold1946 wrote:
The 8.1 does not have a PCV valve.

Harold,

Not denying the accuracy of you statement.
But trying to understand how the crankcase is ventilated on a 8.1 with out a PCV valve.
What new technology is incorporated in the engine to remove crankcase pressure? Just trying to increase my knowledge.

Thanks
Richard

Most fuel-injected engines use a PCV system which recirculates crankcase gasses back through the air intake and into the combustion chamber, and then pass through the exhaust system into the catalytic converter where the gasses are burned up, eliminating the need for the valve.
Do a search for "engines without pcv valve" and you will find a full explination.

harold1946 wrote:
The 8.1 does not have a PCV valve.

Harold,

Not denying the accuracy of you statement.
But trying to understand how the crankcase is ventilated on a 8.1 with out a PCV valve.
What new technology is incorporated in the engine to remove crankcase pressure? Just trying to increase my knowledge.

Thanks
Richard