Air Compressor Air Supply

JackConrad · March 18, 2009, 04:21:00 PM

When we replaced the OEM oil bath air cleaner with a K&N, there was no place to connect the air intake for the air compressor (OEM oil bath filter had a fitting for air compressor intake). We installed a separate air filter for the air compressor and it has worked (see first photo). The new engine has the air compressor air supply plumbed into the engine air intake above the blower (see second photo). Will this compromise the amount of air to the engine? I realize the compressor does not pump unless the governor is caling for additional air pressure, I have just never seen this type of set-up before. Jack

Existing Engine Air Compressor Air Supply

New Engine Air Compressor Air Supply

Sammy · March 18, 2009, 04:42:41 PM

Hi Jack, I have not seen that setup before either.
Looks like it's going into the block of the air compressor.
The air compressor needs a clean, filtered supply of fresh air. - as you already know..

Can you plumb the new engine to your existing setup?
Best of luck with your project.

luvrbus · March 18, 2009, 04:53:20 PM

Jack, that is common on industrial engines I never had a problem with it but I have always wondered if the blower would suck to much air away from the intake on the compressor.

Len Silva · March 18, 2009, 05:04:59 PM

My 4104 6-71 had the compressor intake plumbed to the engine airbox.

junkman42 · March 18, 2009, 05:08:42 PM

Jack, I have a 8v71 out of a air force semi tractor and it is plumbed into the air intake elbow and it is original. If You want a picture or the hardware let Me know, the price is right it is free. You will owe Me a cup of coffie john

buswarrior · March 18, 2009, 06:56:34 PM

Hello Jack.

The relatively small needs of the air compressor should not disrupt the engine breathing.

I like the look of the set-up on your new engine, short hose, elegant execution.

Before you cram it in there, should that compressor be freshened up now?

happy coaching!
buswarrior

artglass · March 18, 2009, 07:01:11 PM

i installed a 8v-71 out of a fire truck in my mci 8 had the same set up only it had a 650 compressor, mci uses a 750 in believe so i change the compressor, left it plumbed the same way no problems for 2 years
Kevin

Sojourner · March 19, 2009, 12:03:33 AM

Quote from: buswarrior on March 18, 2009, 06:56:34 PM
Hello Jack.

The relatively small needs of the air compressor should not disrupt the engine breathing.

I like the look of the set-up on your new engine, short hose, elegant execution.

Before you cram it in there, should that compressor be freshened up now?

happy coaching!
buswarrior

Amen! Air compressor need is so small compare to engine needs...about 4 square inch of engine air filter.
Do you have a air restricter gauge in between filter and blower? That will tell you the condition of what the engine needs are. Yours is non-turbo will have no effect as long the air restricter gauge is in "green" range. I have one and never be without one to maximize fuel economy.
Air Restricter Gauge

Quote from: artglass on March 18, 2009, 07:01:11 PM
i installed a 8v-71 out of a fire truck in my mci 8 had the same set up only it had a 650 compressor, mci uses a 750 in believe so i change the compressor, left it plumbed the same way no problems for 2 years
Kevin

Amen! Buses need more air due to the automatic AD dryer's purge cycling. I am not update on newer trucks but old trucks didn't have automatic purge system but drained by manual system.

Keep up the good work, Gerald

JackConrad · March 19, 2009, 05:46:00 AM

Quote from: buswarrior on March 18, 2009, 06:56:34 PM
Before you cram it in there, should that compressor be freshened up now?
happy coaching!
buswarrior

This compressor was replaced at the time of the rebuild (about 42,000 miles ago).

Yes, I can modify to use my existing separate filter, but I like the looks of the new engine system. I just wanted to make sure there would be no problems. Looks like I will use the "new engine set-up". Thanks for all the comments. Jack

Tony LEE · March 19, 2009, 11:47:01 AM

Jack, my MC8 8V71 has the same system as standard - gets its supply from the engine air inlet above the blower. Cool and well-filtered air. perfect

zimtok · March 19, 2009, 02:26:17 PM

The air compressor on my 1960 4104 with a 6-71 gets its supply of air from the engine block AFTER the blower.

.

hargreaves · March 19, 2009, 03:41:59 PM

Hi Jack, the problem with plumbing any compressor to the low pressure side of the intake is that when the compressor is in the unloaded state it tends to draw oil up past the rings causing more oil to go into the air system. The further away from the low pressure side of the blower the better. The only time this is not true is when the compressor is designed to shuttle the compressed air from one cyl. to the other in the unloaded state. My to bits worth.

Gerry.

NewbeeMC9 · March 20, 2009, 05:15:42 AM

Since your doing the Job and you already have the air filter mounted, might as well go how you have it plumbed now. that air compressor filter may get dirtier since it is getting air from the engine compartment instead outside before the radiator. You also have an extra filter to maintain but probably not a big deal either. The diamond plate is OK but I believe CHROME is in order at this juncture

.

my 1.5 cents

Are you gonna Turbo it while your at it?