Back in the Mack Pack!

[mowerman]

I’m thinking the turbo like a few years ago they were all very loud… bob

[Joseph Cummings]

I wonder how clean the cooling air supply to the intercooler has to be. I would guess it wouldn't have to be as clean as the combustion air going into the engine. You wouldn't want stuff going in that would "sand blast" the blades in the tip turbo, or anything going in that could build upon the heat exchange surfaces. CMCAC doesn't use any filter.

Big thing is the air be cold and there be enough of it

[mrsmackpaul]

I think you all are missing the big issue here, the motor is sucking unfiltered air back thru the intercooler 

There's nothing to stop air entering the intercooler outlet and through the intercooler backwards and straight through to the motor

I'm thinking the air will take the path of the least resistance 

Maybe the turbine is so loud because when it is been driven it is driving against air that's already going the wrong way 

 

Paul

[mrsmackpaul]

And intercooler would have to be filtered

If something happened to the valve that feeds the turbine you could easily suck dirty air into the motor 

Paul

[Joseph Cummings]

13 minutes ago, mrsmackpaul said:

There's nothing to stop air entering the intercooler outlet and through the intercooler backwards and straight through to the motor

I could see that happening when it's sitting there idling, or when the air filter is half plugged up.

I wonder if the combustion air filter, and the intercooler filter elements filtered down to the same microns.

Not sure if I've ever seen the valve on a tip turbo fail, replaced some that the bearings failed in. Then again back then they were all pretty new trucks, now those damn valves are 45 or 50 years old

[Geoff Weeks]

41 minutes ago, mrsmackpaul said:

I think you all are missing the big issue here, the motor is sucking unfiltered air back thru the intercooler 

There's nothing to stop air entering the intercooler outlet and through the intercooler backwards and straight through to the motor

I'm thinking the air will take the path of the least resistance 

Maybe the turbine is so loud because when it is been driven it is driving against air that's already going the wrong way 

 

Paul

yes, I never thought about that!

[Mark T]

5 hours ago, Joseph Cummings said:

I wonder how clean the cooling air supply to the intercooler has to be. I would guess it wouldn't have to be as clean as the combustion air going into the engine. You wouldn't want stuff going in that would "sand blast" the blades in the tip turbo, or anything going in that could build upon the heat exchange surfaces. CMCAC doesn't use any filter.

Big thing is the air be cold and there be enough of it

They didn't require super clean air. Trucks with a strata tube I don't think even used a filter, just the scoop and some cyclonic (?) action in the tube.     I can't for the life of me remember what the inside of one of those air cleaners with the over and under outlets looked like inside. But I do remember one filter was for the engine and one was for the tip turbine.   (where's Mech ???)  

[Joseph Cummings]

40 minutes ago, Mark T said:

They didn't require super clean air. Trucks with a strata tube I don't think even used a filter, just the scoop and some cyclonic (?) action in the tube.     I can't for the life of me remember what the inside of one of those air cleaners with the over and under outlets looked like inside. But I do remember one filter was for the engine and one was for the tip turbine.   (where's Mech ???)  

Tall filter, and short filter with a separator plate in between them. After the intake on top which they shared, two totally different filters and ducting.

The hood scoop ones I think was only 1973 model year same time they went to plastic dash and the plus 3 cab. I know there was some kind of air cleaner under the scoop, but I can't remember what was in it. We only ever owned one, and not for long maybe a year. A guy from Runnemede NJ bought it and was using it to haul steel and somehow ended up flipping it. Shame because it was a really nice truck. After he recovered he put a new cab and hood on it and did away with the scoop

[mrsmackpaul]

In Australia and NewZealand we run a second aircleaner for the tip turbine air only

 

Paul

[Brocky]

2 minutes ago, mrsmackpaul said:

In Australia and NewZealand we run a second aircleaner for the tip turbine air only

 

Paul

Especially on your Outback dirt roads!!!!!!

[Mark T]

40 minutes ago, Joseph Cummings said:

Tall filter, and short filter with a separator plate in between them. After the intake on top which they shared, two totally different filters and ducting.

The hood scoop ones I think was only 1973 model year same time they went to plastic dash and the plus 3 cab. I know there was some kind of air cleaner under the scoop, but I can't remember what was in it. We only ever owned one, and not for long maybe a year. A guy from Runnemede NJ bought it and was using it to haul steel and somehow ended up flipping it. Shame because it was a really nice truck. After he recovered he put a new cab and hood on it and did away with the scoop

Yes.  Separated.   Living separate lives in the same house.  I'm pretty sure a strata tube didn't use an actual filter element per se but the tube itself was like a cyclopac or psychopath   or something that separated the debris enough to go through the tip fan and intercooler.  Anyway.....that T after the Farr ?   Not a good idea, unless somebody really likes changing cylinder kits.

[Mark T]

22 minutes ago, mrsmackpaul said:

In Australia and NewZealand we run a second aircleaner for the tip turbine air only

 

Paul

That's cause you guys down under are typically engaged in extreme truck'n.   Maybe it's not totally dust dust dust. But I but your trucks spend way more time at full power , which equates into way way more air moving through 🤔  everything 

[mechohaulic]

3 hours ago, Mark T said:

They didn't require super clean air. Trucks with a strata tube I don't think even used a filter, just the scoop and some cyclonic (?) action in the tube.     I can't for the life of me remember what the inside of one of those air cleaners with the over and under outlets looked like inside. But I do remember one filter was for the engine and one was for the tip turbine.   (where's Mech ???)  

I'm here racking my brain cells trying to remember  CORRECTLY  the proper system. yes I was involved when systems were brand new ;; which also means the long range problems didn't show up yet. the air filter was a two section set up . tip turbine air came from ??? oil bath with 2 in wire screen removal able prescreen ;; didn't change that many tip turbines due to blade failure . 

[Joseph Cummings]

I liked the oil baths, cheaper to service, so they got serviced more. Not to mention I never opened one up and found flaking rust on the engine side of the element

[BOBWhite]

21 hours ago, mrsmackpaul said:

I think you all are missing the big issue here, the motor is sucking unfiltered air back thru the intercooler 

There's nothing to stop air entering the intercooler outlet and through the intercooler backwards and straight through to the motor

I'm thinking the air will take the path of the least resistance 

Maybe the turbine is so loud because when it is been driven it is driving against air that's already going the wrong way 

 

Paul

Good grief you're right! I don't know how I didn't notice that before, and I keep forgetting that this isn't the original engine. Granted it's been running with this setup since the 80s or 90s and the engine is still very strong with little blow by but I still will take the tubes off to make sure its not dusting itself out. 

Maybe I'll use a piece of paper or a smoke test to see if any air is back feeding through the intercooler. 

[Mark T]

3 minutes ago, BOBWhite said:

Good grief you're right! I don't know how I didn't notice that before, and I keep forgetting that this isn't the original engine. Granted it's been running with this setup since the 80s or 90s and the engine is still very strong with little blow by but I still will take the tubes off to make sure its not dusting itself out. 

Maybe I'll use a piece of paper or a smoke test to see if any air is back feeding through the intercooler. 

Pretty hard to simulate conditions it would go through while running. Should be looked into though.  I bet it's why you mentioned the part about it being loud.

[BOBWhite]

15 hours ago, Joseph Cummings said:

I liked the oil baths, cheaper to service, so they got serviced more. Not to mention I never opened one up and found flaking rust on the engine side of the element

Oil Baths are my favorite as well although running them with turbo chargers makes me a bit nervous. The used engine oil is usually clean enough to be used in oil bath air cleaners so they are pretty much free to operate, lots of people seem to hate them now though

[mrsmackpaul]

A straight bit of pipe on the intake is a easy fix 

Maybe a couple of elbows and stack up a couple of common car type air filters, like off a car type V8, real simple type of paper elements stacked up

Two or three of these stacked up

Should be simple enough and will get you out of trouble for bugger all money

I have seen photos on the forum of B models with a coolpowered motor with no filter on the turbine side 

So I dunno how much filtering the actually need, everything wears I guess

 

Paul

[67RModel]

Could somebody post a picture of what the whole system plumbing is supposed to look like? A photo from an original tip turbine equipped truck?

 

[mrsmackpaul]

I think there was a few different versions of how the plumbing was done

Some years ago on the forum there was a lot of discussion in a thread about this very topic

Someone smarter than me could probably find it and post a link

 

Paul

[Geoff Weeks]

2 hours ago, BOBWhite said:

Oil Baths are my favorite as well although running them with turbo chargers makes me a bit nervous. The used engine oil is usually clean enough to be used in oil bath air cleaners so they are pretty much free to operate, lots of people seem to hate them now though

I'm with you on oil-bath's as well.

The British buses had oil baths the size of waste baskets, they held well over a gal of oil.

Because the buses were designed for RHD, where the right side of the bus was the "street side" they really took a beating when the right side was the curb side, Everytime the bus throttled up, it kicked up the dirt/dust at the curb and straight into the intake.

Oil baths claim to fame, is they maintain a steady pressure drop across the filter through-out its service interval. Slightly more than a brand new "paper filter" but less than a well used paper filter.

Properly maintained they are a excellent choice, but I do understand the concern when used with a turbo, on the other hand Detroit used them for years on their 2 strokes.